Flexible thermoplastic polyurethane-carbon nanotube composites for electromagnetic interference shielding and thermal management

Abstract

• Flexible TPU composites were prepared by NIPS assisted solution mixing method. • Long length MWCNT composites offer a remarkable EMI SE value of 42.5 dB. • Short length MWCNT based composites exhibit excellent thermal management. • Short length MWCNT based composites possess good electromechanical performance. Lightweight, flexible, and thermally conductive electromagnetic interference (EMI) shielding materials have garnered front facet research interest because of urgent demand to address the EM wave pollution. Herein, inspired from the effectiveness of interconnected networks of different types of carbon nanotubes (CNTs), an endeavored to design three types of CNTs based thermoplastic polyurethane (TPU) composites through a facile solution blending with non-solvent induced phase separation (NIPS) strategy. The effect of different length of CNTs on the EMI shielding, electrical and thermal conductivity performance of TPU nanocomposites have been studied explicitly. The composite with long length CNT (10 wt%) offered a remarkable EMI shielding efficiency of 42.5 dB, the electrical conductivity of 1.9 × 10 −3 S/cm, whereas composite with short length CNTs showed a thermal conductivity of 0.51 W/mK and the corresponding thermal conductivity enhancement efficiency exceeded 145% relative to pure TPU. Incorporation of long length CNTs helped to form unique interconnected conductive networks within the TPU matrix that boost more the electron or charge transferability inside the composites, improvement in mechanical properties, EMI shielding, and electrical properties than that of short length CNTs. In contrast, short length CNTs display significant electromechanical performance and heat transferability than that of long length CNTs. The composites showed a high response in electrical conductivity and minor change in EMI shielding efficiency with repeated bending cycles. This work provides a corelated remark of different types of CNT based TPU composites for superior EMI SE and thermal management applications for next generation wearable and stretchable electronics.