A cellulose nanocrystal hybrid material with improved thermal stability and ammonia response function and preparation and application thereof

Abstract

This invention belongs to the field of nanomaterials technology, specifically relating to a cellulose nanocrystalline hybrid material with improved thermal stability and ammonia response, its preparation, and its application. This invention provides a method for preparing the aforementioned cellulose nanocrystalline hybrid material. The prepared cellulose nanocrystalline hybrid material exhibits significantly improved thermal stability, excellent ammonia-responsive color change function, antibacterial function, and ultraviolet absorption performance. Furthermore, the preparation process is simple, environmentally friendly, and low-cost, and suitable for scale-up production, showing broad application prospects in the fields of ammonia visualization detection, ultraviolet blocking materials, and antibacterial materials.

Description

Technical Field

[0001] This invention belongs to the field of nanomaterials technology, specifically relating to a cellulose nanocrystalline hybrid material with improved thermal stability and ammonia response, and its preparation and application. Background Technology

[0002] Cellulose is the most widely distributed and abundant natural biomass raw material in nature. It is rich in resources, lightweight, inexpensive, biocompatible, and biodegradable. Cellulose nanocrystals are nanocrystals derived from cellulose, exhibiting exponentially higher Young's modulus and tensile strength than cellulose, along with a large aspect ratio and numerous hydroxyl groups on their surface. Therefore, cellulose nanocrystals possess unparalleled advantages as reinforcements for polymer matrices. However, cellulose nanocrystals suffer from poor thermal stability, which hinders their melt blending with polymer matrices and affects the performance of the resulting composite materials. Furthermore, cellulose nanocrystals lack certain specific functionalities (such as ammonia responsiveness and antibacterial properties), further limiting their widespread application. Therefore, developing simple and economical methods to prepare cellulose nanocrystal hybrid materials with improved thermal stability, antibacterial properties, and ammonia responsiveness holds great promise for future applications. Summary of the Invention

[0003] Based on the above background, this invention provides a cellulose nanocrystalline hybrid material with improved thermal stability and ammonia response, as well as its preparation and application. The cellulose nanocrystalline hybrid material prepared by this invention exhibits excellent thermal stability, ammonia-responsive color change function, and antibacterial function. Furthermore, the preparation process is simple, environmentally friendly, and low-cost, and suitable for large-scale production.

[0004] Technical solution of the present invention:

[0005] A method for preparing a cellulose nanocrystalline hybrid material with improved thermal stability and ammonia response includes the following steps:

[0006] (1) Disperse 23 parts of cellulose nanocrystals in a mixed solvent of 1000 parts of deionized water and 3000 parts of methanol, stir at room temperature for 30 min to obtain a uniform cellulose nanocrystal dispersion for later use.

[0007] (2) Weigh 29.1 parts of cobalt nitrate hexahydrate and dissolve it in 2000 parts of methanol to obtain a homogeneous cobalt nitrate solution for later use;

[0008] (3) Add the cobalt nitrate solution obtained in step (2) to the cellulose nanocrystal dispersion obtained in step (1), stir at room temperature for 3 hours to obtain a uniform blend, and set aside.

[0009] (4) Weigh 48.3 parts of 2-indolecarboxylic acid and 16.8 parts of KOH and dissolve them in 3000 parts of methanol solvent. Stir at room temperature for 3 hours to obtain a homogeneous mixture for later use.

[0010] (5) The blend obtained in step (4) is added dropwise to the blend obtained in step (3), and the mixture is stirred and reacted at room temperature for 48 hours. Then, it is centrifuged, washed with methanol, and dried to obtain a cellulose nanocrystal hybrid material with improved thermal stability and ammonia response.

[0011] The beneficial effects of this invention are as follows:

[0012] The cellulose nanocrystalline hybrid material prepared by this invention has the functions of improving thermal stability and ammonia response. It has excellent thermal stability, ammonia response color change function, antibacterial function and ultraviolet absorption performance. Moreover, the preparation process is simple, environmentally friendly and low cost, and it is suitable for large-scale production. It has broad application prospects in the fields of ammonia visualization detection, ultraviolet blocking materials and antibacterial materials. Attached Figure Description

[0013] Figure 1 Infrared spectra of cellulose nanocrystals and the cellulose nanocrystal hybrid material prepared in this invention;

[0014] Figure 2 Photographs showing the antibacterial activity of the cellulose nanocrystal hybrid material prepared in this invention against Escherichia coli.

[0015] Figure 3 Photographs showing the antibacterial activity of the cellulose nanocrystal hybrid material prepared in this invention against Staphylococcus aureus.

[0016] Figure 4 The UV-Vis absorption spectra of cellulose nanocrystals and the aqueous dispersion of the cellulose nanocrystal hybrid material prepared in this invention. Detailed Implementation

[0017] The present invention will be specifically described below through embodiments. It should be noted that these embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of the present invention. Those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention. Unless otherwise specified, the parts of raw materials mentioned are all parts by mass.

[0018] In the following specific embodiments and comparative formulations and preparation methods, the cellulose nanocrystals used are products provided by Guilin Qihong Technology Co., Ltd., with a diameter of 5-20 nm and a length of 100-500 nm; 2-indolecarboxylic acid is an analytical grade reagent provided by Beijing Huawirui Chemical Co., Ltd.; cobalt nitrate hexahydrate, methanol, and potassium hydroxide are analytical grade reagents provided by Xilong Scientific Co., Ltd.

[0019] Example:

[0020] A method for preparing a cellulose nanocrystalline hybrid material with improved thermal stability and ammonia response includes the following steps:

[0021] (1) Disperse 23 parts of cellulose nanocrystals in a mixed solvent of 1000 parts of deionized water and 3000 parts of methanol, stir at room temperature for 30 min to obtain a uniform cellulose nanocrystal dispersion for later use.

[0022] (2) Weigh 29.1 parts of cobalt nitrate hexahydrate and dissolve it in 2000 parts of methanol to obtain a homogeneous cobalt nitrate solution for later use;

[0023] (3) Add the cobalt nitrate solution obtained in step (2) to the cellulose nanocrystal dispersion obtained in step (1), stir at room temperature for 3 hours to obtain a uniform blend, and set aside.

[0024] (4) Weigh 48.3 parts of 2-indolecarboxylic acid and 16.8 parts of KOH and dissolve them in 3000 parts of methanol solvent. Stir at room temperature for 3 hours to obtain a homogeneous mixture for later use.

[0025] (5) The blend obtained in step (4) is added dropwise to the blend obtained in step (3), and the mixture is stirred and reacted at room temperature for 48 hours. Then, it is centrifuged, washed with methanol, and dried to obtain a cellulose nanocrystal hybrid material with improved thermal stability and ammonia response.

[0026] The cellulose nanocrystals used in this invention are white in color and do not change color when exposed to ammonia. However, the cellulose nanocrystal hybrid material product prepared by this invention, which has the function of improving thermal stability and ammonia response, is pink in color and changes color rapidly (within 1 minute) to brownish-yellow when exposed to ammonia. This indicates that the cellulose nanocrystal hybrid material has excellent ammonia-responsive color-changing performance.

[0027] The antibacterial properties of the cellulose nanocrystalline hybrid material products were evaluated using the inhibition zone antibacterial activity test method. The cellulose nanocrystalline hybrid material products synthesized by the method in the embodiments of this invention exhibited significant inhibition zones against *Escherichia coli* and *Staphylococcus aureus* (see...). Figure 2 and Figure 3This indicates that the cellulose nanocrystal hybrid material has excellent antibacterial effects.

[0028] The thermal stability of the product was evaluated using a thermogravimetric analyzer (SDT-Q600, TA Instruments, USA). The cellulose nanocrystals used in this invention have an initial thermal degradation temperature of 235°C. The cellulose nanocrystal hybrid material product prepared by this method has an initial thermal degradation temperature of 258°C, indicating that the cellulose nanocrystal hybrid material product has significantly improved thermal stability.

[0029] In summary, the cellulose nanocrystalline hybrid material product prepared by this invention has significantly improved thermal stability, excellent antibacterial properties, ammonia-responsive color change properties, and ultraviolet absorption properties. Moreover, the preparation process is simple, environmentally friendly, and low-cost, and it is suitable for large-scale production. It has broad application prospects in the fields of visual detection of ammonia, ultraviolet blocking materials, and antibacterial materials.

[0030] The content of this invention is not limited to the embodiments listed. Any equivalent modifications made by those skilled in the art to the technical solutions of this invention by reading this specification are covered by the claims of this invention.

Claims

1. A method for preparing a cellulose nanocrystalline hybrid material with improved thermal stability and ammonia response, characterized in that... Includes the following steps: (1) Disperse 23 parts of cellulose nanocrystals in a mixed solvent of 1000 parts of deionized water and 3000 parts of methanol, stir at room temperature for 30 min to obtain a uniform cellulose nanocrystal dispersion for later use. (2) Weigh 29.1 parts of cobalt nitrate hexahydrate and dissolve it in 2000 parts of methanol to obtain a homogeneous cobalt nitrate solution for later use; (3) Add the cobalt nitrate solution obtained in step (2) to the cellulose nanocrystal dispersion obtained in step (1), stir at room temperature for 3 hours to obtain a uniform blend, and set aside. (4) Weigh 48.3 parts of 2-indolecarboxylic acid and 16.8 parts of KOH and dissolve them in 3000 parts of methanol solvent. Stir at room temperature for 3 hours to obtain a homogeneous mixture for later use. (5) The blend obtained in step (4) is added dropwise to the blend obtained in step (3), and the mixture is stirred and reacted at room temperature for 48 hours. Then, it is centrifuged, washed with methanol, and dried to obtain a cellulose nanocrystal hybrid material with improved thermal stability and ammonia response.

2. The cellulose nanocrystal hybrid material with improved thermal stability and ammonia response function obtained by the preparation method according to claim 1.

3. The application of the cellulose nanocrystalline hybrid material with improved thermal stability and ammonia response function obtained by the preparation method according to claim 1, characterized in that, It is used in the fields of visual detection of ammonia, ultraviolet blocking materials, and antibacterial materials.

Images