Effect of residual solvent on the photodegradation of poly(vinyl chloride)

Abstract

The effect of residual solvent on the photodegradation of poly(vinyl chloride) (PVC) films cast from tetrahydrofuran (THF) and dichloroethane (DCE) solutions was examined by infra-red and ultra-violet-visible absorption spectroscopy, and gel permeation chromatography (GPC). Residual THF reduced not only the formation of conjugated polyenes longer than five units, but also that of shorter conjugated double bonds; diene, triene and tetraene. However, residual DCE did not affect appreciably the formation of polyene and its sequence length in PVC film. Accumulation of carbonyl groups in PVC film containing residual THF was higher than that of film thermally treated in high vacuo, but residual DCE scarcely affected the formation of carbonyl groups. Slight increases in molecular weight and insoluble portions were observed in PVC film containing residual THF at the early stage of the photodegradation of the polymer.