Dulina Tholibon

Tensile Properties of Unidirectional Kenaf Polypropylene Composite at Various Temperatures and Orientations

The development of bio-composites as biodegradable and renewable materials for sustainable technology are advantageous in creating a green and healthy environment. However, the application of natural fiber as a bio-composite material have been found to be restricted especially as it has lower thermal resistance in comparison to synthetic fiber. Therefore, the objective of this study is to investigate the influence of fiber orientations on the tensile properties at various tensile temperatures for unidirectional kenaf polypropylene (PP) composite. Samples were prepared by hot pressing process. In this study, kenaf long fibers that are produced from water retting process is use as a reinforcement agent while PP as a polymer in the composite fabrication. A tensile test was carried out at different temperatures (30°C, 60°C, 90°C, 120°C) for various orientations (0°, 45° and 90°). It was found that an increase of temperature will reduce the modulus and tensile strength where the highest reduction occurred between 60°C to 120°C and most significantly on the orientation of 45° and 90°, which is lower than pure PP. This concludes that the application of kenaf PP composite is optimum between room temperature with a cut-off temperature at 60°C.

Unidirectional Kenaf Polypropylene Composites: Optimization Process by Two Level Full Factorial

The interest of using kenaf fibers in composite fabrication has grown due to renewable, sustainable and environmental issues. The applications of kenaf composite have been broadly exploited especially in automotive industry. In this research, unidirectional kenaf polypropylene (PP) composites were prepared using the hot pressing method. The processing parameter need to be optimized to ensure that the fabrication process will enhance the mechanical properties of the composite. Thus, a research on the optimization process on the processing parameter (temperature, pressure, pressing time and kenaf percentage) on the tensile properties was conducted by using a two-level full factorial design. The effect of the individual factors and their interaction were observed. From statistical analysis, the main effect of tensile strength and young modulus is the percentage of kenaf fibers with 21.67% contribution. The interaction between kenaf percentage and pressing time also contribute an effect on the tensile properties with 13.29% contribution. Finally, the result showed that at 190°C, pressure 5 MPa, 5 minutes pressing time and 50% fiber content will give the optimum tensile strength and young modulus which is 163.12 MPa and 11.17 GPa respectively with improvement of 486% tensile strength compared to pure PP.