Polymer and Materials Science
Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Poly(diacetylene)s dissolved in common organic solvents undergo random chain scission, if irradiated by UV-light. The pure polymers and their solutions are, however, stable, if they are photoirradiated within the main-absorption band of the polymer backbone. The usual triplet sensitizers, especially in the presence of oxygen, and radical donors such as 2,2′-azoisobutyronitrile (AIBN) enhance the rate of photodegradation. Suitable dyes are able to sensitize the chain-scission in the visible regions as well. Random chain scission occurs also in the dark, but only at temperatures above room temperature and is enhanced by the addition of radical-donors, e.g. AIBN. A mechanism of chain scission, induced by the attack of a radical to a multiple bond of the polyconjugated backbone of the polymer is proposed.
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