State Key Laboratory of Biotherapy and Cancer Center, and Department of Neurosurgery, West China Hospital, Sichuan University, and Collaborative Innovation Center for Biotherapy , Chengdu , 610041 , P. R. China.
College of Light Industry, Textile and Food Engineering , Sichuan University , Chengdu 610065 , P. R. China.
ACS Appl Mater Interfaces. 2018 Dec 12;10(49):42992-43002. doi: 10.1021/acsami.8b14841. Epub 2018 Dec 3.
Strengthened poly(lactic acid) (PLA)-based materials with improved mechanical performance and improved thermal resistance, notably, are prepared by introducing stereocomplex crystallite (SC), an ideal filler, into the materials. Owing to the intermolecular hydrogen bond among the stereoisomer chains, the melting point of the special crystallite is up to 200 °C, which is 50 °C higher than the isostatic crystallite. The modulus of the PLA-based materials can be enhanced to several 100 MPa because of the integrated polymer chain arrangement. In this study, we electrospun hybrid nanofibers consisted of PLA stereoisomers and induced the stereocomplex crystallization under a mild condition (65 °C for 1 h). The mild warming is favorable for the protection of chlorogenic acid (CA) that was selected as the antibacterial agent. Both of Gram-positive and Gram-negative bacteria were efficiently cleared away using the warmed nanofibers that released CA rapidly within just a few hours. Used as filters, the SC electrospinning membrane also presented a potent filtering effect, leaving no bacteria retained in the filtrates. Attributing to SC, the PLA-based nanofibers showed extremely increased melting temperature over 200 °C and improved Young's modulus up to 270.0 MPa. The durable nanofibers prepared in present study are meaningful for enlarging the application of PLA-based materials, for example, as filters, masks, and packages.
通过向材料中引入立构复合结晶相（SC）这种理想的填充剂，制备出了机械性能和耐热性能得到改善的增强型聚乳酸（PLA）基材料。由于立体异构体链之间的分子间氢键，特殊结晶相的熔点高达 200°C，比等规结晶相高 50°C。由于聚合物链的整体排列，PLA 基材料的模量可以增强到数百兆帕。在这项研究中，我们通过静电纺丝制备了由 PLA 立体异构体组成的混合纳米纤维，并在温和条件（65°C 下 1 小时）下诱导立构复合结晶。温和的升温有利于保护绿原酸（CA），CA 被选为抗菌剂。升温后的纳米纤维能够迅速释放 CA，在短短几个小时内就能有效清除革兰氏阳性菌和革兰氏阴性菌。用作过滤器时，SC 静电纺丝膜也表现出强大的过滤效果，滤出液中没有细菌残留。由于 SC 的存在，基于 PLA 的纳米纤维的熔融温度超过 200°C，杨氏模量提高到 270.0 MPa。本研究制备的耐用纳米纤维对扩大 PLA 基材料的应用具有重要意义，例如用作过滤器、口罩和包装材料。
