| 摘要 |
PURPOSE:To obtain a high-molecular graft polysaccharide copolymer capable of forming an aqueous solution which has a stable viscosity even at high temperatures, by graft-polymerizing an acrylic monomer with a high-molecular polysaccharide molecularly dispersed in water, in the presence of a cerium salt. CONSTITUTION:A high-molecular polysaccharide such as xanthane gum produced from glucose by microorganisms is colloidally dispersed in water, and the solution is heated to a temperature >=60 deg.C to disperse the high-molecular polysaccharide molecularly. An acrylic monomer of the formula (wherein R is H or methyl, and R' is -NH2, -OH, or the like), e.g., acrylamide, is added thereto and graft-polymerized in the presence of a cerium salt (e.g., ammonium ceric sulfate) to obtain the titled graft copolymer. An aqueous solution of this graft copolymer does not undergo abrupt viscosity drop even when it is heated to 60 deg.C or above. |
