Kenaf fibers reinforced thermoplastics natural rubber composites

摘要

New kenaf fiber (KF) based thermoplastic natural rubber (TPNR) composite with polypropylene (PP) were compounded by melt blending method. Kenaf fiber and TPNR were mixed at various fiber fraction (0, 5, 10, 15, 20 V_f %) using internal mixer, Thermo Haake 600p. The effects of mixing parameters were investigated for KF-TPNR composites at various mixing conditions (mixing temperature, rate of rotation and mixing time). Mechanical properties were evaluated for their tensile strength (σ_(max)), Young's modulus (E) and maximum strain. The study was found that the optimum processing parameters obtained at mixing speed of 11rpm, temperature of 180℃ and processing time of 12minutes. The mechanical properties of the composites were investigated using tensile, impact, and flexural test. The incorporation of the fiber into TPNR matrix has resulted in the improvement of the tensile strength, impact strength, Young's modulus and flexural modulus. Maleic anhydride grafted polypropylene (MAPP) was employed to improve the interfacial adhesion between kenaf fiber and TPNR matrix. Better performance has been attributed with the addition of compatibilizer due to improvements of the wetting of the fiber surface. The present of MAPP had improved tensile strength, Young's modulus and flexural stiffness. Scanning electron microscope was also employed to examine the fiber surface, fiber pull-out, and fiber-matrix interaction. SEM micrographs have shown that good adhesion between kenaf fiber and TPNR was achieved when the compatibilizer was applied. Thermal properties of composites were studied using thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA). TGA measurements have revealed that the present of compatibilizer had improved the degradation temperature of the composites. DMA difractogram showed that the KF-TPNR composites with higher fiber loading demonstrated higher storage modulus (E') and loss modulus (E"). An addition of compatibilizer enhanced the tan δ values indicating the improvement in the interphase.