Silica microparticle, composition forming polyimide aerogel, polyimide aerogel and manufacturing method thereof, and composite material

The invention provides a silica microparticle, a composition forming a polyimide aerogel, the polyimide aerogel and a manufacturing method thereof, and a composite material. The silica microparticle containing an amino group is prepared by subjecting alkoxy silane as shown in a formula (I) and alkoxy silane as shown in a formula (II) to hydrolytic condensation in the presence of a catalyst, wherein the formula (I) is Si(OR ) , and the formula (II) is (NH -Y)-Si(OR ); in the formula (I), R is an alkyl group with a carbon number of 1 to 10; and in the formula (II), Y is an alkyl group with a carbon number of 1 to 10 or an alkyl group with a carbon number of 2 to 10, R is an alkyl group with a carbon number of 1 to 10, and m is an integer in a range of 1 to 3. According to the invention, the polyimide aerogel has the characteristics of high porosity, good thermal insulation properties, good flexural strength, flame resistance, resistance to UV light and chemicals, low dielectric coefficient and the like, do