Preparation method of nano-crystalline cellulose aerogel and thermal insulation material

A technology of nanocellulose and cellulose, applied in the field of thermal insulation materials

Active Publication Date: 2018-03-27
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are very few studies on the functional design of nanocellulose and its application in the field of thermal insulation.

Method used

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  • Preparation method of nano-crystalline cellulose aerogel and thermal insulation material
  • Preparation method of nano-crystalline cellulose aerogel and thermal insulation material
  • Preparation method of nano-crystalline cellulose aerogel and thermal insulation material

Examples

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preparation example Construction

[0031] The invention provides a kind of preparation method of nano-cellulose airgel, comprising the following steps:

[0032] Pretreating the cellulose pulp with tetramethylpiperidine nitrogen oxide and bromide to obtain a cellulose mixture;

[0033] In the presence of lye, the cellulose mixture and the strong oxide are oxidized to obtain an oxidized product;

[0034] Washing the oxidized product with water after ultrasonication to obtain a nanocellulose suspension;

[0035] mixing the nanocellulose suspension with the acidified alkylsilsesquioxane to obtain a mixed solution;

[0036] The mixed liquid is atomized and freeze-dried to obtain nanocellulose airgel.

[0037] The preparation method provided by the invention can realize the uniform methylation of the nanocellulose molecules, and inhibit the destruction of the nanocellulose airgel structure skeleton by the growth of ice crystals in the freezing process. This method has the advantages of low preparation cost, simple...

Embodiment 1

[0053] Take 2.0g of wood pulp fiber and slowly pour it into the conical flask, then add 0.01g of tetramethylpiperidine nitrogen oxide and 0.05g of sodium bromide into the conical flask, mix and stir evenly, then add 0.5g The mass fraction is 10% sodium hypochlorite solution, then the two are continuously and slowly stirred, during the stirring period, the pH value of the monitoring mixture system is maintained at 10 unchanged. The reaction was terminated when the pH value of the mixture no longer decreased. The reacted mixed solution was subjected to ultrasonic treatment for 30 min at an ultrasonic frequency of 15 KHz, and then washed three times with water to obtain nanocellulose suspension. Mix the prepared nanocellulose suspension with the acidified methyltrimethoxysilane according to the mass ratio of 1:0.05, pour it into the atomizer, and atomize the nanocellulose into the tank filled with liquid nitrogen by air pressure. in a copper can. Finally, the copper can was pu...

Embodiment 2

[0060] Take 3.0g of wood pulp fiber and slowly pour it into the conical flask, then add 0.05g of tetramethylpiperidine nitrogen oxide and 0.3g of sodium bromide in the conical flask, mix and stir evenly, then add 0.5g 10% sodium hypochlorite solution, then the two are continuously stirred slowly, during the stirring period, monitor the pH value of the mixture system, adjust the pH value of the mixed reaction system by dripping 0.5mol / L sodium hydroxide solution and maintain it at 10 . The reaction was terminated when the pH value of the mixture no longer decreased. The reacted mixed solution was subjected to ultrasonic treatment for 30 min, and the ultrasonic frequency was 15KHz. Then rinse with water three times to obtain a nanocellulose suspension; mix the obtained nanocellulose suspension with acidified methyltrimethoxysilane according to a mass ratio of 1:0.1, pour it into an atomizer, and pass Air pressure atomizes the nanocellulose into a copper tank filled with liquid...

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Abstract

The invention provides a preparation method of a nano-crystalline cellulose aerogel and a thermal insulation material. The preparation method comprises the following steps: pre-treating a cellulose raw stock, tetramethyl piperidine piperidine and bromide to obtain a cellulose mixture; in the presence of alkali liquor, carrying out an oxidizing reaction on the cellulose mixture and a strong oxide to obtain an oxidized product; washing the oxidized product after ultrasonic treatment to obtain a nano cellulose suspension; mixing the nano cellulose suspension with acidified alkyl silsesquioxane toobtain a mixed liquid; and atomizing the mixed liquid and freezing and drying the same to obtain the nano-crystalline cellulose aerogel. With cellulose wood pulp as a raw material, fiber bundles aredepolymerized to obtain the nano cellulose suspension, and the nano-crystalline cellulose aerogel with excellent hydrophobicity is obtained by in situ graft modification, spraying and freezing-dryingmethods. The nano-crystalline cellulose aerogel also has a relative low heat conductivity coefficient, and has a wide application prospect in thermal insulation field. The method is low preparation cost, simple to operate, high in controllable degree and good in repeatability.

Description

technical field [0001] The invention relates to the technical field of thermal insulation materials, in particular to a preparation method of nano-cellulose airgel and thermal insulation materials. Background technique [0002] Airgel is a special condensed material with nano- or micro-porous structure that uses gas as the filling medium to replace the liquid in the gel without changing the structure and composition of the gel. It has the characteristics of high porosity and high specific surface area, and is one of the solid materials with the lowest density known so far. It is widely used in sound insulation, heat preservation, adsorption and catalyst carrier. Especially in the field of thermal insulation, the airgel multi-mesoporous structure can inhibit the effect of hot air convection, and use the characteristics of multiple labyrinth channels to disperse most of the effect of heat conduction. It is an excellent thermal insulation material. [0003] There are many type...

Claims

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Application Information

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IPC IPC(8): C08J9/28C08J3/075C08L1/04C08L83/04C08B15/02
CPCC08B15/02C08J3/075C08J9/28C08J2201/0502C08J2201/0504C08J2301/04C08J2483/04
Inventor 张和平潘月磊程旭东龚伦伦
Owner UNIV OF SCI & TECH OF CHINA
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