Sodium bicarbonate treatment of coir fiber on wettability and shear strength of coir fiber-epoxy composite

Abstract

This research presented the influence of treated coir fiber with sodium bicarbonate on wettability and interfacial shear strength (IFSS) of coir fiber-epoxy composite. Coir fibers were immersed in the solution of sodium bicarbonate with three different densities (8wt%, 10wt%, and 12wt %) for 24 hours and 120 hours. Epoxy resin was utilized as a matrix of composite. Wettability and IFSS of coir fiber-matrix adhesion were evaluated. Fiber wettability to the matrix was performed by measuring the droplet contact angle. In addition, the IFSS of coir fiber - epoxy matrix was investigated by pull out method. The surface morphology of interfacial bonding between fiber and matrix after pull out testing was evaluated by scanning electron microscopy (SEM). The results show that fiber surface wettability was influenced by sodium bicarbonate where the contact angle decrease after treatment. It suggests that good wetting of fiber and matrix. While the density of 12 wt% sodium bicarbonate for 120 hours possessed the highest interfacial shear strength of fiber-epoxy adhesion compared with other densities.