Synthesis of pH-responsive biomass color-changing dye and hydrochloric-free acid color fixation method for cellulose fibers

Abstract

The invention provides a pH-responsive biomass color-changing dye synthesis method and a cellulose fiber acid-free acidic color fixation method, which comprises the following steps: firstly, preparing a pH-responsive biomass color-changing dye in a manner that an animal-derived active component and a plant equivalent react with an amino silane coupling agent in a water-alcohol system, and constructing a pH-responsive color-changing material by using the acid-free acidic color fixation method; the raw materials are green and environment-friendly, the reaction is carried out in a mild mode, the experimental steps are simple and safe, and the prepared product stimulates response discoloration, discoloration reversibility and discoloration sensitivity in different pH environments, so that the method can be applied to the field of medicine. The method can assist in diagnosing some diseases related to abnormal pH value of sweat, and can be applied to the fields of high-grade commodity package anti-counterfeiting, brackish water detection and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of functional materials, in particular to a method for synthesizing a pH-responsive biomass color-changing dye and fixing the color of cellulose fibers with salt-free acid. Background Art

[0002] pH-responsive color-changing materials have great application potential in many fields because of their ability to change color according to changes in the pH value of the environment. In environmental monitoring, they can reflect the changes in pH in water, soil and air in real time, providing strong support for environmental protection; in the medical and health field, the pH value changes of human body fluids are used to reflect health conditions, providing a new way to diagnose diseases; in addition, pH-responsive color-changing materials are also widely used in the fields of safety protection and smart textiles, providing intuitive warnings and information displays through color changes, and promoting the development of the textile industry towards intelligence.

[0003] Most of the current pH-responsive color-changing materials are artificially synthesized, which have the problems of ecological and environmental hazards, cumbersome synthesis routes, and strict control parameters. For example, chemically synthesized pH indicator dyes may be unsafe or even carcinogenic; the extraction and purification process of natural dyes may be complicated and costly; the synthesis of polymer materials and nanomaterials often requires complex chemical reactions and strict control conditions. These problems limit the widespread application of pH-responsive color-changing materials. With the enhancement of environmental awareness, researchers are paying more and more attention to the development of green, intelligent, and multifunctional pH-responsive color-changing materials, and applying pH-responsive color-changing materials to more fields, such as wearable devices, smart packaging, environmental monitoring, etc., to expand their application range and market prospects.

[0004] The pH-responsive color-changing materials and methods studied so far, for example, CN107254491A patent proposes a method for dyeing cotton fabrics with a biosynthesized pyrrole structure red nano-pigment based on pH response. The method produces pyrrole structure red nano-pigment by fermentation of high-yield Serratia marcescens, and uses the pigment suspension to dye cotton fabrics. The whole process does not require the use of organic solvents, which not only reduces environmental pollution, but also gives cotton fabrics a bright red color. More importantly, the dyeing method also enables cotton fabrics to have significant antibacterial properties, and has a good inhibitory effect on common bacteria such as Escherichia coli and Staphylococcus aureus. This dyeing method that combines environmental protection and functionality has broad application prospects in the field of textile printing and dyeing; CN114059367A patent focuses on pH and temperature-responsive cotton salt-free dyeing and hand finishing agents. The patent develops a finishing agent that can replace traditional neutral electrolytes by synthesizing linear double-terminal epoxy polyether siloxanes and amino-block hyperbranched silicone surfactants. During the dyeing process, by adjusting the pH value and temperature of the dye solution, the surfactant can be efficiently adsorbed to the surface of the cotton fiber, thereby improving the dye uptake rate of the dye. This salt-free dyeing method not only reduces the salt content in the printing and dyeing wastewater, solves the problem of environmental pollution, but also gives the cotton fabric a soft feel. This environmentally friendly and economical dyeing and finishing technology has brought new development opportunities to the textile industry. Although they have made significant progress in environmentally friendly dyeing and finishing technologies, they still face some challenges. The pyrrole structure red nano pigment dyeing method of CN107254491A needs to further optimize the stability and durability of the pigment, ensure that it remains efficient and cost-effective in large-scale production, and continue to pay attention to the environmental protection and sustainability of the entire production chain. The salt-free dyeing and hand finishing agent of CN114059367A needs to improve the adsorption efficiency and stability of the surfactant, study its applicability on different fiber types, and formulate a standardized process to ensure consistent effects. In addition, modern technological development is also generally faced with the challenges of technological maturity and commercialization process, as well as the increasing pressure of environmental protection and sustainability, while intellectual property protection and transformation issues are also urgently needed. Solving these problems will help promote the textile printing and dyeing industry to develop in a more environmentally friendly, efficient and sustainable direction. Summary of the invention

[0005] In view of the above problems, the purpose of this application is to provide a method for synthesizing pH-responsive biomass color-changing dyes and a salt-free acid fixation method for cellulose fibers, so as to solve the limitations of the current pH-responsive color-changing material preparation process, strict process control conditions, and high costs.

[0006] To achieve some or all of the above purposes or other purposes, the present application provides the following technical solution: a method for synthesizing a pH-responsive biomass color-changing dye and fixing the color of cellulose fibers in a salt-free acidic manner, comprising the following steps: S100, taking biomass animal-derived active components and plant equivalent naphthoquinone substances and uniformly mixing them in a water-alcohol system, adding glacial acetic acid to adjust the pH value, adding an aminosilane coupling agent to react, and after the mixed solution reacts, treating it to obtain a pH-responsive biomass color-changing dye for use; S200, fully dissolving the pH-responsive biomass color-changing dye in an alkaline medium to prepare a uniform mixed liquid phase, and dyeing the cotton fabric using a salt-free acid fixation method to obtain a pH-responsive color-changing cotton fabric; S300, fully dissolving the pH-responsive biomass color-changing dye described in step S100 in an alkaline medium to prepare a uniform mixed liquid phase, and dyeing the apocynum ramie with a salt-free acid fixation method to obtain a pH-responsive color-changing apocynum ramie yarn; S400, fully dissolving the pH-responsive biomass color-changing dye in step S100 in an alkaline medium to prepare a uniform mixed liquid phase, and dyeing cotton fiber pulp using a salt-free acid fixation method to obtain a pH-responsive color-changing paper-based material.

[0007] Furthermore, the step S100 includes: S110, take 2g astaxanthin and 0.3g 2-hydroxy-1,4-naphthoquinone and completely dissolve them in equal volumes of deionized water and anhydrous ethanol (volume ratio is 1:1), add glacial acetic acid to adjust the pH value of the system (adjust the pH value of the system to 4), add 5ml 3-aminopropyltriethoxysilane, and heat and stir the mixture in an oil bath at 60℃ for 12h, with a rotation speed of 30r / min; S120. After the reaction of the mixed solution is completed, it is centrifuged twice, the centrifugal speed is 4000r / min, and the processing time is 10min; after the centrifugal treatment, the original solution is neutrally precipitated with deionized water at a ratio of 1:20, and the precipitate is centrifuged and washed 5 times, the centrifugal speed is 10000r / min, and the processing time is 10min; the centrifugal precipitate is dried in an oven at 40℃, and then extracted and separated in a methanol system at a temperature of 90~95℃ and dried for 12 h to obtain a pH-responsive biomass color-changing dye.

[0008] Furthermore, the step S200 includes: The pH-responsive biomass color-changing dye was placed in an alkaline system to form a mixed liquid phase and then subjected to oscillation dyeing with cotton fabric in a constant temperature shaking incubator for 1 hour. The pH was then adjusted to pH=10, pH=7, and pH=3 with citric acid. Constant temperature shaking dyeing was continued for 1 hour at each pH value, and then the fabric was washed and dried to obtain pH-responsive color-changing cotton fabric.

[0009] Furthermore, the step S300 includes: The pH-responsive biomass color-changing dye is placed in an alkaline system to form a mixed liquid phase, which is then shaken and dyed with the apocynum in a constant temperature shaking incubator for 1 hour. The pH is then adjusted to pH=10, pH=7, and pH=3 with citric acid. Constant temperature shaking dyeing is continued for 1 hour at each pH value, and then the pH-responsive color-changing apocynum yarn is obtained by washing and drying.

[0010] Furthermore, the step S400 includes: The pH-responsive biomass color-changing dye is placed in an alkaline system to form a mixed liquid phase and then subjected to shaking dyeing treatment with cotton fiber pulp in a constant temperature shaking incubator for 1 hour. The pH is then adjusted to pH=10, pH=7, and pH=3 with citric acid, and constant temperature shaking dyeing is continued for 1 hour at each pH value. After all dyeing steps are completed, the cotton fiber pulp after the salt-free acid fixation dyeing treatment is taken out and washed with deionized water for 5 minutes. After washing for 3 times, the pH-responsive color-changing paper-based material is obtained by filtration-extrusion.

[0011] Furthermore, the pH-responsive color-changing cotton fabric is applied to sweat detection.

[0012] Furthermore, the pH-responsive color-changing apocynum yarn is applied to anti-counterfeiting detection.

[0013] Furthermore, the pH responsive color-changing paper-based material is applied to the detection of brackish water.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) the present invention exhibits significant green chemical characteristics, and the reaction process is mild and orderly; specifically, the animal-derived active components derived from biomass and the plant equivalent naphthoquinone substances are placed in a water-alcohol mixture system and uniformly mixed; then, the pH of the system is adjusted with the help of glacial acetic acid and an aminosilane coupling agent is added for reaction; after the reaction of the above mixed solution is completed, it undergoes a specific treatment process to finally obtain a pH-responsive biomass color-changing dye; in this process, the raw materials required for the experiment are easily accessible, and the entire reaction process is also easy to accurately control; the present invention exhibits innovative advantages in many aspects, such as the mildness of the product formation path and the non-toxic and harmless nature of the process.

[0015] (2) The present invention adopts an environmentally friendly color fixing method; through the hydrochloric acid color fixing technology, that is, using citric acid to cleverly control the pH value of the system, the prepared pH-responsive biomass color-changing dye is firmly attached to various carriers; this salt-free acid color fixing technology can solve a series of serious problems currently faced by the dyeing industry, such as excessive salt content in dyeing wastewater, serious pollution to the environment, and a large amount of water resources. The significant characteristics of the present invention, such as low cost and easy implementation, as well as the simple and easy preparation process of pH-responsive color-changing materials, are fully in line with the current trend of the dyeing industry's transformation towards green sustainable development and environmentally friendly production.

[0016] (3) The present invention successfully achieves the firm adhesion of dyes on a variety of materials such as cotton fabrics, ramie and cotton fiber pulp by relying on the core method of salt-free acid fixation technology, thereby preparing pH-responsive color-changing materials; the material exhibits color change in response to stimulation in different pH environments, and the color change process exhibits reversibility and sensitivity; based on the above performance, the present invention has considerable potential application value in this field. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 An optical photograph of the pH-responsive color-changing cotton fabric provided in Example 1 of the present invention; Figure 2 An optical photograph of the pH-responsive color-changing apocynum yarn provided in Example 2 of the present invention; Figure 3 An optical photograph of the pH-responsive color-changing paper-based material provided in Example 3 of the present invention; Figure 4 Provide optical photographs of pH-responsive color-changing cotton fabrics that change color in response to stimulation in different pH environments for Example 1 of the present invention; Figure 5 Provides optical photographs of pH-responsive color-changing apocynum yarn changing color in response to stimulation under different pH environments for Example 2 of the present invention; Figure 6 Provides optical photographs of pH-responsive color-changing paper-based materials changing color in response to stimulation in different pH environments for Example 3 of the present invention; Figure 7 Provide a pH-responsive color-changing cotton fabric reversible optical photograph for Example 1 of the present invention; Figure 8 Provide a pH-responsive color-changing reversible optical photograph of apocynum flax yarn for Example 2 of the present invention; Fig. 9 Provide a pH-responsive color-changing paper-based material reversible color-changing optical photograph for Example 3 of the present invention; Fig.10 A curve diagram showing the variation of K / S of pH-responsive color-changing cotton fabric with wavelength is provided for Example 1 of the present invention; Fig.11 A curve diagram of the K / S of the pH-responsive color-changing apocynum yarn as a function of wavelength is provided for Example 2 of the present invention; Fig.12 A curve diagram of the K / S of the pH-responsive color-changing paper-based material changing with wavelength is provided for Example 3 of the present invention; Fig.13 Provide a pH-responsive color-changing cotton fabric CIE1931 diagram for Example 1 of the present invention; Fig.14 Provide a pH-responsive color-changing apocynum yarn color-changing CIE1931 diagram for Example 2 of the present invention; Fig.15 Provide a pH-responsive color-changing paper-based material color-changing CIE1931 diagram for Example 3 of the present invention; Fig.16 Provide a test chart of color fastness to soaping of pH-responsive color-changing cotton fabric for Example 1 of the present invention; Fig.17 Provide a pH response color change cotton fabric light fastness test chart for Example 1 of the present invention; Fig.18 Provides a pH-responsive color-changing cotton fabric rubbing color fastness test chart for Example 1 of the present invention; Fig.19 Provide a pH-responsive color-changing cotton fabric anti-ultraviolet test chart for Example 1 of the present invention; Fig. 20 Provides an application diagram of pH-responsive color-changing cotton fabric for detecting simulated sweat for Example 1 of the present invention; Fig.21 Provide a pH-responsive color-changing Apocynum venetum anti-counterfeiting application diagram for Example 2 of the present invention; Fig. 22 Provided is an application diagram of bitter and brackish water detection using pH-responsive color-changing paper-based material for Example 3 of the present invention. DETAILED DESCRIPTION

[0018] In order to make the structure and function of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Example

[0019] The present invention provides a method for synthesizing a pH-responsive biomass color-changing dye and fixing the color of cotton fabric with salt-free acid, comprising the following steps: (1) Weigh 2g of astaxanthin and 0.3g of 2-hydroxy-1,4-naphthoquinone (commonly known as henna quinone) and add them to a water-alcohol system consisting of anhydrous ethanol (CH3CH2OH) and deionized water (close to pure water) in a volume ratio of 1:1 to fully dissolve them. Then add glacial acetic acid to adjust the pH of the system to 4, and then weigh 5ml of 3-aminopropyltriethoxysilane and add it to the above system to mix evenly. Stir the reaction at 60°C for 12h at a speed of 30r / min to form a biomass mixed solution system for standby use; (2) Centrifuge the biomass mixed solution system obtained in step (1) to allow the impurities in the biomass mixed solution system to settle to the bottom. The centrifuge speed is 4000 rpm, 10 min each time, and repeated 2 times. Subsequently, the stock solution after centrifugation is neutrally precipitated with deionized water at a ratio of 1:20, and then the precipitate is taken and washed with deionized water to remove the unreacted related compounds and functional reagents. The centrifuge speed is 10000 rpm, 10 min each time, and repeated 5 times; the centrifuged precipitate is dried in an oven at 40°C, and then extracted and separated in a methanol system at a temperature of 90~95°C and dried for 12 h to obtain a pH-responsive biomass color-changing dye; (3) 0.1 g of pH-responsive biomass color-changing dye was fully dissolved in 50 mL of 1 mol / L NaOH solution to prepare a uniform mixed liquid phase, and then placed in a constant temperature oscillation dyeing device together with 2 g of cotton fabric, and oscillated and dyed at 25°C for 1 hour at a speed of 140 rpm. Thereafter, 1 mol / L of citric acid was added to adjust the pH value of the system to 10, and the system was oscillated and dyed again in the constant temperature oscillation dyeing device for 1 hour; then, citric acid was continued to be used to adjust the pH to neutral (pH=7), and the third oscillation dyeing treatment was carried out under the same conditions for 1 hour; finally, the system pH was further adjusted to acidic (pH=3), and the fourth oscillation dyeing was completed in the constant temperature oscillation dyeing device, and the duration was also 1 hour; after completing all dyeing steps, the cotton fabric after the salt-free acid fixation dyeing treatment was taken out and washed with deionized water for 5 minutes. After washing three times, the pH-responsive color-changing cotton fabric was obtained. Example

[0020] The present invention provides a method for fixing apocynum venetum with a pH-responsive biomass color-changing dye in a non-salt acidic manner, comprising the following steps: (1) Same as step (1) in Example 1; (2) Same as step (2) in Example 1; (3) 0.1 g of pH-responsive biomass color-changing dye was fully dissolved in 50 mL of 1 mol / L NaOH solution to prepare a uniform mixed liquid phase, and then placed in a constant temperature oscillation dyeing device together with 2 g of apocynum ramie, and oscillated and dyed at 25°C for 1 hour at a rotation speed of 140 rpm. Thereafter, 1 mol / L of citric acid was added to adjust the pH value of the system to 10, and the system was oscillated and dyed again in the constant temperature oscillation dyeing device for 1 hour; then, citric acid was continued to be used to adjust the pH to neutral (pH=7), and the third oscillation dyeing treatment was carried out under the same conditions for 1 hour; finally, the system pH was further adjusted to acidic (pH=3), and the fourth oscillation dyeing was completed in the constant temperature oscillation dyeing device, and the duration was also 1 hour; after completing all the dyeing steps, the apocynum ramie treated with salt-free acid fixation dyeing was taken out and washed with deionized water for 5 minutes. After washing for 3 times, pH-responsive color-changing apocynum ramie yarn was obtained. Example

[0021] The present invention provides a method for fixing cotton fiber pulp with a pH-responsive biomass color-changing dye using a salt-free acidic method, comprising the following steps: (1) Same as step (1) in Example 1; (2) Same as step (2) in Example 1; (3) 0.1 g of pH-responsive biomass color-changing dye was fully dissolved in 50 mL of 1 mol / L NaOH solution to prepare a uniform mixed liquid phase, and then placed in a constant temperature oscillation dyeing device together with 1 g of cotton fiber pulp, and oscillated and dyed at 25°C for 1 hour at a speed of 140 rpm; thereafter, 1 mol / L of citric acid was added to adjust the pH value of the system to 10, and the system was oscillated and dyed again in the constant temperature oscillation dyeing device for 1 hour; then, citric acid was continued to be used to adjust the pH to neutral (pH=7), and the third oscillation dyeing treatment was carried out under the same conditions for 1 hour; finally, the system pH was further adjusted to acidic (pH=3), and the fourth oscillation dyeing was completed in the constant temperature oscillation dyeing device, and the duration was also 1 hour; after completing all dyeing steps, the cotton fiber pulp after the salt-free acid fixation dyeing treatment was taken out and washed with deionized water for 5 minutes. After washing for 3 times, the pH-responsive color-changing paper-based material was obtained by filtration-extrusion.

[0022] It should be noted that the steps of Examples 1 to 3 are basically the same, except that the dyeing carriers are different. The products of Examples 1 to 3 are respectively subjected to color change performance measurement in different pH environments, color change reversible performance measurement in different pH environments, color change K / S value measurement in different pH environments, color change reflectivity measurement in different pH environments, color change CIE1931 measurement in different pH environments, color fastness to soaping measurement, color fastness to light measurement, color fastness to rubbing measurement, etc. The differences in product characteristics are not large, and the testing process of the products of Examples 1 to 3 is described below as an example.

[0023] 1. Test the color-changing performance of pH-responsive color-changing materials in response to stimulation in different pH environments. Figure 1-9 ; See also Figure 1 is an optical photograph of the product of Example 1; see Figure 2 is an optical photograph of the product of Example 2; see Figure 3 This is an optical photograph of the product of Example 3; See also Figure 4 , Optical photographs of the pH-responsive color-changing cotton fabric obtained in Example 1 changing color in response to stimulation in different pH environments. The pH-responsive color-changing cotton fabric was inserted from air atmosphere into solutions of different pH values ​​and its color change was recorded. In the alkaline environment of pH=14 to pH=9, the color of the pH-responsive color-changing cotton fabric changed from lavender to emerald green and the change was relatively sensitive; in the environment of pH=8, the pH-responsive color-changing cotton fabric changed from lavender to reddish purple; in the relatively neutral environment of pH=7 to pH=5, the pH-responsive color-changing cotton fabric changed from lavender to reddish purple; in the environment of pH=4 to pH=3, the color of the pH-responsive color-changing cotton fabric changed to pink; in the acidic environment of pH=2 to pH=1, the color of the pH-responsive color-changing cotton fabric changed to red, and the color change sensitivity was high.

[0024] See also Figure 5 , Optical photographs of the pH-responsive color-changing apocynum obtained in Example 2 that change color in response to stimulation in different pH environments. The pH-responsive color-changing apocynum was inserted from air atmosphere into solutions of different pH values ​​and its color change was recorded. In an alkaline environment of pH=14 to pH=10, the color of the apocynum changes from light purple to emerald green and the change is relatively sensitive; in an environment of pH=9 to pH=8, the color of the apocynum changes from light purple to dark purple; in an environment of pH=7 to pH=3, the color of the apocynum changes from light purple to dark purple; in an environment of pH=2 to pH=1, the color of the apocynum changes from light purple to red.

[0025] See also Figure 6, Optical photographs of the pH-responsive color-changing paper-based material obtained in Example 3 changing color in response to stimulation in different pH environments. The pH-responsive color-changing paper-based material was inserted from the air atmosphere into solutions of different pH values ​​and its color change was recorded. In the alkaline environment of pH=14 to pH=12, the light purple color changed to dark blue and the change was relatively sensitive; in the environment of pH=11 to pH=10, the pH-responsive color-changing paper-based material changed to green; in the relatively neutral environment of pH=9 to pH=8, the pH-responsive color-changing paper-based material changed from light purple to blue-green; in the relatively neutral environment of pH=7, the pH-responsive color-changing paper-based material changed from light purple to dark purple; in the environment of pH=6 to pH=4, the pH-responsive color-changing paper-based material changed to pink purple; in the acidic environment of pH=3 to pH=1, the color changed to red, and the color change sensitivity was high.

[0026] See also Figure 7 The color change reversibility of the pH-responsive color-changing cotton fabric obtained in Example 1 is that the pH-responsive color-changing cotton fabric is inserted from the air atmosphere into an acidic environment of pH=1 and turns red. Then it is taken out and inserted into an alkaline environment of pH=14. The pH-responsive color-changing cotton fabric changes from red to emerald green. Then it is placed in an environment of pH=1 and changes back to its initial color state, which proves the feasibility of the pH-responsive color-changing cotton fabric having acid-base color-changing properties and color-changing reversibility properties.

[0027] See also Figure 8 The color change reversibility of the pH-responsive color-changing Lop Neck Hemp obtained in Example 2 is that the pH-responsive color-changing Lop Neck Hemp is inserted from the air atmosphere into an acidic environment of pH=1 and turns red, then taken out and continued to be inserted into an alkaline environment of pH=14, and the pH-responsive color-changing Lop Neck Hemp changes from red to emerald green, and then placed in an environment of pH=1 and changes back to its initial color state, proving the feasibility of the pH-responsive color-changing Lop Neck Hemp having acid-base color-changing properties and color-changing reversibility properties.

[0028] See also Fig. 9 The color change reversibility of the pH responsive color-changing paper-based material obtained in Example 3 is that the pH responsive color-changing paper-based material is inserted from the air atmosphere into an acidic environment of pH=1 and turns red. Then it is taken out and inserted into an alkaline environment of pH=14, and the pH responsive color-changing paper-based material changes from red to dark blue. Then it is placed in an environment of pH=1 and changes back to its initial color state, which proves the feasibility of the pH responsive color-changing paper-based material having acid-base color-changing properties and reversible color-changing properties.

[0029] 2. pH-responsive color-changing materials are tested using a spectrophotometer after changing color in response to stimulation in different pH environments. Fig.10 - 15; See also Fig.10, the color performance of the pH-responsive color-changing cotton fabric obtained in Example 1. First, a series of buffers with different pH values ​​were prepared to ensure that the complete pH range of the material color change was covered. Subsequently, the samples were immersed in buffers of each pH value, and the absorbance of each sample was measured at a specific wavelength using a spectrophotometer to quantify the color intensity. By comparing the absorbance of the samples under different pH conditions, the color intensity of the samples was quantified. K / S We deeply analyzed the pH response color change characteristics of the material and recorded all experimental data and results in detail to form a complete test report.

[0030] See also Fig.11 , the color performance of pH-responsive color-changing apocynum obtained in Example 2. First, a series of buffers with different pH values ​​were prepared to ensure that the complete pH range of material color change was covered. Subsequently, the samples were immersed in buffers of each pH value, and the absorbance of each sample was measured at a specific wavelength using a spectrophotometer to quantify the color intensity. By comparing the pH values ​​of the samples under different pH conditions, the color intensity of the samples was quantified. K / S We deeply analyzed the pH response color change characteristics of the material and recorded all experimental data and results in detail to form a complete test report.

[0031] See also Fig.12 , the color performance of the pH-responsive color-changing paper-based material obtained in Example 3. First, a series of buffers with different pH values ​​were prepared to ensure that the complete pH range of the material color change was covered. Subsequently, the samples were immersed in buffers of each pH value, and the absorbance of each sample was measured at a specific wavelength using a spectrophotometer to quantify the color intensity. By comparing the absorbance of the samples under different pH conditions, the color intensity of the samples was quantified. K / S We deeply analyzed the pH response color change characteristics of the material and recorded all experimental data and results in detail to form a complete test report.

[0032] See also Fig.13 , the color performance of the pH-responsive color-changing cotton fabric obtained in Example 1. In order to evaluate the color change characteristics of the pH-responsive color-changing material in the patent. First, we prepared samples according to the patent requirements and calibrated the test equipment to the CIE1931 colorimetric system standard. Subsequently, under constant environmental conditions, the samples were immersed in solutions of different pH values ​​in turn. After the color stabilized, a colorimeter was used to measure and record the X, Y, and Z tristimulus values ​​in the CIE1931 colorimetric system at each pH value. By drawing a chromaticity diagram and calculating the color difference, the color change trend of the sample with the change of pH value was systematically analyzed, and finally the evaluation conclusion of its pH-responsive color-changing characteristics was obtained.

[0033] See also Fig.14, the color performance of pH-responsive color-changing apocynum obtained in Example 2. In order to evaluate the color change characteristics of the pH-responsive color-changing material in the patent. First, we prepared samples according to the patent requirements and calibrated the test equipment to the CIE1931 colorimetric system standard. Subsequently, under constant environmental conditions, the samples were immersed in solutions of different pH values ​​in turn. After the color stabilized, a colorimeter was used to measure and record the X, Y, and Z three stimulus values ​​in the CIE1931 colorimetric system at each pH value. By drawing a chromaticity diagram and calculating the color difference, the color change trend of the sample with the change of pH value was systematically analyzed, and finally the evaluation conclusion of its pH-responsive color-changing characteristics was drawn.

[0034] See also Fig.15 , the color performance of the pH-responsive color-changing paper-based material obtained in Example 3. In order to evaluate the color change characteristics of the pH-responsive color-changing material in the patent. First, we prepared samples according to the patent requirements and calibrated the test equipment to the CIE1931 colorimetric system standard. Subsequently, under constant environmental conditions, the samples were immersed in solutions of different pH values ​​in turn. After the color stabilized, a colorimeter was used to measure and record the X, Y, and Z tristimulus values ​​in the CIE1931 colorimetric system at each pH value. By drawing a chromaticity diagram and calculating the color difference, the color change trend of the sample with changes in pH value was systematically analyzed, and finally an evaluation conclusion of its pH-responsive color-changing characteristics was drawn.

[0035] 3. pH response color change cotton fabric color fastness performance test and UV resistance test, see Fig.16 - 19; See also Fig.16 , the pH-responsive color-changing cotton fabric obtained in Example 1 was tested for color fastness to soap washing. This test was conducted according to the ISO 105-C10:2006 standard method, using 5 g / L sodium dodecyl sulfate solution as a detergent, and simulated washing was performed at a constant 40°C condition to comprehensively evaluate the color stability of the fabric under different washing times (1 hour, 2 hours, and 3 hours). The experimental results showed that after the above-mentioned soap washing treatment, the color change of the cotton fabric dyed with the pH-responsive biomass color-changing dye was compared with that of the original fabric. K / S The values ​​remained relatively constant during different washing periods, with no significant downward trend. This result fully confirms that the dye has an excellent fixation effect on cotton fibers, and a strong bond is formed between the dye molecules and the cotton fibers, effectively resisting the effects of mechanical forces and chemical reactions on the dye molecules during the washing process, thereby ensuring the durability and stability of the fabric color.

[0036] See also Fig.17, the light color fastness test of the pH-responsive color-changing cotton fabric obtained in Example 1. This test is based on the ISO105-B02:2014 standard method. The light color fastness test simulates the long-term exposure of fabrics to sunlight or artificial light sources and is an important indicator for evaluating their color stability. The test results show that after long-term light exposure, the color change of cotton fabrics dyed with pH-responsive biomass color-changing dyes is still small. K / S The value remains relatively stable, showing good light fastness. This shows that the dye has good stability under light conditions, is not prone to photolysis or fading, and ensures the long-lasting bright color of the fabric.

[0037] See also Fig.18 , the pH-responsive color-changing cotton fabric obtained in Example 1 was tested for color fastness to friction. The color fastness to friction of this product was tested according to ISO 105-X12:2016 standard, using a friction color fastness tester, and the color transfer of the fabric under friction was evaluated by dry friction. The test results showed that the cotton fabrics dyed with pH-responsive biomass color-changing dyes showed good color fastness, and the color change after friction was minimal. K / S The value does not change much, indicating that the color layer formed by the dye on the surface of cotton fabric has high wear resistance and is not easy to fall off or change color due to friction. The excellent color fastness performance of pH-responsive biomass color-changing dye on cotton fabric was verified through comprehensive tests of color fastness to soaping, color fastness to rubbing and color fastness to light. The dye not only has good color change response characteristics, but also can maintain stable color performance under various environmental conditions, providing strong support for the development of intelligent color-changing textiles.

[0038] See also Fig.19, the anti-ultraviolet performance test of the pH-responsive color-changing cotton fabric obtained in Example 1. According to my country's national standard GB / T 18830-2009 "Evaluation and Test Methods for Ultraviolet Protection Performance of Textiles", this study uses the advanced YG912E textile ultraviolet protection performance test system, with ultraviolet protection factor (UPF) as the core evaluation index, supplemented by the quantitative analysis of long-wave ultraviolet rays (UVA, 315-400nm) and short-wave ultraviolet rays (UVB, 280-315nm) transmittance, and systematically compares the ultraviolet protection performance of pH-responsive color-changing cotton fabrics with undyed reference cotton fabrics. The experimental results show that the pH-responsive color-changing cotton fabric exhibits a significantly higher ultraviolet protection factor (UPF) than the undyed cotton fabric, which directly reflects the superiority of the former in resisting ultraviolet radiation. Further analysis shows that in the subdivided area of ​​the ultraviolet spectrum, the transmittance of undyed cotton fabrics for UVA and UVB bands is significantly higher than that of pH-responsive color-changing cotton fabrics, and the ratio of its UVA to UVB transmittance coefficients is several times higher than that of the latter. This difference highlights the high efficiency of pH-responsive color-changing cotton fabrics in absorbing and reflecting ultraviolet rays within a specific wavelength range, indicating that such fabrics have broad application potential and market prospects in the development of high-performance ultraviolet protection colored textiles. This discovery is of great significance for promoting technological innovation in the textile industry, improving the functionality and added value of textiles, and meeting consumers' growing demand for health protection textiles.

[0039] IV. Application performance test of pH response color changing materials, see Fig. 20 - twenty two; See also Fig. 20 , an in-depth study was conducted on the pH-responsive color-changing cotton fabric prepared in Example 1. The experimental process involved placing the cotton fabric in an acid sweat simulation solution (pH=4.42), deionized water in a neutral environment (pH=7), and an alkaline sweat simulation solution (pH=8.14), and observing its color change in detail. The results show that when the pH-responsive color-changing cotton fabric is in an acid sweat simulation solution, its color can completely change from the initial lavender to pink; while in an alkaline sweat simulation solution, the color completely changes from lavender to blue-green. It is worth noting that the color change process presents the remarkable characteristics of a short response time and has a high color change sensitivity. This characteristic of showing pink and blue-green colors under acid sweat and alkaline sweat conditions, respectively, makes the fabric show great application potential in the field of human sweat monitoring. Real-time monitoring of the pH of human sweat can provide important data support for related fields such as medical diagnosis and sports physiology research. For example, during the training of athletes, the changes in sweat pH can be monitored to understand the athlete's body metabolic state and adjust the training plan; in the medical field, it can assist in the diagnosis of certain diseases related to abnormal sweat pH.

[0040] According to the method of GB / T3922-2013 “Textiles - Tests for Colour Fastness - Colour Fastness to Perspiration”, acidic sweat and alkaline sweat were prepared respectively, and the pH-responsive colour-changing cotton fabric was simulated and applied in sweat detection.

[0041] See also Fig.21 , the anti-counterfeiting application study of the pH-responsive color-changing apocynum obtained in Example 2, firstly, the pH-responsive color-changing apocynum yarn is used to carefully embroider specific patterns, such as the "Centennial School Celebration" and "Pomegranate" patterns. In order to enhance the concealment of the anti-counterfeiting effect, yarns of the same color system are selected as the background. Under natural light conditions, the embroidered patterns cannot be recognized by the naked eye. Subsequently, the fabrics embroidered with patterns are placed in different pH environments for testing. When in a strong alkaline environment of pH=14, the pH-responsive color-changing apocynum yarn changes color, so that the pattern is clearly visible; when it is placed in a strong acidic environment of pH=1, the yarn turns pink; when it is placed in an alkaline environment again, the pH-responsive color-changing apocynum shows the original pattern again. This process fully proves that its color change is reversible. This unique pH-responsive color-changing property is of extremely high value in anti-counterfeiting applications. In the field of high-end commodity packaging with extremely high anti-counterfeiting requirements, this technology can effectively prevent counterfeiting and ensure the authenticity and safety of items. For example, in the anti-counterfeiting design of commemorative coins, this special color-changing flax yarn is used to mark specific patterns to improve the anti-counterfeiting level of the goods.

[0042] A specific pattern was embroidered with pH-responsive color-changing apocynum yarn. In order to enhance the concealment of the anti-counterfeiting effect, yarn of the same color was selected as the background. Under natural light conditions, the embroidered pattern could not be recognized by the naked eye. Subsequently, the fabrics embroidered with the pattern were placed in different pH environments for testing. In an alkaline environment, the pH-responsive color-changing apocynum yarn changed color to show the pattern, simulating the application of pH-responsive color-changing apocynum yarn in the field of anti-counterfeiting.

[0043] See also Fig. 22 In Example 3, the application of pH-responsive color-changing paper-based materials in the detection of brackish water is demonstrated in detail. During the experiment, the pH-responsive color-changing paper-based material was placed in a brackish water sample. The results showed that the color of the pH-responsive color-changing paper-based material changed from lavender to blue-green. There are a large number of brackish water resources in Xinjiang. This characteristic of the pH-responsive color-changing paper-based material gives it a broad application prospect in the field of brackish water detection. By quickly and conveniently detecting the existence and distribution of brackish water, it can provide an important basis for the rational development and utilization of water resources, water quality monitoring, and related water conservancy project construction. For example, in the early stage of water source detection in the brackish water desalination project, the use of this color-changing paper-based material can quickly determine the distribution range and pH of brackish water, which is helpful to formulate a scientific and reasonable desalination treatment plan.

[0044] When the pH responsive color-changing paper-based material is placed in brackish water, the pH responsive color-changing paper-based material changes from lavender to blue-green, thus simulating the application of the pH responsive color-changing paper-based material in the detection of brackish water.

[0045] The above disclosure is only the preferred embodiment of the present application, which certainly cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application are still within the scope covered by the present application.

Claims

1. Synthesis of pH-responsive biomass color-changing dyes and a method for fixing the color of cellulose fibers in a non-salt acidic manner, characterized in that: The following steps are involved: S100, taking biomass animal-derived active components and plant equivalent naphthoquinone substances and uniformly mixing them in a water-alcohol system, adding glacial acetic acid to adjust the pH value, adding an aminosilane coupling agent to react, and after the mixed solution reacts, treating it to obtain a pH-responsive biomass color-changing dye for use; S200, fully dissolving the pH-responsive biomass color-changing dye described in step S100 in an alkaline medium to prepare a uniform mixed liquid phase, and dyeing the cotton fabric using a salt-free acid fixation method to obtain a pH-responsive color-changing cotton fabric; S300, fully dissolving the pH-responsive biomass color-changing dye described in step S100 in an alkaline medium to prepare a uniform mixed liquid phase, and dyeing the apocynum ramie with a salt-free acid fixation method to obtain a pH-responsive color-changing apocynum ramie yarn; S400, fully dissolving the pH-responsive biomass color-changing dye in step S100 in an alkaline medium to prepare a uniform mixed liquid phase, and dyeing cotton fiber pulp using a salt-free acid fixation method to obtain a pH-responsive color-changing paper-based material.

2. The method for synthesizing pH-responsive biomass color-changing dye and fixing the color of cellulose fibers by non-salt-acidic method according to claim 1, characterized in that: The step S100 includes: S110, take 2g astaxanthin and 0.3g 2-hydroxy-1,4-naphthoquinone and completely dissolve them in equal volumes of deionized water and anhydrous ethanol (volume ratio is 1:1), add glacial acetic acid to adjust the pH value of the system (adjust the pH value of the system to 4), add 5ml 3-aminopropyltriethoxysilane, and heat and stir the mixture in an oil bath at 60℃ for 12h, with a rotation speed of 30r / min; S120. After the reaction of the mixed solution is completed, it is centrifuged twice, the centrifugal speed is 4000r / min, and the processing time is 10min; after the centrifugal treatment, the original solution is neutrally precipitated with deionized water at a ratio of 1:20, and the precipitate is centrifuged and washed 5 times, the centrifugal speed is 10000r / min, and the processing time is 10min; the centrifugal precipitate is dried in an oven at 40℃, and then extracted and separated in a methanol system at a temperature of 90~95℃ and dried for 12 h to obtain a pH-responsive biomass color-changing dye.

3. The method for synthesizing pH-responsive biomass color-changing dye and fixing the color of cellulose fiber in a non-salt acidic environment according to claim 1, characterized in that: The step S200 includes: The pH-responsive biomass color-changing dye was placed in an alkaline system to form a mixed liquid phase and then subjected to oscillation dyeing with cotton fabric in a constant temperature shaking incubator for 1 hour. The pH was then adjusted to pH=10, pH=7, and pH=3 with citric acid. Constant temperature shaking dyeing was continued for 1 hour at each pH value, and then the fabric was washed and dried to obtain pH-responsive color-changing cotton fabric.

4. The method for synthesizing pH-responsive biomass color-changing dye and fixing the color of cellulose fiber by non-salt-acidity according to claim 1, characterized in that: The step S300 includes: The pH-responsive biomass color-changing dye is placed in an alkaline system to form a mixed liquid phase, which is then shaken and dyed with the apocynum in a constant temperature shaking incubator for 1 hour. The pH is then adjusted to pH=10, pH=7, and pH=3 with citric acid. Constant temperature shaking dyeing is continued for 1 hour at each pH value, and then the pH-responsive color-changing apocynum yarn is obtained by washing and drying.

5. The method for synthesizing pH-responsive biomass color-changing dye and fixing the color of cellulose fiber in a non-salt acidic environment according to claim 1, characterized in that: The step S400 includes: The pH-responsive biomass color-changing dye is placed in an alkaline system to form a mixed liquid phase and then subjected to shaking dyeing treatment with cotton fiber pulp in a constant temperature shaking incubator for 1 hour. The pH is then adjusted to pH=10, pH=7, and pH=3 with citric acid, and constant temperature shaking dyeing is continued for 1 hour at each pH value. After all dyeing steps are completed, the cotton fiber pulp after the salt-free acid fixation dyeing treatment is taken out and washed with deionized water for 5 minutes. After washing for 3 times, the pH-responsive color-changing paper-based material is obtained by filtration-extrusion.

6. The method for synthesizing pH-responsive biomass color-changing dye and fixing the color of cellulose fiber in a non-salt acidic environment according to claim 1, characterized in that: The pH-responsive color-changing cotton fabric is applied to sweat detection.

7. The method for synthesizing pH-responsive biomass color-changing dye and fixing the color of cellulose fiber in a non-salt acidic environment according to claim 1, characterized in that: The pH responsive color-changing apocynum yarn is applied to anti-counterfeiting detection.

8. The method for synthesizing pH-responsive biomass color-changing dye and fixing the color of cellulose fibers in a non-salt acidic environment according to claim 1, characterized in that: The pH responsive color-changing paper-based material is applied to brackish water detection.

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