Photodegradation of Aromatic Polyimides
Technical rept. no. 4, 1 Jun 1989-31 May 1990
UNIVERSITY OF SOUTHERN MISSISSIPPI HATTIESBURG DEPT OF POLYMER SCIENCE
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The photolysis results for a soluble polyimide, 6F-ODA, based on 2,2- bis3,4-dicarboxyphenyl hexafluoropropane dianhydride 6F and 4,4- oxydianiline ODA were compared to the polyimides, PMDA-ODA and BTDA-ODA, based on, pyromellitic dianhydride PMDA and 3,34,4-benzophenone tetracarboxylic dianhydride BTDA, which were reacted with ODA. All the photolyses involved the exposure of thin polymeric films to a medium pressure mercury lamp unfiltered in air. The IR, UV, and weight loss results for the polymers suggest that an ablative process occurs upon photolysis. The spectral and weight loss changes were much greater for 6F-ODA. Dilute solution viscometric and gel permeation chromatographic analyses of the pristine and photolyzed 6F-ODA points toward a very rapid and efficient chain scission process along the polymer backbone. The strength of the charge transfer CT interactions in the respective polymers may explain in part the greater UV stability observed for the PMDA-ODA and BTDA-ODA.
- Polymer Chemistry