| 摘要 |
Hydrophilic particulate polyacrylamide having a combined acrylamide content of at least 85% by weight containing a hydrophilic polyacrylamide-chromic complex as a water-solubilizing agent is made by subjecting water-soluble monomeric material containing at least 85% of acrylamide to redox polymerization in aqueous medium in the presence of a small amount of a water-soluble chromic salt, until the monomer has polymerized to an alkanol-insoluble state, and precipitating the polymer in particulate form by addition of an alkanol. Alternatively, a similar product may be made by contacting polyacrylamide with an alkanol-water mixture containing a water-soluble chromic salt, until an effective amount of the salt has reacted with the polymer. Chromic salts specified are the chloride, acetate, sulphate and a tanning solution. Polymers specified are polyacrylamide, copolymer of acrylamide with acrylic acid, 2-vinyl pyridine diethylaminoethyl acrylate quaternized with methyl chloride, and trimethylvinyl phenyl ammonium chloride, and a copolymer containing 5% of vinylamine units. |
