Influence of Network Structure on Glass Transition Temperature of Elastomers
<p>Performance of an elastomer under loading force and after its removal: (<b>a</b>) plastic deformation of an uncrosslinked elastomer; and (<b>b</b>) elastic recovery of a crosslinked elastomer.</p> "> Figure 2
<p>Structures formed as a result of curing intermolecular crosslinks: (<b>a</b>) carbon-carbon crosslinks; (<b>b</b>) sulfidic crosslinks, intramolecular modifications of the polymer chains: (<b>c</b>) cyclic sulfur structures; and (<b>d</b>) pendant groups.</p> "> Figure 3
<p>Crosslink density and crosslink structures formed during the curing process with use of various curatives. The columns in each series correspond to the samples with an increasing amount of curatives, as listed in <a href="#materials-09-00607-t002" class="html-table">Table 2</a>.</p> "> Figure 4
<p>“Static” <span class="html-italic">T</span><sub>g</sub> as a function of crosslink density for the uncrosslinked reference and all cured series of samples.</p> "> Figure 5
<p>Tan delta as a function of temperature for the uncrosslinked reference and the DPG/S<sub>8</sub> cured series of samples.</p> "> Figure 6
<p>“Dynamic” <span class="html-italic">T</span><sub>g</sub>, determined by a maximum of the tan delta peak, as a function of the crosslink density for the uncrosslinked reference and all cured series of samples.</p> "> Figure 7
<p>“Dynamic” <span class="html-italic">T</span><sub>g</sub>, determined by a maximum of <span class="html-italic">E</span>’’, as a function of crosslink density for the uncrosslinked reference and all cured series of samples.</p> "> Figure 8
<p>Height of tan delta peak as a function of crosslink density for the uncrosslinked reference and all cured series of samples.</p> "> Figure 9
<p>Width of tan delta peak in the half of height, as a function of crosslink density for the uncrosslinked reference and all cured series of samples.</p> "> Figure 10
<p>Dependence between height of tan delta at 70 °C and the crosslink density for the uncrosslinked reference and all cured series of samples.</p> "> Figure 11
<p>Density of samples as a function of crosslink density for the uncrosslinked reference and all cured series of samples.</p> "> Figure 12
<p>Size of free volumes as a function of crosslink density for the uncrosslinked reference and all cured series of samples.</p> ">
Abstract
:1. Introduction
2. Experimental
2.1. Materials
2.2. Sample Preparation
2.2.1. Mixing
2.2.2. Curing
2.3. Extraction with Acetone
2.4. Crosslink Density Analysis
- ν—crosslink density per unit volume (mol/cm3);
- Vr—volume fraction of rubber in a swollen sample (-);
- V0—solvent molar volume (for toluene: V0 = 106.9 cm3/mol);
- f—functionality of crosslinks (f = 4, assuming the formation of tetra-functional crosslinks);
- χ—Flory-Huggins rubber-solvent interaction parameter (for investigated SBR-toluene system: χ = 0.378 [14]).
2.5. Crosslink Structure Analysis
2.6. Buoyancy Method
2.7. Differential Scanning Calorimetry (DSC)
2.8. Dynamic Mechanical Analysis (DMA)
2.9. Positron Annihilation Lifetime Spectroscopy (PALS)
3. Results and Discussion
3.1. Crosslink Density and Crosslink Structures
3.2. Effect of Curing on the Glass Transition Temperature
3.2.1. Glass Transition Temperature Determined by Differential Scanning Calorimetry
3.2.2. Glass Transition Process Monitored by Dynamic Mechanical Analysis
3.3. Effect of Curing on the Molecular Structure and Packing of the Polymer Chains
3.3.1. Density Determined by Buoyancy Method
3.3.2. Free Volume Size Determined by Positron Annihilation Lifetime Spectroscopy
4. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Name (Purity; Producer) | Structural Formula | Molecular Formula, Molecular Weight (g/mol) |
---|---|---|
MBTS 2,2’-dibenzothiazyl disulfide (94%; Arlanxeo, Maastricht, The Netherlands) | C14H8N2S4 332.49 | |
DPG 1,3-diphenylguanidine (97%; Arlanxeo, Maastricht, The Netherlands) | C13H13N3 211.26 | |
CBS N-cyclohexyl-1-benzothiazyl sulfenamide (95%; Arlanxeo, Maastricht, The Netherlands) | C13H16N2S2 264.41 | |
TMTD Tetramethylthiuram disulfide (96%; Arlanxeo, Maastricht, The Netherlands) | C6H12N2S4 240.43 | |
TBzTD Tetrabenzylthiuram disulfide (70%; Shandong Yanggu Huatai Chemical, Yanggu, China) | C30H28N2S4 544.82 | |
Vulcuren® 1,6-bis(N,N′-dibenzylthio-carbamoyl-dithio)-hexane (87%; Arlanxeo, Maastricht, The Netherlands) | C36H40N2S6 693.11 | |
ZDT 2-ethylhexyl zinc dithio-phosphate [13] (50%; Arlanxeo, Maastricht, The Netherlands) | C32H68O4P2S4Zn 772.47 | |
DCP Dicumyl peroxide (98%; Merck Schuchardt, Hohenbrunn, Germany) | C18H22O2 270.37 | |
S8 Rhombic sulfur (99.9%; Siarkopol Tarnobrzeg, Tarnobrzeg, Poland) | S8 256.52 |
Sample Name | Amount of Curatives Added (phr) | |||||
---|---|---|---|---|---|---|
Ref. | 0.0 | |||||
DCP | 0.35 | 0.60 | 0.75 | 1.20 | 2.20 | - |
TMTD | 1.5 | 3.0 | 4.5 | 5.5 | 7.0 | 10.0 |
TBzTD | 2.5 | 5.0 | 8.0 | 11.0 | 15.0 | 22.0 |
Vulcuren® | 3.0 | 5.0 | 7.0 | 9.0 | 11.0 | 18.0 |
S8 | 1.0 | 2.0 | 3.5 | 4.2 | 5.0 | 6.5 |
DPG/S8 | 1.5/1.5 | 2.0/2.0 | 2.5/2.5 | 3.0/3.0 | 3.6/3.6 | 4.1/4.1 |
CBS/S8 | 0.7/0.7 | 1.2/1.2 | 1.8/1.8 | 2.4/2.4 | 3.0/3.0 | 3.4/3.4 |
MBTS/S8 | 0.8/0.8 | 1.5/1.5 | 2.0/2.0 | 3.0/3.0 | 4.0/4.0 | 4.4/4.4 |
ZDT/S8 | 1.5/1.5 | 2.2/2.2 | 3.0/3.0 | 5.0/5.0 | 6.5/6.5 | - |
Sample Name | Ratio (-) |
---|---|
DPG/S8 | 1.18 |
CBS/S8 | 0.92 |
MBTS/S8 | 0.73 |
ZDT/S8 | 0.17 |
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Bandzierz, K.; Reuvekamp, L.; Dryzek, J.; Dierkes, W.; Blume, A.; Bielinski, D. Influence of Network Structure on Glass Transition Temperature of Elastomers. Materials 2016, 9, 607. https://doi.org/10.3390/ma9070607
Bandzierz K, Reuvekamp L, Dryzek J, Dierkes W, Blume A, Bielinski D. Influence of Network Structure on Glass Transition Temperature of Elastomers. Materials. 2016; 9(7):607. https://doi.org/10.3390/ma9070607
Chicago/Turabian StyleBandzierz, Katarzyna, Louis Reuvekamp, Jerzy Dryzek, Wilma Dierkes, Anke Blume, and Dariusz Bielinski. 2016. "Influence of Network Structure on Glass Transition Temperature of Elastomers" Materials 9, no. 7: 607. https://doi.org/10.3390/ma9070607