【作者】 李畅；

【导师】 丁雨田； 蒲忠杰； 董飒英；

【作者基本信息】 兰州理工大学 ， 材料学， 2010， 硕士

【摘要】 近年来镁合金在医疗行业的应用越来越受到人们的关注。良好的力学性能和生物相容性使之可被用作医疗介入材料,但它耐蚀性差、在人体中腐蚀速度过快的特点却严重制约了其发展和应用。本文主要研究生物可降解聚合物涂层对WE43镁合金耐蚀性的影响,并优选出最适合作为WE43镁合金可降解防护涂层的聚合物材料。研究结果表明：在浸泡初始阶段,无论是何种可降解聚合物涂层均可以提高WE43镁合金在PBS溶液中的耐蚀性。但由于聚合物种类和分子量的差异,涂层防护效果并不相同。PLGA (LA/GA=50/50、80/20)和PDLLA (Mw=20万)在浸泡过程中出现加速WE43镁合金基体腐蚀的现象,而PLGA (LA/GA=70/30)和PDLLA (Mw=40万)则未出现加速现象,因此PLGA70和PDLLA40适合作为WE43镁合金防护涂层材料使用。在PLGA70和PDLLA40中加入不同重量的β-TCP,研究β-TCP改性涂层对WE43镁合金耐蚀性的影响。研究发现,β-TCP使聚合物涂层致密性下降,所以浸泡初期β-TCP改性涂层对于镁合金保护性比纯聚合物涂层差。但在整个浸泡过程中,由于β-TCP水解呈碱性减慢聚合物的降解速度,延长了可降解聚合物涂层对镁合金的保护时间。研究得到β-TCP的最佳添加量为5%。在PDLLA40和PLGA70中加入不同粒径的HA,以研究不同粒径HA改性涂层对镁合金耐蚀性的影响。研究发现HA颗粒也会破坏涂层的致密性,使可降解聚合物涂层初始防护作用减弱。实验发现,在涂层浸泡过程中纳米HA比微米HA更容易从涂层中脱落,从而使涂层提早失效。所以微米HA更适合做可降解聚合物添加剂。更多还原

【Abstract】 People have paid more and more attention to the use of magnesium alloy in the medical industry recently. Because of good mechanical properties and biocompatibility, it is used as medical intervention materials. But it corrodes so quickly in human bodies for its inferior corrosion resistance, the development and application of magnesium alloy is seriously restricted.The influence on the corrosion resistance of WE43 magnesium alloy by the biodegradable polymer coating is mainly concerned in this paper and the optimal protective coating of degradable polymers for WE43 magnesium alloy is selected.Results show that the corrosion resistance of WE43 magnesium alloy in PBS solution can be improved by all biodegradable polymer coating at the preliminary stage of soaking, but different characteristics and molecular weights of polymers also lead to different protective effect of coating. When soaked in PBS solution, the corrosion of WE43 magnesium alloy was accelerated by PLGA(LA/GA=50/50、80/20)and PDLLA(Mw=20,000)coatings while PLGA (LA/GA=70/30) and PDLLA (Mw=40,000) coating samples did not show this accelerating phenomenon. So PLGA (LA/GA=70/30) and PDLLA (Mw=40,000) are more suitable as protective coating material for WE43 magnesium alloy.Different gravities ofβ-TCP are added into PLGA70 and PDLLA40 to study the influence to the corrosion resistance of WE43 magnesium alloy with theβ-TCP modified coating. The results show thatβ-TCP decreases the compactness of polymer coating, so the protective effect of theβ-TCP modified coating is weaker than the polymer coating at the preliminary stage of soaking. Because of the alkaline hydrolyzing of P-TCP during the whole soaking period, the degradation speed of the polymer can be decreased while the protective time to magnesium alloy by the degradation polymer coating is extended. The optimal content of theβ-TCP is 5%.HA with different particle size is added into PLGA70 and PDLLA40 to study the influence of different particle size of HA to the corrosion resistance of WE43 magnesium alloy. The results show that HA can also decrease the compactness of polymer coating and the protective effect of the HA composite coating is weaker than the preliminary stage of soaking. The micron-HA is more suitable as the additive of biodegradable polymer for the nano-HA falls off from the coating more easily during the soaking period which can lead to the failure of coating in advance.更多还原