| 摘要 |
<p>1362363 Photodegradable polymers GOVERNING COUNCIL OF THE UNIVERSITY OF TORONTO 27 April 1971 [27 April 1970 14 May 1970] 20101/70 and 23387/70 Heading C3P Fabricated photodegradable articles comprise a photodegradable polymer of a vinylidene unsaturated monomer and containing in its polymeric backbone a ketonic structural unit of general formula wherein R<SP>1</SP> represents a hydrogen atom, or an alkyl group having from 1 to 6 carbon atoms and R represents a substituted or unsubstituted alkyl group, a substituted or unsubstituted alkaryl group, a substituted or unsubstituted alkenyl group or a substituted or unsubstituted aryl group, having from 1 to 9 carbon atoms, the ketonic structural units being present in an amount such that the carbonyl group thereof comprises from 0À02 weight per cent to 2 weight per cent, based on the total polymer. Photodegradable polymers in which the ketone carbonyl content is from 0À02 to 1À2 weight per cent can be prepared by copolymerizing the vinylidene unsaturated monomer with an unsaturated copolymerizable ketone of general formula R<SP>1</SP>-C(=CH 2 )-COR. Copolymers of ethylene and certain ketones having a ketone carbonyl content of 0À02 to 2 weight per cent are claimed per se. In the examples methyl methacrylate, methyl vinyl ketone, styrene, phenyl vinyl ketone, methyl acrylate, ethylene, carbon monoxide, methyl isopropenyl ketone, ethyl vinyl ketone and vinyl acetate are copolymerized in the presence of lauroyl peroxide, toluene, ethyl acetate, benzoyl peroxide, ditert-butyl peroxide and benzene. The copolymers are dissolved in benzene or made into films or moulded test pieces and exposed to ultraviolet light from a mercury vapour arc to degrade the copolymer.</p> |
