▎ 摘　　要

NOVELTY - Preparing polyimide-based composite gas gel comprises (i) dispersing graphene oxide in deionized water, and carrying out ultrasonic dispersion to obtain a graphene oxide stable dispersion; (ii) adding hydrazine hydrate and ammonia solution into graphene oxide dispersion and heating and stirring to obtain at least partially reduced graphene oxide dispersion; (iii) dissolving water-soluble polyamic acid in dispersion to obtain at least partially reduced graphene oxide-polyamic acid solution; and (iv) carrying ultrasonic treatment to partially reduced graphene oxide-polyamic acid solution. USE - The composite gas gel is useful for heat-insulating material and a flame-retardant material (claimed). ADVANTAGE - The method: is simple and easy. The composite gas gel: has excellent flame retardance property. DETAILED DESCRIPTION - Preparing polyimide-based composite gas gel comprises taking graphene oxide, and water-soluble polyimide precursor - polyamic acid at mass ratio of 0.2:100-10:100, (i) dispersing the graphene oxide in deionized water, and carrying out ultrasonic dispersion to obtain a graphene oxide stable dispersion; (ii) adding 5-50 mu l hydrazine hydrate (20-80%) and 30-150 mu l ammonia solution(20-28% ) into the graphene oxide dispersion and heating and stirring at 50-100 degrees C to obtain at least partially reduced graphene oxide dispersion; (iii) dissolving the water-soluble polyamic acid in the dispersion obtained in step (ii) to obtain at least partially reduced graphene oxide-polyamic acid solution; (iv) carrying ultrasonic treatment to partially reduced graphene oxide - polyamic acid solution obtained in step (iii) for period of time, and carrying sol-gel process to obtain partially reduced graphene oxide-polyamic acid hydrogel, (v) pre-cooling the partially reduced graphene oxide-polyamic acid hydrogel obtained in step (iv) for period of time, transferring into refrigerator or liquid nitrogen, freezing to obtain solid, and freeze-drying in lyophilizer to obtain an at least partially reduced graphene oxide-polyamic acid gas gel; and (vi) carrying thermal imidization the at least partially reduced graphene oxide-polyamic acid airgel in a nitrogen atmosphere. An INDEPENDENT CLAIM is also included for polyimide-based composite gas gel prepared by above mentioned method.