METHOD FOR SYNTHESIZING AQUEOUS SOLUTION OF HOMOPOLYMER N VINYL BUTYROLACTAM (K60) WITH LOW RESIDUAL MONOMER AND MIDDLE HIGH MOLECULAR WEIGHT

摘要

pDisclosed is a method for synthesizing an aqueous solution of homopolymer N vinyl butyrolactam (K60) with low residual monomer and a middle high molecular weight using 20 50% weight of an aqueous solution of N vinyl butyrolactam monomer as a raw material in the presence of an inert gas at a polymerization temperature of 57°C 72°C carrying out a reaction under stirring for 4 6 h during which the temperature is increased in stages and an initiator is added in decreasing amounts the initiator being azobisisoheptonitrile the total amount of the initiator added being 0.01~2% of the mass of the N vinyl butyrolactam monomer; after the K value of the system reaches 58~65 adding sulphuric acid to adjust the pH to be at 4.2 4.5 maintaining the temperature at 90 140°C and stirring for more than 4 hours to remove the residual monomer so as to obtain 20 50% weight of a colourless and transparent aqueous solution of homopolymer N vinyl butyrolactam (K60) with low residual monomer and a middle high molecular weight and having residual monomer below 10 ppm and the K value of 58 65./p