IMDEA Materials, C/Eric Kandel 2, 28906, Getafe,Madrid, Spain; Department of Material Science and Engineering, Universidad Carlos III de Madrid, Leganés,Madrid, 28911, Spain.
IMDEA Materials, C/Eric Kandel 2, 28906, Getafe,Madrid, Spain.
J Mech Behav Biomed Mater. 2021 Nov;123:104781. doi: 10.1016/j.jmbbm.2021.104781. Epub 2021 Aug 14.
The shear strength and the corrosion resistance of the fiber/matrix interface after immersion in simulated body fluid was studied in poly-lactic acid/Mg fiber composites. The shear strength of the interface was measured by means of push-out tests in thin slices of the composite perpendicular to the fibers. It was found that the interface strength dropped from 15.2 ± 1.4 MPa to 7.8 ± 3.7 MPa after the composite was immersed in simulated body fluid for 148 h. The reduction of the interface strength was associated to the fast corrosion of the fibers as water diffused to the interface through the polymer. The expansion of the fibers due to the formation of corrosion products was enough to promote radial cracks in the polymer matrix which facilitate the ingress of water and the development of corrosion pitting in the fibers. Moreover, cell culture testing on the material showed that early degradation of the Mg fibers affected the proliferation of pre-osteoblasts near the Mg fibers due to the local changes in the environment produced by the fiber corrosion. Thus, surface modification of Mg fibers to delay degradation seems to be a critical point for further development of Mg/PLA composites for biomedical applications.
研究了在模拟体液中浸泡后纤维/基体界面的抗剪强度和耐腐蚀性在聚乳酸/镁纤维复合材料中。通过对垂直于纤维的复合材料薄片进行推拔试验来测量界面的抗剪强度。结果发现，复合材料在模拟体液中浸泡 148 小时后，界面强度从 15.2 ± 1.4 MPa 降至 7.8 ± 3.7 MPa。界面强度的降低与纤维的快速腐蚀有关，因为水通过聚合物扩散到界面。纤维因腐蚀产物的形成而膨胀，足以在聚合物基体中产生径向裂纹，从而促进水的进入和纤维的腐蚀点蚀发展。此外，对该材料的细胞培养测试表明，由于纤维腐蚀产生的局部环境变化，早期降解的镁纤维影响了靠近镁纤维的前成骨细胞的增殖。因此，对镁纤维进行表面改性以延缓降解似乎是进一步开发用于生物医学应用的镁/聚乳酸复合材料的关键点。
