Effects of fiber extraction,morphology, and surface modification on the mechanical properties and water absorption of bamboo fibers‐unsaturated polyester composites

Bamboo fibers reinforced unsaturated polyester (UPE) composites were prepared by compression molding. Effects of fiber extraction, morphology, and chemical modification on the mechanical properties and water absorption of the bamboo fibers‐UPE composites were investigated. Results showed that the unidirectional original bamboo fibers resulting composites demonstrated the highest tensile strength, flexural strength, and flexural modulus; the 30–40 mesh bamboo particles resulting composites had the lowest tensile strength and flexural strength, but had comparable flexural modulus with that of chemical pulp fibers. The treatment of bamboo fibers with 1,6‐diisocyanatohexane (DIH) and 2‐hydroxyethyl acrylate (HEA) significantly increased the tensile strength, flexural strength and flexural modulus, and water resistance of the resulting composites. Fourier Transform Infrared and X‐ray photoelectron spectroscopy analyses showed that DIH and HEA were covalently bonded onto bamboo fibers. Scanning electron microscopic images of the fractured surfaces of the composites showed that the treatment of bamboo fibers greatly improved the interfacial adhesion between the fibers and UPE resins. The water absorption kinetics of the composites was also investigated; and the results showed that the water absorption of the composites fitted Fickian behavior well. POLYM. COMPOS., 37:1612–1619, 2016. © 2014 Society of Plastics Engineers