▎ 摘　　要

NOVELTY - Low-density flexible high-thermal-conductivity wave-absorbing silica gel sheet is prepared by (a) adding ferric nitrate, barium nitrate, cerium nitrate and citric acid to distilled water, uniformly stirring and dissolving, adding sodium hydroxide, aging and calcining, (b) ultrasonically dispersing graphene oxide in N,N-dimethylformamide solvent, adding hexamethylene diisocyanate trimer, reacting, centrifugally separating, and washing with dichloromethane and ethanol, (c) ultrasonically dispersing isocyanate modified graphene in acetone solvent, adding terminal hydroxyl polydimethylsiloxane, stirring and dissolving, adding stannous octoate, performing grafting reaction, adding distilled water, and centrifugally washing, and (d) uniformly mixing graphene-grafted polydimethylsiloxane, porous cerium-doped barium ferrite and polydimethylsiloxane, adding reinforcing agent zinc oxide, hindered phenol antioxidant and vulcanizing agent, performing vulcanization treatment, and injection molding. USE - Low-density flexible high-thermal-conductivity wave-absorbing silica gel sheet. ADVANTAGE - The silica gel sheet has excellent impedance matching performance, dielectric loss and magnetic loss performance for electromagnetic waves, the uniformly dispersed graphene and cerium-doped barium ferrite have high thermal conductivity, which improves the thermal conductivity of silicon rubber sheet, accelerates the heat dissipation performance of electromagnetic wave electronic instruments, and effectively dissipates heat. DETAILED DESCRIPTION - Low-density flexible high-thermal-conductivity wave-absorbing silica gel sheet is prepared by (a) adding ferric nitrate, barium nitrate, cerium nitrate and citric acid to distilled water, uniformly stirring and dissolving, adding sodium hydroxide, uniformly stirring for 2-3 hours, leaving and aging for 10-15 hours, placing aged product in resistance furnace, and calcining in air atmosphere to obtain porous cerium-doped barium ferrite, (b) ultrasonically dispersing graphene oxide in N,N-dimethylformamide solvent, adding hexamethylene diisocyanate trimer, reacting at 60-75 degrees C for 5-10 hours, centrifugally separating, and washing with dichloromethane and ethanol to prepare isocyanate-modified graphene, (c) ultrasonically dispersing isocyanate modified graphene in acetone solvent, adding terminal hydroxyl polydimethylsiloxane, uniformly stirring and dissolving, adding stannous octoate, performing grafting reaction, adding distilled water, and centrifugally washing to obtain graphene grafted polydimethylsiloxane, and (d) uniformly mixing graphene-grafted polydimethylsiloxane, porous cerium-doped barium ferrite and polydimethylsiloxane, placing the mixture in flat-plate vulcanizing machine, adding reinforcing agent zinc oxide, hindered phenol antioxidant and vulcanizing agent, performing vulcanization treatment, and injection molding to obtain low-density flexible high-thermal-conductivity wave-absorbing silica gel sheet.