Abstract: The aqueous two-phase copolymerization of acrylamide(AM) and methacryloyloxyethyl trimethyl ammonium chloride(DMC) with the initiator 2,2’-azobis[2-(2-imidazolin-2-yl)propane]-dihydrochloride in aqueous poly(ethylene glycol)(PEG) solution was studied. In order to determine the phase separation point where the transmittance declined suddenly, the spectrophotometer was employed to detect the transmittance of the reaction solution on-line. The effect of various parameters on the critical conversion of the reaction solution with total mass 50.0g was measured by improved bromating method. The critical conversion kept at about 37~38% as the initiator amount increased from 0.005g to 0.025g and the temperature increased from 45℃ to 65℃. And it decreased sharply as the monomers amount increased from 2.5g to 12.5g, decreased little with PEG amount increased from 2.5g to 12.5g, and also decreased with PEG molecular weight increased from 600 to 20000. But it increased with the mole fraction of DMC increased from zero to 20%. The critical molecular weight was also investigated by gel permeation chromatogram(GPC). When the initiator amount increased or temperature rose, the critical molecular weight both decreased linearly. When the overall monomers amount or PEG amount increased, the critical molecular weight increased firstly, and then decreased. The highest critical molecular weight was 3.64×105 and 7.59×105, respectively. As the mole fraction of DMC increased, the critical molecular weight decreased linearly. But when PEG molecular weight increased, it increased accordingly. The results showed that the effects of PEG molecular weight and mole fraction of DMC were most remarkable, the effects of overall monomers amount and PEG amount were little smaller, and the effects of initiator amount and temperature were smallest. Therefore, in order to bring about effective phase separation of the aqueous two-phase copolymerization system, the reaction parameters should be controlled in the suitable range. That is, initiator amount 0.005~0.025g, temperature 45~65℃, overall monomers amount 5.0~12.5g, PEG amount 7.5~12.5g, PEG molecular weight 10000~20000, mole fraction of DMC 5~10%, respectively.

Key words: acrylamide;methacryloyloxyethyl trimethyl ammonium chloride;aqueous twophase copolymerization;critical conversion, critical molecular weight

摘要： 在聚乙二醇（PEG）水溶液中进行丙烯酰胺（AM）与甲基丙烯酰氧乙基三甲基氯化铵（DMC）的双水相共聚。用分光光度计在线检测双水相聚合过程中体系透光率变化，确定了分相点并用改进溴化法测定了临界转化率，研究了反应条件对临界转化率的影响。引发剂用量或温度变化对临界转化率影响不大；单体用量、PEG用量或PEG分子量增加，临界转化率下降；DMC比例增加时，临界转化率增大。用凝胶渗透色谱法（GPC）测定了临界分子量，发现引发剂用量增加、温度升高或DMC比例增加，均使临界分子量减小；总单体用量或PEG用量增加，临界分子量先增大后减小；而PEG分子量增大增加时，临界分子量随之增大。

关键词: 丙烯酰胺, 甲基丙烯酰氧乙基三甲基氯化铵, 双水相共聚, 临界转化率, 临界分子量