| Abstract: | Ultra-high modulus polyethylene (UHMPE) fiber was treated with oxygen plasma and a silane coupling agent in order to improve the interfacial adhesion between the UHMPE fiber and vinylester resin. The oxygen plasma and γ-methylmethacryloxypropyltrimethoxysilane (γ-MPS)-treated UHMPE fiber/vinylester composites showed a slightly higher interlaminar shear strength than the oxygen plasma-treated UHMPE fiber/vinylester composites. The interfacial adhesion of the oxygen plasma-treated UHMPE fiber/vinylester composites in this study is mainly due to mechanical interlocking between the micropits formed by the oxygen plasma treatment and the vinylester resin. The γ-MPS molecules adsorbed onto the UHMPE fiber surface neither affected the morphology of the UHMPE fiber surface, nor reduced the extent of mechanical interlocking. The improved interfacial adhesion by the γ-MPS treatment is due to enhanced wettability and chemical interaction through the chemically adsorbed γ-MPS molecules, as detected by Fourier-transform infrared (FT-IR) spectroscopy. The γ-MPS molecules adsorbed onto the ultra-high molecular weight polyethylene (UHMWPE) plate surface also reduced the aging effect of the oxygen plasma-treated UHMWPE surface. |
