| abstract |
A process for preparing a copolymer consisting of 30 to 70 mole percent maleic anhydride, and 30 to 70 mole percent acrylamide or methacrylamide; The copolymer is characterized by having a relative viscosity of 1.02 to 1.1.0 in dimethyl sulfoxide, at a concentration of 0.5 g. per deciliter, and a solubility of less than 0.10 g. by g. of the solution (water), at room temperature; said procedure consists of: heating a mixture of maleic anhydride and acrylamide or methacrylamide in a chain transfer solvent mixture, at 120ºC, at least; introducing 2 to 20 percent of a free radical initiator, and continuing to maintain the mixture at a minimum temperature of 120°C, until polymerization is essentially complete. |