硫酸铵-水-聚丙烯酰胺及阳离子型聚丙烯酰胺体系相分离

Phase separation of ammonium sulfate-water-polyacrylamide and cationic polyacrylamide aqueous two-phase systems

通过测量硫酸铵(AS)-水-聚丙烯酰胺(PAM)、AS-水-阳离子型聚丙烯酰胺(CPAM)双水相体系分相所需的加盐量,评价各种因素对相分离的影响。实验结果表明,添加一些特殊的物质(如液体石蜡、环己烷、正己烷等),以及在有大量单体存在的条件下添加叔丁醇或聚乙二醇200(PEG200),能起到促进分相的作用。考察了单体丙烯酰胺(AM)、温度、搅拌强度、保护剂聚丙烯酰氧乙基三甲基氯化铵(PDAC)、聚合产物PAM、CPAM对分相所需加盐量的影响。研究发现,体系中大量存在的单体能大幅削弱盐溶液的极性,是阻碍分相的最为重要的因素。

Phase separation is the foundation of aqueous two-phase polymerization.The polymerization process cannot proceed normally without phase separation.Phase separation is regarded as the result of superposition of various factors.Ammonium sulfate （AS） concentration is one of these factors and increasing AS concentration is obviously beneficial to phase separation.If the change of some other factor can reduce the amount of AS needed to achieve phase separation,this change is in favor of phase separation.In this paper,the amount of AS for phase separation was used as the standard to evaluate the effects of various factors on phase separation,and the lower AS amount the better.The amounts of AS for phase separation of AS-water-polyacrylamide （PAM）,AS-water-CPAM aqueous two-phase systems were measured.The experiment results showed that adding some special material （such as liquid paraffin,cyclehexane,n-hexane,or t-butanol,PEG200 in the case of plentiful existence of monomer）,lowering temperature,and increasing PAM concentration were beneficial to phase separation.But plentiful existence of monomer could significantly decrease polarity of AS solution,which was the most important factor affecting phase separation.