Aerogel gradient thermal insulation material containing endothermic opacifying agent

Abstract

The invention provides an aerogel gradient thermal insulation material containing an endothermic opacifying agent. The aerogel gradient thermal insulation material comprises 3-5 layers of thermal insulation layers, wherein each layer is composed of a SiO2 aerogel, reinforcing fiber doped therein and a core-shell structure opacifying agent. Specifically, the opacifying agent shell is an opacifyingmaterial, and the core is a phase-change material. The aerogel matrix has low thermal conductivity and can suppress heat conduction. The opacifying shell can inhibit radiative heat transfer. The phase-change material absorbs heat in the melting process and improves the thermal inertia of the material. Therefore, the material has the characteristics of low thermal conductivity, low radiation heat transfer capacity, large apparent specific heat and the like, greatly improves the high-temperature and short-acting heat insulation performance of SiO2 aerogel, can meet the high-temperature and short-acting heat insulation requirements of aerospace, military use and the like, and also meets the long-acting heat insulation requirements of industrial high temperature thermal protection and the like. By adding the fiber and endothermic opacifying agent, the aerogel gradient thermal insulation material provided by the invention solves the low strength, phase-change material leakage after melting,high thermal conductivity, infrared light transmission and the like in existing latent heat type thermal insulation materials, and has strong practicability.

Description

technical field [0001] The invention relates to the field of high-temperature heat insulation, and relates to an airgel gradient heat insulation material containing a heat-absorbing sunscreen agent. Background technique [0002] SiO 2 Airgel is a typical nanoporous material, which is composed of a three-dimensional nano-solid framework and gas filled in nano-scale pores, and has a low density (~0.003g / cm 3 ), low thermal conductivity (under normal temperature and pressure can be as low as (~0.013W / (m K)) and good thermal stability (~1200℃), it is a super thermal insulation material with great application prospects in energy saving , new energy technology, aerospace and other fields have broad application prospects. But from the perspective of the basic principle of heat transfer, it has two obvious defects: 1) it has light transmission in the range of 3-8 μm, which makes it in the The heat insulation performance is greatly reduced when used in a high temperature environmen...

AI Technical Summary

Problems solved by technology

However, from the perspective of the basic principle of heat transfer, it has two obvious defects: 1) it has light transmission in the range of 3-8 μm, which greatly reduces its heat insulation performance when used in a high-temperature environment; 2) It has very small density and specific heat, resulting in small thermal inertia, fast temperature response under unsteady conditions, and insufficient short-term heat insulation capacity

However, in order to meet the thermal insulation requirements of short-term high temperature (such as the order of thousands of seconds), it is difficult to significantly improve the high-temperature short-term thermal insulation performance of the material itself simply from the type, particle size and content of the opacifying agent.

[0004] In order to solve the problem of small thermal inertia of airgel, airgel phase change composite materials are usually prepared by infiltration method. The phase change composite materials produced by this method generally have the characteristics of easy leakage after melting of phase change materials, high thermal conductivity and infrared transparency. light and other shortcomings

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