Improved mechanical properties of in situ microfibrillar polypropylene/polyamide6 composites through constructing strong interfacial adhesion

In situ fibrillation technology can effectively improve the mechanical properties of low compatibility polymer blends, but the enhancement effect is greatly reduced due to the weak interfacial adhesion of such blends. In this work, a novel compatibilizer polypropylene grafted graphene oxide was synthesized and added to a typical low compatibility blends polypropylene/nylon 6 by a two-step method. Comparing with no compatibilizer or adding traditional compatibilizer by a one-step method, polypropylene grafted graphene oxide not only enhances the fibrils strength, but also reduces the interfacial tension, resulting in a fine and uniform network structure of polypropylene. Especially the profiled fibrils with a large number of nodules on the surface were obtained, which can increase the interfacial adhesion. With the addition of 0.6 wt% of polypropylene grafted graphene oxide, the tensile and flexural strength of the blends were enhanced by 19.77% and 42.19%, respectively, compared with pure polypropylene This enhancement effect is 3-16% higher than adding traditional compatibilizer (2.5-8 wt%) by a one-step method. Furthermore, the maximum tensile strength of in situ microfibrillar polypropylene/polyamide6 composites correlated with the rheological gel points by adding polypropylene grafted graphene oxide. This study sheds light on the preparation of in situ microfibrillar composites with high mechanical strength and broadens the effective way of reinforcing universal plastics with engineering plastic.