Morphology and properties of EVA/empty fruit bunch composites

Abstract

Composites based on ethylene vinyl acetate (EVA) copolymers with 18% and 28% VA contents and empty fruit bunch (EFB) fibre were reported in this study. The EVA-EFB composites were prepared by melt mixing using a Brabender plastograph mixer. Scanning electron microscopy (SEM) results show an improved extent of interfacial adhesion between the polymer and the fibre, with an increase amount of VA in the copolymers. Differential scanning calorimetry (DSC) results reveal that the melting and crystallization enthalpies decreased significantly with increasing VA content, while the presence of EFB fibre had very little influence on the melting and crystallization behaviour of both EVA18 and EVA28. Thermogravimetric analysis (TGA) results show that EVA18 is more thermally stable than EVA28 due to the higher amount of VA in EVA28, and the decomposition of EFB fibre seems to be retarded when it is incorporated into the EVA copolymers. Dynamic mechanical analysis (DMA) results show that both the storage modulus and loss modulus decrease significantly with an increase in VA content, and that these two properties observably increased with the incorporation of the fibre. The glass transition temperature also increased observably with increasing fibre loading, and decreased with an increase in the VA content. The stress and strain at break showed a similar decrease with increasing fibre content for both EVA18 and EVA28, while Young’s modulus increased much more significantly with increasing fibre content for EVA28. Generally, it seems as if the improvement in interaction between EVA28 and EFB was not significant enough to overcome the inherent weak properties of EVA28.