【作者】 尚冰冰；

【导师】 王进义；

【作者基本信息】 西北农林科技大学 ， 化学生物学， 2010， 硕士

【摘要】 壳聚糖(chitosan)是广泛存在于自然界的一种氨基多糖,是甲壳素(chitin)经脱乙酰后的产物。由于其良好的生物相容性,无毒,生物可降解以及抗菌性等特点,引起了很多领域对之进行相关研究。壳聚糖是一种阳离子聚合物,这使得它可以吸附一些带负电荷的胶体颗粒和细菌而用在废水处理中的,但是壳聚糖在酸中不稳定的特点限制了它的应用,而通过化学改性的办法是拓宽其应用的一种有效办法。本文主要是合成了一种新的壳聚糖衍生物,它以壳聚糖为原料,氨基保护后与氯甲酸乙酯接枝,之后水合肼去保护同时交联形成一种新的网状结构的生物大分子。其后对这种新的衍生物进行了FT-IR,1H-NMR,XRD,DSC,TGA等一系列的表征,结果发现这种衍生物具有良好的热稳定性,能吸附大量的细菌并对生物被膜生长具有一定的促进作用。因此,其有望作为一种新的吸附材料用在废水处理中以及在细菌被膜方面的研究中具有很大价值。本论文主要由以下几个方面组成(1)文献综述从甲壳素和壳聚糖开始,介绍了其分子结构,理化性质和生物学活性,对壳聚糖的化学改性和应用做了详细概述,并介绍了其相关的国内外研究成果,并对壳聚糖及其衍生物在废水处理中的研究进展做了综述,最后对细菌被膜做了简单介绍。(2)壳聚糖衍生物的合成与表征壳聚糖原料与邻苯二甲酸酐在110℃高温下反应6小时,生成氨基保护的壳聚糖,然后用氯甲酸乙酯通过羟基接枝于保护的壳聚糖上,最后用水合肼解除保护并用来交联,生成一种网状结构的大分子衍生物。这种新型的衍生物用FT-IR, 1H-NMR,XRD, DSC,TGA等进行了一系列的表征,溶胀实验表明这种衍生物只在酸和碱液中溶胀,其化学稳定性和热稳定性与原料相比都有所提高。(3)壳聚糖衍生物的细菌吸附研究为了研究壳聚糖衍生物的细菌吸附情况,我们以大肠杆菌为实验菌株,先把壳聚糖衍生物涂布在玻璃和聚苯乙烯塑料皿上成膜,用超纯水、甲醇洗涤3-5次,室温干燥后备有。研究结果发现,用这种新制备的壳聚糖衍生物修饰玻璃和聚苯乙烯后能促进大量细菌的粘附,随着时间的增加,能看到明显的细菌被膜生成。因此,这种新的衍生物有望在废水处理中作为吸附细菌的材料加以应用,此外,它可以用在一些关于细菌被膜的研究中。更多还原

【Abstract】 Chitosan is derived from deacetylation of chitin with many amino groups. Known to be biocompatible, non-toxic, biofunctional and biodegradable, it has been attractive for many fields. The cationic nature of chitosan make it adsorb negatively colloidal particles and bacterial in waste waters, but chitosan can dissolve in acid medium, which restricts its application, chemical modification is an common method to solve this problem and widen the application. In this study, a new chitosan derivative was synthesized by chitosan, ethyl cholorocarbonate was introduced to hydroxyl group of phthaloyl-chitosan through nucleophilic reaction, then hydrazine was added to give recovery of amino groups of chitosan and also give crosslinking to give network of this new derivative. The new chitosan derivative was characterized by FT-IR, 1H-NMR, XRD, DSC and TGA, respectively, the results indicate this new derivative has improved thermal stability and chemical stability compared to chitosan, and in bacterial adsorption studies, the bacteria adhere significantly and amounts of biofilm formed obviously. It is very attractive for adsorption in waste water treatment and studies about biofilm. The main composition of this paper is as follows:(1) Literature reviewIn this part, chitosan and chitin were introduced. Structure, physical and chemical properties of chitosan, chemical modification of chitosan and studies about it all over the world, application of chitosan and chitosan derivative in waste water treatment, and biofilm were presented.(2) Synthesis and characterization of the new chitosan derivativeThe new chitosan derivative was synthesized as follows: Firstly, the chitosan was protected by phthalic anhydride at 110 for 6h, then grafted by ethyl chlorocarbonate on hydroxyl groups of chitosan, and finally deprotected by hydrazine and also crosslinked by hydrazine, therefore, the amino groups appear again in the backbone of this new derivative with network structure. The new compound was characterized by FT-IR, 1H-NMR, XRD, DSC and TGA respectively. The new derivative only swells in acid medium and alkaline medium, the chemical and thermal stability of this new chitosan derivative has improved.(3) Bacterial adhesion studyIn order to study bacterial adsorption of the new chitosan derivative, chitosan derivative was formed film on glass or Polystyrene (PS) Petri dishes, dried in air at room temperature overnight, then washed by ultra pure water and methanol 3-5 times. The modified surface by chitosan derivative has presented good capability of bacteria adsorption and enhanced biofilm formation significantly, so it is interesting for adsorption in waste water treatment and biofilm studies.更多还原