In situ microfibril structure can significantly improve the mechanical properties of incompatible blends. In this work, the in situ microfibrils were constructed in isotactic polypropylene/polylactic acid (iPP/PLA) blends by direct injection molding process, and the effect of viscosity ratio on the morphology was systematically analyzed. The results of scanning electron microscope and rheology show that the viscosity ratio plays a decisive role in the formation of in situ microfibrils. When the viscosity ratio of PLA/iPP is near 1, deformation and microfibrillation of PLA particles can be conducted due to the larger and more uniform distributed PLA domains as well as stronger viscous drag forces. However, irregular cylinders are observed when the viscosity ratio is far lower than 1. The poor deformation ability of PLA particles should be attributed to the much smaller size and weaker viscous drag forces. The well‐defined PLA microfibrils are conducive to avoid damage at the interface, and play a significant role in the enhancement of tensile strength and modulus. This work can simplify the traditional preparation process, construct in situ microfibrils directly by using conventional melt processing techniques and provide a new ideal for the high performance of incompatible polymer blends. POLYM. ENG. SCI., 60:832–840, 2020. © 2020 Society of Plastics Engineers

中文翻译：

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粘度比控制的不相容等规聚丙烯/聚乳酸共混物中的原位微纤维结构

原位微纤维结构可以显着改善不相容共混物的机械性能。在这项工作中，通过直接注射成型工艺在等规聚丙烯/聚乳酸（iPP / PLA）共混物中构建原位微纤维，并系统地分析了粘度比对形态的影响。扫描电子显微镜和流变学结果表明，粘度比在原位形成中起决定性作用微纤维。当PLA / iPP的粘度比接近1时，由于更大和更均匀分布的PLA域以及更强的粘性阻力，PLA颗粒可以发生变形和微纤化。但是，当粘度比远低于1时，会观察到不规则的圆柱体。PLA颗粒的变形能力差应归因于其较小的尺寸和较弱的粘性阻力。定义明确的PLA微纤维有利于避免界面处的损坏，并在增强抗拉强度和模量方面发挥重要作用。这项工作可以简化传统的制备过程，就地构建通过使用常规的熔融加工技术直接形成微细纤维，为不相容的聚合物共混物的高性能提供了新的理想选择。POLYM。ENG。SCI。，60：832–840，2020.©2020塑料工程师协会