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Preparation method of cellulose nano-fibril aerogel suitable for layer-by-layer self-assembly process

A layer-by-layer self-assembly and nanofibril technology, applied in the field of aerogels, can solve the problems of reduced utilization, easy agglomeration, and inability to achieve nano-level scale control, and achieves high wet strength, high surface charge, good The effect of shape stability

Active Publication Date: 2020-09-04
SHAANXI UNIV OF SCI & TECH
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

However, most inorganic functional materials cannot form a good dispersion with nanocellulose, and are prone to agglomeration
And some functional materials are wrapped by nanocellulose, resulting in a greatly reduced utilization rate
It can be seen that the traditional hybrid preparation method cannot effectively control the microscopic properties of functional materials, let alone achieve nanoscale scale control.

Method used

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  • Preparation method of cellulose nano-fibril aerogel suitable for layer-by-layer self-assembly process
  • Preparation method of cellulose nano-fibril aerogel suitable for layer-by-layer self-assembly process
  • Preparation method of cellulose nano-fibril aerogel suitable for layer-by-layer self-assembly process

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preparation example Construction

[0019] The preparation method of the cellulose nanofibril airgel applicable to the layer-by-layer self-assembly process of the present invention, the steps are as follows:

[0020] 1. Ultrasonic dispersion of cellulose nanofibrils (CNF) produced by TEMPO oxidation into water to obtain a 1wt% cellulose nanofibril dispersion;

[0021] 2. Dilute polyethyleneimine (PEI) aqueous solution with a molecular weight of 70000 to 15%;

[0022] 3. Mix the cellulose nanofibril dispersion obtained in step 1) with the polyethyleneimine aqueous solution obtained in step 2) at a mass ratio of 1:2 to 2:1, disperse it evenly, and let stand to obtain the structure Stable CNF hydrogel;

[0023] 4. Pre-freeze the CNF hydrogel obtained in step 3), and then freeze-dry to obtain the CNF aerogel suitable for the LBL process.

[0024] In order to better understand the steps of the above preparation method, it is described in detail.

Embodiment 1

[0026] A method for preparing a cellulose nanofibril aerogel suitable for a layer-by-layer self-assembly process, comprising the following steps:

[0027] 1) Ultrasonic dispersion of cellulose nanofibrils (CNF) prepared by TEMPO oxidation into water to obtain a 1 wt% cellulose nanofibril dispersion. Among them, the cellulose nanofibrils (CNF) prepared by the TEMPO oxidation method were purchased from Tianjin Wood Spirit Technology Co., Ltd. The obtained nanocellulose has a diameter of 5-20 nm and a length of 1-5 μm.

[0028] 2) Dilute polyethyleneimine (PEI) aqueous solution with a molecular weight of 70000 and a concentration of 50% to 15% with deionized water.

[0029] 3) Control the mass ratio of CNF dispersion liquid to PEI aqueous solution to be 1:1. Specifically: after mixing 30 mL of the cellulose nanofibril dispersion (CNF dispersion) obtained in step 1) with 2 g of a polyethyleneimine aqueous solution with a concentration of 15% obtained in step 2), stir rapidly wit...

Embodiment 2

[0034] A method for preparing a cellulose nanofibril aerogel suitable for a layer-by-layer self-assembly process, comprising the following steps:

[0035] 1) Ultrasonic dispersion of cellulose nanofibrils (CNF) prepared by TEMPO oxidation into water to obtain a 1 wt% cellulose nanofibril dispersion. Among them, the cellulose nanofibrils (CNF) prepared by the TEMPO oxidation method were purchased from Tianjin Wood Spirit Technology Co., Ltd. The obtained nanocellulose has a diameter of 5-20 nm and a length of 1-5 μm.

[0036] 2) Dilute polyethyleneimine (PEI) aqueous solution with a molecular weight of 70000 and a concentration of 50% to 15% with deionized water.

[0037] 3) Control the mass ratio of CNF dispersion liquid to PEI aqueous solution to be 1:2. Mix 30mL of the 1wt% cellulose nanofibril dispersion obtained in step 1) with 4g of a 15% polyethyleneimine aqueous solution, stir rapidly with a magnetic stirrer for 2 hours to disperse evenly, and then let it stand for mo...

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Abstract

The invention relates to a preparation method of cellulose nano-fibril aerogel suitable for a layer-by-layer self-assembly process. The preparation method comprises the following steps: 1) dispersingcellulose nano-fibrils in water to obtain a dispersion liquid; 2) diluting an aqueous polyethyleneimine solution until a concentration is 15%; 3) mixing the cellulose nano-fibril dispersion liquid obtained in the step 1) with the aqueous polyethyleneimine solution obtained in the step 2) to uniformly disperse the cellulose nano-fibril dispersion liquid, and then carrying out standing to obtain a cellulose nano-fibril hydrogel with a stable structure; and 4) carrying out gradient pre-freezing on the cellulose nano-fibril hydrogel obtained in the step (3), and then carrying out freeze drying toobtain the cellulose nano-fibril aerogel. The aerogel prepared by the preparation method disclosed by the invention has high wet strength, and high shape stability, compressibility and restorability in water.

Description

technical field [0001] The invention belongs to the technical field of airgel, and relates to a composite airgel, in particular to a cellulose nanofibril airgel suitable for a layer-by-layer self-assembly process based on gradient directional freezing and its preparation method and application . Background technique [0002] Nanocellulose airgel is a green biodegradable nanoporous material. It not only combines the excellent properties of traditional silica airgel and polymer-based airgel, such as low density, high specific surface area and high porosity, but also has the unique properties of natural cellulose itself, such as hydrophilicity and biocompatibility. These characteristics make nanocellulose aerogels have a wide range of applications in environmental restoration, catalysts, energy storage, and insulating materials for optoelectronic devices. At present, the preparation process of nanocellulose airgel is mainly to separate and disintegrate the cellulose componen...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28C08J3/075C08L79/02C08L1/04
CPCC08J9/28C08J3/075C08J2379/02C08J2401/04C08J2479/02C08J2301/04C08J2201/0484C08J2205/026
Inventor 林涛张能殷学风蔺家成王忠祥王俊魏潇瑶蔡雪
Owner SHAANXI UNIV OF SCI & TECH
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