A kind of preparation method of carbon airgel thermal insulation material

Abstract

A preparation method of a carbon aerogel thermal insulation material comprises the steps as follows: 1) preparing phenolic prepolymer sol with an acid-base two-step method; 2) preparing organic gel with a solvothermal method; 3) preparing organic aerogel with a normal-pressure drying technology; 4) preparing carbon aerogel with a carbonization cracking technology. Linear phenolic molecules are linked and woven into an isotropic 3D network structure with hexamethylene tetramine as a crosslinking point on the nanoscale with the acid-base two-step method which firstly adopts acid catalysis and then alkaline crosslinking, the framework strength is improved, and the crosslinking degree and uniformity of the framework structure are increased. By the aid of the solvothermal method, the gel polymerization reaction is accelerated, the technological period is shortened, and the gel polymerization reaction is fully conducted, so that the crosslinking degree and strength of the nano network framework are enhanced. The method is simple, efficient and low in cost, the problems of long preparation period and high cost of traditional technologies and higher shrinkage in a normal-pressure drying technology are solved, and the obtained carbon aerogel thermal insulation material has high mechanical strength and low heat conductivity.

Description

technical field [0001] The invention generally belongs to the technical field of thermal insulation materials, and in particular relates to a carbon airgel thermal insulation material and a preparation method thereof. Background technique [0002] Airgel is called solidified smoke, which is the smallest solid in the world, with a high specific surface area (200-1200m 2 g -1 ), high porosity (95%), ultra-low density, and extremely low thermal conductivity make it have excellent thermal insulation performance (thermal conductivity at room temperature is 0.02W m -1 ·K -1 )【J.Mate.Proc.Technol.,2008,199:10-26】, has extremely broad application prospects in civil fields such as building energy conservation and high-tech weaponry such as aerospace. [0003] Aerogels are generally divided into oxide aerogels, carbon aerogels, carbide aerogels, and biomass aerogels. SiO 2 Airgel, as a representative of oxide aerogels, is the most widely used thermal insulation material at presen...

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Problems solved by technology

[0008] The purpose of the invention is to overcome the problems of the prior art, especially the simple use of NaCO in the traditional method 3 It is a basic catalyst. During the drying process under normal pressure, due to the low intrinsic strength of the organic airgel, the shrinkage is too large, which leads to the final preparation of the carbon airgel with a higher density, a lower specific surface area, and a higher thermal conductivity. To solve the problem, provide a carbon airgel thermal insulation material with high mechanical strength and low thermal conductivity and its preparation method. The preparation method adopts the normal pressure drying process, the process cycle is short, the cost is low, and the performance of the material is obtained. it is good

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