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以甲基丙烯酸-(N,N-二甲氨基)乙酯(DMAEMA)和丙烯酸乙酯(EA)为共聚单体,二甲基丙烯酸乙二醇酯(EGDMA)为交联剂,采用半连续乳液聚合法,制备了具有pH响应性的阳离子型微凝胶,并研究不同聚合条件对所合成的微凝胶性质的影响.利用透射电子显微镜(TEM)、激光粒度分析仪和流变仪对微凝胶进行一系列表征.研究了介质pH值对微凝胶的形态、平均粒径、zeta电位、溶液浊度(透光率)的影响,以及NaCl盐溶液对微凝胶分散体系稳定性的影响.结果表明,这类阳离子型微凝胶体系具有良好的pH响应性,在pH=7左右发生相转变.此外,研究表明不同浓度NaCl溶液对微凝胶的稳定性有一定影响,临界絮凝浓度约为1.3mol·L-1.
In the experiment, ethylene glycol dimethacrylate (EGDMA) was used as crosslinking agent with DMAEMA and EA as comonomers, Emulsion polymerization method was used to prepare pH-responsive cationic microgels and the effects of different polymerization conditions on the properties of microgels synthesized were characterized by transmission electron microscopy (TEM), laser particle size analyzer and rheometer The effects of pH on the morphology, average particle size, zeta potential and solution turbidity (light transmittance) of the microgels were studied, as well as the stability of the microgel solution using NaCl salt solution .The results show that these cationic microgels have good pH responsiveness and phase transition occurs at about pH 7. In addition, the results show that different concentrations of NaCl solution have some influence on the stability of microgels, the critical Flocculation concentration of about 1.3mol · L-1.