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The kinetics of polyarylate hydrolytic embrittlement
Author(s) -
Golovoy A.,
Cheung M. F.,
Zinbo M.
Publication year - 1988
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.1988.070350802
Subject(s) - embrittlement , hydrolysis , ductility (earth science) , activation energy , brittleness , materials science , kinetics , glass transition , composite material , humidity , surface tension , polymer chemistry , chemical engineering , chemistry , thermodynamics , polymer , organic chemistry , physics , quantum mechanics , engineering , creep
The hydrolysis of polyarylate in water between 55 and 98°C was found to be a zero‐order process with an activation energy of 19.2 kcal/mol, determined by changes in molecular weight. The equation for the effect of temperature on the rate of hydrolysis is ln k = 34.1 − 10 4 / T , where k is in day −1 . The decrease in molecular weight is accompanied by a loss in ductility. The transition from a ductile to brittle failure in tension occurs at M̄ w of about 35,000 and M̄ n of 12,700. At 27°C (80°F) and high humidity environment this would occur after 21 years. But during injection molding, the material, if not properly dried, would embrittle in a matter of seconds.