Effect of Fibre Content on Mechanical Properties and Water Absorption Behaviour of Pineapple/HDPE Composite

Abstract

The present study investigates the effect of varying content of pineapple fibre in pineapple/HDPE composite on the tensile strength, tensile modulus, hardness (Shore-D)and water absorption behaviour. The content of pineapple fibres is kept as 5%, 15% and 25% (by wt.) and the HDPE matrix is taken as 50-50 mixture of fresh and recycled HDPE. The results obtained for 25% pineapple/HDPE composite are compared with those obtained for pineapple-sisal (each 12.5%)/HDPE composite. Prior to the fabrication of composite, the fibres were subjected to chemical treatments with NaOH and maleic anhydride coupling agent for enhancing their adhesion with HDPE matrix. It is observed that the tensile strength and hardness of pineapple/HDPE composite decrease with increasing fibre content. Though, the tensile modulus increases with the increase in fibre content. The pineapple-sisal/HDPE composite exhibits higher tensile strength and hardness, thought lower tensile modulus, as compared to pineapple/HDPE composite, when the total fibre content is 25% in both the composites.The 48 hours water absorption study indicates that amongst all the composites, the water absorption is the minimum for 5%pineapple/HDPE composite. SEM examination of the tensile fractured surface reveals that fibre pull-out, fibre delamination and fibre breakage are the primary mechanisms responsible for tensile failure of the specimen.