Self-Reinforced Polypropylene/Graphene Composite with Segregated Structures To Achieve Balanced Electrical and Mechanical Properties
Tong Sun, Wei Luo, Yinfu Luo, Yuan Wang, Shengtai Zhou, Mei Liang, Yang Chen, Huawei Zou
Abstract
Conductive polymer composites (CPCs) play an important role in various industrial applications including anti-static materials, electromagnetic interference shielding, sensors, and so forth. However, the contradiction between high conductivity and mechanical properties, especially tensile strength, is hard to balance many CPCs. In this paper, a self-reinforced polypropylene (PP)/graphene composite with segregated structures was fabricated by a novel coating-reducing-pressing method. By controlling the hot-pressing parameters, a special structure consisting of both an interconnected conductive graphene network and an unmolten fiber phase in a PP matrix can be obtained. PP/graphene composites with such a structure showed not only excellent electric properties but also outstanding mechanical properties. A super-low electrical percolation threshold of 0.0043 vol % was reached for the composites because of an effective formation of the conductive graphene network. The conductivity of composites with only 1.85 wt % graphene reached to 4.09 S/m. The composites also showed good electromagnetic shielding effectiveness under an X band with the highest EMI of 29.3 dB at 10 GHz. The existence of the PP fiber phase contributed to the improved mechanical strength and toughness of the self-reinforcing conductive composites compared to the blending samples, which made it even stimuli-responsive for bending deformation. These results were believed helpful in the design and fabrication of a new kind of conductive self-reinforced polymer composites.