硕士学位论文论文题目壳聚糖纤维/结冷胶复合水凝胶的力学性质和保水性研究生姓名刘丽梅指导教师姓名白同春（教授）专业名称物理化学研究方向化学热力学论文提交日期2013年5月苏州大学学位论文独创性声明本人郑重声明：所提交的学位论文是本人在导师的指导下，独立进行研究工作所取得的成果。
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非涉密论文□论文作者签名：日期：导师签名：日期：壳聚糖纤维/结冷胶复合水凝胶的力学性质与保水性摘要壳聚糖纤维/结冷胶复合水凝胶的力学性质与保水性摘要结冷胶（Gellan gum），是经美国食品和药物管理局批准的食品添加剂，由于其形成的水凝胶含水量高、良好的生物相容性和机械性能可控、为软骨细胞的增殖和分化提供更接近人体真实软骨细胞外基质的微环境，在软骨修复和替代材料等方面备受关注。
但是单一的结冷胶由于较差的力学性能并不能满足软骨替代材料的要求，需要添加其他成分来弥补这一缺陷。
因壳聚糖纤维（CSFs）具有纤维形态和壳聚糖材料的双重优点而被用作增强相。
本论文主要研究壳聚糖纤维增强的结冷胶复合水凝胶的结构与物理化学性质之间的关系，对人工组织材料的研发具有重要意义。
主要内容有以下三方面：1．制备了不同CSFs含量的高酰基结冷胶（HG）水凝胶（CSF-HG）。
研究了不同CSFs含量的CSF-HG水凝胶材料的流变性能、断裂形貌、溶胀行为、失水动力学和介电性能。
结果表明，由于CSFs穿梭于HG水凝胶的三维网络之间，显著地提高了HG水凝胶的储能模量（G'）。
而且CSFs能够阻碍HG大分子链段的宏观运动，降低了水凝胶的溶胀度和平衡水含量，并使得CSF-HG水凝胶在脱水过程中显示出较HG水凝胶低的吸热焓。
CSFs大分子上富有亲水性的氨基基团，使得CSF-HG水凝胶与水分子之间形成更强的相互作用，提高了其脱水活化能。
另外，极性的氨基基团大幅提升了CSF-HG水凝胶的介电常数。
2．将CSFs加入具有一定比例的高酰基与低酰基混合结冷胶（HLG）中，制备钙离子（Ca2+）交联的复合水凝胶，研究了CSFs与HLG大分子链之间的相互作用及其对复合水凝胶材料力学性质，溶胀行为，热学稳定性和介电性能的影响。
结果表明，CSFs与HLG大分子之间形成了大量的氢键，使得CSF-HLG水凝胶的热稳定性增强，I摘要壳聚糖纤维/结冷胶复合水凝胶的力学性质与保水性力学强度提高。
由于CSFs阻碍了HLG大分子链段的运动，使得复合水凝胶的溶胀度和平衡水含量较HLG水凝胶低的多，其在脱水过程中的吸热焓也有一定程度的下降。
，扫瞄式电子显微镜（SEM）显示，CSF-HLG复合水凝胶在经烘箱干燥后，仍有大量的孔洞结构，而HLG水凝胶的3D结构完全塌陷无孔洞存在，说明CSFs对复合水凝胶的网孔起支撑作用。
3. 在低酰基结冷胶（LG）中加入CSFs，制备CSF-LG复合水凝胶。
考察了凝胶体系的流变性能，热失水动力学。
利用Kissinger–Akahira–Sunose (KAS)等转化率法获得凝胶的非等温失水活化能与转化率之间的关系，即转化率增大，活化能降低。
结冷胶中加入壳聚糖纤维，使其失水活化能增加。
关键词：结冷胶，壳聚糖纤维，水凝胶，力学性能，脱水动力学作者：刘丽梅指导老师：白同春（教授）Mechanical and water-holding properties of chitosan fiber/gellan gum composite hydrogels AbstractMechanical and water-holding properties of chitosan fiber/gellan gum composite hydrogelsAbstractGellan gum is a food additive approved by U.S.A Food and Drug Administration (FDA). It has attracted much attention due to its good biocompatibility, controllable mechanical properties, and it also can provide microenvironment similar to cartilage extracellular matrix for chondrocyte proliferation and differentiation. However, the mechanical property of gellan gum is so poor that it cannot meet the requirements for cartilage substitute materials. Chitosan fibers (CSFs)were used to be the reinforcing phase since its high strength. In this thesis, the relationship between the structure and physicochemical properties of chitosan fiber reinforced composite gellan gum hydrogel was studied, and this study would promote the development of artificial tissue materials.Firstly, the CSF and high-acyl gellan gum (HG) hydrogels with different CSFs content were prepared. And the rheological properties, fracture morphology swelling behavior, dehydration kinetics and dielectric properties were systematically studied. The result shows that the CSFs significantly improve the storage modulus (G') of HG hydrogel. In addition, CSFs were interspersed in the three-dimensional network of CSF-HG hydrogels, which hinder the motion of HG chain segments, and reducing the swelling degree and the water content in equilibrium. The 2.0CSF-HG hydrogel has lower endothermic enthalpy than that of HG hydrogel during the dehydration process. Moreover, the hydrophilic amino groups of CSFs would form stronger interaction between water and macromolecules in 2.0CSF-HG hydrogel, and increase its dehydration activation energy. Besides these, the polar amino groups endow the oven-dried 2.0CSF-HG hydrogel with significantlyIIIAbstract Mechanical and water-holding properties of chitosan fiber/gellan gum composite hydrogels enhanced dielectric constant, 878 at 1 Hz.Secondly, we added CSFs into a mixed gellan gum of high-acyl (HG) and low-acyl gellan gum (LG), which was cross-linked by calcium ion (Ca2+). Then, the interaction between CSFs and HLG macromolecule, and its effect on mechanical strength, swelling behavior, thermal stability and dielectric properties of composite hydrogels were systematically studied. The results showed that a large number of hydrogen bonds between CSFs and HLG macromolecules were formed, which improve the thermal stability and mechanical strength of 2.0CSF-HLG hydrogel. Similarly, hindered by CSFs, the HLG macromolecular chain segments cannot change by a large margin to absorb water, so the 2.0CSF-HLG hydrogel showed low swelling degree and water content in equilibrium, and its endothermic enthalpy is also lower than that of HG hydrogel during the dehydration process. However, due to the supporting effect by CSFs, there were plenty of holes in 2.0CSF-HLG hydrogel after it was dried in thermal oven. By this treatment, the 3D structure of HLG hydrogel was collapsed.Finally, CSFs were added into LG to prepared CSF-LG hydrogels, the rheological properties and thermal dehydration kinetics of CSF-LG hydrogels were studied. By using the iso-conversional method of Kissinger-Akahira-Sunose (KAS), the relationship between the dehydration activation energy and the conversion rate was obtained. It is found that the activation energy decreases as the conversion rate increases, and increases with the content of CSFs.Keywords:gellan gum, chitosan fibers, hydrogel, mechanical property, dehydration kinetics.Written by: Limei LiuSupervised by: Prof. Tongchun Bai目录第一章文献综述 (1)1.1 水凝胶支架材料分类 (1)1.1.1 天然聚合物 (1)1.1.2 人工合成聚合物 (5)1.2 用于软骨修复水凝胶的研究进展 (6)1.2.1 可注射水凝胶 (6)1.2.2 双网络结构水凝胶 (9)1.3 本课题研究内容及意义 (11)第二章壳聚糖纤维增强的高酰基结冷胶水凝胶的力学性能和保水性 (13)2.1前言 (13)2.2 实验部分 (14)2.2.1原料 (14)2.2.2 HG水凝胶的制备 (14)2.2.3 CSF-HG水凝胶的制备 (14)2.2.4性能测试 (14)2.3 结果与讨论 (16)2.3.1 流变性能 (16)2.3.2 断面形貌 (17)2.3.3 溶胀行为 (17)2.3.4 脱水动力学 (18)2.3.5 介电性能 (24)2.4 本章小结 (25)第三章壳聚糖纤维/高-低酰基结冷胶水凝胶的结构与性能 (26)3.1 前言 (26)3.2 实验部分 (27)3.2.1原料 (27)3.2.2 HLG水凝胶的制备 (27)3.2.3 CSF-HLG水凝胶的制备 (27)3.2.4性能测试 (27)3.3 结果与讨论 (29)3.3.1 红外、拉曼、XRD和TG表征 (29)3.3.2 流变分析 (33)3.3.3 水凝胶的溶胀性能 (34)3.3.4 凝胶形态 (35)3.3.5介电性能 (36)3.3.6 脱水动力学 (37)3.4 本章小结 (45)第四章壳聚糖纤维/低酰基结冷胶复合水凝胶的力学性质与失水动力学 (46)4.1 前言 (46)4.2 实验部分 (46)4.2.1原料 (46)4.2.2 LG水凝胶的制备 (47)4.2.3 CSF-LG水凝胶的制备 (47)4.2.4性能测试 (47)4.3 结果与讨论 (47)4.3.1 流变行为 (47)4.3.2 脱水动力学 (48)4.4 本章小结 (55)结论 (56)参考文献 (57)攻读硕士学位期间发表的论文 (67)致谢 (68)壳聚糖纤维/结冷胶复合水凝胶的力学性质与保水性第一章第一章文献综述关节软骨是一种无血管、无神经和淋巴的组织，由Ⅱ型胶原、蛋白多糖、含水细胞外基质(ECM)和软骨细胞构成[1-2]。