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The thermal stability of radiation‐grafted poly(vinyl chlorides)
Author(s) -
Yamakawa S.,
Stannett V.
Publication year - 1974
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1974.070180723
Subject(s) - vinyl chloride , styrene , materials science , copolymer , thermal stability , polymer chemistry , thermogravimetric analysis , polyvinyl chloride , irradiation , grafting , methyl methacrylate , polymer , polymerization , yield (engineering) , composite material , chemistry , organic chemistry , physics , nuclear physics
The thermal Stability of radiation‐grafted poly(vinyl chloride) (PVC) has been investigated by thermogravimetric analysis and compared with the thermal stability of the corresponding PVC polymer blends. Although both the grafting of methyl methacrylate and styrene and the blending of the corresponding homopolymers yield products of improved thermal stability as compared with unmodified PVC, the radiation grafting is somewhat more efficient for the stabilization of PVC than blending. Further, the rate of dehydrochlorination of PVC–g–styrene at relatively high temperatures exhibits a retardation, whereas that of unirradiated PVC show significant acceleration. A detailed study about a series of PVC–g–styrenes polymerized under various conditions shows that the retardation effect is more noticeable in the samples irradiated to 2.0–3.0 Mrad than in those irradiated to less than 1.0 Mrad. From the dose dependency, it has been suggested that the retardation effect is due to the interruption of the propagation of dehydrochlorination by branch sites produced by the radiation process. On the other hand, the graft copolymers of vinyl pyridines, PVC‐poly(vinyl pyridine), and PVC irradiated in the presence of pyridine are much less stable than unmodified PVC. The instability is explained in terms of the substitution reaction with the bases and the base‐catalyzed dehydrochlorination of PVC.