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Oxidative degradation of poly(vinyl chloride)
Author(s) -
Decker Christian
Publication year - 1976
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.1976.070201213
Subject(s) - radical , vinyl chloride , chemistry , alkoxy group , chlorine , oxygen , polymer chemistry , bond cleavage , order of reaction , induction period , decomposition , polystyrene , photochemistry , polymer , organic chemistry , reaction rate constant , kinetics , catalysis , alkyl , physics , quantum mechanics , copolymer
Rates of oxygen consumption and formation of oxidation products were determined in γ‐initiated oxidation of poly(vinyl chloride) (PVC) at 25°C. Data are given for five dose rates and correlated on the basis that the overall oxidation is the sum of two reactions that are first order and half order in rate of initiation. The principle oxidation product is hydroperoxide, formed by the half‐order reaction, whereas alcohol and carbonyl compounds result mostly from first‐order reactions. These products account for 77–80% of the total oxygen absorption. The presence of oxygen was found to increase twofold the rate of dehydrochlorination of irradiated PVC. A reaction scheme is developed which assumes that a significant fraction of the interactions of tertiary peroxy radicals is nonterminating and yields alkoxy radicals which propagate or decompose by β‐scission. This decomposition occurs mostly by splitting off a chlorine atom with formation of a ketone and, to a lesser extent, by CC cleavage which accounts for the observed decrease in molecular weight of the oxidized PVC. Polystyrene was found to be much more resistant to oxidation than PVC. A classification of some commercial polymers in function of their susceptibility to oxidation is proposed.