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Viscosity changes during isothermal and adiabatic urethane network polymerization
Author(s) -
Richter E. B.,
Macosko C. W.
Publication year - 1980
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760201402
Subject(s) - isothermal process , materials science , polymerization , adiabatic process , branching (polymer chemistry) , viscosity , thermodynamics , composite material , shear rate , polymer chemistry , polymer , physics
Viscosity was measured as a function of time for the polymerization of a reaction injection molding (RIM) type urethane system: 4,4′‐diphenyl methane diisocyanate (MDI) with a polyester triol and dibutyl tin dilaurate catalyst. Viscosity was found to be independent of shear rate. Isothermal viscosity rise was related to extent of reaction and to M w , by branching theory. Isothermal results at several temperatures were able to predict viscosity rise under adiabatic conditions. The gel point test commonly used to evaluate RIM systems is shown to be essentially an adiabatic test.