Highly fire safe and flexible nanoarchitectures with tunable interface towards excellent electromagnetic interference shielding

To meet the demand for practical applications, it is imperative to develop flexible electromagnetic interference (EMI) shielding materials with fire safety. In this work, highly fire safe and flexible thermoplastic polyurethane (TPU)-based EMI shielding nanocomposites were prepared via melt blending polyphenyl phosphate ester amide (PPPEA) with MXene/carboxylic multiwalled carbon nanotubes hybrid (MC), air-assisted thermocompression and layer-by-layer stacking. Combining PPPEA with MC led to peak of heat release rate, total heat release and total smoke release of TPU nanocomposite containing 5.0 wt% PPPEA and 2.0 wt% MC decreased by 39.0%, 24.5% and 23.8%, respectively. Furthermore, the hierarchical TPU/5PA/2.0MC/carbon fiber cloth (CF) nanocomposite showed a prominent averaged EMI shielding effectiveness (SE) of 35.5 dB and a high normal SE value of 29.6 dB/mm, which were superior to most previously reported results. Catalytic carbonization of PPPEA and multiply reflected and scattered effect of MC together with continuous conductive network of CF were responsible for the improvement of these performances.