聚乙二醇单甲醚改性壳聚糖及羧甲基壳聚糖的研究.pdf

天津大学硕士学位论文聚乙二醇单甲醚改性壳聚糖及羧甲基壳聚糖的研究姓名:冯梦凰申请学位级别:硕士专业:材料学指导教师:董岸杰 20041201 中文摘要为了改善壳聚糖的溶解性,本文对聚乙二醇单甲醚(MePEG)接枝改性壳聚糖进行了研究。首先,通过官能团偶联反应,将端基改性为醛基的聚乙二醇单甲醚接枝到壳聚糖分子链上,制得了梳状、可溶于水的聚乙二醇单甲醚接枝壳累糖()。采用元素分析、红外光谱和透射电镜等方法对产物的结构和性质进行了表征。研究表明,所制得的CTS—g—MePEG在水溶液中能够自鲴装成皎束,且在酸性溶液中表现出有别于壳聚糖的流变性。采用上述方法,本文还制备了可以在更广泛的pH值范围内分散的聚乙二醇单甲醚接枝羧甲基壳聚糖(),并对其流变性、两性聚电解质性质及其与水溶性壳聚糖的复合行为进行了研究。为了保留壳聚糖上的氨基,本论文探索了另一种接枝改性壳聚糖的途径,即用邻苯二甲酸酐对壳聚糖上的氨基进行保护,然后用甲苯二异氰酸酯为偶联剂将聚乙二醇单甲醚接枝到壳聚糖大分子链上,最后用水合联氨为还原剂解除对氨基的保护。实验结果表明,该方法可以使氨基得到保护,并能把聚乙二醇单甲醚接枝到壳聚糖上,但水合联氨在脱保护氨基的同时也还原了接枝链上的氨酯键,导致了聚乙二醇单甲醚的去接枝化。关键词:壳聚糖;羧甲基壳聚糖;聚乙二醇单甲醚;接技反应 ABSTRACT Inorder toimprove thepoorsolubility ofchitosan,monomethoxy poly(ethylerie glyc01)graftedchitosan(CTS—g—MePEGl wel℃prepared by thereacting ofaldehyded monomethoxy poly(ethylene91yc01)and the 2-amino functions b·-shaped CTS—g-MePEG products present good watersolubility. Elemental analysis、IR spectroscopy and TEM meth,:.ds were used:o estimate the properties of the grafted rcsnks indicate that ihe prepared CTS·g-MePEG Callself-assemble intomieelles indistilled water thegrafted chitosan presents different rheological property from chitosan inacidic medium. Using the same method,the present paper also prepared monomethoxy poly(ethyleneglyc01)gaffed carboxymethyl chitosan(CMCTS·g—MePEG),which Can be dispersed inwater over allpH rheological property,amphoteric polyelectrolyte property and plexing behavior of CMCTS and CMCTS—g—MePEG with water-soluble chitosan were investigated. Inordertoremain thefreeamino groups onchitosan,chitosan-0一monomethoxy poly(ethylene glyc01)Wasprepared by thegrafting ofMePEG—NCO tothehydroxyl groups ofN·phthaloyl groups were removed witllhydrazine monohydrate toregenerate thefreeamino resultsshowed thattheamino groups call beprotected byphthalic anhydride and MePEG callbegrafted onto CTS atthehydroxyl ,the hydroxyl groups were partly deoxidised