FEATURES OF RADICAL COPOLYMERIZATION OF WATER-SOLUBLE MONOMERS

The radical copolymerization reactions of acrylamide (AA) with N-vinylpyrrolidone (VP) in water and DMSO were studied by NMR and Raman spectroscopies. The compositions of copolymers were determined at various degrees of conversion, and reactivity ratios were calculated. For the AA-VP copolymerization in water, the reactivity ratios calculated at small conversions are r(1) 1.2 +/- 0.2 (for AA) and r(2) 0.8 +/- 0.2; in DMSO, both constants are equal to unity. The composition of copolymers formed during the copolymerization in an aqueous solution did not vary until about a 70% conversion was reached. An analysis of the present results and previous data on the copolymerization of AA with other water-soluble monomers in aqueous solutions shows that the lack of dependence of the copolymer composition on conversion is a specific feature of systems under consideration, which is caused by hydrophobic interactions in aqueous polymer solutions.