Multifunctional composite polyvinyl alcohol films prepared with economic conductive carbon black and MXene microcapsuled APP

Multifunctional flexible electrothermal film has the advantages of high heating efficiency, good heat dissipation conditions, high surface power density, flame retardant and so on, which is widely used in construction, medical, agriculture, military, household products and other fields. In this work, a new type of economical, environmentally friendly, fire-safe electrothermal and electromagnetic (EMI) shielding composite film with PVA as the binder was prepared by introducing MXene-microcapsuled ammonium polyphosphate (MAPP) and conductive carbon black (CCB). After the addition of MAPP as a synergist, the conductivity of the PVA/CCB/MAPP films was increased by 66.5%. In addition, it shows excellent EMI shielding effectiveness (47.1 dB, 0.4 mm thickness). Furthermore, the PVA/CCB/MAPP thin film can reach 100 °C at an applied voltage of 12 V. These results also show good cycling and long-term electrothermal performance. In the combustion performance test, compared with PVA-0, the PVA/CCB/MAPP film had an 86.6% lower pHRR, and the THR was decreased by 59.9%. The surface temperatures of the wood sticks and FPUF reached 79.9 °C and 62.1 °C, respectively, showing excellent electrothermal effects. The PVA/CCB/MAPP film can also completely inhibit the combustion of FPUF. In short, the study offers a novel method to gain eco-friendly, fire safety and EMI shielding electrothermal films that can be coated on different substrates.