【作者】 郝晓丽；

【导师】 夏延致；

【作者基本信息】 青岛大学 ， 材料学， 2010， 博士

【摘要】 海藻酸钠是从海带、马尾藻等褐藻类植物中提取的天然多糖,作为一种重要的海洋生物资源,它来源丰富,对环境友好,随着材料科学和生物医学的深入研究,海藻酸盐作为生物医用材料前景十分广阔。本研究工作结合目前的多孔材料制备技术,采用冷冻干燥法制备海藻酸钙多孔膜材料；基于互穿网络理论,提出海藻酸钙-聚乙烯醇和海藻酸钙-明胶互穿网络聚合物模型,采用分步互穿法,制备了海藻酸钙基互穿网络膜材料,考察研究材料的形态结构和性能。(1)采用冷冻干燥法制备海藻酸钙多孔膜材料。海藻酸钙冻干膜为白色或乳白色的海绵,FTIR和SEM分析表明海藻酸钠和钙离子形成了网状交联结构。预冻温度和浓度对冻干膜的形貌影响较大,2%海藻酸钠经-5℃预冻所得海藻酸钙冻干膜的形态结构较为理想,孔形状多以圆形和椭圆形为主,孔径范围为100-300μm。(2)采用自然晾干法和冷冻干燥法制备两种海藻酸钙膜材料,探讨了制备方法对材料结构和性能的影响。测试结果表明：海藻酸钙晾干膜为无色透明的致密膜,冻干膜为具有三维贯通孔洞的多孔膜；海藻酸钙膜材料具有盐敏感性,且表现出优异的吸水性能、保水性能和溶胀性能,冻干膜的吸水性能、保水性能和溶胀性能明显优于晾干膜；海藻酸钙膜材料具有较好的力学性能,晾干膜的最大断裂力和拉伸强度明显高于冻干膜。(3)采用分步互穿法,以戊二醛和氯化钙为交联剂,制备了海藻酸钙-聚乙烯醇互穿网络及海藻酸钙-明胶互穿网络晾干膜和冻干膜,对材料的结构和性能进行了研究。(I) SEM、FTIR、DSC和TEM分析表明在海藻酸钙基互穿网络中,组分间相互贯穿,相容性较好。海藻酸钙-聚乙烯醇互穿网络冻干膜孔形状多为圆形,孔径范围为10-150μm。海藻酸钙-明胶互穿网络冻干膜孔形状多为圆球形,类似蜂窝状,孔径范围为500-600μm,从而可以满足组织工程中不同种类细胞的培养和能量交换的要求。(Ⅱ)接触角测试结果表明海藻酸钙基互穿网络膜材料具有较好的表面亲水性,海藻酸钙-明胶互穿网络晾干膜的表面亲水性优于海藻酸钙-聚乙烯醇互穿网络晾干膜。(Ⅲ)吸水率、保水率及溶胀率测试结果表明海藻酸钙基互穿网络膜材料具有具有盐敏感性、优异的吸水性能、保水性能和溶胀性能,有望成为理想的医用敷料。(Ⅳ)晾干膜中,海藻酸钙-聚乙烯醇互穿网络膜的吸水性能、保水性能和溶胀性能较好,冻干膜中,海藻酸钙-明胶互穿网络膜的吸水性能、保水性能和溶胀性能较好。随互穿网络中聚乙烯醇和明胶浓度的增加,海藻酸钙基互穿网络膜材料的吸水率和保水率先增大后减小。(Ⅴ)最大断裂力、拉伸强度和断裂伸长率测试结果表明海藻酸钙基互穿网络膜材料具有较好的力学性能,海藻酸钙-聚乙烯醇互穿网络膜材料的最大断裂力和拉伸强度高于海藻酸钙-明胶互穿网络膜材料,且拉伸强度随互穿网络中聚乙烯醇和明胶浓度的增加而提高,符合医用生物材料的要求。更多还原

【Abstract】 Alginate is a naturally occurring linear polysaccharide found in all species of brown algae and some species of bacteria. It is hydrophilic, non-toxic, biocompatible, and relatively economical with desirable physical properties. In recent years, Alginate has been widely commercialized and explored for biomedical and pharmaceutical applications. The interpenetrating polymer networks (IPN) have extracted extensive research interests due to their unique properties.In the thesis, porous Calcium Alginate(CA) membranes were prepared using freeze-drying method and CA-based IPN membranes were prepared by stepwise IPN technique. The structure and the performances of those materials were studied.(1) Porous CA membranes were prepared by freeze-drying method, which displayed a highly porous, three-dimensional and well interconnected pore structure. Their morphology was highly dependent on the preliminary freeze temperature and initial concentration of Sodium Alginate (SA), investigated by infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). FTIR spectroscopy showed the formation of cross-linked bonds in the system. The optimum membranes were formed when 2% SA were preliminary frozen at-5℃.The pores were round or oval in shape and pore diameters were 100-300μm, which were beneficial to cells penetration, propagation and adhesion.(2) Two kinds of CA membranes were obtained by nature-drying and freeze-drying methods respectively. Typical morphologies and properties were evaluated, including water absorbency, retention ratio, swelling ratio and mechanical properties.The nature-dried membranes were dense membranes of colorless and transparent, while the freeze-dried membranes were white and porous sponges. The results showed that CA membranes were salt-sensitive. Comparatively, the water absorbency and water retention performance of freeze-dried membranes were better but the maximum force and tensile strength of nature-dried membranes were stronger.(3)Calcium Alginate-Poly(vinyl Alcohol)(CA-PVA) IPN and Calcium Alginate-Gelatin(CA-Gel) IPN membranes were cross-linked with glutaraldehyde and calcium chloride step by step using nature-drying and freeze-drying methods respectively. The results indicated that the CA-based IPN membranes were salt-sensitive, and possessed excellent water absorbency, water retention performance and mechanical properties, which were desirable for medical wound dressing and tissue-engineering scaffold material.The obtained membranes were characterized by FTIR, SEM, differential scanning calorimetry (DSC) and Transmission electron microscopy (TEM). The results revealed that the interpenetration between two networks increased the compatibility. The pores of freeze-dried CA-PVA IPN membranes were oval in shape and 10-150μm in sizes. The pores of freeze-dried CA-Gel IPN membranes were spherical and honeycombed, and pore sizes were 500-600μm.The results of contract angle revealed that the hydrophilicity of CA-Gel IPN membranes were better than that of CA-PVA IPN membranes. Comparatively, the water absorbency and water retention performance of CA-PVA IPN were better to nature-dried membranes but those of CA-Gel IPN were better to freeze-dried membranes. With the increasing of PVA and Gel, the water absorbency and water retention performance of the CA-based IPN membranes increased at first and then decrease.The mechanical test results showed that the maximum force and tensile strength of CA-based IPN membranes increased, while elongation at break decreased. Comparatively, the maximum force and tensile strength of CA-PVA IPN membranes were superior. The tensile strength of the CA-based IPN membranes increased with the increasing of PVA and Gel.更多还原