▎ 摘　　要

NOVELTY - Modifying composite material involves preparing mixed solvent containing aqueous solution of sodium thiocyanate and sodium nitrate in ratio of 1:2-1:5. Graphene powder is mixed with 5-10 wt.% solvent, and then ultra-sonicated for 1-3 hours to obtain graphene suspension. Polyacrylonitrile powder is mixed with solvent for 12-36 hours, and then heated at 50-80 degrees C with stirring to obtain polyacrylonitrile solution. The polyacrylonitrile and solvent are mixed in ratio of 1:3-1:10. The polyacrylonitrile solution is mixed with graphene suspension and mixed solvent with stirring at 50-80 degrees C. USE - Method for modifying composite material (claimed). ADVANTAGE - The method enables to modify composite material that has improved performance at high temperature. DETAILED DESCRIPTION - Modifying composite material involves preparing mixed solvent containing aqueous solution of sodium thiocyanate and sodium nitrate in ratio of 1:2-1:5. Graphene powder is mixed with 5-10 wt.% solvent, and then ultra-sonicated for 1-3 hours to obtain graphene suspension. Polyacrylonitrile powder is mixed with solvent for 12-36 hours, and then heated at 50-80 degrees C with stirring to obtain polyacrylonitrile solution. The polyacrylonitrile and solvent are mixed in ratio of 1:3-1:10. The polyacrylonitrile solution is mixed with graphene suspension and mixed solvent with stirring at 50-80 degrees C for 12-24 hours under vacuum to obtain polyacrylonitrile-modified solution. The obtained polyacrylonitrile-modified solution is placed in vacuum impregnation apparatus at -0.1 mega-pascal vacuum at 80-120 degrees C to obtain modified composite material.