Material propertiesMechanical properties of preferentially aligned short pineapple leaf fiber reinforced thermoplastic elastomer: Effects of fiber content and matrix orientation

Composites of preferentially aligned pineapple leaf fiber (PALF) and Santoprene, a thermoplastic elastomer, were studied. PALF filled Santoprene composites were first prepared by melt mixing on a two-roll mill with different PALF contents. Then, the molten mixture was sheeted out using a narrow nip with some stretching to give prepregs with PALF preferentially aligned along the machine direction. These prepregs were then stacked and compression molded at 175 °C and 195 °C to form composite sheets. Wide angle x-ray scattering patterns revealed that the prepregs had matrix orientation which still remained after molding at 175 °C but not at 195 °C. Tensile and tear properties in directions parallel and perpendicular to the fiber axis were measured. Modulus at 10% strain and tear strength in the longitudinal direction increased significantly with increasing PALF content (up to 15%), while tensile strength and elongation at break decreased. The effect of PALF content was less significant in the transverse direction. In addition, compression molding temperature also affected all these properties but to different extents. The two most affected properties were modulus and tear strength in the longitudinal direction. Composites prepared at 175 °C displayed significantly higher modulus and tear strength than that prepared at 195 °C with the same PALF content. This was attributed to the remnant matrix orientation.