【作者】 李娟莹；

【导师】 黄剑锋；

【作者基本信息】 陕西科技大学 ， 材料物理与化学， 2010， 博士

【摘要】 羟基磷灰石(hydroxyapatite, Ca10(PO4)6(OH)2, HA)是脊椎动物骨骼和牙齿的主要无机成分,在齿骨中约占97%,骨骼中占77%。HA具有优良的生物相容性、生物活性、骨传导作用和骨诱导作用等生物学性能,人体骨细胞可以和HA在HA表面形成化学键合,且结合强度高、稳定性好。研究表明,植入骨中的HA具有诱导骨细胞生长的作用,并逐步参与代谢,是可以完全与生物体骨、齿结合成一体的一类生物陶瓷,因此被广泛用作硬组织修复和替代材料。但HA本身强度低、脆性大且重复性差,只能被应用在牙槽脊增高、耳小骨替换以及颌面骨修复等非承重材料方面,而难以应用于承重骨方面,因此需要对HA进行增强增韧。以分析纯硝酸钙[Ca(NO3)2·4H2O]、磷酸氢二铵[(NH4)2HPO4]、尿素[CO(NH2)2]和正硅酸乙酯(TEOS)为起始原料,采用微波化学反应法制备出纳米Si-HA粉体,粉体在800℃热处理3 h。结果表明,所制备的Si-HA粉体的晶粒平均尺寸随Ca(NO3)2·4H2O溶液浓度的增加呈现先减小后增大的趋势,随反应时间的延长和反应温度的升高,晶粒平均尺寸随之减小；球磨反应原料或产物,均易于获得粒度较小的结晶产物；延长陈化时间,有利于形成与人体骨组织成分更接近的Si-HA粉体；反应产物用无水乙醇洗涤,有益于粉体的分散。以Si-HA粉体为原料,碳纤维为增强相,丙烯酸/衣康酸的缓冲液中加入柠檬酸钠为凝固剂作为固相,在室温条件下,将固、液两相均匀调和后制备出硅羟基磷灰石骨水泥(Cf/Si-HAC)生物材料。结果表明,Cf/Si-HAC的抗折强度随碳纤维体积含量、硅烷偶联剂KH-550质量含量和柠檬酸钠质量含量的增加均呈现先增大后减小的趋势。当碳纤维体积含量为30%、硅烷偶联剂KH-550质量含量为0.8%、柠檬酸钠质量含量为25%时,骨水泥的抗折强度达到极大值43.8 MPa。Cf/Si-HAC生物复合材料的孔隙率随Si含量的增加呈现先减小后增大(61%-63%)的趋势,和抗折强度的变化趋势正好相反,当Si含量为4wt%时,复合材料的孔隙率值最小,为49%。孔隙率随烧结温度的增加而增加(45%-68%),所制备复合材料的孔隙率均满足人体自然骨对孔隙率的要求,说明合成骨水泥材料所采用的工艺是合适的。Cf/Si-HAC复合材料的凝结时间随Si含量的增加近似呈线性增加,初凝时间从6min增加到15min。以聚甲基丙烯酸甲酯(PMMA)、甲基丙烯酸甲酯(MMA)和Si-HA为反应原料,过硫酸钾(KPS)为引发剂,碳纤维纤维为增强相,采用悬浮聚合的方法,制备出Cf/Si-HAC/PMMA-PMA生物复合材料。结果表明,Cf/Si-HAC/PMMA-PMA生物复合材料的抗折强度和抗压强度均随复合材料中PMMA/PMA体积比、KPS引发剂质量含量、W/O体积比、溶液反应温度和碳纤维体积含量的增加呈现先增大后减小的趋势,抗压强度大于抗折强度,当PMMA/PMA体积比、KPS引发剂质量含量、W/O体积比、溶液反应温度和碳纤维体积含量分别为8/2、1.5%、3/1、80℃和1.5%时,复合材料的抗折强度和抗压强度分别达到最大值109.5MPa和239.8MPa、111.7MPa和240.5MPa、110.8MPa和240.6MPa、110.8MPa和240.2MPa以及110.9 MPa和240.8MPa。以壳聚糖和HA为原料,碳纤维为增强相,通过悬浮聚合的方法制备出Cf/Si-HAC/CS生物复合材料。结果表明,Cf/Si-HAC/CS生物复合材料的抗折强度和抗压强度均随复合材料中HA/CS体积比、戊二醛交联剂质量含量、溶液反应温度和碳纤维体积含量的增加呈现先增大后减小的趋势,抗压强度大于抗折强度,当Si-HA/CS体积比、戊二醛交联剂质量含量、溶液反应温度和碳纤维体积含量分别为2/20、0.4%、60℃和1.5%时,复合材料的抗折强度和抗压强度分别达到最大值65.57MPa和76.58MPa、70.10MPa和86.32MPa、70.08MPa和92.34MPa以及62.12 MPa和105.15MPa。Cf/Si-HAC/PMMA-PMA和Cf/Si-HAC/CS生物复合材料分别在模拟体液(simulated body fluid, SBF)中浸泡时,随浸泡时间的延长(1d-28d),两种复合材料的表面逐渐被沉积的HA所覆盖,同时复合材料的力学性能变化很小,以上两点说明所制备的生物复合材料不仅具有良好的生物活性,而且在SBF中的浸泡对其力学性能几乎没有影响。更多还原

【Abstract】 Hydroxyapatite (HA) is the main inorganic component of vertebrates in bones and teeth with similar structure, which contains 77% in body bones and 97% in dental bones. The bone cells can react with HA in its surface to form good combination intensity and good stability due to its excellent biocompatability, bioactivity, conductibility and induction of bone, etc. It shows that the HA has been widely used in human hard tissue repair and replacement because it can take effect in inducing the bone cells to grow and metabolize gradually, so it is the kind bioceramic which can combine with organism bones and teeth. However, HA only used in alveolar ridge augmentation, ear bones replacement and maxillofacial bone repair in virtue of the weak intensity and repeatability of HA itself. Hence, it is important to be reinforced and toughened.Nano-Si-HA powders sintered at 800℃for 3h were prepared by the microwave chemical reaction process using calcium nitrate [Ca(NO3)2·4H2O], ammonium dibasic phosphate [(NH4)2HPO4], carbamide and ethyl silicate;tetraethyl orthosilicate(TEOS)as raw materials. The results show that the particles average size display a trend of decreasing firstly and then increasing with Ca(NO3)2·4H2O solution concentration. The particles average size decrease with the increasing of reaction time and temperature. The smaller particles were easy to obtain by ball grinding the raw materials and products and extending the aging time. The as-prepared products washed by alcohol anhydrous are helpful to disperse.Carbon fiber reinforced silicon-substituted hydroxyapatite bone cements (Cf/Si-HAC) biocomposites were prepared using a buffer solution of acrylic acid and itaconic acid as gelling agent. The results show that the flexural strenth display a trend of increasing to a maximum and then decreasing with the carbon fibers volume fraction, silane coupling agent KH-550 mass fraction and sodium citrate content. When the carbon fibers volume fraction, silane coupling agent KH-550 mass fraction and sodium citrate content reaches 30%,0.8% and 25%, respectively, the flexural strength reaches the maximum value of 43.8 MPa.The porosity of Cf/Si-HAC biocomposites decreases firstly and then increases (61%-63%) with the increasing of Si content, which is opposite with the flexural strength. When the Si mass fraction is 4%, the porosity of the composite reaches the mimimum of 49%. The porosity increases (45%-68%) with sintering temperature, it shows that the as-prepared composites are conform to body bones.The setting time of the Cf/Si-HAC increased almost linearly from 6min to 15min with the Si content.Carbon fiber reinforced polymethyl methacrylate (PMMA)-polymethyl acrylate (PMA) biocomposites (Cf/Si-HAC/PMMA-PMA) were prepared by suspension polymerization process using polymethylmethacrylate (PMMA), methyl methacrylate (MMA) and Si-HA powders as raw materials, potassium persulfate (KPS) as initiator. The results show that the flexural strength and compressive strength of the as-prepared Cf/Si-HAC/PMMA-PMA composites both display a trend of increasing firstly and then decreasing with increasing of the PMMA/PMA volume ratio, KPS mass fraction, W/O volume ratio, the reaction temperature of solutions and carbon fibers volume fraction, and the compressive strength is bigger than the flexural strength. When the PMMA/PMA volume ratio, KPS mass fraction, W/O volume ratio, the reaction temperature of solutions and carbon fibers volume fraction reaches 8/2,1.5%,3/1,80℃and 1.5%, respectively, the flexural strength and compressive strength Cf/PMMA-PMA composite arrived to a maximum of 109.5Mpa and 239.8MPa, 111.7Mpa and 240.5MPa,110.8Mpa and 240.6MPa,110.8Mpa and 240.2MPa, 110.9 Mpa and 240.8MPa.Carbon fiber reinforced chitosan and Si-HA biocomposites (Cf/Si-HAC/CS) were prepared by suspension polymerization process using chitosan and HA as raw materials. The results show that the flexural strength and compressive strength of the as-prepared Cf/Si-HAC/CS composites both display a trend of increasing firstly and then decreasing with increasing of the Si-HA/CS volume ratio, gultaraldehyde cross-linking mass fraction, reaction temperature of solutions and carbon fibers volume fraction, and the compressive strength is bigger than the flexural strength. When the Si-HA/CS volume ratio, gultaraldehyde cross-linking mass fraction, reaction temperature of solutions and carbon fibers volume fraction reaches the 2/20,0.4%,60℃and 1.5%, respectively, the flexural strength and compressive strength of the Cf/HA-CS composite arrived to a maximum of 65.57Mpa and 76.58MPa,70.10Mpa and 86.32MPa,70.08Mpa and 92.34MPa and 62.12Mpa and 105.15MPa.The surface of the as-prepared Cf/Si-HAC/PMMA-PMA and Cf/Si-HAC/CS biocomposites were both covered by Si-HA when they were immersed from 1 day to 28 days in simulated body fluid (SBF), and the mechanical properties almost no changing. It shows that the two biocomposites not only shows the excellent bioactivity, but also the mechanical properties of them have almost no change in SBF solutions.更多还原