How aerogel is made?
The manufacturing process of aerogel rolled felt combines the aerogel preparation technology and composite material technology. The following are the main steps of its manufacturing.
1. Preparation of aerogel precursor
The core of aerogel roll felts is aerogel, so it is necessary to prepare aerogel precursors first. Common aerogel precursors include silicon sources (such as TEOS) or organic precursors (such as resorcinol and formaldehyde). The precursor was dissolved in the solvent by the sol gel method, and the wet gel with three-dimensional network structure was formed through hydrolysis and condensation reaction.
2. Selection and pretreatment of fiber substrate
The flexibility and strength of aerogel roll felts mainly depend on the fiber substrate. Common fiber materials include glass fiber, ceramic fiber, or polymer fiber. These fiber materials need to be pretreated to improve their adhesion to aerogels. The pretreatment steps may include cleaning, surface modification or coating coupling agent to ensure a good interface between the fiber and the aerogel.
3. Aerogel and fiber composite
After the wet gel is formed, it is compounded with the fiber substrate. This step can be achieved by immersion method: immerse the fiber substrate into the wet gel solution, so that the aerogel precursor can fully penetrate into the fiber network. After impregnation, through gel reaction, aerogel forms a stable three-dimensional network structure in the fiber substrate.
4. Aging and solvent exchange
The compounded gel needs aging treatment to enhance the mechanical strength of the aerogel network. After aging, carry out solvent exchange to replace the solvent in the gel with a liquid suitable for supercritical drying (such as ethanol or liquid carbon dioxide). The purpose of this step is to reduce the surface tension during the drying process and prevent the collapse of the aerogel structure.
5. Supercritical drying
Supercritical drying is a key step in manufacturing aerogel rolled felt. Put the compounded gel into a high-pressure vessel, inject liquid carbon dioxide, and heat it to supercritical conditions (usually 31 ° C and 7.39 MPa). In the supercritical state, liquid carbon dioxide is directly converted into gas, which avoids the destruction of the structure of the gel by the liquid surface tension, thus obtaining the aerogel felt with high porosity.
6. Post processing and molding
After supercritical drying, aerogel rolled felt may need post-treatment to improve its performance. For example, enhancing its waterproof performance through surface hydrophobic treatment, or increasing its density and mechanical strength through hot pressing process. Finally, the aerogel roll felt is cut into the required size and shape, and curled for transportation and use.
7. Applications and advantages
The aerogel rolled felt combines the ultra-low thermal conductivity of aerogel and the flexibility of fiber materials, and has the following advantages:
Excellent thermal insulation performance: The thermal conductivity is as low as 0.015 W/(m · K), which is 2-4 times that of traditional insulation materials.
Lightweight and soft: easy to install, suitable for complex shaped pipelines and equipment.
Fire resistance and flame retardancy: both aerogel and fiber materials have excellent fire resistance.
Environmentally friendly and durable: Long service life, reducing energy consumption and material waste.
Aerogel rolled felt is widely used in industrial pipeline insulation, building wall insulation, new energy vehicle battery thermal management and other fields. With the continuous advancement of manufacturing technology, its production cost is gradually decreasing, and its future application prospects in the field of energy conservation and environmental protection will be even broader.
summarize
The manufacture of aerogel roll felts is a complex process, involving many steps such as aerogel preparation, fiber compounding, supercritical drying and post-treatment. By optimizing the process, the aerogel rolled felt not only retains the excellent performance of the aerogel, but also has good practicability and economy, becoming an important member of modern thermal insulation materials.
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