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Gelation in thermosets formed by chain addition polymerization
Author(s) -
Heise M. S.,
Martin G. C.,
Gotro J. T.
Publication year - 1990
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.760300204
Subject(s) - diglycidyl ether , imidazole , materials science , differential scanning calorimetry , polymerization , thermosetting polymer , gel point , viscosity , polymer chemistry , dynamic mechanical analysis , ether , chemical engineering , composite material , dielectric , polymer , bisphenol a , epoxy , organic chemistry , thermodynamics , chemistry , engineering , physics , optoelectronics
The physical behavior of the diglycidyl ether of bisphenol A, cured with different concentrations of 2‐ethyl‐4‐methylimidazole, was examined with dynamic mechanical and dielectric analyses, differential scanning calorimetry, and solvent extraction studies, ‘The network formation process was shown to depend strongly on the imidazole concentration’. At high imidazole concentrations, the gel point was characterized by a decrease in sol fraction, the crossover of the dynamic moduli and a rapid increase in viscosity. At low imidazole concentrations, the viscosity remained low until the sol fraction approached zero. For this system, the gel point, which occurred prior to the dynamic moduli crossover, was characterized by comparing the thermal properties of the network with the viscosity and dielectric behavior of the resin system during cure.