ABSTRACT
The PVC thermal stability is very dependent on the presence of chemical additives. Some critical phenomena associated with degradation of PVC are the sharp variation of the reaction rate, the elimination of HCl, the dependence on the processing temperature and the sample size. Polyurethane, polymers are thermodynamically compatible with PVC, and degradation accelerates with elimination of HCl due to the presence of nitrogen-containing groups and their ability to build electrophile complexes with HCl. The degradation of PVC blends with polymethylmethacrylate (PMMA) is characterized by a diminishing rate of PVC thermal dehydrochlorination in comparison with the pure polymer. Methylmethacrylate-butadiene-styrene copolymer (MBS) within the range 5–50 mass.% in the blends of PVC and PMMA effectively reduces VHCl in PVC thermal degradation the higher the MBS content and processing temperature the greater the observed reduction of HCl elimination. Poly-a-olefins, contain no functional groups are thermodynamically incompatible with PVC and have no influence on PVC.
