Comparison of Type of Rubber in PLA/Rubber/Kenaf Biocomposite: Rheological, Mechanical and Morphological Properties

Polylactic acid/rubber/kenaf biocomposites are prepared via melt blending in an internal mixer, followed by compression molding. The effect of different type of rubber is studied based on processing torque, tensile properties, and morphology. Natural rubber (NR) and acrylonitrile butadiene rubber are used, respectively. The content of rubber is fixed at 10 wt%, while kenaf loading has been varied from 0 to 20 phr. Incorporation of NR in biocomposite showed higher processing and stabilization torque compared to acrylonitrile butadiene rubber, However, NR offers higher tensile strength and elongation at break to the biocomposite due to superior properties of NR and strain-induced crystallization phenomenon. Based on tensile-fractured morphology, biocomposite with NR shows more tearing effect, which is associated with higher strength. In regard to kenaf loading, the results show that higher kenaf loading causes the tensile properties to decrease and also higher processing torque during mixing. Besides, poor interfacial adhesion is shown by biocomposite with high kenaf loading in the field emission scanning electron microscope micrograph, proven by a smoother fractured surface and more voids due to filler pull-out.