β羧基丙酸羟丙基甲基纤维素酯的制备与特性研究

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1、摘要羟丙基甲基纤维素(肿MC)的热凝胶转变主要缘于体系中对温度非常敏感的分子间或链段间的缔合或组装。本工作通过酸酐对HPMC进行酰化制备了D．羧基丙酸羟丙基甲基纤维素酯和6．羧基丙酸醋酸羟丙基甲基纤维素酯，并重点对其凝胶转变和特性进行了研究。采用丁二酸酐和醋酸酐为酯化剂、无水醋酸钠为催化剂与HPMC通过酯化反应在冰醋酸溶剂中制备了一系列合成产物，即B．羧基丙酸羟丙基甲基纤维素酯([3-CPHPMC)和p．羧基丙酸醋酸羟丙基甲基纤维素酯(p-CPAHPMC)。采用电导率滴定法测定了产物中的D．羧基丙酰基的含量；采用FT-IR红外光谱

2、、粘度分析和流变仪等方法对其结构和性能进行了表征。结果表明：平均每个D．羧基丙酸羟丙基甲基纤维素酯分子链上D．羧基丙酰基的含量为2．9～12．42；1wt％13．CPHPMC溶液的凝胶温度从56．65℃降至41．9℃，而1叭％HPMC溶液的凝胶温度为59．85℃；6．羧基丙酰基的含量越多，13-CPHPMC凝胶温度越低；凝胶强度也随着增大；与13-cP唧Mc相比，[3-CPAHPMC由于引入乙酰基，其凝胶强度大大增加。关键词：羟丙基甲基纤维素；热凝胶；D．羧基丙酸羟丙基甲基纤维素酯；p．羧基丙酸醋酸羟丙基甲基纤维素酯；丁二酸酐；醋

3、酸酐；凝胶温度；凝胶强度；缔合；组装ABSTRACTThethermoreversiblegelationofhydroxypropyImethylcellulose(HPMC)isgeneratedmainlyduetothetemperature．sensitiveintermolecularassociationorassembly．Inthiswork，hydroxypropylmethylcellulosederivativeswerepreparedbvesterificationwithacidanhydride，w

4、hichwereinvestigated，layingastrongemphasisontheirthermogelationandproperties．Therefore，twoseriesofhydroxypropylnlethylcellulosederivatives，whichare13-carboxypropionatehydroxypropylmethylcellulose(13-CPHPMC)andp’carboxypropionateacetatehydroxypropylmethylcellulose(13．C

5、PAHPMClweresynthesizedfromhydroxypropylmethylcellulose(HPMC)byesterificationusingSUCClnlCanhydrideand／oraceticanhydrideasesterifyingagent，anhydroussodiumacetateascatalystandaceticacidasorganicsolvent．Thecontentof13-carboxypropionylgroupin13-CPHPMCwasdeterminedbyconduc

6、tometrictitfation．Thestructureandpropertiesof13-CPI-IPMCwereanalyzedbyFT-Rviscometerandrheometer．Theresultshowedthatthenumberof13-carboxypropionylgroupspercellulosicmacromolecularchainwasfrom2．9t012．42andthegelationtemperatureof1％byweight／3-CPHPMCsolutionsrangedfrom56

7、．65。Cto41．9"C．whereasthatofalwt％HPMCsolutionwas59．85V，thatwithallincreaseintheCO力tentof13-carboxypropionylgroups，thegelationtemperatureof13-CPI-IPMCdecreasesbutitsgelstrengthIncreasesandthatincomparisonwithI]-CPI-tPMC，thegelstrengthof[3-CPAHPMCisconsiderablyhighbecaus

8、eofacetylgroupsonitsmoIecularchains．KEYWORDS：hydroxypropylmethylcellulose，thermoreversiblegelation，13-carboxypropionatehydro