Mechanical Behaviour of Polypropylene Reinforced Palm Fibers Composites

Nowadays, a great attention has been dedicated to natural fibers as reinforcement for polymers. Natural fibers, compared to glass fibers, exhibit better mechanical properties, such as stiffness, impact strength, flexibility and modulus. However certain drawbacks, such as the incompatibility between fibers and polymer matrices, the tendency to form aggregates during processing and the poor resistance to moisture, reduce the use of these natural fibers as reinforcements in polymers. Several treatments and modifications are being used to improve fibers/matrix compatibility, such as bleaching, acetylation and use coupling agent. In this work, the effect of coupling agent in the palm fibers/PP composites was evaluated on mechanical behaviour. Palm fibers were mixed with the polymeric matrix (PP) in a thermokinetic mixer, with speed rate maintained at 5250 rpm, in which fibers were responsible for 5 wt% in the composition. When the coupling agent was used, the proportion of PP was 95 wt% and the coupling agent was 5 phr. After the mixture, composites were dried, ground in mill and placed in an injector camera according to ASTM D-790 specification. Results showed that, the addition of coupling agent in the composites improved significantly the flexible strength and modulus when compared to the pure polymer. (C) 2011 Published by Elsevier Ltd. Selection and peer-review under responsibility of ICM11