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Microcavity formation in poly(ester–carbonate) exposed to hot, humid environments
Author(s) -
Robeson L. M.,
Dickinson B. L.,
Crisafulli S. T.
Publication year - 1986
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.1986.070320725
Subject(s) - polycarbonate , carbonate , materials science , nucleation , scanning electron microscope , bisphenol a , chemical engineering , phase (matter) , composite material , chemistry , organic chemistry , epoxy , metallurgy , engineering
The behavior of polycarbonate in hot, humid environments has been well documented in the technical literature. Poly(ester–carbonate)s based on bisphenol A connected with carbonate and tere/isophthalate units are the subject of this investigation. Poly(ester–carbonate) exhibits many similarities to polycarbonate in microcavity formation when exposed to cycling hot, humid environments. These microcavities consist of concentric bands around a central nucleation site. Scanning electron microscopy reveals that the bands consist of rings of dense material alternating with rings of material containing microvoids. Water phase separation at the nucleation site (due to cycling temperature) leads to internal pressure and thus a dilatant stress around the edge of the microcavity. It is hypothesized that this allows for the ease of further water phase separation at the periphery of the microcavity, thus yielding microvoids. The mechanical properties of poly(ester–carbonate) exposed to 96°C water immersion and 132°C steam sterilization cycling were determined and show significant loss in performance in these environments similar to that previously reported for polycarbonate.