Wet Gel Drying via Sub-Critical Pressure Control
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Solution Overview
Problem
Current methods for converting wet gels into aerogels are expensive and time-consuming due to the requirement for supercritical drying, which is costly and requires specialized equipment.
Innovation Solution
A method involving a reaction mixture of hydroxybenzene compounds, aldehyde compounds, and additives such as carboxylic acids, anhydrides, homopolymers, or copolymers is used to produce wet gels that can be dried under controlled pressures, resulting in dried gels with specific pore sizes, surface areas, and volumes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If supercritical drying is used to convert wet gels into aerogels, then the aerogel product is obtained with desired properties, but the process becomes expensive and time-consuming requiring specialized equipment
Solution Approach 1:
The patent changes the drying parameters by maintaining pressure below the critical pressure of the solvent throughout the drying process, allowing direct conversion of wet gels to aerogels without supercritical conditions. This parameter modification eliminates the need for specialized supercritical drying equipment while producing aerogels with desired properties.
Solution Approach 2:
The patent replaces expensive, complex supercritical drying equipment with simpler, more accessible drying apparatus. By using readily available equipment that can maintain sub-critical pressures, the process becomes more economically viable and accessible to broader applications.
2Reliability
If supercritical drying is used to produce aerogels, then aerogel product is obtained, but the process becomes time-consuming
Solution Approach 1:
By changing the pressure parameter to remain below critical pressure throughout drying, the process achieves faster drying times compared to supercritical drying. The modified parameters allow for more rapid solvent removal while still producing aerogels with the desired quality and structure.
3Ease of manufacture
If conventional drying methods are used on monolithic polymer gels, then drying is simpler, but the gels are difficult and expensive to convert into aerogels
Solution Approach 1:
The patent identifies and modifies the critical pressure parameter as the key control point during drying. By maintaining pressure below this threshold throughout the process, the method enables conventional drying equipment to successfully produce aerogels, combining simplicity with reliability.
Solution Approach 2:
The patent implements monitoring and control of pressure parameters during the drying process to ensure it remains below the critical pressure of the solvent. This feedback control ensures consistent aerogel formation while using simpler equipment, bridging the gap between ease of manufacture and product reliability.
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
This method allows for the production of dried gels with improved properties like increased pore volume, size, and surface area, reducing the need for expensive and time-consuming supercritical drying processes.
Implementation Method 1
A pressure exerted on the wet gel during drying can be maintained below a critical pressure of the solvent
Implementation Method 2
reacting at least the hydroxybenzene compound and the aldehyde compound to produce a wet gel
Data Source
AI summary
Methods for making wet gels and dried gels therefrom are provided. The method for making a wet gel can include combining a hydroxybenzene compound, an aldehyde compound, and an additive to produce a reaction mixture. The additive can include a carboxylic acid, an anhydride, a homopolymer, a copolymer, or any mixture thereof. At least the hydroxybenzene compound and the aldehyde compound can be reacted to produce a wet gel. The reaction mixture can include about 10 wt % to about 65 wt % of the hydroxybenzene compound, about 5 wt % to about 25 wt % of the aldehyde compound, up to about 85 wt % of the carboxylic acid, up to about 40 wt % of the anhydride, up to about 40 wt % of the homopolymer, and up to about 40 wt % of the copolymer, where weight percent values are based on the combined weight of the hydroxybenzene compound, the aldehyde compound, and the additive.