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A method for regulating the long-range ordered structure of nanocellulose airgel

A technology of nanocellulose and long-range ordering, which is applied in the field of regulating the long-range ordering structure of nanocellulose airgel, which can solve the problem of restricting the preparation and precise regulation of oriented porous airgel, making it difficult to prepare airgel, and affecting the efficient orientation of the medium Problems such as transmission application research, to achieve excellent anisotropy effect

Active Publication Date: 2022-04-08
NANJING FORESTRY UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] However, the airgel produced by the existing directional freeze-drying technology tends to form an "inverted trapezoidal" uneven channel structure with a small bottom and a large top. This phenomenon becomes more obvious with the extension of the directional freezing distance, so it is difficult to The preparation of airgel with a long-range ordered structure is also a common problem that needs to be solved in the process of directional freezing, which greatly restricts the preparation and precise regulation of long-range uniform and ordered porous aerogels, affecting the Subsequent research on the application of medium efficient directional transmission

Method used

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  • A method for regulating the long-range ordered structure of nanocellulose airgel
  • A method for regulating the long-range ordered structure of nanocellulose airgel
  • A method for regulating the long-range ordered structure of nanocellulose airgel

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Embodiment 1

[0032] Put deionized water (500mL) in a beaker, add TEMPO (0.09g), sodium bromide (0.6g), wood pulp fiber (10g) in sequence, mix and stir on a heating type magnetic stirrer for 20min, stirring speed 500r / min; add 50 mmol of 12% sodium hypochlorite solution, then adjust the pH of the system with hydrochloric acid (0.6 mol / L) solution, and continue stirring for 30 min at room temperature. During the reaction process, sodium hydroxide (0.7mol / L) solution was continuously added dropwise to maintain the system pH=10, until the sodium hydroxide was no longer consumed, and ethanol (20mL) was added to terminate the reaction; the product was washed with deionized water several times to For neutrality, add an appropriate amount of deionized water, and ultrasonically treat for 10 minutes (power 80%) in an ice bath to obtain a 0.5 wt% nanocellulose dispersion.

[0033] The bottom of the container containing the nanocellulose dispersion is contacted with liquid nitrogen (freezing solution...

Embodiment 2

[0035]Deionized water (500 mL) was placed in a beaker, and 0.09 g of 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) (Shanghai Aladdin Biochemical Technology Co., Ltd.) and bromine Sodium chloride (analytical pure, Shanghai Aladdin Biochemical Technology Co., Ltd.) 0.6g, wood pulp fiber (powder, Nippon Paper Chemicals Co., Ltd.) 10g, mixed and stirred on a heating type magnetic stirrer for 20min, stirring speed 500r / min. Add the 12% sodium hypochlorite solution of 50mmol, then regulate system pH with hydrochloric acid (0.6mol / L) solution and be about 10, continue to stir 30min under the room temperature; Constantly drip sodium hydroxide (0.7mol / L) solution in the reaction process, with Maintain the system pH=10 until the sodium hydroxide is no longer consumed, then add ethanol (20mL) to terminate the reaction; wash the product with deionized water several times to neutrality, add an appropriate amount of deionized water, and sonicate for 10min under ice bath conditions (po...

Embodiment 3

[0042] (1) Put deionized water (500mL) in a beaker, add 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) (Shanghai Aladdin Biochemical Technology Co., Ltd.) 0.09 G, sodium bromide (analytically pure, Shanghai Aladdin Biochemical Technology Co., Ltd.) 0.6g, wood pulp fiber (powder, Nippon Paper Chemicals Co., Ltd.) 10g, mixed and stirred 20min on a heating type magnetic stirrer, stirring speed 500r / min. Add 50 mmol of 12% sodium hypochlorite solution, then adjust the pH of the system with hydrochloric acid (0.6 mol / L) solution, and continue stirring for 30 min at room temperature; continuously add sodium hydroxide (0.7 mol / L) solution dropwise during the reaction to maintain the pH of the system =10, until the sodium hydroxide is no longer consumed, add ethanol (20mL) to terminate the reaction; wash the product with deionized water several times to neutrality, add an appropriate amount of deionized water, and sonicate for 10min under ice bath conditions (power 80%) Afterw...

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Abstract

The invention discloses a method for regulating the long-range ordered structure of nanocellulose aerogel, which comprises the steps of placing deionized water in a beaker, and sequentially adding 2, 2, 6, 6-tetramethylpiperidine-1- Oxygen radicals, sodium bromide, wood pulp fiber, mix and stir; add sodium hypochlorite solution, continue stirring at room temperature; continuously add sodium hydroxide solution dropwise during the reaction, add ethanol to terminate the reaction; wash the product with deionized water until neutral , add deionized water, and ultrasonically treat under ice bath conditions to prepare nanocellulose dispersion; contact the bottom of the test tube containing the dispersion with liquid nitrogen, and apply a syringe pump to the test tube that is perpendicular to the growth direction of ice crystals Conversely, the speed of 0.06mm / s keeps the front of the ice crystal slightly above the freezing liquid level. The present invention solves the problem of forming a non-uniform "inverted trapezoidal" pore structure with a small bottom and a large top when the long-range porous aerogel is prepared by the traditional method.

Description

technical field [0001] The invention belongs to the technical field of airgel preparation, and in particular relates to a method for regulating and controlling the long-range ordered structure of nano-cellulose airgel. Background technique [0002] Airgel is a porous solid material. Generally speaking, traditional silicon, alumina, tin dioxide, and carbon aerogels have disadvantages such as greater brittleness and poor flexibility, which makes researchers start looking for new alternative materials for preparing aerogels. In recent years, nanocellulose airgel has both green and renewable cellulose materials (high specific surface area, high tensile strength, high purity, high degree of polymerization, high adsorption, etc.) and traditional porous airgel materials (low Density, high porosity, etc.) have become one of the research hotspots in the field of composite materials. With the further deepening of research, people began to focus on the research on the mechanical prop...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08J9/28C08L1/04C08K7/00C08K3/08C08B15/02
CPCC08J9/28C08B15/02C08J2301/04C08K7/00C08K2201/011C08K2003/0806C08J2201/0484
Inventor 蒋少华陈一鸣段改改梅长彤
Owner NANJING FORESTRY UNIV