RADICAL POLYMERIZATION OF VINYLSULFONIC A CID AND ITS COPOLYMERIZATION WITH ACRYLAMIDE IN AQUEOUS-SOLUTION

Radical polymerization of vinylsulfonic acid in aqueous solution and i ts copolymerization with acrylamide were studied. The rate of homopoly merization of vinylsulfonic acid and the magnitude of k(p)/k(o)1/2 dec rease with an increase in Ph from 0.15 to 1.65. When the pH is increas ed further, the reaction rate increases, reaches a maximum at pH about 2.5 - 3.0, and remains virtualy constant until pH 11.5 is attained. T he reaction order of polymerization with respect to monomer is also a function of pH and it equals 1.1 at pH 0.15 and 1.63 at pH 7; at pH 10 .2, the reaction order with respect to monomer is variable exceeding 1 .O. The rate of copolymerization of vinylsulfonic acid or its salt wit h acrylamide decreases with an increase in the content of sulfo-contai ning monomer in the monomer feed. In all cases, composition of the cop olymers formed is enriched with acrylamide units and is independent of reaction conversion up to high conversions. For acrylamide-vinylsulfo nic acid, reactivity ratios, as calculated for the initial stage of th e process, are r1 = 3.5 +/- 0.15 and r2 = 0.30 +/- 0.10 both at pH 1.6 5 and pH 11. Possible explanation of the obtained experimental results is presented.