▎ 摘　　要

Polyaniline (PANI) and its nanocomposites with graphene have been synthesized using simple chemistry based method and are utilized to mitigate the problem of electromagnetic pollutions in high-frequency range (X-band: 8.2-12.4 GHz) of the microwave region. The PANI/graphene nanocomposites showed total shielding effectiveness as high as 64 dB with 8 wt% loading of graphene in PANI. The EMI shielding effectiveness via absorption for all the samples dominates over the reflective part due to high dielectric losses in bulk of sample. The enhancement in shielding effectiveness properties are occurred due to strong polarization, charge propagation and formation of conducting pathways due to encapsulation of graphene in PANI. Moreover, the high dielectric losses (epsilon 'asymptotic to 35-175) and total ac conductivities (sigma m asymptotic to 11-102 S/m) contribute in enhanced shielding effectiveness. The very high values of shielding effectiveness for these samples make them suitable materials for industrial as well as defense/aerospace applications.