Polymer composites made of multi-walled carbon nanotubes and graphene nano-sheets: Effects of sandwich structures on their electromagnetic interference shielding effectiveness

This study proposes producing polymer composites with a sandwich structure. The surface layers are identical with two alternative interlayers. The surface layers are composites that are composed of polypropylene and multi-walled carbon nanotubes. Interlayers are polyvinyl alcohol (PVA)/MWCNTs composites and PVA/graphene nano-sheets composites. Maleic anhydride grafted polypropylene (PP-g-MA) serves as the coupling agent for the surface layers and the interlayer, in order to create sandwich-structured composites. The polymer composites that are constructed with different combinations are then evaluated for electromagnetic interference shielding effectiveness (EMI SE). The test results show that the incorporation of PP-g-MA reinforces the interfacial adhesion between the sandwich-structured composites, and thereby fortifies their tensile strength. When consisting of a PVA/MWCNTs interlayer, the polymer composites have an optimal electrical conductivity of 5.8 S/cm, and EMI SE of −28.60 dB for 0.0003GHz–1 GHz, −32.89 dB for 1 GHz–2 GHz, and −33.52 dB for 2 GHz–3 GHz. The sandwich-structured polymer composites that have good mechanical properties, good flexibility and high EMI SE can be achieved by using a simple and effective manufacturing method.