基于超分子作用的可自修复海藻酸水凝胶

发布时间：2018-11-24 12:29

【摘要】：海藻酸是一种天然高分子,主要由褐藻提取而来,具有优异的生物相容性、生物粘附性和生物可降解性,在药物控制、组织工程等生物医学工程领域有应用价值。但目前关于具有自修复功能的海藻酸水凝胶的研究并不多。对海藻酸水凝胶进行自修复功能化,有助于其在药物控释等领域的运用。而目前的自修复水凝胶,多倾向于利用材料本身分子结构的特点完成修复过程,即基于“超分子作用”的自修复。本论文拟将氢键、主客体相互作用这两种超分子作用自修复机制引入到海藻酸上,制备出具有自修复功能的海藻酸水凝胶。主要研究内容及取得的结果如下:(1)制备了不同Bis交联剂含量的聚6-丙烯酰胺基己酸(PA6ACA)水凝胶,测试并总结了交联剂用量对水凝胶力学及自修复性能的影响,结果表明,随交联剂用量增加,水凝胶拉伸强度与模量增加,断裂伸长率降低,自修复率降低。从修复界面间氢键强度与水凝胶主体强度两个因素分析了测试结果。挑选出自修复性能较优的配比,并将其应用到海藻酸水凝胶中,成功制备出具有自修复功能的PA6ACA/海藻酸半互穿网络水凝胶(PA6ACA/SA Semi-IPN水凝胶),同时也测试了交联剂用量及海藻酸钠浓度对半互穿网络水凝胶力学及自修复性能的影响。(2)通过共价接枝的方式将PA6ACA高分子链与海藻酸链相结合,成功制备出具有自修复性能的海藻酸-接枝-PA6ACA水凝胶(SA-g-PA6ACA水凝胶),并考察了交联密度对其自修复性能的影响。结果表明,交联密度对SA-g-PA6ACA水凝胶的自修复性能影响很大,随交联密度增加,自修复效果迅速下降。同时,对比了SA-g-PA6ACA水凝胶与PA6ACA/SA Semi-IPN水凝胶在力学与自修复性能方面的差异,并分析了接枝与半互穿两种网络结构对这种差异的影响。(3)通过将β环糊精(β-CD)接枝于氧化海藻酸钠(OSA)主链,将双键金刚烷(Ad-AAm)与丙烯酰胺共聚,制备了基于β-CD与金刚烷主客体相互作用的水凝胶——OSA-g-β-CD/PAM-Ad水凝胶。并考察了其粘弹性、力学性能及自修复性能。流变实验结果表明,OSA-g-β-CD/PAM-Ad水凝胶内部具有三维网络结构,即β-CD与金刚烷间存在主客体相互作用,构成了凝胶的交联点,使凝胶成型。自修复实验结果表明,水凝胶有较好的自修复效果(自修复率Rs为72%),竞争实验证实了这种自修复行为是凝胶切面间主客体相互作用的结果。
[Abstract]:Alginic acid is a kind of natural polymer, which is mainly extracted from brown algae. It has excellent biocompatibility, bioadhesion and biodegradability. It has application value in biomedical engineering such as drug control, tissue engineering and so on. However, there are few studies on alginate hydrogels with self-repair function. The self-repair functionalization of alginate hydrogel is helpful for its application in drug controlled release. At present, the self-repairing hydrogels tend to use the molecular structure of the materials to complete the repair process, that is, self-repair based on "supramolecular interaction". In this thesis, two supramolecular self-repairing mechanisms, hydrogen bond and host-guest interaction, are introduced to alginic acid to prepare a self-repairing alginate hydrogel. The main results are as follows: (1) Poly (6-acrylamide caproic acid (PA6ACA) hydrogels with different Bis crosslinker contents were prepared, and the effects of crosslinking agent dosage on hydrogel mechanical and self-repairing properties were tested and summarized. The results showed that the tensile strength and modulus of the hydrogel increased, the elongation at break decreased and the self-repair rate decreased with the increase of the amount of crosslinking agent. The results were analyzed from two factors, hydrogen bond strength and hydrogel main strength. The self-repairing ratio of PA6ACA/ alginate hydrogel was selected and applied to alginate hydrogel. The self-repairing PA6ACA/ alginate semi-interpenetrating network hydrogel (PA6ACA/SA Semi-IPN hydrogel) was successfully prepared. At the same time, the effects of the amount of crosslinking agent and the concentration of sodium alginate on the mechanical and self-repairing properties of semi-interpenetrating network hydrogels were also tested. (2) the PA6ACA polymer chain was combined with alginate chain by covalent grafting. Alginic acid-grafted PA6ACA hydrogels (SA-g-PA6ACA hydrogels) with self-repairing properties were successfully prepared and the effects of crosslinking density on their self-repair properties were investigated. The results showed that the crosslinking density had a great effect on the self-repair properties of SA-g-PA6ACA hydrogels, and the self-repairing effect decreased rapidly with the increase of crosslinking density. At the same time, the mechanical and self-repairing properties of SA-g-PA6ACA hydrogel and PA6ACA/SA Semi-IPN hydrogel were compared. The influence of grafted and semi-interpenetrating networks on the difference was also analyzed. (3) by grafting 尾 -cyclodextrin (尾-CD) onto the main chain of sodium alginate oxide (OSA), the double bond adamantane (Ad-AAm) was copolymerized with acrylamide. A hydrogel OSA-g- 尾-CD/PAM-Ad hydrogel based on the interaction of 尾-CD and adamantane was prepared. The viscoelastic properties, mechanical properties and self-repairing properties were also investigated. The results of rheological experiments show that the OSA-g- 尾-CD/PAM-Ad hydrogel has a three-dimensional network structure, that is, there exists a host and guest interaction between 尾-CD and adamantane, which constitutes the crosslinking point of the gel and forms the gel. The results of self-repair experiments show that hydrogels have a good self-repair effect (self-repair rate Rs is 72%). The results of competitive experiments show that the self-repair behavior is the result of the interaction between the host and the host.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：O648.17

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