Cellulose-based fluorescent material, method for preparing the same, and use thereof

Abstract

The present application relates to a cellulose-based fluorescent material and a preparation method and application thereof. The cellulose-based fluorescent material comprises: a base material which is a cellulose derivative; a first fluorescent agent grafted to a molecular chain of the base material; the first fluorescent agent exhibits fluorescence quenching in response to an amine; a second fluorescent agent grafted to a molecular chain of the base material or grafted to a molecular chain of the base material containing the first fluorescent agent; or, the second fluorescent agent is physically mixed in a mixture of the base material and the base material containing the first fluorescent agent; the second fluorescent agent exhibits fluorescence intensity enhancement and emission peak shift in response to an amine; and the first fluorescent agent and the second fluorescent agent have partially or completely overlapping excitation spectra. The technical problem to be solved is how to conveniently realize qualitative detection and quantitative detection of amine compounds and realize visual detection of amine compounds.

Description

Technical Field

[0001] This invention belongs to the field of amine compound detection technology, and in particular relates to a cellulose-based fluorescent material, its preparation method, and its application. Background Technology

[0002] Amine compounds have wide applications in chemical, pharmaceutical, food production, and agriculture fields. However, ammonia has a strong, pungent odor, and its vapor is toxic and corrosive to the skin, eyes, and respiratory system. Chronic ammonia poisoning can cause respiratory diseases such as chronic bronchitis and emphysema, while acute ammonia poisoning can cause persistent coughing. Lower aliphatic amines are easily volatile and have an unpleasant odor. Aromatic amines have a milder odor than aliphatic amines but are more toxic; inhaling their vapors can cause poisoning. Therefore, the detection and monitoring of amine compounds is of great importance.

[0003] Current technologies for detecting amine compounds mainly include spectrophotometry, gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), ion chromatography, and fluorescence detection. However, spectrophotometry, GC-MS, LC-MS, and ion chromatography all require large-scale instruments, are costly, involve complex procedures, and require professional operation. Fluorescence detection is a relatively new method for detecting amine compounds, attracting considerable attention due to its high sensitivity, simple operation, rapid response, and good selectivity. However, current fluorescence detection methods rely on fluorescence sensors, and most of them monitor based on the mechanism of enhancing or weakening a single fluorescence intensity. On the one hand, the human eye's ability to perceive light intensity is greatly affected by human factors, making it difficult to achieve visual detection of amine compounds, resulting in low detection accuracy. On the other hand, when detecting amines based on ratiometric fluorescence, although the fluorescence color changes, the color change is the same after adding different amines, making it impossible to distinguish between different types of amines. At the same time, fluorescent small molecules have poor processability, often requiring mixing with petroleum-based polymers to improve their processing performance, leading to poor environmental friendliness. Summary of the Invention

[0004] The main objective of this invention is to provide a cellulose-based fluorescent material, its preparation method, and its application. The technical problem to be solved is how to conveniently achieve qualitative and quantitative detection of amine compounds, as well as visual detection of amine compounds, so that different types of amines can be distinguished by visual observation. At the same time, it improves the processability of fluorescent small molecules and avoids the problem of poor environmental friendliness caused by mixing them with petroleum-based polymers, thus making them more suitable for practical use.

[0005] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A cellulose-based fluorescent material according to this invention comprises:

[0006] The matrix material is a cellulose derivative;

[0007] The first fluorescent agent is grafted onto the molecular chain of the matrix material; the first fluorescent agent exhibits fluorescence quenching in response to amines.

[0008] The second fluorescent agent is grafted onto the molecular chain of the matrix material or onto the molecular chain of the matrix material containing the first fluorescent agent; or, the second fluorescent agent is physically mixed into a mixture of the matrix material and the matrix material containing the first fluorescent agent; the second fluorescent agent responds to amines by exhibiting enhanced fluorescence intensity and a shifted emission peak; the first fluorescent agent and the second fluorescent agent have excitation spectra that partially or completely overlap.

[0009] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0010] Preferably, in the aforementioned cellulose-based fluorescent material, the cellulose derivative is selected from at least one of cellulose acetate, cellulose acetate butyrate, cellulose propionate, cellulose acetate propionate, cellulose butyrate, and cellulose nitrate.

[0011] Preferably, in the aforementioned cellulose-based fluorescent material, the first fluorescent agent is selected from any one of luminol, isoluminol, isoluminol isothiocyanate, N-(4-aminobutyl)-N-ethyl isoluminol, and 4,5-diaminophthalic acid hydrazide.

[0012] Preferably, in the aforementioned cellulose-based fluorescent material, the second fluorescent agent is selected from any one of perylene-3,4,9,10-tetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic dianhydride, and perylenetetracarboxylic diimide compounds.

[0013] Preferably, in the aforementioned cellulose-based fluorescent material, the mass ratio of the first fluorescent agent to the matrix material is 0.6 to 1.0:1; and the mass ratio of the second fluorescent agent to the first fluorescent agent is 0.01 to 0.05:1.

[0014] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A method for preparing a cellulose-based fluorescent material according to this invention includes the following steps:

[0015] A first fluorescent agent is grafted onto the molecular chain of a matrix material; the matrix material is a cellulose derivative; the first fluorescent agent exhibits fluorescence quenching in response to amines;

[0016] The second fluorescent agent is grafted onto the molecular chain of the matrix material or onto the molecular chain of the matrix material containing the first fluorescent agent; or, the second fluorescent agent is physically blended into the matrix material and the matrix material containing the first fluorescent agent; the second fluorescent agent exhibits enhanced fluorescence intensity and a shifted emission peak in response to amines; the first fluorescent agent and the second fluorescent agent have partially or completely overlapping excitation spectra.

[0017] The objectives of this invention and the technical problems it addresses can be further achieved by the following technical measures.

[0018] Preferably, in the aforementioned method for preparing cellulose-based fluorescent materials, the grafting reaction temperature is 60–110°C and the reaction time is 8–48 h.

[0019] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A method for qualitative detection of amine compounds according to this invention includes the following steps:

[0020] The aforementioned cellulose-based fluorescent material was prepared into a solution;

[0021] Add one drop of an amine compound to the solution and observe the color of the solution under ultraviolet light and sunlight, respectively.

[0022] Based on the color of the solution under ultraviolet light and sunlight, and by referring to a colorimetric card, the types of amine compounds can be determined.

[0023] The objective of this invention and the technical problem it solves are achieved by the following technical solution. A method for quantitative detection of amine compounds according to this invention includes the following steps:

[0024] The aforementioned cellulose-based fluorescent material was prepared into a solution;

[0025] Add one drop of an amine compound to the solution and test the change in the ratio of the fluorescence intensity emitted by the first fluorescent agent to that emitted by the second fluorescent agent;

[0026] The types and contents of amine compounds are determined according to preset standards.

[0027] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, an application of the aforementioned cellulose-based fluorescent material in the detection of amine compounds is proposed, wherein the amine compound is ammonia, morpholine, benzylamine, diethylamine, triethylamine, or urea.

[0028] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, a cellulose-based fluorescent product with adjustable fluorescence color is provided, comprising the aforementioned cellulose-based fluorescent material; the cellulose-based fluorescent product is a cellulose-based fluorescent film, cellulose-based fluorescent fiber, cellulose-based fluorescent coating, or cellulose-based fluorescent ink.

[0029] The objective of this invention and the technical problem it solves are achieved by the following technical solution. According to this invention, an application of a cellulose-based fluorescent product with tunable fluorescent color is proposed, wherein the cellulose-based fluorescent coating and / or the cellulose-based fluorescent ink are coated onto plastic, glass, steel, or paper.

[0030] By employing the above technical solution, the cellulose-based fluorescent material, its preparation method, and its application proposed in this invention have at least the following advantages:

[0031] This invention proposes a cellulose-based fluorescent material, its preparation method, and its application. Using a cellulose derivative as the matrix material, a first fluorescent agent, exhibiting fluorescence quenching in response to amines, is grafted onto the molecular chain of the matrix material. A second fluorescent agent, exhibiting enhanced fluorescence intensity and emission peak shift in response to amines, is combined with the matrix material through grafting or physical mixing, resulting in a cellulose derivative material containing both the first and second fluorescent agents—the cellulose-based fluorescent material of this invention. The cellulose-based fluorescent material of this invention uses a cellulose derivative as the matrix material. Cellulose derivatives possess advantages such as good biocompatibility, excellent processing performance, wide availability, and low cost, making them excellent carriers for scaffold materials. Furthermore, the cellulose derivative molecular chain contains multiple hydroxyl groups capable of derivatization, which can promote the grafting of fluorescent small molecules onto the cellulose backbone. The abundant hydroxyl groups also facilitate the formation of hydrogen bonds with the fluorescent small molecules. The fluorescent small molecules in this invention are of two types: one is a first fluorescent agent that exhibits a negative response (fluorescence quenching) when detecting amines, and the other is a second fluorescent agent that exhibits enhanced fluorescence and a shifted emission peak when detecting amines. These two types of fluorescent agents also share partially overlapping excitation spectra. By observing the change in the ratio of fluorescence intensity emitted by these two types of fluorescent agents, the type and content of amine compounds can be determined. The shift in fluorescence emission peak causes a change in fluorescence color under sunlight and ultraviolet light, producing a clear signal change that is visually identifiable. Visual detection of amines can be achieved through colorimetry, and the type of amine compounds can be qualitatively measured.

[0032] Furthermore, the cellulose-based fluorescent material of the present invention has good biocompatibility and processability, and can be prepared into various cellulose-based fluorescent products with adjustable fluorescent colors; it can be prepared into fluorescent coatings and inks for large-scale anti-counterfeiting coating and smart security printing; it can also be prepared into smart fluorescent films and fluorescent fibers.

[0033] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0034] Figure 1 These are color images of the sample from Embodiment 2 of the present invention under sunlight (left) and ultraviolet light (right);

[0035] Figure 2 These are fluorescence spectra of different amine compounds added to the solution in Example 3 of this invention;

[0036] Figure 3a These are color photographs of the solution in Example 4 of this invention under sunlight (top) and ultraviolet light (bottom) before the addition of the amine compound;

[0037] Figure 3b These are color photographs of the solution in Example 4 of this invention under sunlight (top) and ultraviolet light (bottom) after the addition of different amine compounds;

[0038] Figure 4a These are color images of the fluorescent film 1 in Embodiment 5 of the present invention under sunlight (left) and ultraviolet light (right);

[0039] Figure 4b These are color images of the fluorescent film 2 in Embodiment 5 of the present invention under sunlight (left) and ultraviolet light (right);

[0040] Figure 4c These are color images of the fluorescent film 3 in Embodiment 5 of the present invention under sunlight (left) and ultraviolet light (right);

[0041] Figure 4d These are color images of the fluorescent film 4 in Embodiment 5 of the present invention under sunlight (left) and ultraviolet light (right). Detailed Implementation

[0042] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of a cellulose-based fluorescent material, its preparation method, and its application according to the present invention. In the following description, different "embodiments" or "embodiments" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable manner.

[0043] This invention proposes a cellulose-based fluorescent material, comprising a matrix material, wherein the matrix material is a cellulose derivative; the cellulose derivative is selected from at least one of cellulose acetate, cellulose acetate butyrate, cellulose propionate, cellulose acetate propionate, cellulose butyrate, and cellulose nitrate; due to the good biocompatibility, excellent processing performance, wide availability, and low price of the cellulose derivative, it is an excellent carrier as a backbone material. The molecular chain of the cellulose derivative contains multiple hydroxyl groups capable of derivatization reactions. These hydroxyl groups can promote the grafting of fluorescent small molecules onto the cellulose backbone, and also facilitate the formation of hydrogen bonds with the fluorescent small molecules; therefore, this invention uses the cellulose derivative as a matrix material, providing a basis for the introduction of fluorescent small molecules.

[0044] The cellulose-based fluorescent material of this invention further includes a first fluorescent agent; the first fluorescent agent exhibits fluorescence quenching in response to amines, and is chemically grafted onto the molecular chain of the matrix material. The first fluorescent agent is selected from any one of luminol, isoluminol, isoluminol isothiocyanate, N-(4-aminobutyl)-N-ethylisoluminol, and 4,5-diaminophthalic acid hydrazide. For some first fluorescent agents with low reactivity, to further improve their grafting bond with the matrix material, this invention preferably introduces a transition unit during the grafting of the first fluorescent agent to the matrix material to facilitate grafting. For example, when grafting the first fluorescent agent luminol onto the molecular chain of cellulose acetate, luminol is first nucleophilically added to 4,4'-methylenebis(phenyl isocyanate), and then the product obtained from the nucleophilic addition reaction is grafted onto cellulose acetate, so that 4,4'-methylenebis(phenyl isocyanate) can serve as a bridge between the subsequent first fluorescent agent luminol and cellulose acetate.

[0045] The cellulose-based fluorescent material of this invention further includes a second fluorescent agent; the second fluorescent agent exhibits enhanced fluorescence intensity and a shifted emission peak in response to amines, and can be introduced either through chemical grafting or physical mixing. When the second fluorescent agent is introduced through chemical grafting, it can be grafted onto the molecular chain of the matrix material or onto the molecular chain of the matrix material containing the first fluorescent agent. The second fluorescent agent is selected from any one of perylene-3,4,9,10-tetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic dianhydride, and perylenetetracarboxylic diimide compounds.

[0046] The cellulose-based fluorescent material of this invention introduces two types of fluorescent agents, with the first and second fluorescent agents having partially or completely overlapping excitation spectra. The reason for this design lies in the principle of fluorescence emission: under a certain range of excitation light, the fluorescent agent absorbs light within that range, transitioning from the ground state to an excited state, and then returning from the excited state to the ground state; during this process, fluorescence is emitted. The cellulose fluorescent material designed in this invention simultaneously contains both fluorescence-quenching and fluorescence-enhancing / shifting fluorescent agents. In actual amine detection, under the same ultraviolet excitation, both fluorescent agents must emit fluorescence for amine detection to be successful. Therefore, the technical solution of this invention limits the first and second fluorescent agents to having partially or completely overlapping excitation spectra.

[0047] The mass ratio of the first fluorescent agent to the matrix material is preferably 0.6 to 1.0:1; more preferably 0.6 to 0.8:1. The mass ratio of the second fluorescent agent to the first fluorescent agent is preferably 0.01 to 0.05:1; more preferably 0.01 to 0.03:1.

[0048] The cellulose-based fluorescent material of this invention comprises two types of fluorescent small molecules. Accurate detection of amines can be achieved by observing the change in the ratio of fluorescence intensity emitted by these two types of fluorescent agents and the shift in the fluorescence emission peak. Simultaneously, the fluorescence color changes under sunlight and ultraviolet light, producing a clear signal change that is visible to the naked eye, thereby enabling visual detection of amines.

[0049] This invention also proposes a method for preparing cellulose-based fluorescent materials, which includes the following steps:

[0050] A first fluorescent agent is grafted onto the molecular chain of a matrix material; the matrix material is a cellulose derivative; the first fluorescent agent exhibits fluorescence quenching in response to amines;

[0051] The second fluorescent agent is grafted onto the molecular chain of the matrix material or onto the molecular chain of the matrix material containing the first fluorescent agent; or, the second fluorescent agent is physically blended into the matrix material and the matrix material containing the first fluorescent agent; the second fluorescent agent exhibits enhanced fluorescence intensity and a shifted emission peak in response to amines; the first fluorescent agent and the second fluorescent agent have partially or completely overlapping excitation spectra.

[0052] In practice, it can be implemented in the following ways:

[0053] Method 1 involves mixing the matrix material with a first fluorescent agent and a second fluorescent agent, and then allowing them to undergo a chemical reaction to obtain a cellulose-based fluorescent material.

[0054] Method 2 is as follows: Mix the matrix material with the first fluorescent agent to allow it to react chemically and obtain the first product; then, mix the first product with the second fluorescent agent to allow it to react chemically and obtain the cellulose-based fluorescent material.

[0055] Method 3 is as follows: Mix the matrix material with the first fluorescent agent to allow it to undergo a chemical reaction and obtain the first product; then, mix the first product with the second fluorescent agent, controlling the conditions to prevent a chemical reaction and only perform physical mixing to obtain the cellulose-based fluorescent material.

[0056] Method four is as follows: mix the matrix material with the first fluorescent agent to allow it to react chemically and obtain the first product; mix the matrix material with the second fluorescent agent to allow it to react chemically and obtain the second product; finally, physically mix the first product and the second product to obtain the cellulose-based fluorescent material.

[0057] The cellulose-based fluorescent materials prepared by the above-mentioned specific preparation methods do not show significant differences, and the present invention does not limit the specific steps.

[0058] In the preparation method of the cellulose-based fluorescent material of the present invention, the preferred process conditions for the occurrence of chemical reactions such as nucleophilic addition are a reaction temperature of 60-110°C and a reaction time of 8-48 h.

[0059] This invention also proposes a method for qualitative detection of amine compounds, which includes the following steps:

[0060] The aforementioned cellulose-based fluorescent material of the present invention is prepared into a solution;

[0061] Add one drop of an amine compound to the solution and observe the color of the solution under ultraviolet light and sunlight, respectively.

[0062] Based on the color of the solution under ultraviolet light and sunlight, and by referring to a colorimetric card, the types of amine compounds can be determined.

[0063] The color change of the solution under ultraviolet light and sunlight is due to the shift of the fluorescence emission peak of the fluorescent agent. The color change of this solution under ultraviolet light and sunlight is very obvious, which makes it possible to qualitatively detect the types of amine compounds by means of the cellulose-based fluorescent material of the present invention, that is, to realize the visual detection of amine compounds.

[0064] This invention also proposes a method for quantitative detection of amine compounds, which includes the following steps:

[0065] The aforementioned cellulose-based fluorescent material of the present invention is prepared into a solution;

[0066] Add one drop of an amine compound to the solution and test the change in the ratio of the fluorescence intensity emitted by the first fluorescent agent to that emitted by the second fluorescent agent;

[0067] The types and contents of amine compounds are determined according to preset standards.

[0068] The above detection method can establish a relevant detection standard curve through external standard method or internal standard method, and then set it as a preset standard. Finally, the change in the ratio of the fluorescence intensity emitted by the first fluorescent agent and the second fluorescent agent is compared with the preset standard to determine the type and content of amine compounds, thereby realizing convenient quantitative detection of amine compounds.

[0069] The present invention also proposes an application of the aforementioned cellulose-based fluorescent material in the detection of amine compounds; the method can be used to detect amine compounds such as ammonia, morpholine, benzylamine, diethylamine, triethylamine, or urea.

[0070] The present invention also proposes a cellulose-based fluorescent product with adjustable fluorescence color, which comprises the aforementioned cellulose-based fluorescent material; the cellulose-based fluorescent product is a cellulose-based fluorescent film, a cellulose-based fluorescent fiber, a cellulose-based fluorescent coating, or a cellulose-based fluorescent ink.

[0071] The preparation method of the cellulose-based fluorescent product with tunable fluorescence color is basically the same as the preparation method of cellulose-based products in the prior art. The key difference is that the present invention uses the cellulose-based fluorescent material described in this invention. The preparation methods of various cellulose-based fluorescent products with tunable fluorescence color are described below.

[0072] The method for preparing the cellulose-based fluorescent film with tunable fluorescence color includes the following steps: mixing the cellulose-based fluorescent material with a cellulose derivative to obtain a mixture; the mass ratio of the cellulose-based fluorescent material to the cellulose derivative is 10% to 100%; dissolving the mixture in a solvent to prepare a solution with a mass concentration of 8% to 15%; the solvent is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetic acid, N,N-dimethylacetamide, and acetone; adding an amine compound dropwise to the solution; coating the film; and allowing the solvent to evaporate to obtain the cellulose-based fluorescent film with tunable fluorescence color.

[0073] The method for preparing the cellulose-based fluorescent fiber with tunable fluorescence color includes the following steps: mixing the cellulose-based fluorescent material with a cellulose derivative to obtain a mixture; the mass ratio of the cellulose-based fluorescent material to the cellulose derivative is 10% to 100%; dissolving the mixture in a solvent to prepare a solution with a mass concentration of 10% to 20%; the solvent is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetic acid, N,N-dimethylacetamide, and acetone; adding an amine compound dropwise to the solution; and wet spinning with water as a coagulation bath to obtain the cellulose-based fluorescent fiber with tunable fluorescence color.

[0074] The preparation method of the cellulose-based fluorescent coating with adjustable fluorescence color includes the following steps: dissolving the cellulose-based fluorescent material in a solvent to prepare a solution with a mass concentration of 0.5-10%; the solvent is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetic acid, N,N-dimethylacetamide and acetone; adding an amine compound dropwise to the solution to obtain the cellulose-based fluorescent coating with adjustable fluorescence color.

[0075] The preparation method of the cellulose-based fluorescent ink with adjustable fluorescence color includes the following steps: mixing the cellulose-based fluorescent material with a cellulose derivative to obtain a mixture; the mass ratio of the cellulose-based fluorescent material to the cellulose derivative is 10% to 100%; dissolving the mixture in a solvent to prepare a solution with a mass concentration of 8% to 15%; the solvent is selected from at least one of N,N-dimethylformamide, dimethyl sulfoxide, acetic acid, N,N-dimethylacetamide, and acetone; adding an amine compound dropwise to the solution to obtain the cellulose-based fluorescent ink with adjustable fluorescence color.

[0076] This invention also proposes an application of the aforementioned cellulose-based fluorescent product with tunable fluorescent color. This includes: coating the cellulose-based fluorescent coating and / or cellulose-based fluorescent ink onto plastics, glass, steel, or paper for large-scale anti-counterfeiting coating and smart security printing; it can also be directly processed into smart fluorescent films and fluorescent fibers.

[0077] The present invention will be further described below with reference to specific embodiments, but this should not be construed as a limitation on the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention still fall within the scope of protection of the present invention.

[0078] Unless otherwise specified, all materials and reagents mentioned below are commercially available products well known to those skilled in the art; unless otherwise specified, all methods described are methods known in the art. Unless otherwise defined, the technical or scientific terms used should have the ordinary meaning understood by those skilled in the art to which this invention pertains.

[0079] Example 1:

[0080] The specific steps for preparing cellulose-based fluorescent materials are as follows:

[0081] 1) Grafting of the first fluorescent agent, isoluminol isothiocyanate:

[0082] First, weigh 1.2g of isoluminol isothiocyanate and dissolve it completely in N,N-dimethylformamide; then weigh 1.5g of cellulose propionate and dissolve it completely in N,N-dimethylformamide; mix the above isoluminol isothiocyanate N,N-dimethylformamide solution with the cellulose propionate N,N-dimethylformamide solution, and then add 5-6 drops of dibutyltin dilaurate catalyst to allow it to undergo esterification reaction at 110℃. After reacting for 8 hours, stop heating; slowly pour the reaction mixture into methanol, filter, wash, and dry to obtain sample 1-1.

[0083] 2) Grafting of the second fluorescent agent, 3,4,9,10-perylenetetracarboxylic dianhydride:

[0084] Weigh 0.5 g of cellulose acetate, 0.03 g of 4-dimethylaminopyridine (catalyst), and 0.3 g of dicyclohexylcarbodiimide (dehydrating agent), and dissolve them completely in N,N-dimethylformamide; then add 0.03 g of 3,4,9,10-perylenetetracarboxylic acid dianhydride, and react at 60 °C for 48 h. The resulting product is precipitated, washed, and dried. Samples 1-2 are obtained.

[0085] 3) Preparation of cellulose-based fluorescent materials:

[0086] The above-mentioned samples 1-1 and 1-2 were fully dissolved in dimethyl sulfoxide, then precipitated and dried to obtain cellulose-based fluorescent materials. The cellulose-based fluorescent materials prepared in this embodiment can be used in the preparation of cellulose-based fluorescent products with adjustable fluorescence color in Example 5.

[0087] Example 2:

[0088] The grafting of the first fluorescent agent, luminol, is carried out through the following steps:

[0089] First, weigh 1.15 g of 4,4'-methylenebis(phenyl isocyanate) and dissolve it completely in N,N-dimethylformamide; then weigh 1.02 g of luminol and dissolve it completely in N,N-dimethylformamide; at 60 °C, slowly add the above luminol N,N-dimethylformamide solution to the 4,4'-methylenebis(phenyl isocyanate) N,N-dimethylformamide solution, add 3-4 drops of dibutyltin dilaurate catalyst, and react for 3 h; the reaction in this step is a nucleophilic addition reaction between luminol and 4,4'-methylenebis(phenyl isocyanate), the purpose of which is to bond luminol to 4,4'-methylenebis(phenyl isocyanate), so that 4,4'-methylenebis(phenyl isocyanate) can serve as a bridge between the subsequent first fluorescent agent luminol and cellulose acetate.

[0090] The aforementioned reaction solution was heated to 80°C, and 1.6 g of cellulose acetate was added to it. The reaction was terminated after stirring for 10 h. The reaction solution was slowly poured into methanol, filtered, washed, and dried to obtain sample 2-1, which emitted blue fluorescence under ultraviolet light excitation.

[0091] As attached Figure 1 The image shown is a colorimetric photograph of the sample from Example 1 under sunlight and ultraviolet light, respectively. (From the attached image...) Figure 1 As shown, the sample in this embodiment appears yellow under sunlight and blue under ultraviolet light, indicating that the sample in this embodiment successfully grafted the first fluorescent agent onto the cellulose derivative.

[0092] Example 3:

[0093] The following steps were taken to detect amine compounds using sample 2-1 prepared in Example 2:

[0094] Weigh 10 mg of the sample prepared in Example 2 and dissolve it completely in 10 mL of dimethyl sulfoxide to obtain solution 3-1; take the above solution 3-1, add one drop of an amine compound, and test the fluorescence spectra after adding different amines as shown in the attached figure. Figure 2 As shown.

[0095] Appendix Figure 2 In the figure, the fluorescence spectrum of the solution without added amines corresponds to the Lum-MDI-CA curve. Different amines (urea, triethylamine (TEA), morpholine (MOR), ammonia (NH3), benzylamine (BNZ), and diethylamine (DEA)) were added dropwise to solution 3-1, and the fluorescence spectra of the solutions with each amine added are shown in the attached figure. Figure 2 As shown.

[0096] From the appendix Figure 2As shown, the curve of Lum-MDI-CA almost overlaps with the curve corresponding to urea, indicating that the cellulose-based fluorescent material does not respond to urea; while the fluorescence intensity of solutions with other amine compounds decreased when added.

[0097] Example 4:

[0098] The specific steps for detecting amine compounds are as follows:

[0099] After the reaction solution in Example 2 of this invention was cooled to room temperature after heating was stopped, 10 mg of perylene-3,4,9,10-tetracarboxylic acid was added and stirred for 1 hour. Then the reaction solution was slowly poured into methanol, filtered, washed and dried to obtain sample 2-2.

[0100] Weigh 10 mg of the above sample 2-2 and dissolve it completely in 10 mL of dimethyl sulfoxide to obtain solution 4-1.

[0101] Take 4-1 of the above solution, add one drop of an amine compound, and observe the color change under ultraviolet light and sunlight. (See attached image) Figure 3a and attached Figure 3b As shown, Figure 3a These are color photos of solution 4-1 in this example under sunlight (top) and ultraviolet light (bottom) – before the addition of the amine compound. Figure 3b This is a colorimetric image of solution 4-1 in this example under sunlight (top) and ultraviolet light (bottom) after the addition of different amine compounds.

[0102] From the appendix Figure 3a As can be seen, solution 4-1 appears pink under sunlight and light blue under ultraviolet light; [the text abruptly ends here, likely due to an incomplete sentence or missing information.] Figure 3b As can be seen, after different amine compounds were added, the color of solution 4-1 changed significantly under sunlight and ultraviolet light. Based on this color change, the types of amine compounds can be visually detected.

[0103] Example 5:

[0104] The specific steps for preparing a cellulose-based fluorescent film with tunable fluorescence color are as follows:

[0105] Weigh 1.3g of cellulose acetate, 0.13g of sample 1-1 from Example 1, and 0.03g of the fluorescence-enhancing and shifting fluorescent agent perylene-3,4,9,10-tetracarboxylic acid. Add these to 10g of a mixed solvent of acetone and N,N-dimethylacetamide, wherein the volume ratio of acetone to N,N-dimethylacetamide in the mixed solvent is 2:1, to obtain solution 5-1.

[0106] Solution 5-1 was poured onto a glass plate and scraped to form a film. After drying at room temperature, a blue cellulose-based fluorescent film 1 was obtained. Color images of the film under sunlight and ultraviolet light are attached. Figure 4a As shown.

[0107] Adding 10 μL of ammonia to 10 mL of solution 5-1 yields a fruit-green cellulose-based fluorescent film 2 under ultraviolet light. Color images of the film under sunlight and ultraviolet light are attached. Figure 4b As shown.

[0108] Adding 10 μL of morpholine to 10 mL of solution 5-1 yields a grass-green cellulose-based fluorescent film 3 under ultraviolet light. Color images of the film under sunlight and ultraviolet light are attached. Figure 4c As shown.

[0109] Adding 10 μL of benzylamine to 10 mL of solution 5-1 yields an orange cellulose-based fluorescent film 4 under ultraviolet light. Color images of the film under sunlight and ultraviolet light are attached. Figure 4d As shown.

[0110] The various cellulose-based fluorescent films described above exhibit different colors when different amine compounds are added. In other words, the cellulose-based fluorescent film prepared in this embodiment is a cellulose-based fluorescent film with adjustable fluorescence color.

[0111] The technical features in the claims and / or specification of this invention can be combined, and the combination is not limited to the combinations obtained through reference in the claims. Technical solutions obtained by combining the technical features in the claims and / or specification are also within the scope of protection of this invention.

[0112] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A cellulose-based fluorescent material, characterized in that, It includes: The matrix material is a cellulose derivative; The first fluorescent agent is grafted onto the molecular chain of the matrix material; the first fluorescent agent exhibits fluorescence quenching in response to amines; the first fluorescent agent is selected from any one of luminol, isoluminol, isoluminol isothiocyanate, N-(4-aminobutyl)-N-ethylisoluminol and 4,5-diaminophthalic acid hydrazide. The second fluorescent agent is grafted onto the molecular chain of the matrix material or onto the molecular chain of a matrix material containing the first fluorescent agent; or, the second fluorescent agent is physically mixed into a mixture of the matrix material and a matrix material containing the first fluorescent agent; the second fluorescent agent exhibits enhanced fluorescence intensity and a shifted emission peak in response to amines; the second fluorescent agent is selected from any one of perylene-3,4,9,10-tetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic dianhydride, and perylenetetracarboxylic diimide compounds; the first fluorescent agent and the second fluorescent agent have partially or completely overlapping excitation spectra.

2. The cellulose-based fluorescent material according to claim 1, characterized in that, The cellulose derivative is selected from at least one of cellulose acetate, cellulose acetate butyrate, cellulose propionate, cellulose acetate propionate, cellulose butyrate, and cellulose nitrate.

3. The cellulose-based fluorescent material according to claim 1, characterized in that, The mass ratio of the first fluorescent agent to the matrix material is 0.6 to 1.0:1; the mass ratio of the second fluorescent agent to the first fluorescent agent is 0.01 to 0.05:

1.

4. A method for preparing a cellulose-based fluorescent material, characterized in that, It includes the following steps: The first fluorescent agent is grafted onto the molecular chain of the matrix material; the matrix material is a cellulose derivative; the first fluorescent agent exhibits fluorescence quenching in response to amines; the first fluorescent agent is selected from any one of luminol, isoluminol, isoluminol isothiocyanate, N-(4-aminobutyl)-N-ethyl isoluminol and 4,5-diaminophthalic acid hydrazide. The second fluorescent agent is grafted onto the molecular chain of the matrix material or onto the molecular chain of the matrix material containing the first fluorescent agent; or, the second fluorescent agent is physically blended into a mixture of the matrix material and the matrix material containing the first fluorescent agent; the second fluorescent agent exhibits enhanced fluorescence intensity and a shifted emission peak in response to amines; the second fluorescent agent is selected from any one of perylene-3,4,9,10-tetracarboxylic acid, 3,4,9,10-perylenetetracarboxylic dianhydride, and perylenetetracarboxylic diimide compounds; the first fluorescent agent and the second fluorescent agent have partially or completely overlapping excitation spectra.

5. The method for preparing cellulose-based fluorescent materials according to claim 4, characterized in that, The grafting reaction temperature is 60–110°C, and the reaction time is 8–48 h.

6. A method for qualitative detection of amine compounds, characterized in that, It includes the following steps: The cellulose-based fluorescent material according to any one of claims 1 to 3 is prepared into a solution; Add one drop of an amine compound to the solution and observe the color of the solution under ultraviolet light and sunlight, respectively. Based on the color of the solution under ultraviolet light and sunlight, and by referring to a colorimetric card, the types of amine compounds can be determined.

7. A method for quantitative detection of amine compounds, characterized in that, It includes the following steps: The cellulose-based fluorescent material according to any one of claims 1 to 3 is prepared into a solution; Add one drop of an amine compound to the solution and test the change in the ratio of the fluorescence intensity emitted by the first fluorescent agent to that emitted by the second fluorescent agent; The types and contents of amine compounds are determined according to preset standards.

8. The application of a cellulose-based fluorescent material according to any one of claims 1 to 3 in the detection of amine compounds, characterized in that, The amine compound is ammonia, morpholine, benzylamine, diethylamine, triethylamine, or urea.

9. A cellulose-based fluorescent product with tunable fluorescent color, characterized in that, It comprises the cellulose-based fluorescent material according to any one of claims 1 to 3; the cellulose-based fluorescent product is a cellulose-based fluorescent film, a cellulose-based fluorescent fiber, a cellulose-based fluorescent coating, or a cellulose-based fluorescent ink.

10. An application of the cellulose-based fluorescent product with tunable fluorescent color according to claim 9, characterized in that, The cellulose-based fluorescent coating and / or the cellulose-based fluorescent ink are applied to plastic, glass, steel, or paper.

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