Effects of surface grafting of copper nanoparticles on the tensile and bonding properties of flax fibers

In the present work, functionalized copper nanoparticles (FCuNPs) were grafted onto flax fibers, and the effects on the tensile properties, bonding strength to an epoxy resin, as well as the properties of the flax fiber-epoxy model composites were investigated. The copper nanoparticles were synthesized at ambient temperature by a chemical reduction method. The reduction of solution of copper chloride salt in the polyvinylalcohol medium was done by using sodium borohydrate. Ultraviolet-visible spectroscopy, transmission electron microscopy, and X-ray diffraction studies were used to characterize the size of the synthesized particles. The synthesized copper nanoparticles were applied to saturate the unidirectional flax natural fibers, whose surfaces were previously tailored with the cationic agent triethylammonium chloride. A remarkable improvement in the tensile strength by 75% and modulus by 50% for FCuNPs grafted flax fibers was found. Thermo-mechanical properties of the flax fiber reinforced epoxy composites were studied using DMTA. Finally, the anti-microbial analysis for composites was also conducted against Aspergillus Niger spores, and enhanced anti-microbial performance was observed for treated fiber-based composites.