Evaluation of tensile and flexural properties of hemp and polypropylene based natural fiber composites

Abstract

Increasing worldwide environmental awareness is encouraging scientific research into the development of cheaper, more environmentally friendly and more sustainable construction and packing materials. For environment concern on synthetic fiber (such as glass, carbon, ceramic gibers etc) natural fibers (such as flax, hemp, jute, kenaf) etc are widely used. Industrial hemp fiber is one of the strongest of the natural fibers available and possesses benefits such as low cost and low production energy requirements. The primary objective of this research is to fabricate the natural fiber composites with suitable processing/manufacturing methods and to examine the mechanical properties when subjected to Tension, Bending and Impact loads and to compare & contrast the results with the available literature. In this research work, hemp fiber reinforced polypropylene matrix composites have been developed by extrusion compounding and Injection moulding with varying process parameters, such as fiber condition(untreated and alkali treated),coupling agent(with and without compatibilizers) and different fiber percentages(10%,20% and 30% by weight). The developed composites were then characterized by tensile test, flexural test and impact testing. Results show that the tensile strength and flexural properties increases with the increase in fiber percentage. However after a certain percentage the tensile strength decreas1es again. Compared to untreated hemp fiber, no significant changes in the tensile strength have been observed for treated hemp fiber reinforcement. The flexural strength / modulus of the composite was higher compared to pure Polypropylene (PP) for all filler/fiber loadings.