Akshay Kakar

In this research, the mechanical, acoustical, thermal, morphological, and infrared spectral properties of untreated, heat and alkaline-treated sisal fiber-reinforced poly-lactic-acid bio-composites were analyzed. The bio-composite samples were fabricated using a hot press molding machine. The properties mentioned above were evaluated and compared with heat-treated and alkaline-treated sisal fibers. Composites with heat-treated sisal fibers were found to exhibit the best mechanical properties. Thermo-gravimetric analysis (TGA) was conducted to study the thermal degradation of the bio-composite samples. It was discovered that the PLA-sisal composites with optimal heat-treated at 160°C and alkaline-treated fibers possess good thermal stability as compared with untreated fiber. The results indicated that the composites prepared with 30wt % of sisal had the highest sound absorption as compared with other composites. Evidence of the successful reaction of sodium hydroxide and heat treatment of the sisal fibers was provided by the infrared spectrum and implied by decreased bands at certain wavenumbers. Observations based on scanning electron microscopy of the fracture surface of the composites showed the effect of alkaline and heat treatment on the fiber surface and improved fiber-matrix adhesion

O-MMT treated unsaturated polyester based hybrid composites were prepared using keratin fiber obtained from chicken feathers. Fibers of similar dimension were selected to fabricate composites through hand lay-up method. The preparation and dimensional stability properties of keratin fiber as reinforcements in composites is outlined in this paper. Varying O-MMT contents in nancomposites is performed to investigate the effects on the dimensional stability (water absorption and thickness swelling) of the composites. Results indicated that increasing fiber content deteriorates dimensional stability of the composites and composites. However, improvements in dimensional stability of the keratin fibercomposites were observed with O-MMT. O-MMT treatment reduces the water absorption and thickness swelling, especially at 5wt% of O-MMT concentrationat all range of fiber content. At 5wt% concentration of O-MMt, 10wt% keratin fiber content marks the lowest water absorption and thickness swelling with rate of 0.65% and 1.93%, respectively. Adopting 10wt% of keratin fiber at 5wt% of O-MMT can be utilized for application requiring high dimensional stability.

Biopolymer composites for tensile testing were fabricated according to the American Society for Testing Materials, ASTM D638-10, using poly lactic acid (PLA) as the matrix material and varying volume percentage of heat treated and untreated luffa fiber as the reinforcement material. To achieve the composite materials with the highest tensile strength, optimization of the use of hot press machine for fabrication of composite specimens was given high importance. While optimizing the use of hot press machine, various parameters were considered. These parameters included processing temperature, processing time and cooling time. Combinations of varying magnitudes of these parameters were used to find the optimum processing method. The optimized method was then used to produce PLA – luffa composites. The fiber – matrix interface adhesion was studied using scanning electron microscope (SEM). The results show that composites made with heat treated fibers have higher tensile strength and better interfacial adhesion when compared with the tensile strength of composites made with untreated fiber.  Heat treated fibers showed a remarkable improvement in the tensile strength of the biocomposites, which may be used for a variety of applications in the orthopedic field.

This research was carried out to evaluate how alkali treatment of selected natural fibres (kenaf, luffa, betel nut, banana and rice straw) influences thermal properties, morphological properties and infrared spectrum properties of the composites made from
polypropylene reinforced with natural fibres. Composites were made by compression moulding technique using hydraulic hot press. Composites were characterized by thermo-gravimetric analysis (TGA) to establish their thermal stability. The infrared
spectrum of both treated and untreated natural fibres/PP composites were studied using Fourier transforms infrared spectrometer (FTIR). Infrared spectroscopy is sensitive to the presence of chemical functional groups in the composites. A functional group is a structural fragment within a molecule. Scanning electron microscopy (SEM) was used to investigate the morphology of composites. Increase in the thermal stability and better fibre-matrix compatibility of the composites were noticed in the treated fibres. Thermal stability of all the reinforced natural fibres was found to be around 205oC.
Decomposition of both cellulose and hemicellulose in the fibres took place at 310oC and above, whereas the degradation of reinforced fibre composites took place above 430oC. After the chemical treatment, the FTIR results showed the reduction of OH bonds for all natural fibre composites used in this study. Mercerization had successfully modified the structure of natural fibres and these modifications improved the thermal stability of the composites by promoting better fibre-matrix bonding.

This review paper explores the potential of commercial production and application of Acacia wood—polylactic acid (PLA), and Acacia wood—polyhydroxyalkanoates (PHA) bio-composites. The factors affecting the mechanical and physical properties of these materials were identified and deliberated. It was found that Acacia wood has the prospective to be efficiently produced and used in Borneo. It can be used in a variety of applications, including but not limited to: fire breaker, timber resource, furniture production, soil re-conditioning, and as reinforced materials. Since, today, there is heightened awareness regarding sustainability, manufacturers are driven towards producing completely biodegradable products that are created using PLA and PHA bio-composites. This review provides an overview on the performance of the existing composites and bio-composites, and their implementation and utilization, while focusing on the Borneo region.