| 摘要 |
Block and graft copolymers are obtained by reacting a polymeric material containing amino groups with a photosensitizing dyestuff, and then an ethylenically unsaturated compound containing at least one CH2=C< group is photopolymerized in the presence of the polymerdyestuff reaction product and of a reducing compound. Amino group-containing polymers specified are polyvinylamine, polyvinylaniline, polyethyleneimine and polymers obtained by polymerizing an ethylenic compound in the presence of ammonia or an amine as described in Specification 787,344, suitable monomers for this purpose being styrene, vinyl toluene methyl and ethyl methacrylates, acrylic acid and its esters, acrylonitrile, methacrylonitrile, vinyl and vinylidene chlorides, vinyl acetate and butadiene. As a photosensitizing dyestuff there is specified eosin which may be used either in the form of its lactone or sodium salt of its monochloromethyl ester for reaction with the polymer. As reducing compounds there are specified ascorbic acid and thiourea. The examples describe the following processes: (1) reacting polyvinyl tert. butyl carbamate with hydrochloric acid to produce polyvinylamine hydrochloride which is reacted with eosine lactone and then used in a photopolymerization reaction with acrylamide in the presence of ascorbic acid; (2) as in (1) but using acrylic acid as the grafting monomer; (3) as in (1) but using acrylonitrile as the grafting monomer; (4) as in (1) but using styrene as the grafting monomer; (5) as in (1) followed by the grafting of acrylic acid in a second polymerization stage; (6) polymethyl methacrylate containing terminal amino groups is reacted with eosine lactone and then block photopolymerized with styrene in the presence of thiourea; and (7) as in (6) but using acrylamide as the monomer to form the block copolymer. In the above processes water or acetic acid is used as a solvent for the reactants. The block copolymer of Example (6) may be hydrolysed to yield a mixture of styrene and methyl methacrylate homopolymers.
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