Photodegradation of Polyimides .4. Mechanism for the Photooxidation Process Based on a Model-Compound
Chemistry and Biochemistry
Based on analysis of the photochemistry of a model compound, N-phenylphthalimide, the photolysis of a polyimide derived from 4,4'-oxydianiline (ODA) and a diarylanhydride with a hexafluorinated isopropylidine bridging group (6F) is proposed to proceed via formation of a phthalic anhydride type photoproduct. The quantum yield for product formation of N-phenylphthalimide is quite low ( < 10(-3)) indicating a rather inefficient first step in the overall oxidative degradation process. However, based on the efficiency of the photo-oxidation of the primary photoproducts, a process leading to the ultimate failure and complete ablation of the 6F-ODA films in air upon exposure to the unfiltered output of a mercury lamp is postulated.
Hoyle, C. E.,
(1992). Photodegradation of Polyimides .4. Mechanism for the Photooxidation Process Based on a Model-Compound. Polymer, 33(15), 3162-3168.
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