Structural defects in poly(vinyl chloride)—IV. Thermal degradation of vinyl chloride/acetylene copolymers

✍ Scribed by D. Braun; B. Böhringer; B. Iván; T. Kelen; F. Tüdös

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 336 KB
• Volume: 22
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(86)90205-3

✦ Synopsis

Vinyl chloride/acetylene copolymers have been prepared under subsaturation conditions. Copolymerization rates and molecular weights of the copolymers decrease with increasing concentration of acetylene in the monomer feed, indicating that acetylene is a retarder in vinyl chloride polymerization. The concentration of internal double bonds in the copolymers determined by ozonolysis increases with increasing amount of acetylene in the feed. Thermal degradation has been performed at 110 with solid samples and at 170: in solution under inert atmosphere. The extent of HC1 loss as a function of time shows a rapid initial phase followed by a slower steady rate The initial dehydrochlorination rates are higher for copolymer samples containing higher concentrations of internal double bonds. Quantitative analysis of the u,v. and visible spectra of degraded copolymers shows that the sum of the concentration of polyenes with 4 12 conjugated double bonds increases rapidly in the first phase of degradation, but then decreases slowly, due to secondary reactions of polyene sequences.