Effect of sizing on interfacial adhesion property of glass fiber

This research was undertaken to investigate the influence of the sizing components, principally coupling agents and film formers, of glass fiber on the interface of reinforced polyurethane composites. The contents of film-forming agents and coupling agents were, respectively, checked by acetone extraction and heat treatment. The categories and chemical structures of the film-forming agents, which mainly exist in the extracting solutions, were investigated by nuclear magnetic resonance spectroscopy. The coupling agents, which mainly existed on the extracted glass fiber surfaces, were analyzed by X-ray photoelectron spectroscopy. Then, the interfacial adhesion properties between glass fibers of untreated, extracted and heat-treated and polyurethane resin were measured with micro-droplet test. The results show that the interfacial shear strength of the glass fiber-reinforced polyurethane composite mainly depends on the coupling agents, in which the N-containing groups play a dominant role. The film formers also take some effects, in which the hydroxyl groups have the greatest contribution