Liu Yanan, Liu Huifang, Yuan Dingling, Chen Songyi, Zhu Changjun, Chen Kanghua
Powder Metallurgy Research Institute, Central South University, Changsha, Hunan 410083, China.
Light Alloy Research Institute, Central South University, Changsha, Hunan 410083, China.
Int J Biol Macromol. 2024 Dec;282(Pt 1):135549. doi: 10.1016/j.ijbiomac.2024.135549. Epub 2024 Sep 13.
The polylactic acid (PLA) coatings of different crystallinity were prepared on biodegradable Mg-2.2Zn-0.3Ca alloy wires to improve the long-term anti-corrosion properties. The composition characteristics and microstructure of the samples were investigated by differential scanning calorimetry (DSC), Fourier transform infrared spectroscope (FTIR), wide angle X-ray diffraction (WAXD) and scanning electron microscope (SEM). The corrosion resistance of all samples was investigated by immersion tests and electrochemical techniques in vitro simulated body fluid (SBF). The results indicated heat treatment improved the crystallinity of PLA coating and heated-coating performed protective behaviors in the short and long-term immersion. The corrosion rate of heated samples was lower than that of unheated samples and exhibited superior long term protective effect for Mg alloy wires. The lifetime of heated sample (H2) increased significantly from 33 to 55 days. The initial electrochemical performance of unheated coating was better than heated coating, but it declined more rapidly during the long-term immersion. These results indicated that PLA coating could not ignore the effect of its crystallinity to anti-corrosion ability, and only the suit heat treatment makes PLA coating more ordering and achieves higher corrosion resistance in vitro immersion. Therefore, it has promising potential by controlling effectively the PLA ordering for surgical implant applications.
在可生物降解的Mg-2.2Zn-0.3Ca合金丝上制备了不同结晶度的聚乳酸（PLA）涂层，以提高其长期耐腐蚀性能。通过差示扫描量热法（DSC）、傅里叶变换红外光谱仪（FTIR）、广角X射线衍射仪（WAXD）和扫描电子显微镜（SEM）研究了样品的成分特征和微观结构。通过浸泡试验和电化学技术在体外模拟体液（SBF）中研究了所有样品的耐腐蚀性。结果表明，热处理提高了PLA涂层的结晶度，加热后的涂层在短期和长期浸泡中均表现出保护作用。加热样品的腐蚀速率低于未加热样品，对镁合金丝具有优异的长期保护效果。加热样品（H2）的寿命从33天显著增加到55天。未加热涂层的初始电化学性能优于加热涂层，但在长期浸泡过程中下降更快。这些结果表明，PLA涂层不能忽视其结晶度对耐腐蚀能力的影响，只有适当的热处理才能使PLA涂层更加有序，并在体外浸泡中实现更高的耐腐蚀性。因此，通过有效控制PLA的有序性，在外科植入物应用方面具有广阔的潜力。
