中文摘要：

以乙二胺四乙酸酐（EDTAD）和丁二胺（BDA）为原料，通过酸酐的N-酰化开环反应得到侧链只含羧基的直链共聚物PEB-COO）H，然后用N-羟基丁二酰亚胺（NHS）和二环己基碳二亚胺（DCC）活化PEB-COOH中的羧基，以重均分子量为500的氨基封端聚乙二醇（ATPEG500）为交联剂，制得单体间连接全部为酰胺键、侧链只含羧基的交联网络聚合物PEB-ATPEG500-COOH。pH敏感性测试表明，PEB-ATPEG500—000H具有3个pH敏感范围，分别是pH=2～4、pH-6～7和pH：10-11,表现出明显的两性pH敏感性。研究了该水凝胶在37℃条件下分别在pH=2、7、11介质中的溶胀动力学，并对溶胀速率进行了详细分析。该网络聚合物可望成为一种集完全可降解性、pH敏感性和生物相容性于一身的新型两性pH敏感水凝胶。

英文摘要：

A novel amphoteric pH-sensitive hydrogel with pendent carboxyl groups is designed and synthesized. Firstly, ethylenediaminetetraacetic dianhydride（EDTAD） reacted with butanediamine（BDA） through N-aeylation ringopening polymerization of anhydride groups to give a linear eopolymer with pendant carboxyl groups（PEB-COOH） ; then the earboxyl groups in PEB-COOH are activated by N-hydroxysuceinimide（NHS） and dicyclohexylearbodiimide （DCC） and thereafter cross-linked with amino terminated poly（ethylene glycol） of Mw ： 500 （ATPEGS00）, yielding the desired network polymer（PEB-ATPEGS00-COOH）. Results from FTIR verifiy the successful synthesis of this hydrogel, pH sensitivity tests indicate that this hydrogel demonstrates three pH sensitive zones at pH=2-4, pH= 6-7 and pH： 10-11, respectively. The swelling kinetics of PEB-ATPEGS00-COOH in media of pH： 2, 7 and 11 are also investigated and the swelling rates are analyzed. This novel type of hydrogels potentially feature with biodegradability, sound biocompatibility and pH sensitivity.