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Glass transition temperature ( T g ) versus fractional conversion for a linear thermosetting polyamic acid ester–polyimide system
Author(s) -
Venditti R. A.,
Gillham J. K.,
Chin E.,
Houlihan F. M.
Publication year - 1994
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.1994.070530408
Subject(s) - glass transition , polyimide , thermosetting polymer , materials science , polymer chemistry , torsion pendulum clock , relaxation (psychology) , thermodynamics , composite material , polymer , psychology , social psychology , physics , layer (electronics) , quantum mechanics
The relationship of the glass transition temperature, T g , to fractional conversion, x , for the conversion of the cyclohexylmethyl ester of the benzophenone tetracarboxylic dianhydride–oxydianiline polyamic acid to polyimide has been investigated using dynamic mechanical analysis (torsion pendulum, TBA). The glass transition temperature and conversion measurements were obtained on a single solvent‐free polyamic acid ester specimen during cooling after heating to successively higher cure temperatures. Conversion was determined from the intensity of a sub‐ T g mechanical relaxation peak that has been assigned to a relaxation of the cyclohexyl group. The resulting T g versus x relationship is nonlinear. The T g versus x relationship is adequately modeled using an expression derived by Couchman. © 1994 John Wiley & Sons, Inc.