A method for preparing carbon aerogels from hydrogel precursor materials through a hydrothermal process

A precursor material, carbon aerogel technology, applied in aerogel preparation, colloid chemistry, colloid chemistry and other directions, can solve the problems of low overall yield, many preparation process steps, no application value, etc., to achieve overall yield High, easy structure control effect

Active Publication Date: 2021-07-27
INST OF CHEM CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In view of the above analysis, the embodiment of the present invention aims to provide a method for preparing carbon aerogels from hydrogel precursor materials through a hydrothermal process, in order to solve the following problems in the existing carbon aerogel preparation methods: 1) There are many steps in the preparation process, the cost of the precursor is high, the structure control of the carbonization process is difficult, and the overall yield is low, which makes the cost of preparing qualified carbon aerogels high and has no application value; 2) The drying of the existing organic precursors Supercritical drying is mainly used, and its cost is high due to the need for extreme operating conditions such as high pressure

Method used

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  • A method for preparing carbon aerogels from hydrogel precursor materials through a hydrothermal process
  • A method for preparing carbon aerogels from hydrogel precursor materials through a hydrothermal process
  • A method for preparing carbon aerogels from hydrogel precursor materials through a hydrothermal process

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Embodiment 1

[0055] Chitosan 1.6g, 36wt% concentrated hydrochloric acid 1.0g, water-soluble carbohydrate 20g and deionized water 77.4g form a uniform solution; then add 1.2g Tween-60 and 5.0g liquid paraffin, stir to form a uniformly dispersed system; dropwise 2.2g glutaraldehyde aqueous solution (50wt%), after stirring evenly, leave standstill to form hydrogel; The hydrogel is placed in the stainless steel reaction kettle that has polytetrafluoroethylene liner, left standstill reaction 4.0 hours at 180 ℃; Reaction After finishing, the primary carbonized product is cleaned to a neutral pH value by deionized water, and then by ethanol-n-butanol (V / V:2 / 1, 45g), n-butanol-n-hexane (V / V:3 / 1 , 50g) The system is subjected to solvent replacement in sequence, and the replaced primary carbonized product is vacuum-dried at room temperature until the quality remains unchanged; the dried primary carbonized product is further heat-treated at 800°C, and the heating rate of the process is 3.0°C / min. The...

Embodiment 2

[0059] Chitosan, 36wt% concentrated hydrochloric acid, glucose and deionized water form a uniform solution; then add Tween-60 and liquid paraffin, stir to form a uniformly dispersed system; dropwise add glutaraldehyde aqueous solution (50wt%) (concrete hydrogel composition The conditions are shown in Table 2), stirred evenly and then left to stand to form a hydrogel; the hydrogel was placed in a stainless steel reactor with a polytetrafluoroethylene lining, and was left to react at 180°C for 4.0 hours; after the reaction, the primary The carbonized product is cleaned by deionized water until the pH value is neutral, then by ethanol-n-butanol (V / V:2 / 1, 45g), n-butanol-n-hexane (V / V:3 / 1, 50g) The system was subjected to solvent replacement in sequence, and the replaced primary carbonized products were vacuum-dried at room temperature until the quality remained unchanged; the dried primary carbonized products were further heat-treated at 800 °C, the heating rate of the process was...

Embodiment 3

[0066] Chitosan 1.6g, 36wt% concentrated hydrochloric acid 1.0g, glucose 20g and deionized water 77.4g form a uniform solution; then add 1.2g Tween-60 and 5.0g liquid paraffin, stir to form a dispersed uniform system; Dialdehyde aqueous solution (50wt%), stirred evenly and left to stand to form a hydrogel; the hydrogel was placed in a stainless steel reaction kettle with a polytetrafluoroethylene lining, and was left to react at 180 ° C for 4.0 hours; after the reaction, the primary The carbonized product is cleaned by deionized water until the pH value is neutral, and then the solvent replacement is carried out in sequence by ethanol-n-butanol and n-butanol-n-hexane system (solvent replacement conditions are shown in Table 4), and the replaced primary carbonized product Vacuum drying at room temperature until the quality remains unchanged; the dried primary carbonized product is further heat-treated at 800°C, the heating rate of the process is 3.0°C / min, the nitrogen flow rate...

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Abstract

The invention relates to a method for preparing carbon airgel from a hydrogel precursor material through a hydrothermal process, belongs to the field of new materials, and solves the problems of complicated carbon preparation process and high cost of supercritical drying in the prior art. The invention comprises the following steps: step 1, acidifying chitosan with dilute hydrochloric acid, and forming a mixed solution with water-soluble carbohydrates; step 2, adding polysorbate nonionic surfactant and liquid paraffin, and then adding pentamethylene glycol Aldehydes to form hydrogels; step 3, placing the hydrogels in a reactor for hydrothermal reaction to obtain primary carbonized products; step 4, cleaning the primary carbonized products and replacing them with two-stage solvents; step 5, dissolving the primary carbonized products After further heat treatment, the microstructure was characterized by scanning electron microscopy, and the pore properties of the sample were determined by nitrogen adsorption. The invention utilizes low-cost raw materials to generate the carbon airgel structure in one step; utilizes two-stage solvent replacement to realize normal-pressure drying of the carbon airgel structure.

Description

technical field [0001] The invention relates to the technical field of new materials, in particular to a method for preparing carbon airgel from a hydrogel precursor material through a hydrothermal process. Background technique [0002] Kistler first proposed the concept of airgel in 1932, which refers to a solid structure that does not collapse after the liquid in the gel is replaced by gas. Silica structure is the most researched airgel, which is relatively mature. In 2003, Aspen Aerogels and Cabot Aerogels have begun mass production of silica airgel particles and molding materials. [0003] Carbon aerogels are a relatively special class of materials, which usually require an organic high-resolution airgel as a precursor and are obtained through carbonization. The precursor materials commonly used in carbon airgel are: resorcinol formaldehyde airgel (RF), melamine formaldehyde airgel (MF), phenolic airgel (PF), polyacrylonitrile and polyurethane system . The application...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B32/05B01J13/00
CPCB01J13/0091C01B32/05
Inventor 李峰波袁国卿宋延林
Owner INST OF CHEM CHINESE ACAD OF SCI
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