Surface graft polymerization of glycidyl methacrylate onto polyethylene and the adhesion with epoxy resin

Abstract

AbstractSurface graft polymerization of glycidyl methacrylate (GMA) was carried out onto a high‐ density polyethylene (PE) sheet pretreated with corona to introduce peroxides onto the PE surface. Graft polymerization of GMA was effected by UV irradiation of the coronatreated PE in the presence of monomer solution without the use of any photosensitizer. The graft layer was found by staining the PE cross section to localize in the surface region of PE. The physical change in the PE surface was characterized by scanning electron microscopy, while the chemical changes due to the GMA graft polymerization were assessed by the dynamic contact angle, FT‐IR, and x‐ray photoelectron spectroscopy (XPS) measurement. The peroxide formation by corona exposure was confirmed by the XPS measurement after derivatization with SO2. The epoxy groups introduced onto the PE surface by the GMA graft polymerization were reactive with water (in the presence of HCI) and amines. The adhesion between the GMA‐grafted PE and an epoxy resin was studied by means of a shear strength test method. The GMA‐grafted PE exhibited strong interfacial adhesion with the epoxy resin, compared to the original and corona‐treated PE. The adhesion strength of the GMA‐grafted PE was nearly two times higher than that of the corona‐treated PE. This strongly suggests that the enhanced adhesion between the surface‐grafted PE and the epoxy resin is ascribed to covalent bonding of the epoxy groups on the GMA‐grafted surface to the amines in the epoxy resin. © 1995 John Wiley & Sons, Inc.