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Effects of physical aging and carbon dioxide absorption in bisphenol‐A polycarbonate
Author(s) -
Risch Brian G.,
Wilkes Garth L.
Publication year - 1995
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.1995.070561113
Subject(s) - polycarbonate , glass transition , desorption , bisphenol a , mass fraction , absorption (acoustics) , carbon dioxide , materials science , thermal desorption , diffusion , composite material , chemistry , polymer chemistry , polymer , organic chemistry , thermodynamics , adsorption , epoxy , physics
Thermal and mechanical behavior of bisphenol‐A polycarbonate was studied as a function of thermal history and absorbed mass fraction of CO 2 . Physical aging at 120°C for one week produced dramatic changes in both the thermal and mechanical behavior. Gas absorption studies indicated that although initial diffusion was somewhat retarded in the aged samples, both aged and unaged polycarbonate samples showed identical equilibrium absorbed gas values at 6500 K Pa and identical gas desorption behavior. Absorbed CO 2 was shown to dramatically reduce the glass transition of polycarbonate indicating that CO 2 plasticizes polycarbonate. Additionally, samples which had been aged and absorbed a mass fraction of 0.07–0.10 of CO 2 showed thermal and mechanical behavior identical to that of a glass quenched from above T g with identical absorbed mass fraction. Once the absorbed gas was desorbed, the thermal and mechanical properties were similar to those of a glass freshly quenched from above T g . This study demonstrates that sufficient CO 2 gas absorption followed by desorption reverses physical aging in polycarbonate. © 1995 John Wiley & Sons, Inc.