▎ 摘　　要

NOVELTY - A composite material contains a cyano-containing cellulose derivative and graphene obtained by reducing graphite oxide, in mass ratio of (4-6):100. USE - Composite material (claimed). ADVANTAGE - The composite material has excellent dielectric property and biocompatibility, and is produced by simple method without affecting the environment. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of the composite material, which involves dissolving the cyano-containing cellulose derivative with predetermined dielectric constant in a solvent, mixing the liquid with graphite oxide dispersion liquid, carrying out tape casting, producing composite films, and carrying out in-situ reduction on the graphite oxide in the composite films to obtain cyano-containing cellulose derivative and graphene composite material.