Photochemical reactions in poly(vinyl chloride)/poly(vinyl alcohol) blends

Poly(vinyl chloride) and poly(vinyl alcohol) (PVAL) blends with various molar ratios were UV-irradiated (λ = 254 nm) at room temperature and in air atmosphere. Photochemical reactions were monitored by FTIR and UV-vis absorption spectroscopy. Changes of average molecular weights, indicating chain scission, were measured by gel permeation chromatography. Simultaneously, the amount of insoluble gel formed resulting of photocrosslinking was gravimetrically estimated. The influence of solvent traces (N,N-dimethylformamide) on blend photodegradation was also discussed. It was found that sample composition and macromolecular interactions play an important role in photochemical reactions in PVC/PVAL.