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The influence of thermal properties on the glass transition temperature in styrene/divinylbenzene network–diluent systems
Author(s) -
Ellis T. S.,
Karasz F. E.,
Brinke G. Ten
Publication year - 1983
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.1983.070280103
Subject(s) - ethylbenzene , diluent , divinylbenzene , differential scanning calorimetry , styrene , glass transition , materials science , polystyrene , heat capacity , plasticizer , thermodynamics , polymer , polymer chemistry , chemical engineering , chemistry , organic chemistry , benzene , copolymer , composite material , physics , engineering
The depression of glass transition temperature in polystyrene and styrene/divinylbenzene networks, by the addition of ethylbenzene, ethyl acetate, and m ‐diethylbenzene, respectively, has been investigated by differential scanning calorimetry. The predictive quality of the Couchman–Karasz treatment for the composition dependence of T g in compatible systems was found to provide excellent agreement with experimental results for the depression of T g by ethylbenzene, provided certain modifications were made. Qualitatively, the theory predicts that for a given diluent, the depression of T g is particularly sensitive to the incremental change in heat capacity of the pure polymer or network. The behavior of ethylbenzene provided good quantitative agreement with the theory, provided that the incremental change in heat capacity of the diluent at its T g was approximated by Δ C p = constant/ T and that the incremental change in heat capacity of the network at T g represents only those units capable of thermal activation. The anomalous behavior observed on plasticization by ethyl acetate and m ‐diethylbenzene could in part be explained by a reduction in solvent quality or syneresis of diluent in the highly crosslinked samples.