Surface grafting of bamboo fibers with 1,2-epoxy-4-vinylcyclohexane for reinforcing unsaturated polyester

The present study focused on the surface treatment of bamboo fibers (BFs) with a bifunctional monomer, 1,2-epoxy-4-vinylcyclohexane (EVC), in the presence of N, N-dimethylbenzylamine as the catalyst, which results in the grafting of the fibers with C=C bonds on the surface. The modified BFs carrying C=C bonds were used to prepare bamboo fibers reinforced unsaturated polyester (UPE) composites by hand lay-up compression molding. Hence, chemical connections between the modified-fibers and UPE resins were formed via the free-radical polymerization of the C=C bonds during the preparation of the BFs–UPE composites. XPS analysis proved that the EVC was covalently bonded onto BFs. XRD analysis revealed that EVC-grafting did not alter the crystal structure of the fibers, but slightly decreased their crystallinity degrees. SEM images indicated an markedly improved interfacial adhesion between BFs and UPE matrices after fiber modification, which significantly increased the tensile strength, flexural strength, flexural modulus, storage modulus, glass transition temperature, and water resistance of the resulting BFs–UPE composites.