Multifunctional fireproof electromagnetic shielding polyurethane films with thermal management performance

• The MAPP is prepared by the conductive MXene wrapped on the surface of APP. • The conductive structure of PU film is composed by the 1-D GF and 0-D MAPP. • PU/GF/MAPP film shows the EMI SE as high as 58.9 dB with thickness of 1.0 mm. • PU film presents outstanding mechanical property, joule heating and thermal management performance. • PU/GF/MAPP film reveals excellent flame retardancy and smoke suppression properties. A multifunctional polyurethane film (PU) with superior electromagnetic shielding performance, joule heating performance, thermal conductivity and flame retardancy has been carefully designed. The ammonium polyphosphate (APP) wrapped with conductive MXene (MAPP) is prepared by microencapsulation technology and added in PU solution for enhancing the electric conductivity of PU/graphite fiber (GF) film. The three-dimensional (3D) conductive network composed of GF and MAPP promotes electron transmission efficiency and electromagnetic (EM) wave dissipation through multiple absorbtion and reflection. Compared with the PU/GF film, the electric conductivity and thermal conductivity of PU/GF/MAPP film enhanced by 57.7% and 59.3%, respectively. What’s more, the PU composite film shows excellent mechanical properties, joule heating performance and high fire safety performance. Therefore, the prepared multifunctional PU film demonstrates excellent performance, and has broad application prospects in EMI shielding and thermal management of advanced microelectronic systems.