Torque rheological properties of agro-waste-based polypropylene composites: Effect of filler content and green coupling agent

This study investigates the effect of filler content and green coupling agent (GCA) on the torque rheological properties of polypropylene (PP)/cocoa pod husk (CPH) composites. The GCA was prepared from coconut oil and it was used to improve the properties of PP/CPH composites. The processing torque of PP/CPH composites was increased with increasing of filler content and the presence of GCA. The power law index (n) of PP/CPH composites were less than 1.0. Thus, the composites melt showed pseudoplastic character and it exhibited shear thinning effect. The values n of PP/CPH composites increased with higher filler content and after filler modification using GCA. This indicated that the pseudoplasticity of composites were affected by filler-matrix interaction. The viscosity of PP/CPH composites increased after increased filler content and the presence of GCA. The change of viscosity was related to filler-filler interaction and filler-matrix adhesion. The increase of filler content and addition of GCA also increased the activation energy (E-a) of PP/CPH composites. This indicated that the energy of fusion process of PP/CPH composites increased with higher filler content and the addition of GCA. J. VINYL ADDIT. TECHNOL., 24:E30-E35, 2018. (c) 2016 Society of Plastics Engineers