Multifunctional TPU composite foams with embedded biomass-derived carbon networks for electromagnetic interference shielding

Although flexible and lightweight electromagnetic interference (EMI) shielding materials have drawn a host of interest in recent years, it is still an issue to design multifunctional polymer composite foams reinforced with biomass-derived 3D carbon skeletons for integrating outstanding performances in EMI shielding, thermal isolation and joule heating. Herein, lightweight and flexible thermoplastic polyurethane (TPU) composite foams with the combination of highly conductive cotton-derived 3D carbon networks and microporous elastic TPU skeleton have been manufactured by facile freeze-drying method, and they could not only show high shielding effectiveness up to similar to 68 dB at low thickness and density (similar to 0.2 g/cm(3)), but also possess satisfactory thermal-insulation performance and excellent low-voltage driven joule-heating capability with good recyclability and long-term durability. The multifunctionality of such foams could provide the ability to minimize the influence of external temperature on the working performance of protected electronic equipments during EMI shielding, suggesting the availability and effectiveness of biomass-derived 3D carbon skeletons for preparing flexible and multifunctional CPC foams.