Vapor-Phase Graft Copolymerization of Methyl Polypropylene Fiber Oxidized with Methacrylate Ozone

Abstract

After the activation of polypropylene fiber by ozone-oxidation, methyl methacrylate was graft copolymerized onto it. The ability of the activated fiber to initiate vapor-phase graft copolymerization was compared with that of usual liquid-phase one. The structural differences between the graft copolymers (vapor- and liquid-phase samples) prepared by the vapor -phase graft copolymerization method and the liquid-phase one were discussed from the data of the mechanical properties, the crystallinity, the double refraction, and the melting behavior by DSC. The degree of grafting for the vapor-phase sample increased with the ozone -oxidation time, the polymerization time, and the polymerization temperature, while the graft efficiency decreased. These tendencies were the same as those for the liquid-phase one. The number of branch for the vapor-phase sample was higher than that for the liquid -phase one, but the molecular weight of branch estimated by that of homopolymer was lower. The mechanical properties were improved by vapor-phase grafting and liquid-phase one, and the extent of which was small for the vapor-phase sample. The decreases in the crystallinity and the double refraction for the vapor-phase sample was less than that for the liquid -phase one. These facts suggest that the vapor-phase graft copolymerization proceeds near fiber surfa ce in our experimental conditions.