Flexible and flame-retarding phosphorylated MXene/polypropylene composites for efficient electromagnetic interference shielding

Flame-retardant composites with high electromagnetic interference(EMI)shielding performance are desirable for electronic device packaging.Despite great potential of MXene for high EMI,it still remains a great challenge to develop high-performance flame-retardant polymer/MXene composites with excellent EMI shielding effectiveness because of the poor oxidative stability of MXene.Herein,phosphorylated MXene/polypropylene(PP)composites are prepared by coating phosphorylated MXene on PP fabric followed by spraying polyethylenimine(PEI)and hot-pressing.The phosphorylated MXene proves to be more durable against oxidation than pure MXene due to the protection effect of polyphosphates.Upon hot-pressing,melted PP fibers are fused together at their contact points and thus as-prepared composites are bi-continuous with two interpenetrating phases.The composites show significantly improved thermal stability and flame retardancy relative to pure PP,with a low total heat release(THR)of 3.7 kJ/g and a heat release rate(HRR)of 50.0 W/g,which are reduced by 78%and 87%,respectively.In addition,the composites exhibit a high electrical conductivity of~36,700 S/m and an EMI shielding performance of~90 d B over the whole frequency range of 8–12 GHz with a thickness of~400μm.The as-developed PP/MXene composites hold great promise for reliable protection of next-generation electronic devices working in complex environments.