聚丙烯酰胺-聚乙二醇-水体系相图及丙烯酰胺单体在两相中的分配

Phase Diagram of Poly(acrylamide)-poly(ethylene glycol)-water and Partition Coefficient of Acrylamide

聚丙烯酰胺(PAAm)和聚乙二醇(PEG)两种水溶液混合时能形成双水相体系,其中上层为PEG富集相,下层为PAAm和PEG的混合相.用凝胶渗透色谱(GPC)法和浊度滴定法研究了PAAm-PEG-H2O双水相体系的相图,结果表明,随着PEG分子量的升高,体系的分相浓度下降.在PAAm-PEG20000-H2O体系中,随着体系温度升高,分相浓度先下降后升高,55℃时分相浓度最低.丙烯酰胺(AAm)单体能在两相中发生相分配,分配系数随着PAAm浓度和平衡温度的增加而增大,随着PEG浓度的增加而下降.

It is found that when the two aqueous solutions of poly(acrylamide)(PAAm) and poly(ethylene glycol)(PEG) are mixed, an aqueous two-phase system can be formed. The top is the PEG-rich aqueous phase and the bottom is the mixture of rich PAAm and PEG aqueous phase. The phase diagrams of this system are made with gel permeation chromatography(GPC) and turbidity titration methods. As the molecule weight of PEG increases, the critical concentration of phase separation becomes lower. As the temperature of this system increases, the critical concentration of phase separation decreases at first, but when the temperature is higher than 55 ℃, it increases again. Acrylamide(AAm) can be partitioned in PAAm-PEG-H-2O aqueous two-phase system, the partition coefficient(K) of AAm in this system increases with increasing the temperature of phase equilibrium and the PAAm concentration, but decreases with increasing the PEG concentration.