【作者】 郭敏；

【导师】 郑玉峰；

【作者基本信息】 哈尔滨工程大学 ， 材料学， 2013， 博士

【摘要】 医用多孔金属材料，由于独特的孔隙结构可以在避免应力遮挡效应的同时，实现生物固定，近年来受到人们的关注，并取得了较好的临床结果，但是它们具有一些与生俱来的局限，比如低的孔隙度和相对高的弹性模量。金属钯和金属银具有优异的耐蚀性和良好生物相容性，在医学领域的应用越来越受到重视。银还有独特的抑菌性能，被作为抗菌剂广泛应用于医疗保健和疾病治疗。但是，目前尚未见多孔钯和多孔银的研究报导。本文设计了具有三维贯通孔隙结构的多孔碳骨架，通过化学镀、电镀的方法在其上制备金属钯（银）层，通过对化学镀和电镀工艺参数的优化和调整，最终获得孔隙结构可调的多孔钯（银）的新型多孔金属材料，并对多孔钯（银）的孔隙结构、物相组成、压缩行为和生物相容性进行表征，此外还研究了多孔银的抗菌性能。研究结果表明，以不同孔径的聚氨酯海绵为基体，经过酚醛树脂处理及固化，制得的固化泡沫在1100oC真空条件下热解，成功制备了类似泡沫状结构，孔径尺寸287²020μm的多孔碳骨架，制得的多孔碳骨架是一种典型的短程有序的非石墨化玻璃炭材料。1100oC热解使固化泡沫在轴向和径向尺寸产生14¹5%的收缩，两个方向上的收缩是同步的，总体收缩量基本保持相等。孔径55ppi的聚氨酯海绵经酚醛树脂处理固化后1100oC真空热解，所得的多孔碳骨架孔隙率高达95%，孔隙贯通，平均孔径为602±93μm，可作为后期化学镀、电镀的多孔基体材料。制得的多孔碳骨架具有较低的细胞毒性，显示了优良的生物安全性能。以多孔碳骨架为基体，通过化学镀钯、电镀钯工艺成功制得多孔钯。通过对各工艺参数的研究，确定优化制备工艺为：化学镀钯PdCl22g/L，N2H₄10ml/L，EDTA60g/L，NH₄OH340ml/L，pH11，Ce添加剂1.5g/L；电镀钯电流密度1.5A/g，pH值9.0，温度50oC、糖精添加剂2.5g/L。使用优化制备工艺通过调整电镀时间制得了孔隙度82.9%⁶3.5%，表观密度91.7³19.6mg/cm³，孔径尺寸500⁶00μm的高度贯通类似松质骨的多孔钯，制备的钯镀层为面心立方钯单质。多孔钯的孔隙度、表观密度和平均孔径尺寸，均与天然松质骨接近。多孔钯的弹性模量为11.5⁶7.6MPa，与股骨和脊柱部位的松质骨的弹性模量相匹配。多孔钯在模拟体液条件下离子溶出量较低，显示了较低的细胞毒性。制备的多孔钯可作为潜在的植入器械表面多孔涂层应用于齿科种植体或人工关节植入器械中。以多孔碳骨架为基体，通过化学镀银、电镀银工艺成功制得多孔银。通过对各工艺参数的研究，确定优化制备工艺为：化学镀银AgNO316g/L，NH3H2O80ml/L，NaOH12g/L，C₆H₁₂O₆21g/L，C2H5OH75ml/L；电镀银4A/g，pH值9.0，温度25oC。使用优化制备工艺，通过不同的电镀时间，成功获得孔隙度68%⁸1%，表观密度13.1⁹7mg/cm³，平均孔径387⁵75μm的多孔银。制备的多孔银为面心立方银单质，具有高度贯通类似松质骨的孔隙结构；孔隙度、表观密度和平均孔径尺寸，均与天然松质骨接近。不同孔隙度多孔银的弹性模量为1.94⁴9.3MPa，股骨部位的松质骨的弹性模量相近，并且多孔银的压缩行为可以用Gibson-Ashby提出的松质骨力学模型解释。此外，多孔银在模拟体液条件下离子溶出率较低，显示了可以接受的细胞毒性，和优异的抑菌性能。热处理使电镀多孔银镀层致密，提高了多孔银的力学性能，但是影响了多孔银在SBF中的离子溶出行为，降低了生物安全性。更多还原

【Abstract】 Since biomedical porous metal has unique structure which could avoid stress shieldeffect and achieve biomedical fixation, it appears more attention in recent years. Owing toPalladium’s and Silver’s excellent corrosion resistance, low toxicity, good ductility andbiocompatibility, they appear wide applications in medical field. Moreover, silver, which hasparticular bacteriostatic properties, have been wide used as antibacterial agent for healthcareand diseases cure. However, there is no study about porous palladium and porous silver yet.In this paper, we designed a novel preparation process, which a porous carbon skeletonwith three-dimensional interconnected porous structure were introduced, after electrolessplating and electroplating process, the Pd or Ag metallic layer was deposited on the porouscarbon skeleton, resulting a novel porous Pd or Ag scaffolds with foam-like structure withadjustable porosities. The porous structure, phase composition, compression behavior andbiocompatibility evaluations of as-prepared porous Pd and Ag scaffolds were investigated. Inaddition, the antibacterial activity of porous Ag scaffolds was investigated.The open cell polyurethane foam solidified with phenolic resin, were pyrolyzed at1100oC in the vacuum, through which could successfully produce the porous carbon skeletonwith foam-like structure which average pore size287²020μm. The as-prepared porouscarbon skeleton was characterized with short-range ordered non-graphitizing glass-like carbonphase composition. The carbon skeleton prepared by the polyurethane foam with55ppipossessed95%porosity and602±93μm average pore size which was considered to be aappropriate porous structure as substrate of electroless plating and electroplating processafterwards. Moreover, the in vitro cytotoxicity evaluation showed that as-prepared carbonskeleton possessed a good biocompatibility.We successfully prepared porous Pd scaffolds exhibiting highly interconnected porousstructure with porosities82.9%⁶3.5%, apparent densities91.7³19.6g/cm³average pore size500⁶00μm by optimizing the parameters of electroless planting process （PdCl22g/L, N2H₄10ml/L, EDTA60g/L, NH₄OH340ml/L, pH11, Ce additive1.5g/L） and electroplatingprocess （current density1.5A/g, pH value9.0, temperature50oC, additive2.5g/L） on porouscarbon skeleton. The as-prepared porous Pd scaffolds were face-centered cubic palladium. The porous Pd scaffolds had the porosities, apparent densities and average pore size muchsimilar as nature cancellous bone. The porous Pd scaffolds possessed elasticity modulus11.5⁶7.6MPa which was similar as the compression behaviors of femur cancellous bone andspinal cancellous bone. Moreover, the porous Pd scaffolds showed low ion release rate andlow cell toxicity. Therefore, the porous Pd scaffolds may have a promising application forporous coating of dental implant or joint arthroplasty implant.As porous Pd scaffolds, we successfully prepared porous Ag scaffolds with highlyinterconnected porous structure which porosities68%⁸1%, apparent densities13.1⁹7g/cm³average pore size387⁵75μm by optimizing the parameters of electroless plantingprocess (AgNO316g/L, NH3H2O80ml/L, NaOH12g/L, C₆H₁₂O₆21g/L, C2H5OH75ml/L)and electroplating process （current density4A/g, pH value9.0, temperature25oC） on porouscarbon skeleton. The as-prepared porous Ag scaffolds were face-centered cubic silver. Theporous Ag scaffolds had the porosities, apparent densities and average pore size much similaras nature cancellous bone and possessed elasticity modulus1.94⁴9.3MPa which was similaras the compression behavior of femur cancellous bone. Moreover, the porous Ag scaffoldsshowed low ion release rate and acceptable cell toxicity. After heat treatment, the porous Agscaffolds showed a compact smooth metallic layer and a high compress property. However,heat treatment altered the ion release behavior and the treated porous Ag scaffolds showedlower long term biosafty. Consequently, the porous Ag scaffolds may have a promisingapplication for porous coating of dental implant or joint arthroplasty implant.更多还原