Phase separation in aqueous stabilizer-free two-phase polymerization

doi:10.11949/j.issn.0438-1157.20160640

Abstract

Abstract:

Aqueous stabilizer-free two-phase copolymerization of acrylamide (AM), 2-methylacryloylxyethyl trimethylammonium chloride (DMC) and acryloyloxyethyl dimethylbenzyl ammonium chloride (AODBAC) with initiator 2,2'-azobis[2-(2-imidazolin-2-yl) propane]-dihydrochloride was studied. UV spectrophotometer was used to monitor in-line transmittance change of reaction mixture and to detect critical point of phase separation. The conversion rate (X_c) and molecular weight (M_c) at the critical point were measured by improved brominating and viscometric methods, respectively, and were investigated on effect of various factors. The cationic surfmer, AODBAC, was found to have a good performance on promoting phase separation of the system. Change of initiator amount and molar fraction of AODBAC had minimal effect on X_c, which however increased linearly at increase of temperature. The increase of initiator amount, temperature, and molar fraction of AODBAC caused linear decrease of M_c. X_c decreased but M_c increased significantly when molar fraction of AM and overall monomer amount were increased.

Key words: stabilizer-free system, aqueous two-phase, polymerization, phase separation, stability

摘要：

以丙烯酰胺（AM）、季铵类阳离子甲基丙酰氧乙基三甲基氯化铵（DMC）和丙烯酰氧乙基二甲基苄基氯化铵（AODBAC）为单体，以2，2'-偶氮双[2-（5-甲基-2-咪唑啉-2-基）丙烷]二盐酸化物（VA044）为引发剂，在水溶液中进行无稳定剂体系下的双水相共聚。利用紫外分光光度仪在线观察体系的分相过程并测定体系的临界分相点。通过改进的溴化法测定临界转化率（X_c）。利用黏度法测定临界分子量（M_c）。并对各个因素对于X_c和M_c的影响进行研究。结果表明具有表面活性的阳离子单体AODBAC对体系的相分离具有较好的促进作用。引发剂的用量和AODBAC的摩尔分数（f_AODBAC）对于X_c的影响较小，反应温度升高会使X_c增大。总单体浓度和f_AM的升高会使X_c减小。引发剂用量的增加、反应温度和f_AODBAC的升高都会使M_c减小。f_AM和单体浓度的增加会使M_c显著增加。

关键词: 无稳定剂体系, 双水相, 聚合, 相分离, 稳定性

CLC Number:

TQ326.4

FAN Weixiao, SHAN Guorong, PAN Pengju. Phase separation in aqueous stabilizer-free two-phase polymerization[J]. CIESC Journal, 2017, 68(2): 781-787.

范维骁, 单国荣, 潘鹏举. 无稳定剂体系下的双水相聚合相分离[J]. 化工学报, 2017, 68(2): 781-787.

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