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Electron spin resonance studies on graft copolymerization of gaseous styrene onto preirradiated polypropylene. II. Preirradiation under vacuum
Author(s) -
Nunome Keichi,
Eda Bunzo,
Iwasaki Machio
Publication year - 1974
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1974.070180913
Subject(s) - radical , polypropylene , copolymer , grafting , irradiation , styrene , materials science , electron paramagnetic resonance , polymer chemistry , oxygen , polymer , photochemistry , chemistry , composite material , organic chemistry , nuclear magnetic resonance , physics , nuclear physics
Graft copolymerization of gaseous styrene was carried out at 40°C onto polypropylene preirradiated under vacuum. In order to investigate the origin of graft initiation activity, ESR spectra of irradiated polymers were measured and discussed. Although there are about three times as many radicals trapped in the sample irradiated at −78°C as in the sample irradiated at room temperature, both the samples showed nearly same degree of grafting. This is due to the ineffectiveness of radicals trapped in the amorphous region for grafting. The samples irradiated under vacuum showed more grafting than those irradiated in an oxygen atmosphere. This is compatible with the conclusion in the previous paper that in grafting of polypropylene irradiated in an oxygen atmosphere the carbon radicals produced by hydrogen abstraction by trapped peroxy radicals are the effective active centers.