The thermal degradation of polychloroprene-III degradation of polychloroprene/poly(methyl methacrylate) mixtures

The mechanism of dehydrochlorination has been studied by examining the degradation of polychloroprene/poly(methyl methacrylate) blends, using thermal volatilization analysis and infrared spectroscopy; the behaviour has been compared with that previously found for PVC/PMMA blends. Unlike the latter system, the polychloroprene blends did not show any increased production of methyl methacrylate monomer in the early stages of breakdown. The stabilization effect on PMMA due to reaction of ester groups with hydrogen chloride, on the other hand, is much more evident in the case of polychloroprene blends than for PVC, PVC dehydrochlorination is retarded by the presence of PMMA, but evolution of hydrogen chloride from polychloroprene is unaffected to any significant extent. It is concluded that the dehydrochlorination of polychloroprene is not a radical chain process. A unimolecular mechanism is suggested.