Surface modification of aramid fibre by graft polymerization

Abstract

To modify the surface properties of aramid fibre, graft polymerization of acrylamide (AAm) and glycidyl methacrylate (GMA) was performed onto the surface of Kevlar 49. Following plasma treatment and subsequent exposure to air to introduce peroxides onto the fibre surface, the polymer peroxides were decomposed in the monomer solution containing riboflavin by ultra-violet (u.v.) irradiation to effect graft polymerization of the monomers onto the fibre. The monomer solution was prepared from water and dioxane for AAm and GMA, respectively. After removal of homopolymers, the grafted fibre was subjected to surface analysis with attenuated total reflection Fourier-transform infra-red spectroscopy and X-ray photoelectron spectroscopy (XPS). It was found that grafted PAAm and PGMA chains were present in the surface region of the fibre. Graft polymerization was greatly affected by u.v. irradiation time, monomer concentration and plasma treatment time. The reaction of propylamine with the PGMA-grafted surface was accompanied by the appearance of a new nitrogen peak in the XPS spectrum, suggesting the presence of epoxy groups on the surface of PGMA-grafted fibre.