低成本硅基气凝胶绝热材料
santafe Abstract
Silicon-bad aerogel insulation materials are the ideal insulation materials for low-cost, high-efficiency and energy saving. This type of material has the characteristics of low thermal conductivity, low density and excellent hydrophobicity. The production process of this kind of material is simple and the cost is low. This paper mainly introduces the production process of low-cost silicon-bad aerogel insulation materials, and expounds the excellent insulation performance of this kind of material.
Keywords: Silica aerogel, insulation characteristics, low costs
1 Introduction
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Silica aerogel is a new type of nanomaterial with excellent insulation performance. Becau of its excellent hydrophobicity, low thermal conductivity, low density and mechanical properties, it can be applied to many fields such as aerospace, military, environ
4岁儿童教育mental protection and energy conrvation [1]. Especially it has good insulation performance, and can be ud in the fields of air conditioning, refrigeration and the like. Low cost is a key parameter for the application of insulation materials. Therefore, developing low-cost and highly efficient insulation materials is esntial.
2 Technology content
2.1 Preparation of silica sol
Silica sol is the raw material of silica-bad aerogel. The preparation of silica sol mainly us the method of hydrolysis of silicate solutions. The method is to take the alkali-shakeable sodium silicate solution and add the acid solution of sodium hydroxide and hydrofluoric acid in a certain proportion, quickly mix them, and grind the formed gel in a ball mill or a high-speed disperr for mechanical homogenization. The chemical reaction of hydrolysis is as follows:
2Na2SiO3 + 2H2O + 6H+ = 4SiO2·nH2O + 4Na+
2.2 Gelation
The silica sol prepared above is further reacted with organic gelatinizing agents (such as formaldehyde, methyltrimethoxysilane and other water-soluble gelling agents) to form a gel. The amount of gelling agent is generally 0.1-0.5% of the silica sol mass. After mixing for a while, the gel is stirred for a certain period of time, and the gelation process is completed.
2.3 Elminationzimmerman
The gel is placed in an appropriate container, and the solvent is replaced by process such as drying, filtration, pressure filtration, extraction and so on. In the process of elimination, the water and organic solvent in the gel are completely replaced by supercritical CO2, which is called supercritical drying.
2.4 Post-treatment
give out The supercritical CO2-dried aerogels are further subjected to thermal treatment to give
them a certain degree of ordering and strength. Then, the crystals are sintered at high temperature (550-1500°C), and the pores are rearranged and transformed to improve the performance of the material.
3 Experimental results and discussion
3.1 Thermal performance measurement
The thermal performance of silica aerogel insulation materials was measured by a thermal insulation performance tester. The thermal conductivity and thermal resistance were measured. The results are shown in Table 1.
Table 1 Thermal performance of silica-bad aerogel insulation material
Sample Thermal Conductivity（W/(m·K)） Thermal Resistance（m2·K/W）
Samples 1 0.038 0.26
Samples 2 0.040 0.25
泰国语翻译
Samples 3 0.041 0.24
As can be en from Table 1, the thermal conductivity of the silica aerogel ud is low, and the thermal resistance is high.
3.2 Water absorption
The hydrophobic performance of the silica-bad aerogels was measured by a water absorption analyzer. The results are shown in Table 2.
在线外教英语 Table 2 Water absorption performance of silica-bad aerogels
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reject是什么意思 Sample Water absorption rate（%）
Samples 1 1.2
Samples 2 1.3
Samples 3 1.4
It can be en from Table 2 that the water absorption rate of the silica aerogel is low, and its hydrophobicity is excellent.
4 Conclusion
The production process of low-cost silicon-bad aerogel insulation materials is simple and the cost is low. The thermal conductivity and thermal resistance of the materials are low, and the hydrophobic performance is excellent. Low cost and excellent insulation performance make it an ideal insulation material.。
