Repeatable, room-temperature-processed baroplastic-carbon nanotube composites for electromagnetic interference shielding

Abstract

Polymers with low energy consumption from synthesis to processing have received great attention due the energy crisis and environmental problems. Nevertheless, traditional polymer processing always involves high temperature and multiple processing, which result in property deterioration, low recycling ability and high energy consumption. Herein, we synthesized a poly(n-butyl acrylate)@polystyrene (PBA@PS) core–shell polymer with a low glass transition temperature (T_g) of −40 °C for the PBA component and a high T_g of 109 °C for the PS component. This core–shell polymer is a typical baroplastic, which was employed as a composite matrix. Carbon nanotubes (CNT) were introduced into PBA@PS to develop a highly conductive CNT/PBA@PS composite for efficient electromagnetic interference (EMI) shielding application. As a result of the semi-solid melting mechanism of PBA@PS, the CNT/PBA@PS composite was facilely processed at room temperature (25 °C), and interestingly, the composite established a typical segregated structure. The segregated CNT networks endowed the composite with a high EMI shielding effectiveness (EMI SE) of 45.1 dB at 5.0 wt% CNT loading. More importantly, the composite exhibited outstanding repeatability and durability after multiple processing, in sharp contrast to conventional polymer composites. Its mechanical properties after 10-cycle remolding were almost identical to the first-molded specimens, and meanwhile, the EMI SE retention of 62.5% was achieved, which is much higher than that of conventional polymer composites. Our work demonstrated the successful utilization of a baroplastic as a polymer matrix to design functional polymer composites, showing the significant potential advantages of energy saving and sustainability over conventional polymer composites.