Functionalized modified cellulose nanocrystals, and methods of making and using the same

Abstract

The application belongs to the technical field of nanomaterials, and relates to functionalized modified cellulose nanocrystals as well as a preparation method and application thereof. The application uses cellulose nanocrystals, iron sulfate and L-lysine as raw materials, stirs and reacts at room temperature, and then is centrifuged, washed and freeze-dried to obtain the functionalized modified cellulose nanocrystals. The prepared functionalized modified cellulose nanocrystals have excellent temperature-sensitive discoloration performance, ammonia gas response discoloration performance and ultraviolet absorption performance, and have the advantages of simple preparation process, environmental protection, low cost and suitability for large-scale production, and have wide application prospects in the fields of temperature-sensitive materials, visual monitoring of ammonia gas and environmental safety.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of nanomaterials, and particularly relates to a functionalized modified cellulose nanocrystal as well as a preparation method and application thereof. BACKGROUND

[0002] Cellulose nanocrystal (CNC) is a cellulose source nanometer-sized rod-shaped crystal material, which is widely applied to the fields of food and medical drug release, mechanical reinforcement, adsorption, filter membrane, and flame-resistant material, due to its high crystallinity, high specific surface area, adjustable length-diameter ratio, excellent mechanical properties, and good biocompatibility. In addition, a large number of primary and secondary hydroxyl groups exist on the surface of the cellulose nanocrystal, which can be used for modification. Materials with multiple functions (such as temperature-sensitive color change, ammonia response, and ultraviolet absorption) have wide application prospects in the fields of gas sensing, biological medicine, temperature-sensitive materials, ammonia monitoring, and environmental safety. Therefore, it has broad application prospects to develop a simple and economical method for preparing multifunctional (such as temperature-sensitive color change, ammonia response, and ultraviolet absorption) modified cellulose nanocrystals. SUMMARY

[0003] Based on the above background, the application provides a functionalized modified cellulose nanocrystal as well as a preparation method and application thereof. The functionalized modified cellulose nanocrystal provided by the application has excellent temperature-sensitive color change, ammonia response color change performance, and ultraviolet absorption performance, and the preparation process is simple, environmentally friendly, low in cost, and suitable for scale-up production.

[0004] Technical scheme of the application:

[0005] A preparation method of a functionalized modified cellulose nanocrystal, comprising the following steps:

[0006] (1) 30 parts of cellulose nanocrystals are dispersed in 2000 parts of deionized water to obtain a uniform cellulose nanocrystal dispersion liquid, which is prepared for use;

[0007] (2) 20 parts of iron sulfate are taken and dissolved in 1000 parts of deionized water and 2000 parts of an ethanol mixed solvent to obtain a uniform iron sulfate solution, which is prepared for use;

[0008] (3) The iron sulfate solution obtained in step (2) is added to the cellulose nanocrystal dispersion liquid obtained in step (1), and stirred at room temperature for 1 h to obtain a uniform blending liquid, which is prepared for use;

[0009] (4) 7.25 parts of L-lysine are taken and dissolved in 1000 parts of deionized water and 2500 parts of an ethanol mixed solvent, and stirred for 30 min to obtain a uniform L-lysine solution, which is prepared for use;

[0010] (5) the L-lysine solution obtained in step (4) is added to the blending solution obtained in step (3), and the reaction is stirred at room temperature for 20 min, followed by centrifugal separation, washing with deionized water, and freeze-drying, to obtain the functionalized modified cellulose nanocrystals.

[0011] The functionalized modified cellulose nanocrystals obtained by the preparation method.

[0012] The present application has the following beneficial effects:

[0013] The functionalized modified cellulose nanocrystals prepared by the present application have the properties of temperature-sensitive color change, ammonia gas response color change, and ultraviolet absorption, and the preparation process is simple, environmentally friendly, and low in cost, and is suitable for large-scale production, and has a wide application prospect in the fields of temperature-sensitive materials, visual monitoring of ammonia gas, environmental safety, etc. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A scanning electron microscope image of the functionalized modified cellulose nanocrystals prepared in the present application;

[0015] Figure 2 A UV-visible spectrum of unmodified cellulose nanocrystals and the functionalized modified cellulose nanocrystals prepared in the present application. DETAILED DESCRIPTION

[0016] The present application will be described in detail below through examples, and it is necessary to point out here that the examples are only used to further illustrate the present application and cannot be understood as limiting the scope of the present application, and those skilled in the art can make some non-essential improvements and adjustments based on the content of the present application, wherein the raw material parts are mass parts unless otherwise specified.

[0017] In specific examples, the cellulose nanocrystals (i.e. unmodified cellulose nanocrystals in the present application) are products provided by Guilin Qihong Technology Co., Ltd., with a diameter of 4-10 nm and a length of 100-500 nm; the ferric sulfate is an analytical pure reagent provided by Xilong Chemical Co., Ltd.; the L-lysine is a product provided by Shanghai Yinan Chemical Technology Co., Ltd.; and the anhydrous ethanol is a product provided by Tianjin Fuyu Fine Chemical Co., Ltd.

[0018] Example:

[0019] A preparation method of functionalized modified cellulose nanocrystals, comprising the following steps:

[0020] (1) 30 parts of cellulose nanocrystals are dispersed in 2000 parts of deionized water to obtain a uniform cellulose nanocrystal dispersion solution, which is prepared for use;

[0021] (2) Take 20 parts of ferric sulfate, dissolve it in 1000 parts of deionized water and 2000 parts of ethanol mixed solvent to obtain a uniform ferric sulfate solution, ready for use;

[0022] (3) The ferric sulfate solution obtained in step (2) is added to the cellulose nanocrystal dispersion liquid obtained in step (1), stirred at room temperature for 1 h to obtain a uniform blending liquid, ready for use;

[0023] (4) Take 7.25 parts of L-lysine, dissolve it in 1000 parts of deionized water and 2500 parts of ethanol mixed solvent, stir for 30 min to obtain a uniform L-lysine solution, ready for use;

[0024] (5) The L-lysine solution obtained in step (4) is added to the blending liquid obtained in step (3), stirred at room temperature for 20 min, then centrifuged, washed with deionized water, and freeze-dried to obtain the functionalized modified cellulose nanocrystal.

[0025] The unmodified cellulose nanocrystal is white in color and does not change color when placed in a high-temperature environment of 105℃; the modified cellulose nanocrystal, i.e. the functionalized modified cellulose nanocrystal prepared in the example of the present application, is yellow in color and quickly turns dark brown when placed in a high-temperature environment of 105℃, indicating that the functionalized modified cellulose nanocrystal product has excellent temperature-sensitive color-changing performance.

[0026] The unmodified cellulose nanocrystal is white in color and does not change color when exposed to an ammonia environment; the modified cellulose nanocrystal, i.e. the functionalized modified cellulose nanocrystal prepared in the example of the present application, is yellow in color and turns brown in color (within 5 min) when exposed to an ammonia environment, indicating that the functionalized modified cellulose nanocrystal product has excellent ammonia-responsive color-changing performance.

[0027] The ultraviolet-visible spectrometer (Lamdba365, PerkinElmer Instruments) is used to evaluate the ultraviolet-visible performance of the product; Figure 2 The ultraviolet-visible spectra of the unmodified cellulose nanocrystal water dispersion and the functionalized modified cellulose nanocrystal water dispersion prepared in the example of the present application; the results show that the functionalized modified cellulose nanocrystal product prepared by the present method has significantly improved ultraviolet absorption performance compared to the unmodified cellulose nanocrystal.

[0028] In summary, the functionalized modified cellulose nanocrystal prepared by the present application has excellent temperature-sensitive color-changing, ammonia-responsive color-changing performance and ultraviolet absorption performance, and the preparation process is simple, environmentally friendly and low-cost, and is suitable for large-scale production, and has wide application prospects in the fields of temperature-sensitive materials, visual monitoring of ammonia gas, environmental safety, etc.

[0029] The content of the present application is not limited to the examples listed, any equivalent transformation of the technical solutions of the present application taken by a person of ordinary skill in the art through reading the description of the present application is covered by the claims of the present application.

Claims

1. A method for preparing functionalized modified cellulose nanocrystals, characterized in that... Includes the following steps: (1) Disperse 30 parts of cellulose nanocrystals in 2000 parts of deionized water to obtain a uniform cellulose nanocrystal dispersion for later use; (2) Take 20 parts of ferric sulfate and dissolve it in a mixed solvent of 1000 parts of deionized water and 2000 parts of ethanol to obtain a homogeneous ferric sulfate solution for later use. (3) Add the ferric sulfate solution obtained in step (2) to the cellulose nanocrystal dispersion obtained in step (1), stir at room temperature for 1 h to obtain a uniform blend, and set aside. (4) Take 7.25 parts of L-lysine, dissolve it in a mixed solvent of 1000 parts of deionized water and 2500 parts of ethanol, stir for 30 min to obtain a uniform L-lysine solution for later use. (5) Add the L-lysine solution obtained in step (4) to the blend obtained in step (3), stir and react at room temperature for 20 min, then centrifuge, wash with deionized water and freeze dry to obtain functionalized modified cellulose nanocrystals.

2. The functionalized modified cellulose nanocrystals obtained by the preparation method according to claim 1.

3. The application of the functionalized modified cellulose nanocrystals obtained by the preparation method according to claim 1, characterized in that, Used in the fields of temperature-sensitive materials, visual monitoring of ammonia, and environmental safety.

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