A kind of hydrophobic silica/polyimide airgel composite material and its preparation method

Abstract

The invention provides a hydrophobic silicon dioxide / polyimide aerogel composite material. The hydrophobic silicon dioxide / polyimide aerogel composite material comprises hydrophobic modified silicon dioxide aerogel and polyimide aerogel, wherein the polyimide aerogel is used as a substrate of the composite material, and hydrophobic modified silicon dioxide aerogel fillers are embedded into pores of the polyimide aerogel. According to the hydrophobic silicon dioxide / polyimide aerogel composite material, the silicon dioxide aerogel is added to the polyimide aerogel; the polyimide aerogel is usedas the substrate and a framework of a composite heat insulation material to realize the supporting reinforcing effect, so that the mechanical strength of the composite heat insulation material is improved; and the silicon dioxide aerogel is used as the filler and has the hydrophobic function and outstanding heat insulation performance, so that the heat insulation effect is realized in the composite material. The hydrophobic silicon dioxide / polyimide aerogel composite material comprehensively considers the physical performance and the mechanical performance of the composite heat insulation material and has the advantages of being high in strength, high in high temperature resistance, low in volume weight, low in heat conductivity, and high in waterproofing performance, and meets the requirements on performances of the heat insulation material in actual application.

Description

technical field [0001] The invention relates to the technical field of high-performance porous materials, and relates to a silica / polyimide airgel composite material and a preparation method thereof. In particular, it relates to a hydrophobic silicon dioxide / polyimide airgel composite material and a preparation method thereof. Background technique [0002] Airgel, also known as xerogel, is a solid material form, a highly dispersed solid material that is composed of colloidal particles or polymer molecules aggregated into a nanoporous network structure, and filled with a gaseous dispersion medium in the pores , is also one of the solids with very low density in existing materials, which has properties such as ultra-low density, high specific surface area, high porosity and excellent heat insulation, and is used in super heat insulation materials, sound insulation materials, particle detectors, low dielectric The electrical constant airgel film, inertial targeting material an...

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Problems solved by technology

[0005] In 2006, Rhine et al. used rigid dianhydride monomers and diamine monomers as raw materials to form polyamic acid in the solvent NMP, and then added chemical imidization reagents. With the increase of the degree of dehydration and cyclization of polyamic acid , the rigidity of the molecular chain gradually increases, so that its solubility in the solvent gradually decreases and gels (forming a polyimide wet gel), and then the CO 2 Polyimide airgel was obtained by supercritical drying, but the shrinkage rate of the prepared polyimide airgel was high

[0007] However, the existing method for preparing PI airgel still has the following defects. The process of supercritical drying is complex and cumbersome, the production efficiency is low, and the product cost is high, so it is difficult to realize the large-scale, fast and efficient preparation of airgel; and The polyamic acid, the product of the process, will degrade rapidly during storage, resulting in a decrease in its molecular weight, which ultimately affects the performance of polyimide aerogels; in addition, the density of cross-linked PI aerogels prepared by prior art is generally higher , which undoubtedly increases the cost of airgel as a thermal insulation material, and at the same time causes the defect of insufficient thermal insulation performance, making it difficult to meet the requirements of airgel thermal insulation basic materials

[0008] Not only that, with the vigorous development of urbanization in the past ten years, the construction industry has flourished. However, although the insulation materials in the building insulation market have good insulation, they are easy to burn and produce a lot of smoke and poisonous gas, while concrete, foam glass, Inorganic thermal insulation materials such as rock wool board consume a lot of resources; although polyimide airgel has excellent characteristics such as high strength, high temperature resistance, fire resistance, and corrosion resistance, which further expands the selection of thermal insulation materials in the construction field, its relative thermal conductivity Relatively high, mostly above 0.1, and not water resistant

Therefore, the requirements for thermal insulation materials in the construction field cannot be met.

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