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Melt viscosity increase during rheological testing of poly(phenylene sulfide)
Author(s) -
Fagerburg D. R.,
Watkins J. J.,
Lawrence P. B.
Publication year - 1993
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.1993.070501106
Subject(s) - rheology , branching (polymer chemistry) , oligomer , polymer chemistry , polymer , sulfide , intrinsic viscosity , polymerization , phenylene , cleavage (geology) , degree of polymerization , materials science , viscosity , chemistry , organic chemistry , composite material , fracture (geology)
Poly(phenylene sulfide) (PPS) made via the melt polymerization of p ‐diiodobenzene and sulfur has previously been reported to increase in melt viscosity with time during rheological testing. Analysis of the oligomer from cleavage of PPS chains at the disulfide bonds via solution in 1‐chloronaphthalene demonstrated that the disulfide content of the polymer decreased with rheological testing time. DSC of the polymer before and after rheological testing in combination with the T cc and T m of the chain fragments after the dissolution/cleavage in 1‐chloronaphthalene showed that many samples exhibited primarily chain extension rather than chain branching, whereas for many others, some degree of chain branching occurred. This is currently only qualitatively understood. Chain branching as the exclusive mechanism of melt viscosity increase during rheological testing appears untenable in light of the T m , in particular, of the chain fragments and also the polymer prior to chain cleavage. © 1993 John Wiley & Sons, Inc.