Polybenzoxazole nanofiber high-intensity heat insulation fireproof aerogel and preparation method thereof

Abstract

The invention provides polybenzoxazole nanofiber high-intensity heat insulation fireproof aerogel and a preparation method thereof, and belongs to the technical field of aerogel and the preparation method of the aerogel. The inside of the aerogel product is of a network interpenetrating structure formed by nanofiber; the nanofiber has the diameter dimension being 10 to 50nm, the density being 20 to 50mg cm<-3> and the specific surface area being 200 to 400m<2>9<-1>; the porosity is 95 to 99 percent; the energy storage modulus is 2 to 2.5MPa. The method comprises the steps that commercial 1 weight-percent PBO (poly-p-phenylenebenzobisoxazole) fiber is dissolved in a mixed acid solution containing methane sulfonic acid and trifluoroacetic acid with the volume ratio being (0.7 to 0.8):(9.2 to 9.3); stirring is performed for 8 to 12 minutes; the PBO mixed acid solution is prepared and is then poured into a mold; the PBO mixed acid solution together with the mold is put into environment with the humidity being 96 to 99 percent for 46 to 50 hours, so that the PBO mixed acid solution is gelated; PBO gel is soaked by water and is washed until the PH value of the PBO gel is equal to 7; supercritical carbon dioxide is used for performing drying for 10 to 14 hours; the PBO nanofiber aerogel is obtained.

Description

technical field [0001] The invention relates to polybenzoxazole nanofiber high-strength heat-insulating and fire-proof airgel and a preparation method thereof, and belongs to the technical field of airgel and its preparation method. Background technique [0002] In the 1930s, Kistler developed the world's first aerogel. Subsequently, various aerogels such as silica aerogels, cross-linked polymer aerogels, metal foams, pyrolytic carbon materials, and cellulose aerogels have been extensively studied. Airgel has excellent properties such as low density, high porosity, large specific surface area, extremely low thermal conductivity and low dielectric constant, and is widely used in thermal insulation, acoustic insulation, oil and heavy metal adsorption, oil storage, gas storage, catalyst Carriers, supercapacitors and filter materials and other fields. As a thermal insulation and fireproof material, silica airgel has a thermal conductivity as low as 17-21m W m -1 K -1 , but i...

AI Technical Summary

Problems solved by technology

As a thermal insulation and fireproof material, silica airgel has a thermal conductivity as low as 17-21m W m -1 K -1 , but its mechanical properties are poor and fragile

For example, the storage modulus of cellulose airgel can reach up to 1.6GPa. However, for this kind of composite system, the inherent mechanical strength of nanofibers is not high, which limits the overall physical and chemical stability and mechanical properties of the airgel, and the traditional The research methods are relatively complicated, and the prepared materials are not resistant to high temperatures; graphene, carbon nanotubes or all-carbon aerogels have excellent electrical properties and thermal stability, but the mechanical strength of the aerogels of this system is not high

Therefore, the preparation of composite materials with high thermal stability, ultra-high mechanical properties, and ultra-lightweight has become a challenge in this field

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