Lightweight and high-strength GMT/PEFP/GNP composites with absorb-dominated electromagnetic interference shielding property

Abstract

As the problem of electromagnetic wave pollution is becoming more and more serious in our daily life, it is urgent to develop a kind of electromagnetic interference (EMI) shielding materials with high-strength and high absorptivity to meet the demand of industrial application. In this study, a facile method is developed to prepare EMI shielding composites with both powerful absorbing and robust mechanical properties by impregnating the suspensions of graphite nanoplatelets (GNP) and polyacrylate expandable foam particles (PEFP) into the porous glass fiber mat reinforced thermoplastics (GMT), and then hot forming and pressing, the thickness of GMT/PEFP/GNP composites is 2 mm. GNP not only acted as an efficient conductive pathway in the GMT/PEFP/GNP composites matrix, but also formed a conductive cell structure with the foamed PEFP, which increased the electromagnetic waves absorption. The total shielding efficiency (SET) of the GMT/PEFP/GNP-4.0 wt% composite is up to 33.8 dB at 11 GHz, and the power coefficient of reflectivity is 0.71, which is lower 17% than that of GMT/GNP composites without the cell structure constructed by PEFP in the matrix. Furthermore, the melting of polypropylene (PP) in the mats act as the interface adhesive for glass fiber (GF) and GNP, so the tensile strength is enhanced up to 22.8 MPa for the GMT/PEFP/GNP-4.0 wt% composites with lightweight, due to the formation of cell structure constructed by the PEFP. Therefore, this paper provides a simple method to prepare lightweight and high-strength GMT/PEFP/GNP composites for EMI shielding, which is of great significance for industrial application.