Journal Description
Polymers
Polymers
is an international, peer-reviewed, open access journal of polymer science published semimonthly online by MDPI. Belgian Polymer Group (BPG), European Colloid & Interface Society (ECIS), National Interuniversity Consortium of Materials Science and Technology (INSTM) and North American Thermal Analysis Society (NATAS) are affiliated with Polymers and their members receive a discount on the article processing charges.
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- Journal Rank: JCR - Q1 (Polymer Science) / CiteScore - Q1 (General Chemistry )
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 14.5 days after submission; acceptance to publication is undertaken in 3.4 days (median values for papers published in this journal in the first half of 2024).
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Impact Factor:
4.7 (2023);
5-Year Impact Factor:
4.9 (2023)
Latest Articles
Preparation of Lyocell Fibers from Solutions of Miscanthus Cellulose
Polymers 2024, 16(20), 2915; https://doi.org/10.3390/polym16202915 - 16 Oct 2024
Abstract
Both annual (cotton, flax, hemp, etc.) and perennial (trees and grasses) plants can serve as a source of cellulose for fiber production. In recent years, the perennial herbaceous plant miscanthus has attracted particular interest as a popular industrial plant with enormous potential. This
[...] Read more.
Both annual (cotton, flax, hemp, etc.) and perennial (trees and grasses) plants can serve as a source of cellulose for fiber production. In recent years, the perennial herbaceous plant miscanthus has attracted particular interest as a popular industrial plant with enormous potential. This industrial crop, which contains up to 57% cellulose, serves as a raw material in the chemical and biotechnology sectors. This study proposes for the first time the utilization of miscanthus, namely Miscanthus Giganteus “KAMIS”, to generate spinning solutions in N-methylmorpholine-N-oxide. Miscanthus cellulose’s properties were identified using standard methods for determining the constituent composition, including also IR and atomic emission spectroscopy. The dry-jet wet method was used to make fibers from cellulose solutions with an appropriate viscosity/elasticity ratio. The structural characteristics of the fibers were studied using IR and scanning electron microscopy, as well as via X-ray structural analysis. The mechanical and thermal properties of the novel type of hydrated cellulose fibers demonstrated the possibility of producing high-quality fibers from miscanthus.
Full article
(This article belongs to the Special Issue Advances in Cellulose-Based Polymers and Composites, 2nd Edition)
Open AccessArticle
Activated Carbon and Biochar Derived from Sargassum sp. Applied in Polyurethane-Based Materials Development
by
Julie Mallouhi, Miklós Varga, Emőke Sikora, Kitty Gráczer, Olivér Bánhidi, Sarra Gaspard, Francesca Goudou, Béla Viskolcz, Emma Szőri-Dorogházi and Béla Fiser
Polymers 2024, 16(20), 2914; https://doi.org/10.3390/polym16202914 - 16 Oct 2024
Abstract
Activated carbon (AC) and biochar (BC) are porous materials with large surface areas and widely used in environmental and industrial applications. In this study, different types of AC and BC samples were produced from Sargassum sp. by a chemical activation and pyrolysis process
[...] Read more.
Activated carbon (AC) and biochar (BC) are porous materials with large surface areas and widely used in environmental and industrial applications. In this study, different types of AC and BC samples were produced from Sargassum sp. by a chemical activation and pyrolysis process and compared to commercial activated carbon samples. All samples were characterized using various techniques to understand their structure and functionalities. The metal content of the samples was characterized by using an inductively coupled optical emission spectrometer (ICP-OES). A toxicity test was applied to investigate the effect of AC/BC on organisms, where Sinapis alba seed and Escherichia coli bacteria-based toxicity tests were used. The results revealed that the samples did not negatively affect these two organisms. Thus, it is safe to use them in various applications. Therefore, the samples were tested as fillers in polyurethane composites and, thus, polyurethane-AC/BC samples were prepared. The amounts of AC/BC mixed into the polyurethane formulation were 1%, 2%, and 3%. Mechanical and acoustic properties of these composites were analyzed, showing that by adding the AC/BC to the system an increase in the compression strength for all the samples was achieved. A similar effect of the AC/BC was noticed in the acoustic measurements, where adding AC/BC enhanced the sound adsorption coefficient (α) for all composite materials.
Full article
(This article belongs to the Special Issue Challenges and Trends in Polymer Composites—2nd Edition)
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<p><span class="html-italic">Sinapis alba</span> seed test: (<b>a</b>) different types of AC/BC suspended in 20 mL of dilution water; (<b>b</b>) germinated seeds after incubation.</p> Full article ">Figure 2
<p>Zeta potential distribution of the four different activated carbon/biochar samples.</p> Full article ">Figure 3
<p>FTIR spectra of the four different activated carbon/biochar (COMAC, AC, BC, and Reference AC) samples.</p> Full article ">Figure 4
<p>Percentage of the length of the growing root <span class="html-italic">of Sinapis alba</span> (white mustard) seeds exposed to COMAC (commercial activated carbon), AC (activated carbon was prepared from <span class="html-italic">Sargassum</span> sp. by chemical activation), and BC (biochar prepared from <span class="html-italic">Sargassum</span> sp. by pyrolysis) compared to the growing roots exposed to the Reference AC (Norit<sup>®</sup> activated charcoal). The red dotted line refers to the level of germination seeds for the samples in comparison to the Reference AC. Bacterial Test for Activated Carbon and Biochar.</p> Full article ">Figure 5
<p>Bacteria-based toxicity tests in liquid phase: (<b>a</b>) LB flasks containing AC/BC samples with <span class="html-italic">Escherichia coli</span> liquid medium, (<b>b</b>) plates with <span class="html-italic">Escherichia coli</span> grown in LB solid medium, for colony counting, and (<b>c</b>) plate with spread of 100 µL from bacterial suspension with AC/BC samples.</p> Full article ">Figure 6
<p>Average compression force (F) deflection of composite samples PUF/Reference AC, PUF/COMAC, PUF/AC, PUF/BC, and the control PUF sample. The red arrow refers to the PUF/AC at 3% which was not possible to measure. The red dotted line refers to the level of the compression force of all composite samples compared to Control-PUF.</p> Full article ">Figure 7
<p>Sound absorption coefficient (α) for composite samples PUF/Reference AC, PUF/COMAC, PUF/AC, PUF/BC and the control sample PUF.</p> Full article ">
<p><span class="html-italic">Sinapis alba</span> seed test: (<b>a</b>) different types of AC/BC suspended in 20 mL of dilution water; (<b>b</b>) germinated seeds after incubation.</p> Full article ">Figure 2
<p>Zeta potential distribution of the four different activated carbon/biochar samples.</p> Full article ">Figure 3
<p>FTIR spectra of the four different activated carbon/biochar (COMAC, AC, BC, and Reference AC) samples.</p> Full article ">Figure 4
<p>Percentage of the length of the growing root <span class="html-italic">of Sinapis alba</span> (white mustard) seeds exposed to COMAC (commercial activated carbon), AC (activated carbon was prepared from <span class="html-italic">Sargassum</span> sp. by chemical activation), and BC (biochar prepared from <span class="html-italic">Sargassum</span> sp. by pyrolysis) compared to the growing roots exposed to the Reference AC (Norit<sup>®</sup> activated charcoal). The red dotted line refers to the level of germination seeds for the samples in comparison to the Reference AC. Bacterial Test for Activated Carbon and Biochar.</p> Full article ">Figure 5
<p>Bacteria-based toxicity tests in liquid phase: (<b>a</b>) LB flasks containing AC/BC samples with <span class="html-italic">Escherichia coli</span> liquid medium, (<b>b</b>) plates with <span class="html-italic">Escherichia coli</span> grown in LB solid medium, for colony counting, and (<b>c</b>) plate with spread of 100 µL from bacterial suspension with AC/BC samples.</p> Full article ">Figure 6
<p>Average compression force (F) deflection of composite samples PUF/Reference AC, PUF/COMAC, PUF/AC, PUF/BC, and the control PUF sample. The red arrow refers to the PUF/AC at 3% which was not possible to measure. The red dotted line refers to the level of the compression force of all composite samples compared to Control-PUF.</p> Full article ">Figure 7
<p>Sound absorption coefficient (α) for composite samples PUF/Reference AC, PUF/COMAC, PUF/AC, PUF/BC and the control sample PUF.</p> Full article ">
Open AccessArticle
Sustainable Starch-Based Films from Cereals and Tubers: A Comparative Study on Cherry Tomato Preservation
by
Kelly J. Figueroa-Lopez, Ángel Villabona-Ortíz and Rodrigo Ortega-Toro
Polymers 2024, 16(20), 2913; https://doi.org/10.3390/polym16202913 - 16 Oct 2024
Abstract
Biodegradable films are sustainable alternatives to conventional plastics, particularly in food preservation, where the barrier and mechanical properties are crucial for maintaining the physicochemical, microbiological, and sensory qualities of the product. This study evaluated films made from starches of corn, potato, cassava, yam,
[...] Read more.
Biodegradable films are sustainable alternatives to conventional plastics, particularly in food preservation, where the barrier and mechanical properties are crucial for maintaining the physicochemical, microbiological, and sensory qualities of the product. This study evaluated films made from starches of corn, potato, cassava, yam, and wheat to determine their effectiveness in preserving cherry tomatoes. Amylose content, a key factor influencing the crystallinity and properties of the films, varied among the sources, with wheat starch having the highest (28.2%) and cassava the lowest (18.3%). The wheat starch film emerged as the best formulation, exhibiting the highest tensile strength and the lowest water vapor permeability (4.1 ± 0.3 g∙mm∙m−2∙h−1∙KPa−1), contributing to superior barrier performance. When applied to cherry tomatoes, the films based on wheat and corn starch showed the least moisture loss over fifteen days, highlighting their potential in fresh food preservation. These results suggest that starch-based films, specifically those rich in amylose, have significant potential as biodegradable packaging materials for food product conservation.
Full article
(This article belongs to the Section Biobased and Biodegradable Polymers)
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<p>Tensile strength of samples prepared from corn (Fc), potato (Fp), cassava (Fm), yam (Fy), and wheat (Fw) starches. <sup>a–d</sup> Different superscript letters within the different columns indicate significant differences among formulations (<span class="html-italic">p</span> < 0.05).</p> Full article ">Figure 2
<p>Elastic modulus of samples prepared from corn (Fc), potato (Fp), cassava (Fm), yam (Fy), and wheat (Fw) starches. <sup>a–e</sup> Different superscript letters within the different columns indicate significant differences among formulations (<span class="html-italic">p</span> < 0.05).</p> Full article ">Figure 3
<p>Elongation of samples prepared from corn (Fc), potato (Fp), cassava (Fm), yam (Fy), and wheat (Fw) starches. <sup>a–c</sup> Different superscript letters within the different columns indicate significant differences among formulations (<span class="html-italic">p</span> < 0.05).</p> Full article ">Figure 4
<p>Weight loss of cherry tomatoes with and without a coating stored at 70% RH and 30 °C for two weeks.</p> Full article ">
<p>Tensile strength of samples prepared from corn (Fc), potato (Fp), cassava (Fm), yam (Fy), and wheat (Fw) starches. <sup>a–d</sup> Different superscript letters within the different columns indicate significant differences among formulations (<span class="html-italic">p</span> < 0.05).</p> Full article ">Figure 2
<p>Elastic modulus of samples prepared from corn (Fc), potato (Fp), cassava (Fm), yam (Fy), and wheat (Fw) starches. <sup>a–e</sup> Different superscript letters within the different columns indicate significant differences among formulations (<span class="html-italic">p</span> < 0.05).</p> Full article ">Figure 3
<p>Elongation of samples prepared from corn (Fc), potato (Fp), cassava (Fm), yam (Fy), and wheat (Fw) starches. <sup>a–c</sup> Different superscript letters within the different columns indicate significant differences among formulations (<span class="html-italic">p</span> < 0.05).</p> Full article ">Figure 4
<p>Weight loss of cherry tomatoes with and without a coating stored at 70% RH and 30 °C for two weeks.</p> Full article ">
Open AccessArticle
Reduction in Floor Impact Noise Using Resilient Pads Composed of Machining Scraps
by
Donghyeon Lee, Jonghoon Jeon, Wanseung Kim, Narae Kim, Minjung Lee and Junhong Park
Polymers 2024, 16(20), 2912; https://doi.org/10.3390/polym16202912 - 16 Oct 2024
Abstract
Floor impact noise is a significant social concern to secure a quiescent living space for multi-story building residents in South Korea. The floating floor, consisting of a concrete structure on resilient pads, is a specifically designed system to minimize noise transmission. This floating
[...] Read more.
Floor impact noise is a significant social concern to secure a quiescent living space for multi-story building residents in South Korea. The floating floor, consisting of a concrete structure on resilient pads, is a specifically designed system to minimize noise transmission. This floating structure employs polymeric pads as the resilient materials. In this study, we investigated the utilization of helically shaped machining scraps as a resilient material for an alternative approach to floor noise reduction. The dynamic elastic modulus and loss factor of the scrap pads were measured using the vibration test method. The scrap pads exhibited a low dynamic elastic modulus and a high loss factor compared to the polymeric pads. Heavyweight impact sound experiments in an actual building were conducted to evaluate the noise reduction performance. The proposed pads showed excellent performance on the reduction in the structure-borne vibration of the concrete slab and resulting sound generation. The analytical model was used to simulate the response of the floating floor structure, enabling a parametric study to examine the effects of the resilient layer viscoelastic properties. Both experimental and analytical evidence confirmed that the proposed scrap pads contribute to the development of sustainable solutions for the minimization of floor impact noise.
Full article
(This article belongs to the Section Polymer Applications)
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<p>Image of the resilient materials including (<b>a</b>) conventional EPS pad and scrap pads with the same thickness of 3 mm but with different scrap lengths of (<b>b</b>) 60 mm, (<b>c</b>) 90 mm, and (<b>d</b>) 120 mm.</p> Full article ">Figure 2
<p>Experimental setup for measurement of the resilient material’s viscoelastic properties.</p> Full article ">Figure 3
<p>(<b>a</b>) Magnitude and (<b>b</b>) phase of the measured vibration transmissibility functions for the EPS and scraps in length variations.</p> Full article ">Figure 4
<p>The estimated (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor for the EPS and scraps in length variations. The scrap pads showed a lower dynamic elastic modulus and a higher loss factor than the EPS pad. As the length of the scraps increased, the dynamic elastic modulus decreased while the loss factor increased.</p> Full article ">Figure 5
<p>(<b>a</b>) Magnitude and (<b>b</b>) phase of measured vibration transmissibility functions for the EPS attached with scraps in length variations.</p> Full article ">Figure 6
<p>The estimated (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor for the EPS attached with scraps in length variations. Similar to the scrap pad cases, an increase in the length of the scraps resulted in a decrease in the dynamic elastic modulus and an increase in the loss factor.</p> Full article ">Figure 7
<p>Dependence of (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor on the input vibration level for the scrap pad. As the excitation force increases, the dynamic elastic modulus decreases but the loss factor increases.</p> Full article ">Figure 8
<p>Dependence of (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor on the input vibration level for the EPS pad. There was no change in the viscoelastic properties with different excitation forces.</p> Full article ">Figure 8 Cont.
<p>Dependence of (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor on the input vibration level for the EPS pad. There was no change in the viscoelastic properties with different excitation forces.</p> Full article ">Figure 9
<p>Frequency response of Duffing oscillator problem with the nonlinear dynamic modulus of the scrap pad and equivalent modulus with a constant loss factor, analyzed at a vibration level of 1.5 m/s<sup>2</sup>.</p> Full article ">Figure 10
<p>Installation of the floating floor incorporating the layered scrap complex: (<b>a</b>) scrap pads, (<b>b</b>) EPS pads, (<b>c</b>) heating plumbing, and (<b>d</b>) finishing mortar.</p> Full article ">Figure 11
<p>(<b>a</b>) Floor cross-sectrion and (<b>b</b>) microphone location schematic of the experimental setup for the floor impact noise measurement of the transmitted sound level. The microphones were placed at a distance of 0.75 m from the center and four corners. The source room and receiving room have an area of 22.95 m<sup>2</sup> ( 5.1 × 4.5 m<sup>2</sup>) with heights of 2.5 m and 2.4 m, respectively.</p> Full article ">Figure 12
<p>Heavyweight impact sound insulation performance: (<b>a</b>) vibration magnitude and (<b>b</b>) A-weighted sound pressure level in octave bands.</p> Full article ">Figure 13
<p>Elastic–viscoelastic–elastic sandwich structure with compressional damping for the floating floor structure.</p> Full article ">Figure 14
<p>Comparison between the measured and predicted vibration responses of the floating floor structure to identify the influence of the resilient layer: (<b>a</b>) vibration response in narrow bands and (<b>b</b>) levels in octave bands.</p> Full article ">Figure 15
<p>The vibration mode shape of the floating floor structure: (<b>a</b>) in-phase mode observed at 32 Hz and (<b>b</b>) out-of-phase mode observed at 185 Hz.</p> Full article ">Figure 16
<p>Effects of complex dynamic stiffness on frequency response of the concrete slab displacement.</p> Full article ">Figure 17
<p>The predicted vibration level from the concrete slab as a function of the elastic dynamic stiffness of the resilient layer for the floor structure and concrete slab.</p> Full article ">
<p>Image of the resilient materials including (<b>a</b>) conventional EPS pad and scrap pads with the same thickness of 3 mm but with different scrap lengths of (<b>b</b>) 60 mm, (<b>c</b>) 90 mm, and (<b>d</b>) 120 mm.</p> Full article ">Figure 2
<p>Experimental setup for measurement of the resilient material’s viscoelastic properties.</p> Full article ">Figure 3
<p>(<b>a</b>) Magnitude and (<b>b</b>) phase of the measured vibration transmissibility functions for the EPS and scraps in length variations.</p> Full article ">Figure 4
<p>The estimated (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor for the EPS and scraps in length variations. The scrap pads showed a lower dynamic elastic modulus and a higher loss factor than the EPS pad. As the length of the scraps increased, the dynamic elastic modulus decreased while the loss factor increased.</p> Full article ">Figure 5
<p>(<b>a</b>) Magnitude and (<b>b</b>) phase of measured vibration transmissibility functions for the EPS attached with scraps in length variations.</p> Full article ">Figure 6
<p>The estimated (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor for the EPS attached with scraps in length variations. Similar to the scrap pad cases, an increase in the length of the scraps resulted in a decrease in the dynamic elastic modulus and an increase in the loss factor.</p> Full article ">Figure 7
<p>Dependence of (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor on the input vibration level for the scrap pad. As the excitation force increases, the dynamic elastic modulus decreases but the loss factor increases.</p> Full article ">Figure 8
<p>Dependence of (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor on the input vibration level for the EPS pad. There was no change in the viscoelastic properties with different excitation forces.</p> Full article ">Figure 8 Cont.
<p>Dependence of (<b>a</b>) dynamic elastic modulus and (<b>b</b>) loss factor on the input vibration level for the EPS pad. There was no change in the viscoelastic properties with different excitation forces.</p> Full article ">Figure 9
<p>Frequency response of Duffing oscillator problem with the nonlinear dynamic modulus of the scrap pad and equivalent modulus with a constant loss factor, analyzed at a vibration level of 1.5 m/s<sup>2</sup>.</p> Full article ">Figure 10
<p>Installation of the floating floor incorporating the layered scrap complex: (<b>a</b>) scrap pads, (<b>b</b>) EPS pads, (<b>c</b>) heating plumbing, and (<b>d</b>) finishing mortar.</p> Full article ">Figure 11
<p>(<b>a</b>) Floor cross-sectrion and (<b>b</b>) microphone location schematic of the experimental setup for the floor impact noise measurement of the transmitted sound level. The microphones were placed at a distance of 0.75 m from the center and four corners. The source room and receiving room have an area of 22.95 m<sup>2</sup> ( 5.1 × 4.5 m<sup>2</sup>) with heights of 2.5 m and 2.4 m, respectively.</p> Full article ">Figure 12
<p>Heavyweight impact sound insulation performance: (<b>a</b>) vibration magnitude and (<b>b</b>) A-weighted sound pressure level in octave bands.</p> Full article ">Figure 13
<p>Elastic–viscoelastic–elastic sandwich structure with compressional damping for the floating floor structure.</p> Full article ">Figure 14
<p>Comparison between the measured and predicted vibration responses of the floating floor structure to identify the influence of the resilient layer: (<b>a</b>) vibration response in narrow bands and (<b>b</b>) levels in octave bands.</p> Full article ">Figure 15
<p>The vibration mode shape of the floating floor structure: (<b>a</b>) in-phase mode observed at 32 Hz and (<b>b</b>) out-of-phase mode observed at 185 Hz.</p> Full article ">Figure 16
<p>Effects of complex dynamic stiffness on frequency response of the concrete slab displacement.</p> Full article ">Figure 17
<p>The predicted vibration level from the concrete slab as a function of the elastic dynamic stiffness of the resilient layer for the floor structure and concrete slab.</p> Full article ">
Open AccessArticle
Catalytic Hydrolysis of Paraoxon by Immobilized Copper(II) Complexes of 1,4,7-Triazacyclononane Derivatives
by
Michaela Buziková, Hanna Zhukouskaya, Elena Tomšík, Miroslav Vetrík, Jan Kučka, Martin Hrubý and Jan Kotek
Polymers 2024, 16(20), 2911; https://doi.org/10.3390/polym16202911 (registering DOI) - 16 Oct 2024
Abstract
Organophosphate neuroactive agents represent severe security threats in various scenarios, including military conflicts, terrorist activities and industrial accidents. Addressing these threats necessitates effective protective measures, with a focus on decontamination strategies. Adsorbents such as bentonite have been explored as a preliminary method for
[...] Read more.
Organophosphate neuroactive agents represent severe security threats in various scenarios, including military conflicts, terrorist activities and industrial accidents. Addressing these threats necessitates effective protective measures, with a focus on decontamination strategies. Adsorbents such as bentonite have been explored as a preliminary method for chemical warfare agent immobilization, albeit lacking chemical destruction capabilities. Chemical decontamination, on the other hand, involves converting these agents into non-toxic or less toxic forms. In this study, we investigated the hydrolytic activity of a Cu(II) complex, previously studied for phosphate ester hydrolysis, as a potential agent for chemical warfare decontamination. Specifically, we focused on a ligand featuring a thiophene anchor bound through an aliphatic spacer, which exhibited high hydrolytic activity in its Cu(II) complex form in our previous studies. Paraoxon, an efficient insecticide, was selected as a model substrate for hydrolytic studies due to its structural resemblance to specific chemical warfare agents and due to the presence of a chromogenic 4-nitrophenolate moiety. Our findings clearly show the hydrolytic activity of the studied Cu(II) complexes. Additionally, we demonstrate the immobilization of the studied complex onto a solid substrate of Amberlite XAD4 via copolymerization of its thiophene side group with dithiophene. The hydrolytic activity of the resultant material towards paraoxon was studied, indicating its potential utilization in organophosphate neuroactive agent decontamination under mild conditions and the key importance of surface adsorption of paraoxon on the polymer surface.
Full article
(This article belongs to the Special Issue Functional Polymers: Interaction, Surface, Processing and Applications: 2nd Edition)
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Figure 1
<p>Structural formulas of compounds mentioned in the text.</p> Full article ">Scheme 1
<p>Preparation of the polymer catalyst by statistical copolymerization of 2,2′-dithiophene with ligand L1. Noncovalent (hydrophobic) binding/sorption of the polymer on the Amberlite XAD4 beads surface is expected. Macroporous Amberlite XAD4 beads consist of crosslinked polystyrene.</p> Full article ">Scheme 2
<p>Hydrolysis of paraoxon.</p> Full article ">
<p>Structural formulas of compounds mentioned in the text.</p> Full article ">Scheme 1
<p>Preparation of the polymer catalyst by statistical copolymerization of 2,2′-dithiophene with ligand L1. Noncovalent (hydrophobic) binding/sorption of the polymer on the Amberlite XAD4 beads surface is expected. Macroporous Amberlite XAD4 beads consist of crosslinked polystyrene.</p> Full article ">Scheme 2
<p>Hydrolysis of paraoxon.</p> Full article ">
Open AccessArticle
Polyacrylonitrile Ultrafiltration Membrane for Separation of Used Engine Oil
by
Alexandra Nebesskaya, Anastasia Kanateva, Roman Borisov, Alexey Yushkin, Vladimir Volkov and Alexey Volkov
Polymers 2024, 16(20), 2910; https://doi.org/10.3390/polym16202910 (registering DOI) - 16 Oct 2024
Abstract
The separation of used engine oil (UEO) with an ultrafiltration (UF) membrane made of commercial copolymer of poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) has been investigated. The P(AN-co-MA) sample was characterized by using FTIR spectroscopy, 13C NMR spectroscopy, and XRD. The UF membrane with a
[...] Read more.
The separation of used engine oil (UEO) with an ultrafiltration (UF) membrane made of commercial copolymer of poly(acrylonitrile-co-methyl acrylate) (P(AN-co-MA)) has been investigated. The P(AN-co-MA) sample was characterized by using FTIR spectroscopy, 13C NMR spectroscopy, and XRD. The UF membrane with a mean pore size of 23 nm was fabricated by using of non-solvent-induced phase separation method—the casting solution of 13 wt.% P(AN-co-MA) in dimethylsulfoxide (DMSO) was precipitated in the water bath. Before the experiment, the used engine oil was diluted with toluene, and the resulting UEO solution in toluene (100 g/L) was filtered through the UF membrane in the dead-end filtration mode. Special attention was given to the evaluation of membrane fouling; for instance, the permeability of UEO solution was dropped from its initial value of 2.90 L/(m2·h·bar) and then leveled off at 0.75 L/(m2·h·bar). However, the membrane cleaning (washing with toluene) allowed a recovery of 79% of the initial pure toluene flux (flux recovery ratio), indicating quite attractive membrane resistance toward irreversible fouling with engine oil components. The analysis of the feed, retentate, and permeate by various analytical methods showed that the filtration through the UF membrane made of P(AN-co-MA) provided the removal of major contaminants of used engine oil including polymerization products and metals (rejection—96.3%).
Full article
(This article belongs to the Section Polymer Membranes and Films)
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<p>Membrane preparation scheme.</p> Full article ">Figure 2
<p><sup>13</sup>C NMR spectroscopy spectra poly(acrylonitrile-co-methyl acrylate).</p> Full article ">Figure 3
<p>FTIR spectrum of P(AN-co-MA).</p> Full article ">Figure 4
<p>XRD spectrum of polymer: “crystalline” peaks—transparent, “amorphous”—shaded.</p> Full article ">Figure 5
<p>Asymmetric ultrafiltration P(AN-co-MA) membrane images. (<b>a</b>) the original membrane, (<b>b</b>) demonstration of membrane flexibility.</p> Full article ">Figure 6
<p>SEM images of the cross-section (<b>a</b>) and the surface (<b>b</b>) of the P(AN-co-MA) membrane.</p> Full article ">Figure 7
<p>Time dependence of the UEO solution permeance through the P(AN-co-MA) membrane.</p> Full article ">Figure 8
<p>The recovery rate of the membrane fouled during filtration of UEO solution in toluene (100 g/L).</p> Full article ">Figure 9
<p>FTIR spectrum of the P(AN-co-MA) membrane surface before and after filtering.</p> Full article ">Figure 10
<p>Photographs of (1) feed (UEO as received), (2) permeate, and (3) retentate after filtrations of UEO solutions in toluene (100 g/L): permeate and retentate after removal of toluene by distillation.</p> Full article ">Figure 11
<p>Metal content in the UEO, permeate, and retentate. (<b>a</b>) Zn and Na, (<b>b</b>) Cu, Pb and Fe.</p> Full article ">Figure 12
<p>Group hydrocarbon composition of UEO and permeate.</p> Full article ">Figure 13
<p>Chromatograms of used engine oil, permeate, and retentate obtained by the fingerprint method during filtration through a P(AN-co-MA) membrane. Conditions: 50 °C (2 min), 4 °C/min, 300 °C (40 min); carrier gas—helium, column SP-Sil 5 CB; inlet column pressure: 312.8 kPa.</p> Full article ">Figure 14
<p><sup>1</sup>H NMR spectroscopy spectra of oils (9.0−6.0 ppm): feed, permeate, and retentate.</p> Full article ">Figure 15
<p><sup>1</sup>H NMR spectroscopy spectra of oils (2.0−0.0 ppm): feed, permeate, and retentate.</p> Full article ">
<p>Membrane preparation scheme.</p> Full article ">Figure 2
<p><sup>13</sup>C NMR spectroscopy spectra poly(acrylonitrile-co-methyl acrylate).</p> Full article ">Figure 3
<p>FTIR spectrum of P(AN-co-MA).</p> Full article ">Figure 4
<p>XRD spectrum of polymer: “crystalline” peaks—transparent, “amorphous”—shaded.</p> Full article ">Figure 5
<p>Asymmetric ultrafiltration P(AN-co-MA) membrane images. (<b>a</b>) the original membrane, (<b>b</b>) demonstration of membrane flexibility.</p> Full article ">Figure 6
<p>SEM images of the cross-section (<b>a</b>) and the surface (<b>b</b>) of the P(AN-co-MA) membrane.</p> Full article ">Figure 7
<p>Time dependence of the UEO solution permeance through the P(AN-co-MA) membrane.</p> Full article ">Figure 8
<p>The recovery rate of the membrane fouled during filtration of UEO solution in toluene (100 g/L).</p> Full article ">Figure 9
<p>FTIR spectrum of the P(AN-co-MA) membrane surface before and after filtering.</p> Full article ">Figure 10
<p>Photographs of (1) feed (UEO as received), (2) permeate, and (3) retentate after filtrations of UEO solutions in toluene (100 g/L): permeate and retentate after removal of toluene by distillation.</p> Full article ">Figure 11
<p>Metal content in the UEO, permeate, and retentate. (<b>a</b>) Zn and Na, (<b>b</b>) Cu, Pb and Fe.</p> Full article ">Figure 12
<p>Group hydrocarbon composition of UEO and permeate.</p> Full article ">Figure 13
<p>Chromatograms of used engine oil, permeate, and retentate obtained by the fingerprint method during filtration through a P(AN-co-MA) membrane. Conditions: 50 °C (2 min), 4 °C/min, 300 °C (40 min); carrier gas—helium, column SP-Sil 5 CB; inlet column pressure: 312.8 kPa.</p> Full article ">Figure 14
<p><sup>1</sup>H NMR spectroscopy spectra of oils (9.0−6.0 ppm): feed, permeate, and retentate.</p> Full article ">Figure 15
<p><sup>1</sup>H NMR spectroscopy spectra of oils (2.0−0.0 ppm): feed, permeate, and retentate.</p> Full article ">
Open AccessArticle
Effect of Star-like Polymer on Mechanical Properties of Novel Basalt Fibre-Reinforced Composite with Bio-Based Matrix
by
Rochele Pinto, Tatjana Glaskova-Kuzmina, Kristina Zukiene, Gediminas Monastyreckis, Marie Novakova, Vladimir Spacek, Andrejs Kovalovs, Andrey Aniskevich and Daiva Zeleniakiene
Polymers 2024, 16(20), 2909; https://doi.org/10.3390/polym16202909 (registering DOI) - 16 Oct 2024
Abstract
This study is aimed at developing a fibre-reinforced polymer composite with a high bio-based content and to investigate its mechanical properties. A novel basalt fibre-reinforced polymer (BFRP) composite with bio-based matrix modified with different contents of star-like n-butyl methacrylate (n-BMA) block
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This study is aimed at developing a fibre-reinforced polymer composite with a high bio-based content and to investigate its mechanical properties. A novel basalt fibre-reinforced polymer (BFRP) composite with bio-based matrix modified with different contents of star-like n-butyl methacrylate (n-BMA) block glycidyl methacrylate (GMA) copolymer has been developed. n-BMA blocks have flexible butyl units, while the epoxide group of GMA makes it miscible with the epoxy resin and is involved in the crosslinking network. The effect of the star-like polymer on the rheological behaviour of the epoxy was studied. The viscosity of the epoxy increased with increase in star-like polymer content. Tensile tests showed no noteworthy influence of star-like polymer on tensile properties. The addition of 0.5 wt.% star-like polymer increased the glass transition temperature by 8.2 °C. Mode-I interlaminar fracture toughness and low-velocity impact tests were performed on star-like polymer-modified BFRP laminates, where interfacial adhesion and impact energy capabilities were observed. Interlaminar fracture toughness improved by 45% and energy absorption capability increased threefold for BFRP laminates modified with 1 wt.% of star-like polymer when compared to unmodified BFRP laminates. This improvement could be attributed to the increase in ductility of the matrix on the addition of the star-like polymer, increasing resistance to impact and damage. Furthermore, scanning electron microscopy confirmed that with increase in star-like polymer content, the interfacial adhesion between the matrix and fibres improves.
Full article
(This article belongs to the Special Issue Mechanical Properties of 3D Printed Polymer Composites)
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Figure 1
<p>Chemical structures of: (<b>a</b>) DGEBA; (<b>b</b>) phenalkamine; (<b>c</b>) BMA and GMA; and (<b>d</b>) EGDMA.</p> Full article ">Figure 2
<p>Star-like polymer structure: (<b>a</b>) chemical structure of star-like polymer arms; and (<b>b</b>) schematic diagram for star-like polymer structure.</p> Full article ">Figure 3
<p>Schematic representation of possible hydrogen bonding interaction between epoxy and <span class="html-italic">n</span>-BMA block GMA copolymer.</p> Full article ">Figure 4
<p>Materials’ and specimens’ preparation process.</p> Full article ">Figure 5
<p>Image of interface depicting delamination initiation and SEM-analysed area.</p> Full article ">Figure 6
<p>Dependency of viscosity on star-like polymer content.</p> Full article ">Figure 7
<p>Tensile test results: (<b>a</b>) stress-strain curves; (<b>b</b>) tensile strength and modulus of the bio-based matrix with different contents of star-like polymer.</p> Full article ">Figure 8
<p>DMA results: (<b>a</b>) storage modulus; (<b>b</b>) loss modulus; (<b>c</b>) damping factor; (<b>d</b>) glass transition temperatures of the bio-based matrix with different contents of star-like polymer.</p> Full article ">Figure 9
<p>Mode-I interlaminar fracture toughness test results: (<b>a</b>) load-COD curves; (<b>b</b>) critical energy release rates for different contents of star-like polymer.</p> Full article ">Figure 10
<p>Low-velocity impact tests: (<b>a</b>) contact-force vs. deflection; (<b>b</b>) absorbed energy of BFRP modified with different contents of star-like polymer.</p> Full article ">Figure 11
<p>Images of specimens post-impact: (<b>a</b>) neat epoxy; (<b>b</b>) 0.5 wt.%; (<b>c</b>) 1 wt.% of star-like polymer.</p> Full article ">Figure 12
<p>Damage morphology of fractured specimens at different magnifications: (<b>a</b>–<b>c</b>) at 1000×; (<b>d</b>–<b>f</b>) 500×; (<b>g</b>–<b>i</b>) 100× for different contents of star-like polymer.</p> Full article ">
<p>Chemical structures of: (<b>a</b>) DGEBA; (<b>b</b>) phenalkamine; (<b>c</b>) BMA and GMA; and (<b>d</b>) EGDMA.</p> Full article ">Figure 2
<p>Star-like polymer structure: (<b>a</b>) chemical structure of star-like polymer arms; and (<b>b</b>) schematic diagram for star-like polymer structure.</p> Full article ">Figure 3
<p>Schematic representation of possible hydrogen bonding interaction between epoxy and <span class="html-italic">n</span>-BMA block GMA copolymer.</p> Full article ">Figure 4
<p>Materials’ and specimens’ preparation process.</p> Full article ">Figure 5
<p>Image of interface depicting delamination initiation and SEM-analysed area.</p> Full article ">Figure 6
<p>Dependency of viscosity on star-like polymer content.</p> Full article ">Figure 7
<p>Tensile test results: (<b>a</b>) stress-strain curves; (<b>b</b>) tensile strength and modulus of the bio-based matrix with different contents of star-like polymer.</p> Full article ">Figure 8
<p>DMA results: (<b>a</b>) storage modulus; (<b>b</b>) loss modulus; (<b>c</b>) damping factor; (<b>d</b>) glass transition temperatures of the bio-based matrix with different contents of star-like polymer.</p> Full article ">Figure 9
<p>Mode-I interlaminar fracture toughness test results: (<b>a</b>) load-COD curves; (<b>b</b>) critical energy release rates for different contents of star-like polymer.</p> Full article ">Figure 10
<p>Low-velocity impact tests: (<b>a</b>) contact-force vs. deflection; (<b>b</b>) absorbed energy of BFRP modified with different contents of star-like polymer.</p> Full article ">Figure 11
<p>Images of specimens post-impact: (<b>a</b>) neat epoxy; (<b>b</b>) 0.5 wt.%; (<b>c</b>) 1 wt.% of star-like polymer.</p> Full article ">Figure 12
<p>Damage morphology of fractured specimens at different magnifications: (<b>a</b>–<b>c</b>) at 1000×; (<b>d</b>–<b>f</b>) 500×; (<b>g</b>–<b>i</b>) 100× for different contents of star-like polymer.</p> Full article ">
Open AccessArticle
Preparation of Effective NiCrPd-Decorated Carbon Nanofibers Derived from Polyvinylpyrrolidone as a Catalyst for H2 Generation from the Dehydrogenation of NaBH4
by
Ayman Yousef
Polymers 2024, 16(20), 2908; https://doi.org/10.3390/polym16202908 (registering DOI) - 15 Oct 2024
Abstract
The catalytic dehydrogenation of NaBH4 for the generation of H2 has a lot of potential as a reliable and achievable approach to make H2, which could be used as a safe and cost-effective energy source in the near future.
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The catalytic dehydrogenation of NaBH4 for the generation of H2 has a lot of potential as a reliable and achievable approach to make H2, which could be used as a safe and cost-effective energy source in the near future. This work describes the production of unique trimetallic NiCrPd-decorated carbon nanofiber (NiCrPd-decorated CNF) catalysts using electrospinning. The catalysts demonstrated exceptional catalytic activity in generating H2 through NaBH4 dehydrogenation. The catalysts were characterized using SEM, XRD, TEM, and TEM-EDX analyses. NiCrPd-decorated CNF formulations have shown higher catalytic activity in the dehydrogenation of NaBH4 compared with NiCr-decorated CNFs. It is likely that the better catalytic performance is because the three metals in the NiCrPd-decorated CNF structure interact with each other. Furthermore, the NiCrPd-decorated CNFs catalyzed the dehydrogenation of NaBH4 with an activation energy (Ea) of 26.55 KJ/mol. The kinetics studies showed that the reaction is first-order dependent on the dose of NiCrPd-decorated CNFs and zero-order dependent on the concentration of NaBH4.
Full article
(This article belongs to the Special Issue Functional Polymers in Energy Conversion, Management, and Storage)
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<p>Low (<b>a</b>) and high (<b>b</b>) magnification SEM images of Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNFs.</p> Full article ">Figure 2
<p>XRD of calcined NiCr (<b>a</b>) and NiCrPd (<b>b</b>) under vacuum in an Ar atmosphere at 900 °C.</p> Full article ">Figure 3
<p>TEM (<b>a</b>) and HR TEM (<b>b</b>) images Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNFs.</p> Full article ">Figure 4
<p>STEM image for NiCrPd-decorated CNFs (<b>a</b>) and the corresponding line TEM EDX analysis for Ni (<b>b</b>); Pd (<b>c</b>); Cr (<b>d</b>); and C (<b>e</b>).</p> Full article ">Figure 5
<p>H<sub>2</sub> evolution from NaHB<sub>4</sub> using various formulations of NiCrPd-decorated CNFs (<b>a</b>) and the influence of an increase in Cr content on the dehydrogenation process (<b>b</b>).</p> Full article ">Figure 6
<p>H<sub>2</sub> evolution from NaHB<sub>4</sub> catalyzed by different doses of Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNFs (<b>a</b>), and the H<sub>2</sub> generation rate versus the Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNF dose (<b>b</b>).</p> Full article ">Figure 7
<p>H<sub>2</sub> evolution using different concentrations of NaHB<sub>4</sub> (<b>a</b>), and the H<sub>2</sub> generation rate versus the concentration of NaHB<sub>4</sub> (<b>b</b>).</p> Full article ">Figure 8
<p>Effect of temperature on the dehydrogenation of NaBH<sub>4</sub> (<b>a</b>) and logarithmic plot of the ln rate versus 1/T (<b>b</b>).</p> Full article ">Figure 9
<p>The recyclability of the Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNF catalyst.</p> Full article ">
<p>Low (<b>a</b>) and high (<b>b</b>) magnification SEM images of Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNFs.</p> Full article ">Figure 2
<p>XRD of calcined NiCr (<b>a</b>) and NiCrPd (<b>b</b>) under vacuum in an Ar atmosphere at 900 °C.</p> Full article ">Figure 3
<p>TEM (<b>a</b>) and HR TEM (<b>b</b>) images Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNFs.</p> Full article ">Figure 4
<p>STEM image for NiCrPd-decorated CNFs (<b>a</b>) and the corresponding line TEM EDX analysis for Ni (<b>b</b>); Pd (<b>c</b>); Cr (<b>d</b>); and C (<b>e</b>).</p> Full article ">Figure 5
<p>H<sub>2</sub> evolution from NaHB<sub>4</sub> using various formulations of NiCrPd-decorated CNFs (<b>a</b>) and the influence of an increase in Cr content on the dehydrogenation process (<b>b</b>).</p> Full article ">Figure 6
<p>H<sub>2</sub> evolution from NaHB<sub>4</sub> catalyzed by different doses of Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNFs (<b>a</b>), and the H<sub>2</sub> generation rate versus the Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNF dose (<b>b</b>).</p> Full article ">Figure 7
<p>H<sub>2</sub> evolution using different concentrations of NaHB<sub>4</sub> (<b>a</b>), and the H<sub>2</sub> generation rate versus the concentration of NaHB<sub>4</sub> (<b>b</b>).</p> Full article ">Figure 8
<p>Effect of temperature on the dehydrogenation of NaBH<sub>4</sub> (<b>a</b>) and logarithmic plot of the ln rate versus 1/T (<b>b</b>).</p> Full article ">Figure 9
<p>The recyclability of the Ni<sub>0.5</sub>Cr<sub>0.3</sub>Pd<sub>0.2</sub>-decorated CNF catalyst.</p> Full article ">
Open AccessReview
Unraveling the Electrochemical Insights of Cobalt Oxide/Conducting Polymer Hybrid Materials for Supercapacitor, Battery, and Supercapattery Applications
by
Annu, Sang-Shin Park, Md Najib Alam, Manesh Yewale and Dong Kil Shin
Polymers 2024, 16(20), 2907; https://doi.org/10.3390/polym16202907 (registering DOI) - 15 Oct 2024
Abstract
This review article focuses on the potential of cobalt oxide composites with conducting polymers, particularly polypyrrole (PPy) and polyaniline (PANI), as advanced electrode materials for supercapacitors, batteries, and supercapatteries. Cobalt oxide, known for its high theoretical capacitance, is limited by poor conductivity and
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This review article focuses on the potential of cobalt oxide composites with conducting polymers, particularly polypyrrole (PPy) and polyaniline (PANI), as advanced electrode materials for supercapacitors, batteries, and supercapatteries. Cobalt oxide, known for its high theoretical capacitance, is limited by poor conductivity and structural degradation during cycling. However, the integration of PPy and PANI has been proven to enhance the electrochemical performance through improved conductivity, increased pseudocapacitive effects, and enhanced structural integrity. This synergistic combination facilitates efficient charge transport and ion diffusion, resulting in improved cycling stability and energy storage capacity. Despite significant progress in synthesis techniques and composite design, challenges such as maintaining structural stability during prolonged cycling and scalability for mass production remain. This review highlights the synthesis methods, latest advancements, and electrochemical performance in cobalt oxide/PPy and cobalt oxide/PANI composites, emphasizing their potential to contribute to the development of next-generation energy storage devices. Further exploration into their application, especially in battery systems, is necessary to fully harness their capabilities and meet the increasing demands of energy storage technologies.
Full article
(This article belongs to the Special Issue Polymeric Materials in Energy Conversion and Storage, 2nd Edition)
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Figure 1
<p>Hierarchical illustration of electrochemical energy storage devices.</p> Full article ">Figure 2
<p>Representation of different morphologies of cobalt oxide for cobalt oxide/polymer nanocomposites and their possible applications [<a href="#B41-polymers-16-02907" class="html-bibr">41</a>].</p> Full article ">Figure 3
<p>(<b>a</b>) Structure of cobalt oxide spinels CoO and (<b>b</b>) Co<sub>3</sub>O<sub>4</sub> [<a href="#B8-polymers-16-02907" class="html-bibr">8</a>] and (<b>c</b>) different conducting polymers [<a href="#B41-polymers-16-02907" class="html-bibr">41</a>].</p> Full article ">Figure 4
<p>(<b>a</b>) Synthesis of cobalt oxide/PPy nanowires by hydrothermal followed by chemical polymerization [<a href="#B47-polymers-16-02907" class="html-bibr">47</a>]. (<b>b</b>) The charge transfer mechanism and electrochemical performance via CV curves at different potential windows (150 mV s<sup>−1</sup>) and different scan rates (0–1.6 V), GCD curves at different current densities, specific and volumetric capacitance and cycling performance of ASC device (10 mA cm<sup>−2</sup>) with Nyquist plots for the NiCo<sub>2</sub>O<sub>4</sub>/PPy/AC device (reprinted with permission from [<a href="#B49-polymers-16-02907" class="html-bibr">49</a>]; copyright 2015 American Chemical Society). (<b>c</b>) Nyquist plot of electropolymerized cobalt oxide/PPy/CP electrode [<a href="#B42-polymers-16-02907" class="html-bibr">42</a>] and (<b>d</b>) cycle stability of hydrothermally and electrodeposition polymerized CoO/Ppy nanoarrays [<a href="#B43-polymers-16-02907" class="html-bibr">43</a>].</p> Full article ">Figure 5
<p>Synthesis methods: (<b>a</b>) hydrothermal followed by electrodeposition, (<b>b</b>) structural representation of CoO/PANI nanowires showing electron and electrolyte transport [<a href="#B53-polymers-16-02907" class="html-bibr">53</a>], and (<b>c</b>) in-situ chemical oxidative polymerization for NiCo<sub>2</sub>O<sub>4</sub>/PANI nanotubes [<a href="#B54-polymers-16-02907" class="html-bibr">54</a>] (reprinted with permission from [<a href="#B54-polymers-16-02907" class="html-bibr">54</a>]; copyright 2019 American Chemical Society), nanorods (reprinted with permission from [<a href="#B55-polymers-16-02907" class="html-bibr">55</a>]; copyright 2016 American Chemical Society), and a Co<sub>3</sub>O<sub>4</sub>-PANI/ZIF-8 nanoporous carbon (NPC) nanocomposite [<a href="#B56-polymers-16-02907" class="html-bibr">56</a>].</p> Full article ">Figure 6
<p>(<b>a</b>) Electrochemical performance of CoO/PANI nanowires: a—CV curves (scan rate 5 mV/s), b—charge-discharge profiles at 3 A/g, c—Nyquist plots, d—charge-discharge profiles at different current densities, and e—cycling stability curve of optimized PCN2, inset showing last few cycles [<a href="#B53-polymers-16-02907" class="html-bibr">53</a>]. (<b>b</b>) a—Specific capacitance, b—cycling stability at 10 A/g current density, and c—EIS spectra and Nyquist plot of Co<sub>3</sub>O<sub>4</sub> and Co<sub>3</sub>O<sub>4</sub>/PANI nanocomposite, respectively [<a href="#B57-polymers-16-02907" class="html-bibr">57</a>].</p> Full article ">Figure 7
<p>(<b>a</b>) Preparation method of Co<sub>3</sub>O<sub>4</sub>/PPy nanohybrid for batteries showing their SEM images. (<b>b</b>) Electrochemical performance of Co<sub>3</sub>O<sub>4</sub>/PPy nanofibers for LiO<sub>2</sub> battery applications [<a href="#B69-polymers-16-02907" class="html-bibr">69</a>].</p> Full article ">Figure 8
<p>(<b>a</b>) Synthesis of Co<sub>3</sub>O<sub>4</sub>/PANI nanorods as an anode material by chemical bath deposition (CBD) followed by electrodeposition (ED) and its impedance spectra for Li-ion batteries [<a href="#B73-polymers-16-02907" class="html-bibr">73</a>]. (<b>b</b>) Supercapattery device fabrication by Ag/Co<sub>3</sub>O<sub>4</sub>/PANI nanocomposites as battery-type positive electrode material, showing its CV curves at different potential and scan rates, and charge-discharge at different potentials and current densities. Comparative analysis by (<b>c</b>) Nyquist plot and (<b>d</b>) specific capacity and current density of Ag/Co<sub>3</sub>O<sub>4</sub>/PANI nanocomposite along with the cycle stability and energy and power densities of the fabricated device [<a href="#B71-polymers-16-02907" class="html-bibr">71</a>].</p> Full article ">Figure 9
<p>Comparative electrochemical differences in (<b>a</b>) CV and (<b>b</b>) GCD curves of cobalt oxide/conducting polymer (PPy and PANI)-based electrode materials for supercapacitor, battery, and supercapattery applications (ESR is equivalent series resistance) [<a href="#B1-polymers-16-02907" class="html-bibr">1</a>,<a href="#B49-polymers-16-02907" class="html-bibr">49</a>,<a href="#B53-polymers-16-02907" class="html-bibr">53</a>,<a href="#B69-polymers-16-02907" class="html-bibr">69</a>,<a href="#B71-polymers-16-02907" class="html-bibr">71</a>,<a href="#B73-polymers-16-02907" class="html-bibr">73</a>] (<span class="html-italic">reprinted with permission from</span> [<a href="#B1-polymers-16-02907" class="html-bibr">1</a>]; <span class="html-italic">copyright 2018 American Chemical Society</span>).</p> Full article ">
<p>Hierarchical illustration of electrochemical energy storage devices.</p> Full article ">Figure 2
<p>Representation of different morphologies of cobalt oxide for cobalt oxide/polymer nanocomposites and their possible applications [<a href="#B41-polymers-16-02907" class="html-bibr">41</a>].</p> Full article ">Figure 3
<p>(<b>a</b>) Structure of cobalt oxide spinels CoO and (<b>b</b>) Co<sub>3</sub>O<sub>4</sub> [<a href="#B8-polymers-16-02907" class="html-bibr">8</a>] and (<b>c</b>) different conducting polymers [<a href="#B41-polymers-16-02907" class="html-bibr">41</a>].</p> Full article ">Figure 4
<p>(<b>a</b>) Synthesis of cobalt oxide/PPy nanowires by hydrothermal followed by chemical polymerization [<a href="#B47-polymers-16-02907" class="html-bibr">47</a>]. (<b>b</b>) The charge transfer mechanism and electrochemical performance via CV curves at different potential windows (150 mV s<sup>−1</sup>) and different scan rates (0–1.6 V), GCD curves at different current densities, specific and volumetric capacitance and cycling performance of ASC device (10 mA cm<sup>−2</sup>) with Nyquist plots for the NiCo<sub>2</sub>O<sub>4</sub>/PPy/AC device (reprinted with permission from [<a href="#B49-polymers-16-02907" class="html-bibr">49</a>]; copyright 2015 American Chemical Society). (<b>c</b>) Nyquist plot of electropolymerized cobalt oxide/PPy/CP electrode [<a href="#B42-polymers-16-02907" class="html-bibr">42</a>] and (<b>d</b>) cycle stability of hydrothermally and electrodeposition polymerized CoO/Ppy nanoarrays [<a href="#B43-polymers-16-02907" class="html-bibr">43</a>].</p> Full article ">Figure 5
<p>Synthesis methods: (<b>a</b>) hydrothermal followed by electrodeposition, (<b>b</b>) structural representation of CoO/PANI nanowires showing electron and electrolyte transport [<a href="#B53-polymers-16-02907" class="html-bibr">53</a>], and (<b>c</b>) in-situ chemical oxidative polymerization for NiCo<sub>2</sub>O<sub>4</sub>/PANI nanotubes [<a href="#B54-polymers-16-02907" class="html-bibr">54</a>] (reprinted with permission from [<a href="#B54-polymers-16-02907" class="html-bibr">54</a>]; copyright 2019 American Chemical Society), nanorods (reprinted with permission from [<a href="#B55-polymers-16-02907" class="html-bibr">55</a>]; copyright 2016 American Chemical Society), and a Co<sub>3</sub>O<sub>4</sub>-PANI/ZIF-8 nanoporous carbon (NPC) nanocomposite [<a href="#B56-polymers-16-02907" class="html-bibr">56</a>].</p> Full article ">Figure 6
<p>(<b>a</b>) Electrochemical performance of CoO/PANI nanowires: a—CV curves (scan rate 5 mV/s), b—charge-discharge profiles at 3 A/g, c—Nyquist plots, d—charge-discharge profiles at different current densities, and e—cycling stability curve of optimized PCN2, inset showing last few cycles [<a href="#B53-polymers-16-02907" class="html-bibr">53</a>]. (<b>b</b>) a—Specific capacitance, b—cycling stability at 10 A/g current density, and c—EIS spectra and Nyquist plot of Co<sub>3</sub>O<sub>4</sub> and Co<sub>3</sub>O<sub>4</sub>/PANI nanocomposite, respectively [<a href="#B57-polymers-16-02907" class="html-bibr">57</a>].</p> Full article ">Figure 7
<p>(<b>a</b>) Preparation method of Co<sub>3</sub>O<sub>4</sub>/PPy nanohybrid for batteries showing their SEM images. (<b>b</b>) Electrochemical performance of Co<sub>3</sub>O<sub>4</sub>/PPy nanofibers for LiO<sub>2</sub> battery applications [<a href="#B69-polymers-16-02907" class="html-bibr">69</a>].</p> Full article ">Figure 8
<p>(<b>a</b>) Synthesis of Co<sub>3</sub>O<sub>4</sub>/PANI nanorods as an anode material by chemical bath deposition (CBD) followed by electrodeposition (ED) and its impedance spectra for Li-ion batteries [<a href="#B73-polymers-16-02907" class="html-bibr">73</a>]. (<b>b</b>) Supercapattery device fabrication by Ag/Co<sub>3</sub>O<sub>4</sub>/PANI nanocomposites as battery-type positive electrode material, showing its CV curves at different potential and scan rates, and charge-discharge at different potentials and current densities. Comparative analysis by (<b>c</b>) Nyquist plot and (<b>d</b>) specific capacity and current density of Ag/Co<sub>3</sub>O<sub>4</sub>/PANI nanocomposite along with the cycle stability and energy and power densities of the fabricated device [<a href="#B71-polymers-16-02907" class="html-bibr">71</a>].</p> Full article ">Figure 9
<p>Comparative electrochemical differences in (<b>a</b>) CV and (<b>b</b>) GCD curves of cobalt oxide/conducting polymer (PPy and PANI)-based electrode materials for supercapacitor, battery, and supercapattery applications (ESR is equivalent series resistance) [<a href="#B1-polymers-16-02907" class="html-bibr">1</a>,<a href="#B49-polymers-16-02907" class="html-bibr">49</a>,<a href="#B53-polymers-16-02907" class="html-bibr">53</a>,<a href="#B69-polymers-16-02907" class="html-bibr">69</a>,<a href="#B71-polymers-16-02907" class="html-bibr">71</a>,<a href="#B73-polymers-16-02907" class="html-bibr">73</a>] (<span class="html-italic">reprinted with permission from</span> [<a href="#B1-polymers-16-02907" class="html-bibr">1</a>]; <span class="html-italic">copyright 2018 American Chemical Society</span>).</p> Full article ">
Open AccessArticle
Evaluation of U-Notch and V-Notch Geometries on the Mechanical Behavior of PVDF: The DIC Technique and FEA Approach
by
Ingrid C. S. Pereira, José Renato M. de Sousa and Celio A. Costa
Polymers 2024, 16(20), 2906; https://doi.org/10.3390/polym16202906 (registering DOI) - 15 Oct 2024
Abstract
The notch effect of semicrystalline PVDF was investigated using U- and V-notch geometries with different depths, and tensile tests were performed at 23 °C using the DIC technique and FEA. Both unnotched and notched dumbbell-shaped specimens were subjected to tensile loading with the
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The notch effect of semicrystalline PVDF was investigated using U- and V-notch geometries with different depths, and tensile tests were performed at 23 °C using the DIC technique and FEA. Both unnotched and notched dumbbell-shaped specimens were subjected to tensile loading with the DIC technique to obtain mechanical curves and strain maps. The experimental data were compared to a numerical model, analyzing both global mechanical curves and local strain maps around the notch region to assess the accuracy of the simulations. The results demonstrated that the geometry and depth of the notch influence the mechanical behavior of PVDF, presenting a decrease in load and displacement compared to unnotched specimens. This aspect was corroborated by strain maps, which showed the increase in the local strain around the notch tip. For FEA, the global analysis indicated a good correlation with experimental results, and the local analysis demonstrated a reasonable agreement in strain map results within 0.5 mm of the notch neighborhood. Overall, the DIC technique and FEA provided a reliable evaluation of notch behavior on the PVDF used as pressure sheaths with reasonable precision.
Full article
(This article belongs to the Special Issue Mechanical Behavior of Polymeric Materials: Recent Studies, 2nd Edition)
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Figure 1
<p>Illustration of unnotched and notched specimens.</p> Full article ">Figure 2
<p>Schematic of 2D-DIC setup: Step I—acquisition of images, Step II—post-processing, and Step III—the resulting strain map.</p> Full article ">Figure 3
<p>Element finite model showing the tensile test, mesh generation, and boundary conditions in the numerical simulations.</p> Full article ">Figure 4
<p>Illustration of a close-up to observe global mesh and mesh in the notch region.</p> Full article ">Figure 5
<p>True stress–strain curve of PVDF adjusted to multilinear model.</p> Full article ">Figure 6
<p>Comparison between stress versus Lagrangian strain εyy curves of DIC and strain gauge at 23 °C under the rate of 5 mm/min of unnotched specimens.</p> Full article ">Figure 7
<p>Illustrations (<b>a</b>) stress versus time with (<b>b</b>) images during tensile test using DIC to specific points: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, (D) stress at the yield point, and (E) stress at necking.</p> Full article ">Figure 8
<p>Lagrangian strain εyy maps of unnotched specimens that correspond to specific points of Stress versus Lagrangian strain εyy curve: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 9
<p>Poisson’s ratio (v) and longitudinal (<math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>ε</mi> </mrow> <mrow> <mi>y</mi> <mi>y</mi> </mrow> <mrow> <mi>L</mi> <mi>a</mi> <mi>g</mi> </mrow> </msubsup> </mrow> </semantics></math>) and transversal (<math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>ε</mi> </mrow> <mrow> <mi>x</mi> <mi>x</mi> </mrow> <mrow> <mi>L</mi> <mi>a</mi> <mi>g</mi> </mrow> </msubsup> </mrow> </semantics></math>) strains obtained using the DIC at different stretch levels until the yield point for the unnotched PVDF specimen.</p> Full article ">Figure 10
<p>Load–displacement curves for V-notch specimens.</p> Full article ">Figure 11
<p>Load–displacement curves for U-notch specimens.</p> Full article ">Figure 12
<p>Lagrangian strains ε<sub>yy</sub> in V-notch tests at 23 °C and 0.2 and 1.5 mm depths: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 13
<p>Lagrangian strains ε<sub>yy</sub> in U-notch tests at 23 °C and 0.2 and 1.5 mm depths: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 14
<p>Comparison between experimental and FE responses considering notches with 0.2 mm depth in (<b>a</b>) V-notch and (<b>b</b>) U-notch samples: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 15
<p>Comparison between experimental and FE responses considering notches with 1.5 mm depth in (<b>a</b>) V-notch and (<b>b</b>) U-notch samples: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 16
<p>Comparison between DIC technique and FEA at Point A and Point D for V-notch tip with 0.2 mm depth.</p> Full article ">Figure 17
<p>Comparison between DIC technique and FEA at Point A and Point D for V-notch tip with 1.5 mm depth.</p> Full article ">Figure 18
<p>Comparison between DIC technique and FEA at Point A and Point D for U-notch tip with 0.2 mm depth.</p> Full article ">Figure 19
<p>Comparison between DIC technique and FEA at Point A and Point D for U-notch tip with 1.5 mm depth.</p> Full article ">
<p>Illustration of unnotched and notched specimens.</p> Full article ">Figure 2
<p>Schematic of 2D-DIC setup: Step I—acquisition of images, Step II—post-processing, and Step III—the resulting strain map.</p> Full article ">Figure 3
<p>Element finite model showing the tensile test, mesh generation, and boundary conditions in the numerical simulations.</p> Full article ">Figure 4
<p>Illustration of a close-up to observe global mesh and mesh in the notch region.</p> Full article ">Figure 5
<p>True stress–strain curve of PVDF adjusted to multilinear model.</p> Full article ">Figure 6
<p>Comparison between stress versus Lagrangian strain εyy curves of DIC and strain gauge at 23 °C under the rate of 5 mm/min of unnotched specimens.</p> Full article ">Figure 7
<p>Illustrations (<b>a</b>) stress versus time with (<b>b</b>) images during tensile test using DIC to specific points: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, (D) stress at the yield point, and (E) stress at necking.</p> Full article ">Figure 8
<p>Lagrangian strain εyy maps of unnotched specimens that correspond to specific points of Stress versus Lagrangian strain εyy curve: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 9
<p>Poisson’s ratio (v) and longitudinal (<math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>ε</mi> </mrow> <mrow> <mi>y</mi> <mi>y</mi> </mrow> <mrow> <mi>L</mi> <mi>a</mi> <mi>g</mi> </mrow> </msubsup> </mrow> </semantics></math>) and transversal (<math display="inline"><semantics> <mrow> <msubsup> <mrow> <mi>ε</mi> </mrow> <mrow> <mi>x</mi> <mi>x</mi> </mrow> <mrow> <mi>L</mi> <mi>a</mi> <mi>g</mi> </mrow> </msubsup> </mrow> </semantics></math>) strains obtained using the DIC at different stretch levels until the yield point for the unnotched PVDF specimen.</p> Full article ">Figure 10
<p>Load–displacement curves for V-notch specimens.</p> Full article ">Figure 11
<p>Load–displacement curves for U-notch specimens.</p> Full article ">Figure 12
<p>Lagrangian strains ε<sub>yy</sub> in V-notch tests at 23 °C and 0.2 and 1.5 mm depths: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 13
<p>Lagrangian strains ε<sub>yy</sub> in U-notch tests at 23 °C and 0.2 and 1.5 mm depths: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 14
<p>Comparison between experimental and FE responses considering notches with 0.2 mm depth in (<b>a</b>) V-notch and (<b>b</b>) U-notch samples: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 15
<p>Comparison between experimental and FE responses considering notches with 1.5 mm depth in (<b>a</b>) V-notch and (<b>b</b>) U-notch samples: (A) stress at the linear–elastic region, (B) stress at 3.5% of strain, (C) stress at 7.0% of strain, and (D) stress at the yield point.</p> Full article ">Figure 16
<p>Comparison between DIC technique and FEA at Point A and Point D for V-notch tip with 0.2 mm depth.</p> Full article ">Figure 17
<p>Comparison between DIC technique and FEA at Point A and Point D for V-notch tip with 1.5 mm depth.</p> Full article ">Figure 18
<p>Comparison between DIC technique and FEA at Point A and Point D for U-notch tip with 0.2 mm depth.</p> Full article ">Figure 19
<p>Comparison between DIC technique and FEA at Point A and Point D for U-notch tip with 1.5 mm depth.</p> Full article ">
Open AccessArticle
Structure Design on Thermoplastic Composites Considering Forming Effects
by
Wei Xie, Kai Song, Ju Yang, Fengyu Wang, Linjie Dong, Shengjie Jin, Guohua Zhu and Zhen Wang
Polymers 2024, 16(20), 2905; https://doi.org/10.3390/polym16202905 (registering DOI) - 15 Oct 2024
Abstract
Carbon fiber reinforced polypropylene (CF/PP) thermoplastics integrate the superior formability of fabrics with the recoverable characteristics of polypropylene, making them a pivotal solution for achieving lightweight designs in new energy vehicles. However, the prevailing methodologies for designing the structural performance of CF/PP vehicular
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Carbon fiber reinforced polypropylene (CF/PP) thermoplastics integrate the superior formability of fabrics with the recoverable characteristics of polypropylene, making them a pivotal solution for achieving lightweight designs in new energy vehicles. However, the prevailing methodologies for designing the structural performance of CF/PP vehicular components often omit the constraints imposed by the manufacturing process, thereby compromising product quality and reliability. This research presents a novel approach for developing a stamping–bending coupled finite element model (FEM) utilizing ABAQUS/Explicit. Initially, the hot stamping simulation is implemented, followed by the transmission of stamping information, including fiber yarn orientation and fiber yarn angle, to the follow-up step for updating the material properties of the cured specimen. Then, the structural performance analysis is conducted, accounting for the stamping effects. Furthermore, the parametric study reveals that the shape and length of the blank holding ring exerted minimal influence on the maximum fiber angle characteristic. However, it is noted that the energy absorption and crushing force efficiency metrics of the CF/PP specimens can be enhanced by increasing the length of the blank holding ring. Finally, a discrete optimization design is implemented to enhance the bending performance of the CF/PP specimen, accounting for the constraint of the maximum shear angle resulting from the stamping process. The optimized design resulted in a mass reduction of 14.3% and an improvement in specific energy absorption (SEA) by 17.5% compared to the baseline sample.
Full article
(This article belongs to the Special Issue Material-Process-Structure Integrated Design for Advanced Polymeric Composites)
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<p>Mechanical property parameter characterizations of CF/PP prepregs and the CF/PP laminates: (<b>a</b>) the bias-extension equipment for the CF/PP prepreg; (<b>b</b>) the normalized shear force–shear strain curve of single CF/PP prepreg; (<b>c</b>) the bias-extension equipment for the CF/PP laminate; (<b>d</b>) the true stress–true strain curves of CF/PP laminates; and (<b>e</b>) failure positions of three different CF/PP tensile samples.</p> Full article ">Figure 2
<p>Manufacturing process of the hat-shaped CF/PP specimen: (<b>a</b>) the hot stamping machine and the molds; (<b>b</b>) the stamping molds and prepregs are pre-heated first, then the punch moves downwards and finishes the stamping step; the non-orthogonal cured specimen is taken out after cooling stage and trimmed to the final configuration for the further three-point bending test, the red line represents the weft yarn, and the blue line denotes the warp yarn, and the yellow arrow is the fiber direction.</p> Full article ">Figure 3
<p>The three-point bending test fixtures and the typical bending responses of the CF/PP specimen: (<b>a</b>) three-point bending fixture descriptions; (<b>b</b>) force-/energy–displacement curves, deformation patterns and failure modes; and (<b>c</b>) typical historical photos of the CF/PP specimen.</p> Full article ">Figure 4
<p>The establishment and workflow diagrams of the stamping–bending coupled model: (<b>a</b>) multi-step procedure of the stamping–bending coupled analysis in ABAQUS/Explicit, in which the orthogonal fabric configuration turned into a non-orthogonal configuration in the stamping step, and then the stamping information was transferred to the subsequent structural analysis step; (<b>b</b>) the VUMAT flowchart for the stamping–bending coupled finite element model, in which the trimming and mapping VUMAT served as a connecting link between the stamping VUMAT and bending VUMAT.</p> Full article ">Figure 5
<p>The stamping–bending coupled finite element model of the hat-shaped CF/PP tube: (<b>a</b>) the stamping finite element model; (<b>b</b>) the molds removing and material trimming finite element model; and (<b>c</b>) the bending finite element model.</p> Full article ">Figure 6
<p>Comparisons in forming and bending performances of the hat-shaped CF/PP specimen between the simulation and experiment results: (<b>a</b>) typical fiber angle variations; (<b>b</b>) force-/energy–displacement curves; (<b>c</b>) bending damage modes; and (<b>d</b>) bending deformation histories.</p> Full article ">Figure 7
<p>The influences of the cross-sectional shape on the forming and bending characteristics of the CF/PP specimens: (<b>a</b>) the diagrams of stamping molds with three different cross-sectional shapes; (<b>b</b>) the fiber yarn shear angle distributions after the stamping process; (<b>c</b>) the bending force–displacement curves; and (<b>d</b>) the ultimate damage modes and plastic deformations.</p> Full article ">Figure 8
<p>The influences of the blank holding ring shapes on the forming and bending characteristics of the CF/PP specimens: (<b>a</b>) the diagrams of stamping molds with three different blank holding ring shapes; (<b>b</b>) the fiber yarn shear angle distributions after the stamping process; (<b>c</b>) the bending force–displacement curves; and (<b>d</b>) the ultimate damage modes and plastic deformations.</p> Full article ">Figure 9
<p>The influences of the blank holding ring lengths on the forming and bending characteristics of the CF/PP specimens: (<b>a</b>) the diagrams of stamping molds with three different blank holding ring lengths; (<b>b</b>) the fiber yarn shear angle distributions after the stamping process; (<b>c</b>) the bending force–displacement curves; and (<b>d</b>) the ultimate damage modes and plastic deformations.</p> Full article ">Figure 10
<p>Comparisons in the forming and bending performance indicators of the CF/PP specimens: (<b>a</b>) the maximum fiber angle after the stamping process; (<b>b</b>) the peak force indicator; (<b>c</b>) the energy absorption indicator; and (<b>d</b>) the crushing force efficiency indicator.</p> Full article ">Figure 11
<p>The multi-objective discrete optimization flowchart of CF/PP hat-shaped specimen accounting for the stamping process effects, in which the Taguchi approach was employed to deal with the discrete variables, and the gray relational analysis method was adopted to transform the constrained multi-objective problems into the unconstrained single-objective problems.</p> Full article ">Figure 12
<p>Iteration history of gray relational degree.</p> Full article ">
<p>Mechanical property parameter characterizations of CF/PP prepregs and the CF/PP laminates: (<b>a</b>) the bias-extension equipment for the CF/PP prepreg; (<b>b</b>) the normalized shear force–shear strain curve of single CF/PP prepreg; (<b>c</b>) the bias-extension equipment for the CF/PP laminate; (<b>d</b>) the true stress–true strain curves of CF/PP laminates; and (<b>e</b>) failure positions of three different CF/PP tensile samples.</p> Full article ">Figure 2
<p>Manufacturing process of the hat-shaped CF/PP specimen: (<b>a</b>) the hot stamping machine and the molds; (<b>b</b>) the stamping molds and prepregs are pre-heated first, then the punch moves downwards and finishes the stamping step; the non-orthogonal cured specimen is taken out after cooling stage and trimmed to the final configuration for the further three-point bending test, the red line represents the weft yarn, and the blue line denotes the warp yarn, and the yellow arrow is the fiber direction.</p> Full article ">Figure 3
<p>The three-point bending test fixtures and the typical bending responses of the CF/PP specimen: (<b>a</b>) three-point bending fixture descriptions; (<b>b</b>) force-/energy–displacement curves, deformation patterns and failure modes; and (<b>c</b>) typical historical photos of the CF/PP specimen.</p> Full article ">Figure 4
<p>The establishment and workflow diagrams of the stamping–bending coupled model: (<b>a</b>) multi-step procedure of the stamping–bending coupled analysis in ABAQUS/Explicit, in which the orthogonal fabric configuration turned into a non-orthogonal configuration in the stamping step, and then the stamping information was transferred to the subsequent structural analysis step; (<b>b</b>) the VUMAT flowchart for the stamping–bending coupled finite element model, in which the trimming and mapping VUMAT served as a connecting link between the stamping VUMAT and bending VUMAT.</p> Full article ">Figure 5
<p>The stamping–bending coupled finite element model of the hat-shaped CF/PP tube: (<b>a</b>) the stamping finite element model; (<b>b</b>) the molds removing and material trimming finite element model; and (<b>c</b>) the bending finite element model.</p> Full article ">Figure 6
<p>Comparisons in forming and bending performances of the hat-shaped CF/PP specimen between the simulation and experiment results: (<b>a</b>) typical fiber angle variations; (<b>b</b>) force-/energy–displacement curves; (<b>c</b>) bending damage modes; and (<b>d</b>) bending deformation histories.</p> Full article ">Figure 7
<p>The influences of the cross-sectional shape on the forming and bending characteristics of the CF/PP specimens: (<b>a</b>) the diagrams of stamping molds with three different cross-sectional shapes; (<b>b</b>) the fiber yarn shear angle distributions after the stamping process; (<b>c</b>) the bending force–displacement curves; and (<b>d</b>) the ultimate damage modes and plastic deformations.</p> Full article ">Figure 8
<p>The influences of the blank holding ring shapes on the forming and bending characteristics of the CF/PP specimens: (<b>a</b>) the diagrams of stamping molds with three different blank holding ring shapes; (<b>b</b>) the fiber yarn shear angle distributions after the stamping process; (<b>c</b>) the bending force–displacement curves; and (<b>d</b>) the ultimate damage modes and plastic deformations.</p> Full article ">Figure 9
<p>The influences of the blank holding ring lengths on the forming and bending characteristics of the CF/PP specimens: (<b>a</b>) the diagrams of stamping molds with three different blank holding ring lengths; (<b>b</b>) the fiber yarn shear angle distributions after the stamping process; (<b>c</b>) the bending force–displacement curves; and (<b>d</b>) the ultimate damage modes and plastic deformations.</p> Full article ">Figure 10
<p>Comparisons in the forming and bending performance indicators of the CF/PP specimens: (<b>a</b>) the maximum fiber angle after the stamping process; (<b>b</b>) the peak force indicator; (<b>c</b>) the energy absorption indicator; and (<b>d</b>) the crushing force efficiency indicator.</p> Full article ">Figure 11
<p>The multi-objective discrete optimization flowchart of CF/PP hat-shaped specimen accounting for the stamping process effects, in which the Taguchi approach was employed to deal with the discrete variables, and the gray relational analysis method was adopted to transform the constrained multi-objective problems into the unconstrained single-objective problems.</p> Full article ">Figure 12
<p>Iteration history of gray relational degree.</p> Full article ">
Open AccessArticle
Continuous Material Deposition on Filaments in Fused Deposition Modeling
by
Guy Naim, Shlomo Magdassi and Daniel Mandler
Polymers 2024, 16(20), 2904; https://doi.org/10.3390/polym16202904 (registering DOI) - 15 Oct 2024
Abstract
A novel approach, i.e., Continuous Material Deposition on Filaments (CMDF), for the incorporation of active materials within 3D-printed structures is presented. It is based on passing a filament through a solution in which the active material is dissolved together with the polymer from
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A novel approach, i.e., Continuous Material Deposition on Filaments (CMDF), for the incorporation of active materials within 3D-printed structures is presented. It is based on passing a filament through a solution in which the active material is dissolved together with the polymer from which the filament is made. This enables the fabrication of a variety of functional 3D-printed objects by fused deposition modeling (FDM) using commercial filaments without post-treatment processes. This generic approach has been demonstrated in objects using three different types of materials, Rhodamine B, ZnO nanoparticles (NPs), and Ciprofloxacin (Cip). The functionality of these objects is demonstrated through strong antibacterial activity in ZnO NPs and the controlled release of the antibiotic Cip. CMDF does not alter the mechanical properties of FDM-printed structures, can be applied with any type of FDM printer, and is, therefore, expected to have applications in a wide variety of fields.
Full article
(This article belongs to the Special Issue Synthesis, Processing, Structure and Properties of Polymer Materials: 2nd Edition)
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<p>A schematic representation of the Continuous Material Deposition on Filaments treatment (CMDF). A new strand of filament moves through a glass tube through three different liquid phases; a salt-saturated aqueous phase, a Dichloromethane/Tetrahydrofuran (DCM/THF) hydrophobic phase (where the coating occurs), and a thin layer of distilled water, before being dried and used in a 3D printer.</p> Full article ">Figure 2
<p>(<b>A</b>) Photo of CMDF. (<b>B</b>) Treated filament before and after embedding Rhodamine B.</p> Full article ">Figure 3
<p>(<b>A</b>) The Rhodamine B-coated filament and printed sample with cross-section optical microscopy images of (<b>B</b>) The printed sample and (<b>C</b>,<b>D</b>) The filament.</p> Full article ">Figure 4
<p>Cross-section imaging by fluorescence microscopy of the Rhodamine B-coated filament before (<b>A</b>) and after (<b>B</b>) printing.</p> Full article ">Figure 5
<p>The amount of Zn in a coated filament at different locations along the filament. The coating dispersion contains 20 mg/mL of polylactide acid (PLA) and 15 mg/mL of ZnO nanoparticles (NPs). Each point on the graph refers to 20 cm of filament centered of the cut portion of the filament.</p> Full article ">Figure 6
<p>The amount of zinc in a sample as a function of the concentration of ZnO NPs in the dispersion containing 10 or 20 mg/mL of PLA.</p> Full article ">Figure 7
<p>The antibacterial activity of (<b>A</b>) <span class="html-italic">S. aureus</span> and (<b>B</b>) <span class="html-italic">E. coli</span> at different concentrations of PLA and ZnO NPs. The concentrations refer to the coating solutions tested. The bacteria were exposed directly to the printed samples.</p> Full article ">Figure 8
<p>The accumulative release–mass ratio of Ciprofloxacin (Cip) released into the PBS solution from samples printed with a filament passed through a coating solution of 20 mg/mL PLA and 5–50 mg/mL of dissolved Cip.</p> Full article ">
<p>A schematic representation of the Continuous Material Deposition on Filaments treatment (CMDF). A new strand of filament moves through a glass tube through three different liquid phases; a salt-saturated aqueous phase, a Dichloromethane/Tetrahydrofuran (DCM/THF) hydrophobic phase (where the coating occurs), and a thin layer of distilled water, before being dried and used in a 3D printer.</p> Full article ">Figure 2
<p>(<b>A</b>) Photo of CMDF. (<b>B</b>) Treated filament before and after embedding Rhodamine B.</p> Full article ">Figure 3
<p>(<b>A</b>) The Rhodamine B-coated filament and printed sample with cross-section optical microscopy images of (<b>B</b>) The printed sample and (<b>C</b>,<b>D</b>) The filament.</p> Full article ">Figure 4
<p>Cross-section imaging by fluorescence microscopy of the Rhodamine B-coated filament before (<b>A</b>) and after (<b>B</b>) printing.</p> Full article ">Figure 5
<p>The amount of Zn in a coated filament at different locations along the filament. The coating dispersion contains 20 mg/mL of polylactide acid (PLA) and 15 mg/mL of ZnO nanoparticles (NPs). Each point on the graph refers to 20 cm of filament centered of the cut portion of the filament.</p> Full article ">Figure 6
<p>The amount of zinc in a sample as a function of the concentration of ZnO NPs in the dispersion containing 10 or 20 mg/mL of PLA.</p> Full article ">Figure 7
<p>The antibacterial activity of (<b>A</b>) <span class="html-italic">S. aureus</span> and (<b>B</b>) <span class="html-italic">E. coli</span> at different concentrations of PLA and ZnO NPs. The concentrations refer to the coating solutions tested. The bacteria were exposed directly to the printed samples.</p> Full article ">Figure 8
<p>The accumulative release–mass ratio of Ciprofloxacin (Cip) released into the PBS solution from samples printed with a filament passed through a coating solution of 20 mg/mL PLA and 5–50 mg/mL of dissolved Cip.</p> Full article ">
Open AccessArticle
High-Performance Dual-Redox-Mediator Supercapacitors Based on Buckypaper Electrodes and Hydrogel Polymer Electrolytes
by
Garbas A. Santos Junior, Kélrie H. A. Mendes, Sarah G. G. de Oliveira, Gabriel J. P. Tonon, Neide P. G. Lopes, Thiago H. R. da Cunha, Mario Guimarães Junior, Rodrigo L. Lavall and Paulo F. R. Ortega
Polymers 2024, 16(20), 2903; https://doi.org/10.3390/polym16202903 (registering DOI) - 15 Oct 2024
Abstract
In recent years, the demand for solid, thin, and flexible energy storage devices has surged in modern consumer electronics, which require autonomy and long duration. In this context, hybrid supercapacitors have become strategic, and significant efforts are being made to develop cells with
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In recent years, the demand for solid, thin, and flexible energy storage devices has surged in modern consumer electronics, which require autonomy and long duration. In this context, hybrid supercapacitors have become strategic, and significant efforts are being made to develop cells with higher energy densities while preserving the power density of conventional supercapacitors. Motivated by these requirements, we report the development of a new high-performance dual-redox-mediator supercapacitor. In this study, cells were constructed using fully moldable buckypapers (BPs), composed of carbon nanotubes and cellulose nanofibers, as electrodes. We evaluated the compatibility of BPs with hydrogel polymer electrolytes, based on 1 mol L−1 H2SO4 and polyvinyl alcohol (PVA), supplemented with different redox species: methylene blue, indigo carmine, and hydroquinone. Solid cells were constructed containing two active redox species to maximize the specific capacity of each electrode. Considering the main results, the dual-redox-mediator supercapacitor exhibits high energy density of 32.0 Wh kg−1 (at 0.8 kW kg−1) and is capable of delivering 25.9 Wh kg−1 at high power demand (4.0 kW kg−1). Stability studies conducted over 10,000 galvanostatic cycles revealed that the PVA polymer matrix benefits the system by inhibiting the crossover of redox species within the cell.
Full article
(This article belongs to the Special Issue Exploring Polymer Electrolytes for High-Performance Batteries and Supercapacitors)
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<p>(<b>a</b>) Schematic representation and (<b>b</b>) image of the obtained CNT/CNF buckypaper. (<b>c</b>) Schematic of the HGPE buckypaper preparation process and (<b>d</b>) photography of the HGPE buckypaper. (<b>e</b>) Schematic representation of the cell configuration and (<b>f</b>) photography of the flexible solid-state supercapacitor device. Schematic representation of the fabricated symmetric SC device assembled using 0.8-HGPE buckypaper and redox mediator: (<b>g</b>) carmine indigo, (<b>h</b>) methylene blue, (<b>i</b>) hydroquinone.</p> Full article ">Figure 2
<p>(<b>a</b>) Nyquist plot—inset shows the equivalent circuit; (<b>b</b>) GCD curves at J = 1 A g<sup>−1</sup>; (<b>c</b>) specific capacity of SCs based on HGPE electrolyte compared to the liquid electrolyte system at 1 A g<sup>−1</sup> (3.54 mA cm<sup>−2</sup>).</p> Full article ">Figure 3
<p>Cyclic voltammetry for cells constructed with (<b>a</b>) 0.8-HGPE—the inset shows the magnified cyclic voltammetry—and 0.8-HGPE containing (<b>b</b>) methylene blue, (<b>c</b>) hydroquinone, and (<b>d</b>) indigo carmine. The inset also shows the dependence of peak currents on the square root of the scan rate for both anodic and cathodic potentials. The anodic peak current is represented by empty squares, while the cathodic peak current is represented by filled squares.</p> Full article ">Figure 4
<p>Dual-redox-mediator solid-state SC: (<b>a</b>) schematic configuration; (<b>b</b>) GCD curves at different current densities, inset compares the system with 0.8-HGPE SC, at 1 A g<sup>−1</sup>; (<b>c</b>) cyclic voltammetry at different scan rates, inset compares the system with 0.8-HGPE SC, at 100 mV s<sup>−1</sup>; (<b>d</b>) specific capacity compared to 0.8-HGPE SC.</p> Full article ">Figure 5
<p>Dual-redox-mediator solid-state SC: (<b>a</b>) evolution of the potential of the electrodes at different current densities (red line, positive electrode (methylene blue redox mediator); blue line, negative electrode (indigo carmine redox mediator)); (<b>b</b>) cycling stability for 10,000 cycles at 2.5 A g<sup>−1</sup> (8.84 mA cm<sup>−2</sup>) and coulombic efficiency; (<b>c</b>) comparison of the potential evolution of the electrodes at the 1st and the 10,000th cycle. (<b>d</b>) Ragone plot of the dual-redox-mediator solid-state SC, compared with some previously published systems [<a href="#B19-polymers-16-02903" class="html-bibr">19</a>,<a href="#B25-polymers-16-02903" class="html-bibr">25</a>,<a href="#B26-polymers-16-02903" class="html-bibr">26</a>,<a href="#B27-polymers-16-02903" class="html-bibr">27</a>,<a href="#B28-polymers-16-02903" class="html-bibr">28</a>,<a href="#B29-polymers-16-02903" class="html-bibr">29</a>,<a href="#B30-polymers-16-02903" class="html-bibr">30</a>,<a href="#B31-polymers-16-02903" class="html-bibr">31</a>].</p> Full article ">
<p>(<b>a</b>) Schematic representation and (<b>b</b>) image of the obtained CNT/CNF buckypaper. (<b>c</b>) Schematic of the HGPE buckypaper preparation process and (<b>d</b>) photography of the HGPE buckypaper. (<b>e</b>) Schematic representation of the cell configuration and (<b>f</b>) photography of the flexible solid-state supercapacitor device. Schematic representation of the fabricated symmetric SC device assembled using 0.8-HGPE buckypaper and redox mediator: (<b>g</b>) carmine indigo, (<b>h</b>) methylene blue, (<b>i</b>) hydroquinone.</p> Full article ">Figure 2
<p>(<b>a</b>) Nyquist plot—inset shows the equivalent circuit; (<b>b</b>) GCD curves at J = 1 A g<sup>−1</sup>; (<b>c</b>) specific capacity of SCs based on HGPE electrolyte compared to the liquid electrolyte system at 1 A g<sup>−1</sup> (3.54 mA cm<sup>−2</sup>).</p> Full article ">Figure 3
<p>Cyclic voltammetry for cells constructed with (<b>a</b>) 0.8-HGPE—the inset shows the magnified cyclic voltammetry—and 0.8-HGPE containing (<b>b</b>) methylene blue, (<b>c</b>) hydroquinone, and (<b>d</b>) indigo carmine. The inset also shows the dependence of peak currents on the square root of the scan rate for both anodic and cathodic potentials. The anodic peak current is represented by empty squares, while the cathodic peak current is represented by filled squares.</p> Full article ">Figure 4
<p>Dual-redox-mediator solid-state SC: (<b>a</b>) schematic configuration; (<b>b</b>) GCD curves at different current densities, inset compares the system with 0.8-HGPE SC, at 1 A g<sup>−1</sup>; (<b>c</b>) cyclic voltammetry at different scan rates, inset compares the system with 0.8-HGPE SC, at 100 mV s<sup>−1</sup>; (<b>d</b>) specific capacity compared to 0.8-HGPE SC.</p> Full article ">Figure 5
<p>Dual-redox-mediator solid-state SC: (<b>a</b>) evolution of the potential of the electrodes at different current densities (red line, positive electrode (methylene blue redox mediator); blue line, negative electrode (indigo carmine redox mediator)); (<b>b</b>) cycling stability for 10,000 cycles at 2.5 A g<sup>−1</sup> (8.84 mA cm<sup>−2</sup>) and coulombic efficiency; (<b>c</b>) comparison of the potential evolution of the electrodes at the 1st and the 10,000th cycle. (<b>d</b>) Ragone plot of the dual-redox-mediator solid-state SC, compared with some previously published systems [<a href="#B19-polymers-16-02903" class="html-bibr">19</a>,<a href="#B25-polymers-16-02903" class="html-bibr">25</a>,<a href="#B26-polymers-16-02903" class="html-bibr">26</a>,<a href="#B27-polymers-16-02903" class="html-bibr">27</a>,<a href="#B28-polymers-16-02903" class="html-bibr">28</a>,<a href="#B29-polymers-16-02903" class="html-bibr">29</a>,<a href="#B30-polymers-16-02903" class="html-bibr">30</a>,<a href="#B31-polymers-16-02903" class="html-bibr">31</a>].</p> Full article ">
Open AccessArticle
Research on B4C/PEEK Composite Material Radiation Shielding
by
Hongxia Li, Hongping Guo, Hui Tu, Xiao Chen and Xianghua Zeng
Polymers 2024, 16(20), 2902; https://doi.org/10.3390/polym16202902 (registering DOI) - 15 Oct 2024
Abstract
There are various types of charged particles in the space environment, which can cause different types of radiation damage to materials and devices, leading to on-orbit failures and even accidents for spacecraft. Developing lightweight and efficient radiation-shielding materials is an effective approach to
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There are various types of charged particles in the space environment, which can cause different types of radiation damage to materials and devices, leading to on-orbit failures and even accidents for spacecraft. Developing lightweight and efficient radiation-shielding materials is an effective approach to improving the inherent protection of spacecraft. The protective performance of different materials against proton and electron spectra in the Earth’s radiation belts is evaluated using a Geant4 simulation. Based on the simulation results, suitable hardening components were selected to design composite materials, and B4C/PEEK composites with different B4C contents were successfully prepared. The experimental results demonstrate that the simulated and experimental results for the electron, proton and neutron shielding performance of the B4C/PEEK composites are consistent. These composites exhibit excellent radiation shielding capabilities against electrons, protons and neutrons, and the radiation protection performance improves with increasing B4C content in the B4C/PEEK composite materials.
Full article
(This article belongs to the Special Issue Advances in Functional Polymer Nanocomposites)
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Figure 1
<p>Differential cumulative flux spectra of LEO orbital protons protected by different materials and the same mass thickness: (<b>a</b>) differential cumulative flux spectra after different material and thickness protection; (<b>b</b>) proton protection effect of different materials with the same mass thickness.</p> Full article ">Figure 2
<p>Differential cumulative flux spectra of secondary neutrons and gamma rays after LEO orbital protons pass through protective layers of different thicknesses: (<b>a</b>) secondary neutrons; (<b>b</b>) <span class="html-italic">γ</span> rays.</p> Full article ">Figure 3
<p>The differential cumulative flux spectra of the second gamma of GEO orbital electrons through 2 mm protective layer of different materials.</p> Full article ">Figure 4
<p>Simulation calculation results of 1 MeV electron and 16 MeV proton protection rate of materials: (<b>a</b>) protective effect of different materials; (<b>b</b>) electronic protective effect of B<sub>4</sub>C/PEEK at different B<sub>4</sub>C addition levels; and (<b>c</b>) 16 MeV proton protective effect of B<sub>4</sub>C/PEEK at different B<sub>4</sub>C addition levels.</p> Full article ">Figure 5
<p>Preparation flow diagram of B<sub>4</sub>C/PEEK composite materials.</p> Full article ">Figure 6
<p>Distribution curves of film dose tablets along the thickness of B<sub>4</sub>C/PEEK under electron irradiation.</p> Full article ">Figure 7
<p>Proton transmittance of B<sub>4</sub>C/PEEK composites changes with energy: (<b>a</b>) 10 wt% B<sub>4</sub>C/PEEK, (<b>b</b>) 20 wt% B<sub>4</sub>C/PEEK.</p> Full article ">Figure 8
<p>Neutron protection curves of B<sub>4</sub>C/PEEK composite materials with different B<sub>4</sub>C addition amounts: (<b>a</b>) variation curves of neutron count and wavelength; (<b>b</b>) change curves of wavelength and protection effect.</p> Full article ">
<p>Differential cumulative flux spectra of LEO orbital protons protected by different materials and the same mass thickness: (<b>a</b>) differential cumulative flux spectra after different material and thickness protection; (<b>b</b>) proton protection effect of different materials with the same mass thickness.</p> Full article ">Figure 2
<p>Differential cumulative flux spectra of secondary neutrons and gamma rays after LEO orbital protons pass through protective layers of different thicknesses: (<b>a</b>) secondary neutrons; (<b>b</b>) <span class="html-italic">γ</span> rays.</p> Full article ">Figure 3
<p>The differential cumulative flux spectra of the second gamma of GEO orbital electrons through 2 mm protective layer of different materials.</p> Full article ">Figure 4
<p>Simulation calculation results of 1 MeV electron and 16 MeV proton protection rate of materials: (<b>a</b>) protective effect of different materials; (<b>b</b>) electronic protective effect of B<sub>4</sub>C/PEEK at different B<sub>4</sub>C addition levels; and (<b>c</b>) 16 MeV proton protective effect of B<sub>4</sub>C/PEEK at different B<sub>4</sub>C addition levels.</p> Full article ">Figure 5
<p>Preparation flow diagram of B<sub>4</sub>C/PEEK composite materials.</p> Full article ">Figure 6
<p>Distribution curves of film dose tablets along the thickness of B<sub>4</sub>C/PEEK under electron irradiation.</p> Full article ">Figure 7
<p>Proton transmittance of B<sub>4</sub>C/PEEK composites changes with energy: (<b>a</b>) 10 wt% B<sub>4</sub>C/PEEK, (<b>b</b>) 20 wt% B<sub>4</sub>C/PEEK.</p> Full article ">Figure 8
<p>Neutron protection curves of B<sub>4</sub>C/PEEK composite materials with different B<sub>4</sub>C addition amounts: (<b>a</b>) variation curves of neutron count and wavelength; (<b>b</b>) change curves of wavelength and protection effect.</p> Full article ">
Open AccessArticle
Dispersion of Hydrophilic Nanoparticles in Natural Rubber with Phospholipids
by
Jiramate Kitjanon, Nililla Nisoh, Saree Phongphanphanee, Nattaporn Chattham, Mikko Karttunen and Jirasak Wong-ekkabut
Polymers 2024, 16(20), 2901; https://doi.org/10.3390/polym16202901 (registering DOI) - 15 Oct 2024
Abstract
Coarse-grained molecular dynamics (CGMD) simulations were employed to investigate the effects of phospholipids on the aggregation of hydrophilic, modified carbon-nanoparticle fillers in cis-polyisoprene (cis-PI) composites. The MARTINI force field was applied to model dipalmitoylphosphatidylcholine (DPPC) lipids and hydrophilic modified fullerenes
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Coarse-grained molecular dynamics (CGMD) simulations were employed to investigate the effects of phospholipids on the aggregation of hydrophilic, modified carbon-nanoparticle fillers in cis-polyisoprene (cis-PI) composites. The MARTINI force field was applied to model dipalmitoylphosphatidylcholine (DPPC) lipids and hydrophilic modified fullerenes (HMFs). The simulations of DPPC in cis-PI composites show that the DPPC lipids self-assemble to form a reverse micelle in a rubber matrix. Moreover, HMF molecules readily aggregate into a cluster, in agreement with the previous studies. Interestingly, the mixture of the DPPC and HMF in the rubber matrix shows a cluster of HMF is encapsulated inside the DPPC reverse micelle. The HMF encapsulated micelles disperse well in the rubber matrix, and their sizes are dependent on the lipid concentration. Mechanical and thermal properties of the composites were analyzed by calculating the diffusion coefficients (D), bulk modulus (κ), and glass transition temperatures (Tg). The results suggest that DPPC acts as a plasticizer and enhances the flexibility of the HMF-DPPC rubber composites. These findings provide valuable insights into the design and process of high-performance rubber composites, offering improved mechanical and thermal properties for various applications.
Full article
(This article belongs to the Collection Feature Papers in Polymer Processing and Engineering)
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Graphical abstract
Graphical abstract
Full article ">Figure 1
<p>Mapping the atomistic model onto the CG model for <span class="html-italic">cis</span>-PI, DPPC, and HMF molecules: (<b>a</b>) DPPC model with CG bead type names Q0 (charged), Qa (charged), Na (nonpolar), and C1 (apolar) connected beads; (<b>b</b>) pristine fullerene and HMF with CG bead type names SQda (charged) interconnected beads; (<b>c</b>) rubber chain with atom type name C3 (apolar) connected to form a chain. Note that: the bead types Q0, Qa, Na, and C1 are adopted from the standard MARTINI force field [<a href="#B42-polymers-16-02901" class="html-bibr">42</a>].</p> Full article ">Figure 2
<p>Snapshots of (<b>a</b>) DPPC-<span class="html-italic">cis</span>-PI composites and (<b>b</b>) HMF-<span class="html-italic">cis</span>-PI composites. Cyan chain: <span class="html-italic">cis</span>-PI chain, cyan cylinders: lipid tail, dark yellow: phosphate group, pink: glycerol backbone, blue: choline group, and orange: HMF.</p> Full article ">Figure 3
<p>Snapshots of HMF-DPPC-<span class="html-italic">cis</span>-PI composites at DPPC concentrations of 5, 10, 20, and 30 phr. Cyan chain: <span class="html-italic">cis</span>-PI chain, cyan cylinders: lipid tail, dark yellow: phosphate group, pink: glycerol backbone, blue: choline group, and orange: HMF.</p> Full article ">Figure 4
<p>The average cluster size of HMF within DPPC-<span class="html-italic">cis</span>-PI composites as a function of lipid concentration.</p> Full article ">Figure 5
<p>(<b>a</b>) HMF-HMF radial distribution function (RDF) within the HMF-DPPC-<span class="html-italic">cis</span>-PI composites. (<b>b</b>) Snapshots of representative filler configurations corresponding to the specific numbers in figure (<b>a</b>). (<b>c</b>) Side view of Mackay’s icosahedron structure.</p> Full article ">Figure 6
<p>(<b>a</b>) Diffusion coefficients of <span class="html-italic">cis</span>-PI (black line) and HMF (red line). (<b>b</b>) Bulk modulus of HMF-DPPC-<span class="html-italic">cis</span>-PI composites as a function of DPPC concentration.</p> Full article ">Figure 7
<p>Glass transition temperature (<span class="html-italic">T<sub>g</sub></span>) of HMF-DPPC-<span class="html-italic">cis</span>-PI composites as a function of DPPC concentrations.</p> Full article ">
Full article ">Figure 1
<p>Mapping the atomistic model onto the CG model for <span class="html-italic">cis</span>-PI, DPPC, and HMF molecules: (<b>a</b>) DPPC model with CG bead type names Q0 (charged), Qa (charged), Na (nonpolar), and C1 (apolar) connected beads; (<b>b</b>) pristine fullerene and HMF with CG bead type names SQda (charged) interconnected beads; (<b>c</b>) rubber chain with atom type name C3 (apolar) connected to form a chain. Note that: the bead types Q0, Qa, Na, and C1 are adopted from the standard MARTINI force field [<a href="#B42-polymers-16-02901" class="html-bibr">42</a>].</p> Full article ">Figure 2
<p>Snapshots of (<b>a</b>) DPPC-<span class="html-italic">cis</span>-PI composites and (<b>b</b>) HMF-<span class="html-italic">cis</span>-PI composites. Cyan chain: <span class="html-italic">cis</span>-PI chain, cyan cylinders: lipid tail, dark yellow: phosphate group, pink: glycerol backbone, blue: choline group, and orange: HMF.</p> Full article ">Figure 3
<p>Snapshots of HMF-DPPC-<span class="html-italic">cis</span>-PI composites at DPPC concentrations of 5, 10, 20, and 30 phr. Cyan chain: <span class="html-italic">cis</span>-PI chain, cyan cylinders: lipid tail, dark yellow: phosphate group, pink: glycerol backbone, blue: choline group, and orange: HMF.</p> Full article ">Figure 4
<p>The average cluster size of HMF within DPPC-<span class="html-italic">cis</span>-PI composites as a function of lipid concentration.</p> Full article ">Figure 5
<p>(<b>a</b>) HMF-HMF radial distribution function (RDF) within the HMF-DPPC-<span class="html-italic">cis</span>-PI composites. (<b>b</b>) Snapshots of representative filler configurations corresponding to the specific numbers in figure (<b>a</b>). (<b>c</b>) Side view of Mackay’s icosahedron structure.</p> Full article ">Figure 6
<p>(<b>a</b>) Diffusion coefficients of <span class="html-italic">cis</span>-PI (black line) and HMF (red line). (<b>b</b>) Bulk modulus of HMF-DPPC-<span class="html-italic">cis</span>-PI composites as a function of DPPC concentration.</p> Full article ">Figure 7
<p>Glass transition temperature (<span class="html-italic">T<sub>g</sub></span>) of HMF-DPPC-<span class="html-italic">cis</span>-PI composites as a function of DPPC concentrations.</p> Full article ">
Open AccessArticle
A Highly CO2-Sensitive Wood-Based Smart Tag for Strawberry Freshness Monitoring
by
Jin Xu, Yuping Ning, Yalu Yun, Xiling Cheng, Jian Li and Lijuan Wang
Polymers 2024, 16(20), 2900; https://doi.org/10.3390/polym16202900 (registering DOI) - 15 Oct 2024
Abstract
Smart tags are used for monitoring the freshness of foods. However, they often lack significant color changes, and their accuracy needs to be improved. In this study, a poplar veneer with a natural pore structure was selected as a matrix to prepare a
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Smart tags are used for monitoring the freshness of foods. However, they often lack significant color changes, and their accuracy needs to be improved. In this study, a poplar veneer with a natural pore structure was selected as a matrix to prepare a smart tag with high pH sensitivity for tracking the freshness of strawberries. The delignified veneer was modified using 2,3-epoxypropyltrimethylammonium chloride (EPTAC) to be given positive charges to adsorb bromothymol blue (BTB) through electrostatic interactions. The adsorption capacity of the veneer reached 7.0 mg/g at 50 °C for 4 h, and the veneer showed an obvious blue color. The smart tags exhibited distinct color changes at different pHs and showed quick color changes in response to acetic acid. As the freshness of strawberries decreased, the color of the smart tags changed from blue to yellow-green, which indicated that the accuracy was high. In this study, an effective method was fabricated to prepare a highly sensitive tag, promoting popular application to ensure food quality.
Full article
(This article belongs to the Special Issue Cellulose and Cellulose Micro/Nanomaterials: Recent Research and Applications)
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Figure 1
<p>A mechanistic diagram of the preparation process and microstructure of the smart tag.</p> Full article ">Figure 2
<p>FTIR spectra (portion) (<b>a</b>) and XRD patterns (<b>b</b>) of PV, DWV, CWV, and smart tag.</p> Full article ">Figure 3
<p>Full spectra of XPS for DWV and CWV (<b>a</b>); high-resolution XPS spectrum of N1s in CWV (<b>b</b>).</p> Full article ">Figure 4
<p>SEM images of PV (<b>a</b>), DWV (<b>b</b>), CWV (<b>c</b>), and the smart tag (<b>d</b>).</p> Full article ">Figure 5
<p>Porosity of PV and DWV, and pore growth rate (P<sub>i</sub>) of DWV (<b>a</b>); XRD of wood veneers with different delignification times (<b>b</b>).</p> Full article ">Figure 6
<p>Color optical fiber spectra and photographs of PV, DWV, CWV, and the smart tag (BT<sub>50-4</sub>).</p> Full article ">Figure 7
<p>Dryer device (<b>a</b>); moisture absorption rate of smart tags at 11%, 43%, and 75% relative humidity (<b>b</b>).</p> Full article ">Figure 8
<p>Color changes (<b>a</b>) and UV spectra (<b>b</b>) of BTB under different pH buffer solutions; structural changes in bromothymol blue in alkaline and acidic solutions (<b>c</b>).</p> Full article ">Figure 9
<p>Acetic acid response device (<b>a</b>); color changes in smart tags in acetic acid environment with relative humidity of 11%, 43%, and 75% (<b>b</b>).</p> Full article ">Figure 10
<p>A schematic diagram of the color of the smart tag and the status of the strawberry during storage (T<sub>0</sub>–T<sub>4</sub> stand for storage time (h)).</p> Full article ">
<p>A mechanistic diagram of the preparation process and microstructure of the smart tag.</p> Full article ">Figure 2
<p>FTIR spectra (portion) (<b>a</b>) and XRD patterns (<b>b</b>) of PV, DWV, CWV, and smart tag.</p> Full article ">Figure 3
<p>Full spectra of XPS for DWV and CWV (<b>a</b>); high-resolution XPS spectrum of N1s in CWV (<b>b</b>).</p> Full article ">Figure 4
<p>SEM images of PV (<b>a</b>), DWV (<b>b</b>), CWV (<b>c</b>), and the smart tag (<b>d</b>).</p> Full article ">Figure 5
<p>Porosity of PV and DWV, and pore growth rate (P<sub>i</sub>) of DWV (<b>a</b>); XRD of wood veneers with different delignification times (<b>b</b>).</p> Full article ">Figure 6
<p>Color optical fiber spectra and photographs of PV, DWV, CWV, and the smart tag (BT<sub>50-4</sub>).</p> Full article ">Figure 7
<p>Dryer device (<b>a</b>); moisture absorption rate of smart tags at 11%, 43%, and 75% relative humidity (<b>b</b>).</p> Full article ">Figure 8
<p>Color changes (<b>a</b>) and UV spectra (<b>b</b>) of BTB under different pH buffer solutions; structural changes in bromothymol blue in alkaline and acidic solutions (<b>c</b>).</p> Full article ">Figure 9
<p>Acetic acid response device (<b>a</b>); color changes in smart tags in acetic acid environment with relative humidity of 11%, 43%, and 75% (<b>b</b>).</p> Full article ">Figure 10
<p>A schematic diagram of the color of the smart tag and the status of the strawberry during storage (T<sub>0</sub>–T<sub>4</sub> stand for storage time (h)).</p> Full article ">
Open AccessArticle
Preparation and Characterization of Glucose-Based Self-Blowing Non-Isocyanate Polyurethane (NIPU) Foams with Different Acid Catalysts
by
Tianjiao Yang, Antonio Pizzi, Xuedong Xi, Xiaojian Zhou and Qianyu Zhang
Polymers 2024, 16(20), 2899; https://doi.org/10.3390/polym16202899 (registering DOI) - 15 Oct 2024
Abstract
The preparation and application of non-isocyanate polyurethane (NIPU) from biomass raw materials as a substitute for traditional polyurethane (PU) has recently become a research hot topic as it avoids the toxicity and moisture sensitivity of isocyanate-based PU. In the work presented here, self-blowing
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The preparation and application of non-isocyanate polyurethane (NIPU) from biomass raw materials as a substitute for traditional polyurethane (PU) has recently become a research hot topic as it avoids the toxicity and moisture sensitivity of isocyanate-based PU. In the work presented here, self-blowing GNIPU non-isocyanate polyurethane (NIPU) rigid foams were prepared at room temperature, based on glucose, with acids as catalysts and glutaraldehyde as a cross-linker. The effects of different acids and glutaraldehyde addition on foam morphology and properties were investigated. The water absorption, compressive resistance, fire resistance, and limiting oxygen index (LOI) were tested to evaluate the relevant properties of the foams, and scanning electron microscopy (SEM) was used to observe the foams’ cell structure. The results show that all these foams have a similar apparent density, while their 24 h water absorption is different. The foam prepared with phosphoric acid as a catalyst presented a better compressive strength compared to the other types prepared with different catalysts when above 65% compression. It also presents the best fire resistance with an LOI value of 24.3% (great than 22%), indicating that it possesses a good level of flame retardancy. Thermogravimetric analysis also showed that phosphoric acid catalysis slightly improved the GNIPU foams’ thermal stability. This is mainly due to the flame-retardant effect of the phosphate ion. In addition, scanning electron microscopy (SEM) results showed that all the GNIPU foams exhibited similar open-cell morphologies with the cell pore sizes mainly distributed in the 200–250 μm range.
Full article
(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Sustainable and Recyclable Polymers)
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<p>Photograph of GNIPU foams.</p> Full article ">Figure 2
<p>The main reactions leading to a cross-linked network in the foams.</p> Full article ">Figure 3
<p>Water absorption (24 h) of GNIPU foams (F1, F2, F3, and F4).</p> Full article ">Figure 4
<p>Water absorption (24 h) of GNIPU foams (F3, F5, and F6).</p> Full article ">Figure 5
<p>Effects of different initiators on compression performance of GNIPU foams.</p> Full article ">Figure 6
<p>Effect of different additions of glutaraldehyde on compression properties of GNIPU foams.</p> Full article ">Figure 7
<p>Photographic record of ignition experiments.</p> Full article ">Figure 8
<p>LOI of foams F1, F2, F3, F4, F5, and F6.</p> Full article ">Figure 9
<p>TG (<b>a</b>) and DTG (<b>b</b>) curves of GNIPU foams (F1, F2, F3, and F4).</p> Full article ">Figure 10
<p>FT-IR spectra of GNIPU and foams (F1, F2, F3, and F4).</p> Full article ">Figure 11
<p>SEM pictures of GNIPU foams.</p> Full article ">Figure 12
<p>Cell size distributions of GNIPU foams. Gaussian cell size distribution curve indicated in red.</p> Full article ">
<p>Photograph of GNIPU foams.</p> Full article ">Figure 2
<p>The main reactions leading to a cross-linked network in the foams.</p> Full article ">Figure 3
<p>Water absorption (24 h) of GNIPU foams (F1, F2, F3, and F4).</p> Full article ">Figure 4
<p>Water absorption (24 h) of GNIPU foams (F3, F5, and F6).</p> Full article ">Figure 5
<p>Effects of different initiators on compression performance of GNIPU foams.</p> Full article ">Figure 6
<p>Effect of different additions of glutaraldehyde on compression properties of GNIPU foams.</p> Full article ">Figure 7
<p>Photographic record of ignition experiments.</p> Full article ">Figure 8
<p>LOI of foams F1, F2, F3, F4, F5, and F6.</p> Full article ">Figure 9
<p>TG (<b>a</b>) and DTG (<b>b</b>) curves of GNIPU foams (F1, F2, F3, and F4).</p> Full article ">Figure 10
<p>FT-IR spectra of GNIPU and foams (F1, F2, F3, and F4).</p> Full article ">Figure 11
<p>SEM pictures of GNIPU foams.</p> Full article ">Figure 12
<p>Cell size distributions of GNIPU foams. Gaussian cell size distribution curve indicated in red.</p> Full article ">
Open AccessArticle
Compositional Analysis and Mechanical Recycling of Polymer Fractions Recovered via the Industrial Sorting of Post-Consumer Plastic Waste: A Case Study toward the Implementation of Artificial Intelligence Databases
by
Federico Olivieri, Antonino Caputo, Daniele Leonetti, Rachele Castaldo, Roberto Avolio, Mariacristina Cocca, Maria Emanuela Errico, Luigi Iannotta, Maurizio Avella, Cosimo Carfagna and Gennaro Gentile
Polymers 2024, 16(20), 2898; https://doi.org/10.3390/polym16202898 (registering DOI) - 15 Oct 2024
Abstract
Nowadays, society is oriented toward reducing the production of plastics, which have a significant impact on the environment. In this context, the recycling of existing plastic objects is currently a fundamental step in the mitigation of pollution. Very recently, the outstanding development of
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Nowadays, society is oriented toward reducing the production of plastics, which have a significant impact on the environment. In this context, the recycling of existing plastic objects is currently a fundamental step in the mitigation of pollution. Very recently, the outstanding development of artificial intelligence (AI) has concerned and continues to involve a large part of the industrial and informatics sectors. The opportunity to implement big data in the frame of recycling processes is oriented toward the improvement and the optimization of the reproduction of plastic objects, possibly with enhanced properties and durability. Here, a deep cataloguing, characterization and recycling of plastic wastes provided by an industrial sorting plant was performed. The potential improvement of the mechanical properties of the recycled polymers was assessed by the addition of coupling agents. On these bases, a classification system based on the collected results of the recycled materials’ properties was developed, with the aim of laying the groundwork for the improvement of AI databases and helpfully supporting industrial recycling processes.
Full article
(This article belongs to the Special Issue Sustainable Polymers: Design, Synthesis and Recycling)
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Open AccessArticle
The Absence of Phasins PhbP2 and PhbP3 in Azotobacter vinelandii Determines the Growth and Poly-3-hydroxybutyrate Synthesis
by
Claudia Aguirre-Zapata, Daniel Segura, Jessica Ruiz, Enrique Galindo, Andrés Pérez, Alvaro Díaz-Barrera and Carlos Peña
Polymers 2024, 16(20), 2897; https://doi.org/10.3390/polym16202897 (registering DOI) - 15 Oct 2024
Abstract
Phasins are proteins located on the surface of poly-3-hydroxybutyrate (P3HB) granules that affect the metabolism of the polymer, the size and number of the granules, and some also have stress-protecting and growth-promoting effects. This study evaluated the effect of inactivating two new phasins
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Phasins are proteins located on the surface of poly-3-hydroxybutyrate (P3HB) granules that affect the metabolism of the polymer, the size and number of the granules, and some also have stress-protecting and growth-promoting effects. This study evaluated the effect of inactivating two new phasins (PhbP2 or PhbP3) on the cellular growth, production, and molecular mass of P3HB in cultures under low or high oxygen transfer rates (OTR). The results revealed that under high OTRₘₐₓ conditions (between 8.1 and 8.9 mmol L−1 h−1), the absence of phasins PhbP2 and PhbP3 resulted in a strong negative effect on the growth rate; in contrast, the rates of specific oxygen consumption increased in both cases. This behavior was not observed under a low oxygen transfer rate (3.9 ± 0.71 mol L−1 h−1), where cellular growth and oxygen consumption were the same for the different strains evaluated. It was observed that at high OTR, the absence of PhbP3 affected the production of P3HB, decreasing it by 30% at the end of cultivation. In contrast, the molecular weight remained constant over time. In summary, the absence of phasin PhbP3 significantly impacted the growth rate and polymer synthesis, particularly at high maximum oxygen transfer rates (OTRₘₐₓ).
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(This article belongs to the Special Issue Biopolymers and Biodegradable Polymers: Synthesis, Properties, Application and Degradation Behavior)
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<p>Bacterial growth kinetics (<b>a</b>), OTR evolution (<b>b</b>), sucrose (<b>c</b>) and qO<sub>2</sub> evolution (<b>d</b>) for the strains cultured at 500 rpm.</p> Full article ">Figure 2
<p>Bacterial growth kinetics (<b>a</b>), OTR evolution (<b>b</b>), sucrose (<b>c</b>) and qO<sub>2</sub> evolution (<b>d</b>) for the strains cultured at 300 rpm.</p> Full article ">Figure 3
<p>Evolution of the P3HB production (<b>a</b>,<b>b</b>) and intracellular accumulation (<b>c</b>,<b>d</b>) in cultures of three strains of <span class="html-italic">A. vinelandii</span> at different agitation rates (500 and 300 rpm). OP strain (black circles), OP-PhbP2<sup>−</sup> (white circles) and OP-PhbP3<sup>−</sup> strain (black triangles).</p> Full article ">Figure 4
<p>Mean molecular mass (MMM) of P3HB produced for the different strains evaluated in cultures of <span class="html-italic">A. vinelandii</span> developed at 500 rpm.</p> Full article ">Figure 5
<p>Distribution of molecular mass of P3HB produced by the OP (<b>a</b>), OP-PhbP2<sup>−</sup> (<b>b</b>), and OP-PhbP3<sup>−</sup> (<b>c</b>) strains in cultures performed at 500 rpm.</p> Full article ">
<p>Bacterial growth kinetics (<b>a</b>), OTR evolution (<b>b</b>), sucrose (<b>c</b>) and qO<sub>2</sub> evolution (<b>d</b>) for the strains cultured at 500 rpm.</p> Full article ">Figure 2
<p>Bacterial growth kinetics (<b>a</b>), OTR evolution (<b>b</b>), sucrose (<b>c</b>) and qO<sub>2</sub> evolution (<b>d</b>) for the strains cultured at 300 rpm.</p> Full article ">Figure 3
<p>Evolution of the P3HB production (<b>a</b>,<b>b</b>) and intracellular accumulation (<b>c</b>,<b>d</b>) in cultures of three strains of <span class="html-italic">A. vinelandii</span> at different agitation rates (500 and 300 rpm). OP strain (black circles), OP-PhbP2<sup>−</sup> (white circles) and OP-PhbP3<sup>−</sup> strain (black triangles).</p> Full article ">Figure 4
<p>Mean molecular mass (MMM) of P3HB produced for the different strains evaluated in cultures of <span class="html-italic">A. vinelandii</span> developed at 500 rpm.</p> Full article ">Figure 5
<p>Distribution of molecular mass of P3HB produced by the OP (<b>a</b>), OP-PhbP2<sup>−</sup> (<b>b</b>), and OP-PhbP3<sup>−</sup> (<b>c</b>) strains in cultures performed at 500 rpm.</p> Full article ">
Open AccessArticle
Laser Sintering by Spot and Linear Optics for Inkjet-Printed Thin-Film Conductive Silver Patterns with the Focus on Ink-Sets and Process Parameters
by
Dana Mitra, Kalyan Yoti Mitra, Georg Buchecker, Alexander Görk, Maxim Mousto, Thomas Franzl and Ralf Zichner
Polymers 2024, 16(20), 2896; https://doi.org/10.3390/polym16202896 (registering DOI) - 14 Oct 2024
Abstract
The implementation of the laser sintering for inkjet-printed nanoparticles and metal organic decomposition (MOD) inks on a flexible polymeric film has been analyzed in detail. A novel approach by implementing, next to a commonly 3.2 mm diameter spot laser optic, a line laser
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The implementation of the laser sintering for inkjet-printed nanoparticles and metal organic decomposition (MOD) inks on a flexible polymeric film has been analyzed in detail. A novel approach by implementing, next to a commonly 3.2 mm diameter spot laser optic, a line laser optic with a laser beam area of 2 mm × 80 mm, demonstrates the high potential of selective laser sintering to proceed towards a fast and efficient sintering methodology in printed electronics. In this work, a multiplicity of laser parameters, primary the laser speed and the laser power, have been altered systematically to identify an optimal process window for each ink and to convert the dried and non-conductive patterns into conductive and functional silver structures. For each ink, as well as for the two laser optics, a suitable laser parameter set has been found, where a conductivity without any damage to the substrate or silver layer could be achieved. In doing so, the margin of the laser speed for both optics is ranging in between 50 mm/s and 100 mm/s, which is compatible with common inkjet printing speeds and facilitates an in-line laser sintering approach. Considering the laser power, the typical parameter range for the spot laser lays in between 10 W and 50 W, whereas for the line optics the full laser power of 200 W had to be applied. One of the nanoparticle silver inks exhibits, especially for the line laser optic, a conductivity of up to 2.22 × 107 S‧m−1, corresponding to 36% of bulk silver within a few seconds of sintering duration. Both laser sintering approaches together present a remarkable facility to use the laser either as a digital tool for sintering of defined areas by means of a spot beam or to efficiently sinter larger areas by means of a line beam. With this, the utilization of a laser sintering methodology was successfully validated as a promising approach for converting a variety of inkjet-printed silver patterns on a flexible polymeric substrate into functionalized conductive silver layers for applications in the field of printed electronics.
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(This article belongs to the Special Issue Polymer Thin Films and Their Applications)
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<p>Overview of the laser-sintering setup and procedure: (<b>a</b>) photographs of the installed laser module and X-Y-table graphical illustration for the laser-sintering routine with (<b>b</b>) a spot-laser and (<b>c</b>) a line-laser.</p> Full article ">Figure 2
<p>Photographs and microscopic images of the ink Ag-NP1 that is printed and sintered with laser parameters (power and sintering speed): (<b>a</b>) 8 W and 50 mm/s; (<b>b</b>) 10 W and 50 mm/s, and (<b>c</b>) 12 W and 50 mm/s.</p> Full article ">Figure 3
<p>Photographs and microscopic images of the ink Ag-NP2 that is printed and sintered with laser parameters (power and sintering speed): (<b>a</b>) 26 W and 50 mm/s; (<b>b</b>) 26 W and 75 mm/s, and (<b>c</b>) 26 W and 100 mm/s.</p> Full article ">Figure 4
<p>Photographs and microscopic images of the ink Ag-MOD that is printed and sintered with laser parameters (power and sintering speed): (<b>a</b>) 18 W and 50 mm/s; (<b>b</b>) 20 W and 75 mm/s; and (<b>c</b>) 20 W and 100 mm/s.</p> Full article ">Figure 5
<p>Photographs and microscopic images of all three printed inks sintered with the line laser at 200 W with corresponding ink type and sintering speed of: (<b>a</b>) Ag-NP1 #8 at 10 mm/s; (<b>b</b>) Ag-NP1 #9 at 20 mm/s; (<b>c</b>) Ag-NP2 #9 at 40 mm/s; (<b>d</b>) Ag-NP2 #10 at 50 mm/s; (<b>e</b>) Ag-MOD #14 at 10 mm/s; and (<b>f</b>) Ag-MOD #16 at 20 mm/s.</p> Full article ">Figure 6
<p>Graph showing parameter set for the line laser sintering and results of measured sheet resistance of Ag-NP1, Ag-NP2, and Ag-MOD.</p> Full article ">Figure 7
<p>Scanning electron microscopic (SEM) images of selected images for the spot- and the line laser sintering for the three inks, respectively.</p> Full article ">Figure 8
<p>Photographs and corresponding measurements of the sheet resistance for the selected large area laser sintering.</p> Full article ">
<p>Overview of the laser-sintering setup and procedure: (<b>a</b>) photographs of the installed laser module and X-Y-table graphical illustration for the laser-sintering routine with (<b>b</b>) a spot-laser and (<b>c</b>) a line-laser.</p> Full article ">Figure 2
<p>Photographs and microscopic images of the ink Ag-NP1 that is printed and sintered with laser parameters (power and sintering speed): (<b>a</b>) 8 W and 50 mm/s; (<b>b</b>) 10 W and 50 mm/s, and (<b>c</b>) 12 W and 50 mm/s.</p> Full article ">Figure 3
<p>Photographs and microscopic images of the ink Ag-NP2 that is printed and sintered with laser parameters (power and sintering speed): (<b>a</b>) 26 W and 50 mm/s; (<b>b</b>) 26 W and 75 mm/s, and (<b>c</b>) 26 W and 100 mm/s.</p> Full article ">Figure 4
<p>Photographs and microscopic images of the ink Ag-MOD that is printed and sintered with laser parameters (power and sintering speed): (<b>a</b>) 18 W and 50 mm/s; (<b>b</b>) 20 W and 75 mm/s; and (<b>c</b>) 20 W and 100 mm/s.</p> Full article ">Figure 5
<p>Photographs and microscopic images of all three printed inks sintered with the line laser at 200 W with corresponding ink type and sintering speed of: (<b>a</b>) Ag-NP1 #8 at 10 mm/s; (<b>b</b>) Ag-NP1 #9 at 20 mm/s; (<b>c</b>) Ag-NP2 #9 at 40 mm/s; (<b>d</b>) Ag-NP2 #10 at 50 mm/s; (<b>e</b>) Ag-MOD #14 at 10 mm/s; and (<b>f</b>) Ag-MOD #16 at 20 mm/s.</p> Full article ">Figure 6
<p>Graph showing parameter set for the line laser sintering and results of measured sheet resistance of Ag-NP1, Ag-NP2, and Ag-MOD.</p> Full article ">Figure 7
<p>Scanning electron microscopic (SEM) images of selected images for the spot- and the line laser sintering for the three inks, respectively.</p> Full article ">Figure 8
<p>Photographs and corresponding measurements of the sheet resistance for the selected large area laser sintering.</p> Full article ">
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