Fibrillation of Coconut Fibers by Mechanical Refining to Enhance Its Reinforcing Potential in Epoxy Composites

Abstract

The reinforcing potential of coconut fibers, fibrillated by mechanical refining process, in an epoxy matrix was evaluated. The coconut fiber was fibrillated by a conical refiner for different duration (10 to 40 min) and subjected to chemical compositional analysis, size distribution by microscopy and crystallinity by XRD. The fibrillation by mechanical refining process did not affect the crystallinity of coconut fibers. But, cellulose content increased due to the removal of lignin during refining process. The fibrillated coconut fiber (FCF) was used to reinforce epoxy resin by casting process. The melting temperature, as analyzed by DSC, of epoxy composites increased from 294.75 ?C (epoxy alone) to 338.96 ?C (raw coconut fiber, RCF) and a maximum of 353.41 ?C for 20 min processed FCF reinforced composites. The surface resistivity of epoxy control increased from 1.32 e10 ? to 22.6 e10 ? after reinforcing with control coconut fiber. But, the fibrillation process reduced the surface resistivity due to uniform distribution of FCF in the epoxy matrix avoiding the formation of air voids. Similar trend was observed for volume resistivity also. The damage force and tensile load increased significantly for the FCF reinforced composites, 61% and 12%, respectively, when compared to the RCF reinforced composites. Hence, as an alternative of conventional alkali treatment, fibrillation of coconut fibers could significantly improve the performance of epoxy composites.