Influence of structure on the photo-degradation of PVC. Part IV—A conclusive approach to the mechanism of photo-oxidation and photo-dehydrochlorination

摘要: Abstract The photo-oxidation and the photo-dehydrochlorination of a series PVC samples having different isotactic contents have been studied in presence oxygen. build-up carbonyl groups was found to decrease as content increased. Conversely, dehydrochlorination quantum yield appeared increase linearly It is proposed that former result due less favoured hydrogen abstraction reaction at triads, resulting from higher shielding atoms CHCl groups. latter associated with both occurrence some chlorine low dissociation energy located definite type triad CH2 group syndio heterotactic triads. conclusions are discussed on basis local conformations various In particular, role GTTG− conformation mechanisms above emphasized.