星形PDMAEMA的合成与HPAM水凝胶体系构筑

Preparation of Star-shaped PDMAEMA and Construction of Hydrogelsolution System with HPAM

以超支化聚乙烯亚胺(HPEI)与2-溴异丁酰溴(BIB)之间的酰基化反应制备系列支化度水溶性大分子引发剂,在0℃条件下,成功实现了甲基丙烯酸二甲氨基乙酯(DMAEMA)的单电子转移活性自由基聚合(SET-LRP),通过1H-NMR、FT-IR、GPC等手段对聚合物进行了表征。研究表明:DMAEMA/H2O(v/v)对聚合反应有影响,其配比存在最优值,聚合动力学呈一级线性关系,具有活性可控的典型特征。用浊度法研究了不同臂数星形聚甲基丙烯酸二甲氨基乙酯(H-PDMAEMA)的响应行为。结果表明:随着支化度的增大,H-PDMAEMA的LCSTs值降低,溶液相态变化显著。以不同支化度H-PDMAEMA与部分水解聚丙烯酰胺(HPAM)共混构筑水凝胶溶液体系,考察了H-PDMAEMA结构对HPAM水溶液黏度及黏度保持率的影响。结果表明,加入H-PDMAEMA可提高HPAM水溶液的黏度;随着H-PDMAEMA支化度的增加,增黏能力提高;与HPAM相比,HPAM/H-PDMAEMA水凝胶溶液体系具有优良的耐温性能,在一定的盐浓度及剪切速率范围内,HPAM/H-PDMAEMA体系的黏度均高于HPAM溶液。

A series of water-soluble macroinitiators derived from polyethyleneimine(HPEI)were used to initiate the SET-LRP of DMAEMA at 0℃in aqueous solution.The polymers prepared were characterized by 1H NMR,FT-IR and GPC.The effects of DMAEMA/H2O(v/v)on polymerization were studied and the optimum condition was given.The response behavior of star-shaped PDMAEMA(H-PDMAEMA)with different amounts of arms was studied by turbidimetry.The results showed that the process is a well-controlled living radical polymerization.With the increase of the arms,the LCSTs of H-PDMAEMA decreased,the thermo sensitive property of the copolymer can be magnified by the increasing arms.the LCSTs of H-PDMAEMA.The supramolecular hydrogel was constructed by blending H-PDMAEMA with partial hydrolyzed polyacrylamide(HPAM).The effects of H-PDMAEMA structure on the viscosity of HPAM aqueous solution were investigated.The results show that the H-PDMAEMA can improve the viscosity of HPAM aqueous solution;with the increasing arms of H-PDMAEMA,the viscosifying ability is improved;compared with HPAM,the HPAM/H-PDMAEMA supramolecular hydrogel solution system has excellent heat resistance.In a certain range of salt concentration and shear rate,the viscosity of HPAM/H-PDMAEMA is higher than that of HPAM solution.