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A water‐sensitive thermomechanical transition in a polyimide
Author(s) -
Ozari Y.,
Chow R. H.,
Gillham J. K.
Publication year - 1979
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.1979.070230422
Subject(s) - polyimide , torsion pendulum clock , polymer , adsorption , materials science , water vapor , humidity , molecule , polymer chemistry , langmuir , glass transition , composite material , thermodynamics , chemical engineering , analytical chemistry (journal) , chemistry , organic chemistry , layer (electronics) , physics , quantum mechanics , engineering
The effect of water vapor on a polyimide has been investigated in the temperature region of −190 to 325°C using an automated torsion pendulum. A damping peak, T H 2 Odevelopes at −122°C (1 Hz) in the thermomechanical spectra of the polymer which is due to water–polymer interactions. The peak intensifies as the humidity of the conditioning atmosphere, at both 30° and at 325°C, increases and attains a limiting value at about 3000 ppm v H 2 O. The process is reversible. It is concluded that the number of sites in the polymer for interaction with water is low and limited (<0.3 molecule H 2 O per polymer repeat unit) and, assuming direct proportionality between the intensity of the loss peak and the amount of water adsorbed, that the adsorption of water vapor follows the Langmuir isotherm.