华侨大学
姓名：高永康
申请学位级别：硕士
指导教师：肖聪明
20070101
摘要
摘要
本文将生物相容性良好的水溶性聚乙烯醇（PV A），与多糖高分子以化学（接枝到淀粉分子链）或物理
（与含羧基的羧化淀粉和羧甲基纤维素钠混合）的方式相结合，再经冷冻-解冻过程形成物理交联水凝胶，并对其结构和性能之间的关系进行了分析、探讨，得到了如下结果：
1）合成出不同侧链PV A分子量的Starch-g-PV A，并制得相应的物理交联水凝胶。DSC和WAXD分析结果表明，Starch-g-PV A物理凝胶的形成机理与PV A物理凝胶相似，但其形成凝胶的能力受侧链分子量的制约，当侧链分子量低于1.5×104时即无法形成物理交联水凝胶。
2）制得均匀分散的Starch-g-PV A/HA复合凝胶，其再溶胀性能与PV A/HA的相近。冷管>夏普 sh8298u
3）制得不同比例的羧化淀粉与PV A的复合物理水凝胶，羧基的引入，增强了组分间的相互作用，降低了复合物理凝胶的结晶度，提高了凝胶的再溶胀性，且与羧化淀粉的取代度大小有关。
4）制得具有pH响应性的CMC/PV A复合水凝胶。随着CMC含量的增加，CMC/PV A复合凝胶的结晶度下降，凝胶网络中的自由体积增大，再溶胀性提高；同时，对于环境pH的敏感性增强。以牛血红蛋白（HB）为模拟药物，对其释放性能进行初步研究的结果表明，CMC/PV A复合凝胶可用作水溶性蛋白质药物的载体，其释放速率可通过CMC含量来加以调节。
关键词：聚乙烯醇，羧化淀粉，羧甲基纤维素，复合水凝胶，物理交联
ABSTRACT
The physically cross-linked complex hydrogels of poly(vinyl alcohol) (PV A), a water-soluble and biocompatible polymer, and polysaccharides are derived from chemical or physical mixing way and subject to freezing/thawing subsequently. To mix PV A with polysaccharides in chemical or physical way, PV A is grafted onto starch chains or simply blended with carboxylic derivative of starch and sodium carboxyl methyl cellulose (CMC) respectively. The structure, properties and their relationship of the complex hydrogels are analyzed and discussed. The main results of this paper are summarized as follows:
1. Starch-g-PV A physical hydrogel with a controlled PV A branch length was prepared by freezing/thawing first. The result of DSC and WAXD indicated that the starch-g-PV A physical hydrogel was formed based on the crystallization PV A branch as the junction points. PV A branch length can be well controlled by adding chain transfer agent during PV Ac was grafting onto starch. The ability of starch-g-PV A to form gel relied on the molecular weight of PV A. It was found that the starch-g-PV A could not form hydrogel when the molecular weight of PV A branch was lower than
1.5×104.
2. Starch-g-PV A/Hydroxyapatite complex hydrogel was prepared. SEM analysis showed that hydrox
yapatite (HA) was well dispersed in the network of the complex hydrogel, attributed to the hydrogen bond was formed between HA and starch-g-PV A.
3. Carboxylic derivative of starch (MAS) derived from starch and maleic anhydride was mixing with PV A in solution and formed physically cross-linked hydrogel by freezing/thawing too. Compared to the starch/PV A hydrogel prepared in the same way, the interaction between the components of MAS/PV A hydrogel was enhanced due to the introduction of carboxyl groups. As a result, the crystallinity of the gel decreased and the the reswell property of the gel was much improved. In addition, the higher the degree of substitution of MAS is, the gel would reswell better.z11硅钢片
4. A series of CMC/PV A hydrogels that contained different ratio of CMC and PV A were peprared. The hydrogels behaved pH-responsive. With the increase of the content of CMC, the crystallinity of the hydrogels would decrease. Consequently, the free volume of the network enlarged, the gel was much more easily to reswell and the hydrogel became more sensitive to the pH changes. A preliminary study of the CMC/PV A hydrogel as the carrier of the model drug, Hemoglobin (Hb), was performed. It was found that Hb keep active after subject to the freezing/thawing procedure and the release rate can be controlled by the content of the CMC.
Keywords: PV A, carboxylic derivative of starch, sodium carboxyl methyl cellulose, complex hydrogel, physically cross-linked
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