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Carbon dioxide foaming of glassy polymers
Author(s) -
Wessling M.,
Borneman Z.,
Van Den Boomgaard Th.,
Smolders C. A.
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.1994.070531112
Subject(s) - polymer , nucleation , materials science , supersaturation , glass transition , carbon dioxide , porosity , chemical engineering , carbon fibers , glassy carbon , homogeneous , blowing agent , composite material , chemistry , thermodynamics , organic chemistry , polyurethane , physics , composite number , engineering , cyclic voltammetry , electrode , electrochemistry
The mechanism of foaming a glassy polymer using sorbed carbon dioxide is studied in detail. A glassy polymer supersaturated with nitrogen forms a microcellular foam, if the polymer is quickly heated above its glass transition temperature. A glassy polymer supersaturated with CO 2 forms this foam‐like structure at much lower temperatures which indicates the T g ‐depressing effect of CO 2 . Having this interpretation in mind, the overall sample morphology, i.e., a porous foam enclosed by dense outer skins, can be completely explained. The dense skins, however, are not homogeneous but show a nodular structure when analyzed by SEM and AFM. Foaming experiments with samples having a different thermal history suggest that the nucleation mechanism underlying the foaming process is heterogeneous in nature. © 1994 John Wiley & Sons, Inc.