磷酸盐生物水泥劈裂强度和硬度改善的研究

本文主要以活性HAP(羟基磷灰石 :Ca5(PO4) 3OH)、磷酸盐生物水泥PBC为基础 ,研究了碳纤维、原蚕丝纤维和养护条件对水化试样的劈裂强度和表面硬度的改善。实验结果表明 ,生物纤维和适宜的养护条件使水化试体的劈裂强度有一定的提高 ,维氏硬度有较大的提高 ;用SEM和IR初步研究了纤维与水化产物之间的界面结构 ,发现纤维与生物水泥水化产物界面可能有不同程度的化学结合。     

利用城市垃圾、污泥烧制生态水泥

综合评述了国内外城市垃圾、污泥等废弃物的处理现状,列举了它们在生态水泥生产中作为原料的应用情况,分析了水泥厂处理这些废弃物的优势.用城市垃圾和污泥来生产生态水泥既拓宽了原材料来源,减少了天然资源的消耗,降低了水泥生产的成本,又不需填埋场地,保护了自然环境,将是一条很有前途的、有利于水泥工业可持续发展的途径.     

氧化石墨烯增强磷酸钙生物水泥

为了提高磷酸钙水泥(CPCs)的强度,将纳米片状的氧化石墨烯(GO)与CPCs复合。首先,以α-Ca₃(PO₄)₂、CaHPO₄和CaCO₄物质的量之比为1:1:1的CPCs为固相、不同浓度的GO水分散液为固化液,二者按一定的固/液比混合并固化成型,制得GO/CPCs;然后,探讨GO添加量对GO/CPCs力学强度的影响,测量固化时间、在模拟体液中浸泡后的降解率及浸提液的pH,以XRD检测其物相,并通过SEM观察其显微形貌。结果显示:GO添加量对CPCs的抗压强度有显著影响,最佳添加量为0.0500wt%;随老化时间的延长,不同GO添加量的CPCs的抗压强度均明显提高,尤其是在早期阶段;与不加GO的对照组相比,老化2 h和24 h后,0.0500wt% GO/CPCs的抗压强度分别提高了200%和67%。GO/CPCs在模拟体液中的降解率升高且浸提液pH下降。GO/CPCs在同期水化反应中可获得更多的羟基磷灰石相,结晶有序、均匀且细小。所得结论表明掺加GO可以显著改善CPCs的抗压强度。      

Development of magnesium calcium phosphate biocement for bone regeneration

Magnesium calcium phosphate biocement (MCPB) with rapid-setting characteristics was fabricated by using the mixed powders of magnesium oxide (MgO) and calcium dihydrogen phosphate (Ca(H₂PO₄)₂·H₂O). The results revealed that the MCPB hardened after mixing the powders with water for about 7 min, and the compressive strength reached 43 MPa after setting for 1 h, indicating that the MCPB had a short setting time and high initial mechanical strength. After the acid–base reaction of MCPB containing MgO and Ca(H₂PO₄)₂·H₂O in a molar ratio of 2 : 1, the final hydrated products were Mg₃(PO₄)₂ and Ca₃(PO₄)₂. The MCPB was degradable in Tris–HCl solution and the degradation ratio was obviously higher than calcium phosphate biocement (CPB) because of its fast dissolution. The attachment and proliferation of the MG₆₃ cells on the MCPB were significantly enhanced in comparison with CPB, and the alkaline phosphatase activity of MG₆₃ cells on the MCPB was significantly higher than on the CPB at 7 and 14 days. The MG₆₃ cells with normal phenotype spread well on the MCPB surfaces, and were attached in close proximity to the substrate, as seen by scanning electron microscopy (SEM). The results demonstrated that the MCPB had a good ability to support cell attachment, proliferation and differentiation, and exhibited good cytocompatibility.     

钙铝硅酸盐系生物材料的溶胶—凝胶法制备

采用Ｓｏｌ－Ｇｅｌ法制备了ＳｉＯ２－Ａｌ２Ｏ３－Ｐ２Ｏ５－ＣａＯ－ＣａＦ２系生物无机粉末。运用ＤＴＡ和ＸＲＤ等研究手段对粉末的结构性能进行了研究。结果表明,粉末中含有与骨,牙齿成分相近的Ｃａ３（ＰＯ４）２和有助于水泥硬化反应的ＡｌＰＯ４晶相,说明了该粉末可用于制备性能良好的生物无机水泥。     

β—磷酸钙—二水磷酸氢钙—水系统生物胶凝材料掺有机酸的研究

本文对β－磷酸钙（β－ＴＣＰ）－于水磷酸钙（ＤＣＰＤ）－水（Ｈ２Ｏ）系统钙磷酸盐胶凝材料（ＣＰＣ）掺加柠檬酸、丙二酸进行了研究。在接近生理条件（相对湿度１００％,温度３７±１℃）下养护,试样的抗压强度可达３６．２ＭＰａ,该系统胶凝材料的硬化时间为５￣２０分钟。柠檬酸和丙二酸能有效地控制硬化时间。根据Ｘ－光衍射图谱、红上光谱、扫描电镜观察,羟基磷灰石对胶凝、硬化志了重要作用,柠檬酸钙有增强效应。     

Porous silicon nitride–based drug delivery carrier

Tetracalcium phosphate/monetite biocement was modified with the addition of 30 wt% highly porous silicon nitride/α-tricalcium phosphate (α-TCP) microgranules. The volume ratio of Si₃N₄ and α-TCP in microgranules was 1:1 and showed good in vitro simulated body fluid bioactivity with precipitation of hydroxyapatite particles. The intention of addition of microgranules to the biocement was to have a carrier of drug, which can be released into the body in due time. Granules prepared by the freeze granulation of starting mixture of silicon nitride and calcium phosphate and subsequent sintering at 1100°C have a suitable pore structure for the foreseen use. The pore volume was almost 1000 mm³/g with the open porosity of 77 vol%. This porosity and the biocompatible composition of silicon nitride–based granules gave a chance to fabricate a suitable composite cement for dexamethasone (DMZ) drug release into the human body. An accelerated release of dexamethasone from composite cement was observed and the full amount of DMZ was released from the composite biocement after 10 days. The presented results are a good base to adjust the total drug release time by the mixing of an appropriate amount of drug infiltrated ceramic granules with the tetracalcium phosphate/monetite cement.