▎ 摘　　要

The graphene encapsulated polypyrrole-graphene nanocomposites containing 0 to 0.2 wt% of graphene have been synthesized through in-situ chemical oxidative polymerization method. The electromagnetic shielding and dielectric behaviour of nanocomposite have been investigated in X-band (8.2-12.4 GHz) of microwave region. Nanocomposite containing 0.2 wt% of graphene (PG2) possess maximum shielding effectiveness due to absorption (SEA) similar to 33 dB and least due to reflection (SER) << 1 dB in X-band. PG2 nanocomposite also has minimum skin depth similar to 250 mu m (a criteria to decide the thickness of material for microwave application) and maximum attenuation constant. Enhanced microwave absorption and extremely suppressed reflection is attributed to increased dielectric loss. Increased dielectric loss is ascribed to formation of multiple interfaces, interfacial polarization, and formation of conducting pathways due to encapsulation of graphene in polypyrrole-graphene nanocomposites. The material exhibiting increased absorption and decreased reflection could be useful for many important applications such as stealth technology in aerospace, microwave communications, and checking of electromagnetic pollution.