【作者】 杨雯；

【导师】 李文旭；

【作者基本信息】 哈尔滨工业大学 ， 无机化学， 2013， 硕士

【摘要】 聚乙烯醇(Polyvinyl Alcohol，PVA)水凝胶除了具有良好的生物相容性、可降解性以及生物摩擦性能，还具有与人体的软骨组织极为相似的性质，因而成为软骨替代中较为常用的材料。但是其较低的强度和韧性限制了它的应用，通过添加无机颗粒或者纤维可以改善PVA水凝胶的力学性能，同时提高PVA水凝胶的生物活性。因此，本研究通过原位合成PVA-HA复合水凝胶，提高PVA水凝胶作为软骨修复材料的应用价值。采用原位沉淀法在PVA分子链上沉积HA，通过反复的冻结-融化工艺得到PVA-HA复合水凝胶。探讨了浓缩比、PVA加入量和无机盐加入量等工艺条件对PVA-HA水凝胶物相和形貌的影响。同时，利用SEM、XRD、EDS等分析方法研究了PVA-HA水凝胶的体外生物活性，采用万能材料试验机研究水凝胶的抗压强度和应力-应变特性，考察了水凝胶的再溶胀性能。实验结果表明，降低乳白色悬浮液的浓缩比有利于PVA与HA的复合，浓缩比降低至7.5%时，可以得到均匀的白色PVA-HA复合水凝胶。无机盐浓度的变化会影响PVA-HA复合水胶的微观形貌，无机盐浓度越高，PVA-HA复合水凝胶的微观形貌中的颗粒越多，孔结构越少。而提高PVA浓度并降低无机盐浓度能够促进微观网状结构的形成。综上所述，向初始液中加入四水合硝酸钙、磷酸氢二铵和PVA，反应温度为80°C，反应时间为10h，浓缩时间为2h，浓缩比为7.5%，冻结-溶化循环次数为3次，可以得到PVA-HA复合水凝胶。将制得的PVA-HA复合水凝胶放入模拟体液中浸泡28d后，有少量的碱式磷酸氢钙沉积。但是浸泡过程中水凝胶体系中未发现明显的HA生长迹象。水凝胶具备一定的吸水溶胀性，其他条件相同时，PVA-HA水凝胶的再溶胀率随着无机盐加入量的降低而增加，随着PVA加入量的增加而增加。HA在PVA-HA复合水凝胶中起到了提高抗压性能的作用，同时，增大PVA的加入量能够大幅度地提高水凝胶的抗压力学性能，增加冻结-融化循环次数(n)也有利于大幅度提高力学性能。当PVA的质量分数为6wt%，当n从3增大9时，抗压强从0.41MPa增大到0.50MPa度增大了22.0%。PVA-HA复合水凝胶的弹性模量与压缩比呈现指数函数关系,符合人体软骨的力学特征。弹性模量随着随着无机盐加入量的降低而增加，随着PVA加入量的增加而增加。当PVA的质量分数为6wt%，硝酸钙浓度为0.06mol/L时, PVA-HA水凝胶的弹性模量从0.07MPa(压缩比为5%)增加到2.86MPa(压缩比由60%)，增加了40.8倍。更多还原

【Abstract】 Polyvinyl Alcohol hydro gel has good biocompatibility, biodegradability andespecially excellent bio tribiological properties. As it has been matched to humantissues in their properties, it can replace the cartilage tissues. Due to its poorstrength and toughness, it needs to add some inorganic particles and whiskers toimprove its mechanical properties and biology activity. Thus, in order to achieve theapplication, our research chose the hydroxyapatite mix with polyvinyl alcohol hydrogel.PVA-HA hydro gel was synthesized by in situ precipitation method，whichmeans the hydroxyapatite precipitate on the molecular of PVA. And it experiencedthe repeated freeze-thaw cycles to reach the final state. The effect of synthesismethod, the concentration ratio, the concentration of PVA and HA precursor on themicrostructure and phase were studied. Then, in vitro biological activities werecharacterized by Scanning Electron Microscope, X-Ray Diffraction, and EnergyDispersive X-ray Detector. The compression properties and swelling properties weretexted.Reducing the compression ratio can make the PVA and HA linked. When theratio is7.5%, the PVA-HA hydro gel shows the uniform microstructure. Theconcentration of inorganic salts also affects the microstructure. The more inorganicsalts we put into, the more particles porous material we get. In all, the reactants arePVA, calcium nitrate and diammonium phosphate. And the ratio of calcium nitrateand diammonium phosphate was1.67. The reaction temperature was80°C, thereaction time is about10h with2h condensation. Finally, the uniform porousPVA-HA hydro gel was achieved which experienced3freeze-thaws cycles.When the concentration of calcium nitrate was0.24mol/L, the ratio of calciumnitrate and diammonium phosphate was1.67, the mass fraction of PVA was2wt%,the PVA-HA hydro gel was attained which experienced3freeze-thaws cycles. Thesamples we got above were put into Simulated Body Fluid. After28days, thecalcium hydrogen phosphate hydroxide was deposited. In addition, adding the HA oradding the PVA can both enhance the mechanical properties and the swellingproperties. The concentration of PVA went up and the concentration of inorganicsalts went down, it could improve the swelling properties. When the concentrationof calcium nitrate was0.06mol/L, the ratio of calcium nitrate and diammoniumphosphate was1.67, the mass fraction of PVA was6wt%; the mechanical propertiesof hydro gel were better than others. When the freeze-thaw time goes up from3to9,the compression strength increased from0.41MPa to0.50MPa，about22.0%. The compression modulus fits the exponent function, which is similar to the naturecartilage. When the compression ratio of the PVA-HA hydro gel is from5%to60%，compression modulus of the PVA-HA hydro gel increased from0.07MPa to2.86MPa，about40.8time.更多还原