ISSN:
0032-3888
Schlagwort(e):
Chemistry
;
Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Copolymers of vinyl chloride with 2-chloropropene were prepared as models for tertiary-chlorine branching in PVC. Rates of thermal dehydrochlorination of copolymers containing up to 2 mol percent 2-chloropropene were found to be a linear function of composition. By comparing the decomposition rates of the copolymers with that of PVC prepared under similar conditions, we estimate the maximum tertiary-chlorine content of PVC at 0.1 to 0.2 mol percent. This figure is of the same magnitude as estimates of the content of tertiary-chlorine, random unsaturation, and long-chain branching obtained in previously published studies of PVC. Possible mechanisms for tertiary-chlorine branch formation include chain-transfer to polymer and copolymerization with unsaturated chain-ends. By applying the conventional copolymerization equation, using the reactivity ratios of the vinyl chloride/2-chloropropene system, it is shown that the copolymerization mechanism predicts a tertiary-chlorine branch content close to the estimated value. Both mechanisms also agree qualitatively with reported effects of polymerization temperature and conversion on branching and thermal stability.
Zusätzliches Material:
4 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pen.760140503
