Silica Aerogel Mat Manufacturing With Ambient Drying and Low Shrinkage
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Solution Overview
Problem
Conventional methods for manufacturing silica aerogel mats under ambient drying conditions lead to increased density and shrinkage, damaging fibers and weakening adhesion, while using expensive alkoxides or supercritical apparatuses is costly and complex.
Innovation Solution
A method using water glass as the raw material, involving the preparation of a wet gel with an acidic solution and organic solvent, followed by surface modification and a two-step drying process at ambient and elevated temperatures, to stabilize the porous structure and enhance fiber coupling without expensive equipment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ambient drying method is used to manufacture aerogel mat, then manufacturing cost is reduced and process is simplified, but drying shrinkage occurs due to solid/liquid interfacial forces causing increased density
Solution Approach 1:
The patent introduces an organic solvent (such as ethanol or isopropanol) as an intermediary substance to replace water in the gel pores during the drying process. This intermediary solvent has lower surface tension than water, reducing solid/liquid interfacial forces and preventing capillary pressure-induced shrinkage. The organic solvent acts as a bridge between the aqueous gel structure and the final dry aerogel, maintaining pore structure integrity while enabling ambient pressure drying.
Solution Approach 2:
The patent changes the physical-chemical parameters of the drying environment by controlling the replacement of water with organic solvent, adjusting surface tension and capillary pressure parameters. This parameter change allows the drying process to proceed at ambient pressure without the high capillary forces that would otherwise cause shrinkage, thus maintaining the porous structure while simplifying the manufacturing process.
2Quantity of substance
If water glass is used instead of expensive alkoxide to reduce raw material cost, then additional sol-preparation process through ion exchange columns and wet-gel cleansing is required
Solution Approach 1:
The patent extracts and removes the problematic impurities (such as sodium ions and other contaminants) from the water glass solution through a simplified filtration and washing process. By taking out these impurities early in the process and using water glass with controlled composition, the need for complex ion exchange columns and multiple cleansing rounds is eliminated, reducing process complexity while maintaining cost effectiveness.
Solution Approach 2:
The patent employs a disposable-like approach by using water glass that requires minimal preparation - essentially a single-stage filtration and washing process rather than multiple complex purification steps. This simplifies the equipment needed and reduces operational complexity while still achieving the desired gel quality for aerogel mat production.
3Stability of the object's composition
If unmodified hydrophilic gel is impregnated into fibers and subjected to hydrophobic modification reaction, then fibers are damaged and adhesion between fibers and aerogel is weakened
Solution Approach 1:
The patent applies preliminary action by pre-modifying the gel surface with hydrophobic groups (such as methyl or ethyl groups from alkoxysilanes) before fiber impregnation. This preliminary hydrophobic modification creates a compatible interface between the gel and hydrophobic fibers, preventing fiber damage during impregnation and ensuring strong adhesion. The surface modification is performed in advance to avoid harsh conditions that would damage fibers during the impregnation process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the production of silica aerogel mats with improved properties and reduced costs, allowing for continuous manufacturing and enhanced adhesion to fibers, preventing shrinkage and damage, thus maintaining the aerogel's unique characteristics.
Implementation Method 1
The silica aerogel, which is a common type of inorganic aerogel, may be obtained by forming a gel, by subjecting a silica precursor solution to a sol-gel condensation reaction
Implementation Method 2
the materials of water glass and an alkoxide are mixed together in a certain ratio, a fiber web is immersed in the mixed solution, and the processes of aging, replacing pore water, and surface-modification are applied
Implementation Method 3
there may be drying shrinkage caused by solid/ liquid interfacial forces from the water or organic solvent remaining within the silica network
Implementation Method 4
drying the gel under supercritical conditions or ambient-pressure conditions, to yield an aerogel having a porous structure full of air
Data Source
Figure 1
AI summary
The present invention relates to a method of manufacturing a mat containing aerogel and to a mat manufactured using this method. A method of manufacturing a mat containing silica aerogel according to an aspect of the invention includes: (S1) producing a wet gel by mixing water glass and alcohol in a reactor; (S2) modifying a surface of the wet gel by adding an organic silane compound and an organic solvent to the reactor and mixing; (S3) separating a upper liquid from a solution in the reactor and impregnating a fibrous matrix with the upper liquid; and (S4) drying the fibrous matrix impregnated with the upper liquid. According to an aspect of the invention, a mat containing silica aerogel can be manufactured using only water glass as raw material, even when applying the drying process in an ambient environment, without using expensive materials or supercritical apparatus.