Faculty of Fiber Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan; Osaka Gas Co., Ltd., Chuo-ku, Osaka, 541-0046, Japan.
Faculty of Fiber Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto, 606-8585, Japan.
Carbohydr Polym. 2019 Jan 1;203:95-102. doi: 10.1016/j.carbpol.2018.09.033. Epub 2018 Sep 18.
Bio-composites made of polylactic acid (PLA) matrix reinforced with cellulose fibers (CF) were prepared using a twin-screw extruder and injection molding. The CFs were coated with epoxy-based surface treatment agents. Accelerated degradation tests were carried out on these PLA/CF composites at high temperatures (60 °C) or at constant temperature and constant humidity (60 °C/70% RH), and the higher-order structure changes and degradation characteristics of the molded products were evaluated. In the accelerated degradation test at 60 °C, the thermal and mechanical properties of PLA/CF composites showed no degradation, whereas at 60 °C and 70% RH, the melting point decreased ca. 25 °C and the storage modulus with increasing elapsed time decreased more than 50%. However, the thermal and mechanical properties of the PLA/CF composites treated with low-molecular-weight epoxy did not degrade, even at the high humidity of 70% RH. These results strongly suggest that the surface treatment agent not only improves interfacial adhesion between CF and PLA but also plays an important role in inhibiting degradation of the PLA matrix.
采用双螺杆挤出机和注塑成型工艺制备了以聚乳酸（PLA）为基体、纤维素纤维（CF）增强的生物复合材料。CF 用基于环氧树脂的表面处理剂进行了涂层处理。在高温（60°C）或恒温和恒湿（60°C/70%RH）条件下对这些 PLA/CF 复合材料进行了加速降解试验，评估了成型制品的高级结构变化和降解特性。在 60°C 的加速降解试验中，PLA/CF 复合材料的热性能和机械性能没有降解，而在 60°C 和 70%RH 下，熔点降低了约 25°C，储能模量随时间的延长降低了 50%以上。然而，经低分子量环氧树脂处理的 PLA/CF 复合材料的热性能和机械性能没有降解，即使在 70%RH 的高湿度条件下也是如此。这些结果强烈表明，表面处理剂不仅改善了 CF 和 PLA 之间的界面粘结，而且在抑制 PLA 基体降解方面也起着重要作用。
