在超声作用下,以甲基丙烯酸为原料,N,N’-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,自由基引发聚合制备了pH敏感水凝胶聚甲基丙烯酸,采用红外光谱(FT-IR)和扫描电镜(SEM)对水凝胶分子结构与性能进行表征.在此基础上,重点研究了超声合成对于水凝胶的溶胀性能、消溶胀性能等性质的影响.实验结果表明,超声作用下合成的聚甲基丙烯酸水凝胶溶胀动力学性能以及响应灵敏性均优于常规合成方法. Under the action of ultrasound, methacrylic acid as raw material, N, N’-methylenebisacrylamide as crosslinking agent, potassium persulfate as initiator, free radical initiated polymerization to prepare pH-sensitive hydrogel polymethacrylic acid , The molecular structure and properties of hydrogel were characterized by FT-IR and SEM. On the basis of this, we focused on the properties of hydrogel such as swelling property, swelling-removing property and so on .The experimental results show that the swelling kinetics and the response sensitivity of the poly (methacrylic acid) hydrogels synthesized under the action of ultrasound are superior to those of the conventional synthesis methods.