表面强化交联聚(N-异丙基丙烯酰胺)水凝胶的温敏和浓缩分离性能

Thermo-sensitive and separation properties of poly(N-isopropylacrylamide) hydrogels with enhanced surface crosslinking

为了提高聚(N异丙基丙烯酰胺)(PNIPA)凝胶粒子的浓缩分离效果,以过硫酸铵/N,N,N′,N′,四甲基乙二胺为引发体系,N,N′亚甲基双丙烯酰胺(BIS)和二乙烯苯(DVB)为复合交联剂,通过反相悬浮聚合合成了表面强化交联的PNIPA凝胶粒子.考察了凝胶颗粒形态、温敏特性及其浓缩分离聚乙二醇/水性能.发现得到的凝胶为紧密珠状粒子,低临界溶解温度为32℃;随着溶质聚乙二醇相对分子质量增大或浓度减小,凝胶对聚乙二醇/水的分离效率提高;增加合成PNIPA凝胶时的BIS用量,可提高凝胶对聚乙二醇/水的分离效率,但溶胀率显著下降;增加DVB用量,分离效率大幅提高,而凝胶溶胀率基本不变.

To improve the separation efficiency of thermo-sensitive poly（N-isopropylacrylamide） （PNIPA） hydrogels, an inverse suspension polymerization process was used to prepare PNIPA hydrogels by using ammonium persulfate and N,N,N＇,N＇-tetramethylethylenediamine as a pair of redox initiators, and N, N＇-methylene bisacrylamide （BIS） and divinylbenzene （DVB） as the multiple crosslinking agents. The morphology, thermo-sensitivity and the application to the separation of poly（ethylene oxide） glycol （PEG） aqueous solution of the resultant PNIPA hydrogels were investigated. It was found that the obtained hydrogels were in the form of beads with a rather compact structure and had a lower critical solution temperature （LCST） of 32℃. The separation efficiency increased with the increase of the molecular mass or with the decrease of the concentration of PEG. Increasing the amount of crosslinking agents could also improve the separation efficiency, and the introduction of hydrophobic DVB was an effective way to improve the separation efficiency without the loss of swelling ratio of hydrogels.