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Polymerization of vinyl chloride in presence of substituted olefins: Effects on molecular weight and melt rheology
Author(s) -
Langsam Michael
Publication year - 1979
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.1979.070230321
Subject(s) - vinyl chloride , polymer , polymer chemistry , isobutylene , melt flow index , polymerization , molar mass distribution , chain transfer , olefin fiber , rheology , materials science , tacticity , chemistry , radical polymerization , copolymer , composite material
Vinyl chloride (VCM) was polymerized by free‐radical suspension procedures in presence of methyl‐substituted olefins such as propylene, isobutylene, cis ‐2‐butene, trimethylethylene, and tetramethylethylene. Dilute solution viscosities of polymer formed in the presence of these olefins were measured and compared to that of trichloroethylene, a chlorinated chain‐transfer agent. A pseudo‐chain‐transfer coefficient for these olefins was calculated based on solution viscosity determinations and found to be exponentially proportional to the number of allylic hydrogens. The effects on melt flow of the olefin distribution in the polymer chain were examined. Olefins at the ends of polymer chains were found to have no effect on melt rheology, whereas those in internal portions of chains were found to significantly increase melt flow.