School of Materials Science & Engineering, Block N4.1, College of Engineering, 50 Nanyang Avenue, Nanyang Technological University, Singapore 639798, Singapore.
J Mech Behav Biomed Mater. 2012 Feb;6:80-8. doi: 10.1016/j.jmbbm.2011.11.001. Epub 2011 Nov 11.
A series of triblock copolymers comprising end block of PLLA modified with PCL, and random copolymer of PCL and PTMC as soft segment were synthesized. DSC data show that PCL disrupted the crystallinity of PLLA, making the hard block to be completely amorphous when the PCL content is 50%. Correspondingly, the addition of PCL into PLLA block enhances the elongation of the triblock considerably. With regards to the elasticity, however, creep test results show that adding PCL to PLLA block seems to reduce the "equilibrium" recovery, while cyclic test results shows that the instantaneous recovery increased significantly with more PCL inside PLLA block. It was also observed that the degradation rate of triblock with added PCL inside the PLLA was slower compared to triblock with pure PLLA hard block. Compared to biodegradable polyurethane, these polymers are expected to yield less harmful degradation products, and offer more variables for the manipulation of properties. These polymers are also processable from the melt at temperatures exceeding about 130 °C. We expect to use these polymers in a variety of applications, including stent coatings, fully-degradable stents and atrial septal defect occluders.
我们合成了一系列三嵌段共聚物，其由 PLLA 的端基封端嵌段与 PCL 及聚（三亚甲基碳酸酯）的无规共聚物软段组成。DSC 数据表明 PCL 破坏了 PLLA 的结晶性，使得当 PCL 含量为 50%时硬段完全无定形。相应地，PCL 加入 PLLA 嵌段会显著提高三嵌段的伸长率。然而，关于弹性，蠕变测试结果表明，向 PLLA 嵌段中添加 PCL 似乎会降低“平衡”恢复，而循环测试结果表明，随着 PLLA 嵌段中 PCL 含量的增加，瞬时恢复显著增加。还观察到，与具有纯 PLLA 硬段的三嵌段相比，添加 PCL 的三嵌段的降解速率较慢。与可生物降解的聚氨酯相比，这些聚合物预计会产生更少的有害降解产物，并为控制性能提供更多的变量。这些聚合物也可以在超过约 130°C 的温度下从熔体进行加工。我们期望将这些聚合物应用于各种应用中，包括支架涂层、完全可降解的支架和房间隔缺损封堵器。
