Method for in-situ preparation of conjugated schiff base on cotton fabric and application thereof

Abstract

The application discloses a method for preparing a conjugated Schiff base in situ on cotton fabric and application thereof, and utilizes sodium periodate to oxidize cotton fabric to obtain aldehyde fiber, and then forms a loaded conjugated Schiff base cotton fabric in situ on the aldehyde fiber through a p-phenylenediamine and glyoxal polycondensation reaction, tests the UPF, tensile breaking strength, crease recovery angle and contact angle of the cotton fabric before and after finishing to represent changes in ultraviolet resistance, tensile property, crease recovery and hydrophilicity of the cotton fabric. + The in-situ grafting process of the cotton fabric has a smaller influence on the strength of the cotton fabric, and the crease recovery angle and the contact angle of the finished cotton fabric are obviously increased.

Description

Technical Field

[0001] This invention belongs to the field of functional cotton fabric technology, specifically relating to a method and application for in-situ preparation of conjugated Schiff bases on cotton fabrics. Background Technology

[0002] Cotton fiber, a fiber derived from nature, is widely used in textiles, clothing, and other fields due to its superior properties such as softness, comfort, recyclability, and environmental friendliness. As human society places increasingly higher demands on the environment, people are setting higher standards and expectations for cotton products. However, cotton fiber, along with many other fiber textiles, can breed bacteria under suitable conditions due to its structural form. Microorganisms release unpleasant odors during metabolism, making natural fibers more susceptible to microbial contamination. If these issues are not addressed, people may become contaminated when using natural fibers. More seriously, contact with fibers or fabrics can lead to infection by pathogenic microorganisms, posing a threat to human life and health. In the textile industry, antibacterial agents are widely used to prevent bacterial growth and protect people from disease. Therefore, the research and development of antibacterial textiles is of paramount importance. Currently, commonly used natural antibacterial agents mainly include chitosan, cellulose derivatives, proteins, and other biomaterials. Furthermore, the harmful effects of ultraviolet radiation on human health are becoming increasingly significant. Ultraviolet radiation causes most types of skin cancer. Furthermore, because cotton fibers lack highly reactive molecules such as benzene rings and aromatic amino acids, which have excellent UV absorption properties, the UV resistance of cotton fabrics is affected, thus causing significant harm to human health. Additionally, cotton's inherent moisture absorption and breathability make it susceptible to bacterial contamination. Therefore, improvements are necessary to enhance the UV resistance of cotton fabrics. Moreover, cotton fabrics are generally not wrinkle-resistant, easily crease, and prone to getting wet; these are also technical problems that need to be addressed. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments.

[0004] As one aspect of the present invention, the present invention provides a method for in-situ preparation of conjugated Schiff bases on cotton fabrics, which comprises the following steps.

[0005] Pretreatment of cotton fabrics: Soak cotton fabrics in sodium periodate aqueous solution, react in the dark, wash, and obtain aldehyde fibers;

[0006] Preparation of cotton fabric loaded with conjugated Schiff base: The aldehyde fiber was soaked in p-phenylenediamine solution and reacted at room temperature. Then glyoxal and p-phenylenediamine were added and the soaking was continued by heating. The treated cotton fabric was taken out, washed and dried to obtain cotton fabric loaded with conjugated Schiff base.

[0007] As a preferred embodiment of the method for in-situ preparation of conjugated Schiff bases on cotton fabrics according to the present invention: in the pretreatment of the cotton fabrics, the washing is performed by first soaking the cotton fabrics in an aqueous solution of ethylene glycol, and then washing them with water.

[0008] As a preferred embodiment of the method for in-situ preparation of conjugated Schiff bases on cotton fabrics according to the present invention, the concentration of the sodium periodate aqueous solution is 0.04-0.05 g / mL.

[0009] As a preferred embodiment of the method for in-situ preparation of conjugated Schiff bases on cotton fabrics according to the present invention, the temperature of the light-protected reaction is 35-40°C and the time is 4-4.5 h.

[0010] As a preferred embodiment of the method for in-situ preparation of conjugated Schiff bases on cotton fabrics according to the present invention, the reaction is carried out at room temperature for 2-3 hours.

[0011] As a preferred embodiment of the method for in-situ preparation of conjugated Schiff bases on cotton fabrics according to the present invention, the heating and soaking is performed by heating to 60-65°C and soaking for 4-4.5 hours.

[0012] As a preferred embodiment of the method for in-situ preparation of conjugated Schiff bases on cotton fabrics according to the present invention: the p-phenylenediamine solution is an ethanol solution of p-phenylenediamine, prepared by adding 0.005-0.015 mol of p-phenylenediamine solution to 20 mL of ethanol; the addition of glyoxal and p-phenylenediamine is achieved by adding 0.0099-0.0297 mol of glyoxal and 0.006-0.018 mol of p-phenylenediamine to the p-phenylenediamine solution.

[0013] As a preferred embodiment of the method for in-situ preparation of conjugated Schiff bases on cotton fabrics according to the present invention, the washing and drying process involves washing with ethanol followed by drying in an oven at 50–60°C.

[0014] The cotton fabric described in this invention has the functions of UV protection, antibacterial properties, improved hydrophobicity, and improved crease recovery angle.

[0015] The beneficial effects of this invention are as follows: This invention utilizes sodium periodate to oxidize cotton fabric to obtain aldehyde fibers, and then forms a loaded conjugated Schiff base cotton fabric on the aldehyde fibers through in-situ polycondensation reaction of p-phenylenediamine and glyoxal. The changes in UV protection, tensile strength, crease recovery angle, and contact angle of the cotton fabric before and after treatment are characterized by testing the UPF, tensile breaking strength, crease recovery angle, and contact angle. The results show that the treated cotton fabric has high antibacterial activity, with an average inhibition rate of up to 100% against Escherichia coli and Staphylococcus aureus. It also exhibits low UVA and UVB transmittance and a UPF value as high as 100. +In-situ grafting of cotton fabrics has little impact on their strength, but the crease recovery angle and contact angle of the finished cotton fabrics are significantly increased. Attached Figure Description

[0016] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0017] Figure 1 A photograph showing the appearance of cotton fabric.

[0018] Figure 2 for Figure 2 SEM image of cotton fabric.

[0019] Figure 3 This is the energy spectrum of a cotton fabric.

[0020] Figure 4 This is the FTIRR plot of the cotton fabric.

[0021] Figure 5 XPS image of cotton fabric.

[0022] Figure 6 This is the absorption spectrum of cotton fabric.

[0023] Figure 7 To assess the antibacterial properties of cotton fabrics against Staphylococcus aureus.

[0024] Figure 8 To assess the antibacterial properties of cotton fabrics against Escherichia coli.

[0025] Figure 9 The tensile breaking strength of cotton fabric.

[0026] Figure 10 This is a contact angle diagram for cotton fabrics.

[0027] Figure 11 This is a diagram illustrating the reaction process for preparing oxidized cotton fabric.

[0028] Figure 12 The diagram shows the reaction process for preparing cotton fabric loaded with conjugated Schiff base. Detailed Implementation

[0029] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to specific examples.

[0030] Example 1:

[0031] Experimental materials: Standard lining pure cotton fabric (raw cotton) was purchased from the Shanghai Textile Industry Technical Supervision Institute. Its specifications were: 12.5tex × 12.5tex, 424 threads / 10cm × 290 threads / 10cm, 112.8g / m². 2 ,plain weave.

[0032] Pretreatment of cotton fabric: A standard pure cotton fabric (0.75g) was ultrasonically washed in deionized water for 5 minutes. It was then removed and immersed in a sodium periodate aqueous solution (0.0428g / mL, 50mL). The mixture was reacted at 40℃ in the dark for 4 hours. After removal, it was immersed in an ethylene glycol aqueous solution (0.0062g / mL, 50mL) for 0.5 hours and washed with a large amount of deionized water to remove the ethylene glycol, yielding oxidized cotton fabric: aldehyde fiber. The reaction process is as follows... Figure 11 As shown.

[0033] Preparation of conjugated Schiff base-loaded cotton fabrics: Three pieces of the aldehyde fiber were respectively immersed in three groups of p-phenylenediamine ethanol solutions of different concentrations (0.005 mol, 0.010 mol, and 0.015 mol, 20 mL), and reacted at room temperature for 2 h. Then, glyoxal (0.0099 mol, 0.0198 mol, and 0.0297 mol added to the above solutions, and the immersion was continued at 65 °C for 4 h. The pure cotton fabrics were removed, washed with ethanol, and dried in an oven at 60 °C to obtain conjugated Schiff base-loaded cotton fabrics with different loading amounts, denoted as conjugated Schiff base-loaded cotton fabric 1, conjugated Schiff base-loaded cotton fabric 2, and conjugated Schiff base-loaded cotton fabric 3, respectively. The reaction process is as follows. Figure 12 As shown.

[0034] Structural Characterization: Surface Morphology Observation: The surface morphology of the fabric before and after finishing was observed using a Nova NanoSEM 450 scanning electron microscope (SEM, FEI). The magnifications were 500x, 2500x, and 5000x, the test voltage was 5000V, and the vacuum degree was 1.15×10⁻⁶. 3 Finally, the inspector carefully examines the fabric and takes photographs to document the process.

[0035] Chemical composition analysis: In order to determine the changes in the types of elements on the surface of the fabric before and after finishing, EDS energy dispersive spectroscopy analysis is performed on the fabric. Different types of elements release different energies through atomic transitions in the energy spectrum, which can be used to determine the element type.

[0036] Functional group analysis of cotton fabrics loaded with conjugated Schiff bases was performed using a NEXUF-670 Fourier transform infrared spectrometer (FTIR, NICOLET). The test scan range was 4000 nm. -1-500cm -1 To determine the effectiveness of in-situ modification, the infrared characteristic peaks of the cotton fabric were analyzed. Before testing, the fabric was dried in an oven to ensure no moisture remained. The intensity of the infrared characteristic peaks on the cotton fabric can be used to assess the effect of the modification.

[0037] X-ray photoelectron spectroscopy (XPS, Thermo Fisher Scientific, USA) was used to characterize the elemental composition, elemental content, and chemical valence states of the fabric surface. Based on photoionization, a beam of photons is irradiated onto the fabric surface. Electrons in the orbitals of atoms of a certain element absorb the photons, gain energy, and are excited, causing inner-shell electrons to be emitted with a certain kinetic energy, forming free photoelectrons. The atom itself becomes an excited-state ion. Under the excitation of the source energy, the energy of the photoelectrons is only affected by the element type and the ionized atomic orbitals. Therefore, the elemental type of the substance can be qualitatively analyzed by the binding energy of the photoelectrons. By irradiating with X-rays, the photoelectron intensity is linearly correlated with the concentration of the atom, which allows for not only semi-quantitative analysis of the elements but also analysis of their chemical valence states.

[0038] Absorption spectral analysis: Tests were performed using a UV-3600Plus UV-Vis-NIR spectrophotometer (Shimadzu Corporation, Japan). A 1cm × 1cm sample was selected, and absorbance and reflectance data were obtained using integrating sphere mode. Absorption or reflectance was selected. Transmittance was not measured for this sample.

[0039] Performance testing:

[0040] Antibacterial performance: According to the GB / T 20944 test standard, approximately 0.75g of the fabric to be tested and the control sample (cotton standard lining fabric) were placed separately into different Erlenmeyer flasks. Each flask contained an appropriate amount of test bacterial solution, with the viable colony count controlled between 200 CFU and 250 CFU. The flasks were shaken at a specific temperature and time to determine the required test duration. The flasks were then placed on a shaking test platform, and the viable colony concentration in the bacterial solution was measured before and after shaking. The inhibition rate was calculated using the following formula:

[0041]

[0042] In the formula, Y: the antibacterial rate of the sample;

[0043] W t : Colony count in the culture dish after 18 hours of shaking contact with the original sample;

[0044] Q t : Colonies in the culture dish after shaking contact with the sample for 18 hours.

[0045] UV protection performance: According to the GB / T 18830-2002 test standard, five circular samples with a diameter greater than 45mm were prepared and tested on the YG(B)912E textile UV protection performance tester. Parallel beams were used to irradiate the samples and an integrating sphere was used to collect all transmitted light. Monochromatic or multicolor ultraviolet light was used to irradiate the samples, and the total spectral projection light was collected to determine the total spectral transmittance, thereby calculating the UPF value of the sample.

[0046] Tensile properties: According to the GB / T 3923-2013 test standard, the tensile breaking strength of the cotton fabric before and after finishing was tested. 20cm×6cm strips of fabric were cut along the warp and weft directions, and then the strips were torn into 20cm×5cm sizes using the edge-pulling yarn strip method. Finally, the test was conducted on a YG(B)815D-1 type strength tester, about 5 to 6 times, and the final result was the average value.

[0047] Crease recovery performance: According to GB / T 3819-1997 "Determination of crease recovery of textiles - Recovery angle method", 10 samples were cut in each direction (warp and weft) from a distance >150mm from the selvage, avoiding defects, wrinkles, and deformed areas. The recovery wings were 15mm × 20mm in size, and the fixed wings were 40mm × 20mm in size. The samples were folded under a pressure of 10N for 15s, the load was removed, and the samples were allowed to recover for 5 minutes. The crease recovery angle was then measured, and this angle represents the crease recovery ability of the fabric.

[0048] Hydrophilicity: According to the GB / T 14210 test standard, a 1mm × 1mm sample was placed on the glass slide of a JC200D3 contact angle measuring instrument and placed on the operating table. 0.6–1.0 μL of deionized water was dispensed using a micro-syringe. The contact state of the water droplet was photographed using the measuring instrument, and the image was frozen. The contact angle and surface tension values ​​were then obtained using the protractor method and the pendant drop method. Each sample was tested three times, and the average value was calculated.

[0049] Experimental results:

[0050] Physical morphology analysis of cotton fabrics: Images and SEM images of raw cotton fabrics and cotton fabrics with different loads of conjugated Schiff bases are shown in Figures 1 and 2, respectively. Figure 2 As shown. From an appearance perspective, as... Figure 1 As shown, the raw cotton is grayish-white, and the treated cotton fabric is brown, with the color gradually deepening as the amount of conjugated Schiff base increases; SEM images before and after treatment are shown below. Figure 2 As shown, the original cotton fabric has a smooth fiber surface with natural longitudinal twists; after grafting conjugated Schiff bases, the fiber surface becomes rough with flocculent material deposits, which may be due to the grafting of conjugated Schiff bases onto the fabric surface. Figure 1Photographs of the appearance of cotton fabrics: (a) raw cotton fabric; (b) cotton fabric 1 loaded with conjugated Schiff base; (c) cotton fabric 2 loaded with conjugated Schiff base; (d) cotton fabric 3 loaded with conjugated Schiff base. Figure 2 SEM images of cotton fabrics: (a) raw cotton fabric; (b) cotton fabric 1 loaded with conjugated Schiff base; (c) cotton fabric 2 loaded with conjugated Schiff base; (d) cotton fabric 3 loaded with conjugated Schiff base.

[0051] Chemical composition analysis of cotton fabrics:

[0052] EDS analysis: EDS spectra of raw cotton fabric and cotton fabrics with different amounts of conjugated Schiff bases are shown below. Figure 3 As shown, the grafting of conjugated Schiff bases can be obtained by observing the elemental changes on the fabric surface. It can be seen that Figure (a) only contains C and O elements, while Figures (b), (c), and (d) show that cotton fabrics grafted with different concentrations of conjugated Schiff bases will have an additional N element on their surface. This may be because the conjugated Schiff base is grafted and polymerized in situ onto the original cotton, since the molecular structure of the conjugated Schiff base contains abundant N elements. Figure 3 The energy spectrum of cotton fabrics are as follows: (a) raw cotton fabric; (b) cotton fabric 1 loaded with conjugated Schiff base; (c) cotton fabric 2 loaded with conjugated Schiff base; (d) cotton fabric 3 loaded with conjugated Schiff base.

[0053] FTIR analysis: The FTIR spectra of raw cotton fabric and cotton fabric loaded with conjugated Schiff base 3 are as follows. Figure 4 As shown. Infrared spectroscopy indicates that at 3338 cm⁻¹... -1 and 2913cm -1 The absorption peaks that appear represent the OH absorption peak and the CH ether bond absorption peak, respectively. At 1604 cm⁻¹ -1 The absorption peak is caused by the skeletal vibration of the benzene ring, at 1513 cm⁻¹. -1 The absorption peak corresponds to the C=N absorption peak, and the absorption peak caused by the stretching vibration of the CN bond is located at 1312 cm⁻¹. -1 In addition, 831cm -1 The absorption peak at that point is due to the in-plane bending vibration of the CH bond in the benzene ring. This indicates that the cotton fabric has been loaded with a conjugated Schiff base. Figure 4 FTIR plots of cotton fabrics: (a) raw cotton fabric; (b) cotton fabric loaded with conjugated Schiff base 3.

[0054] XPS analysis: XPS spectra of raw cotton fabric and cotton fabric 3 loaded with conjugated Schiff base are shown below. Figure 5 As shown in the figure, the cotton fabric 3 loaded with the conjugated Schiff base has an additional nitrogen element compared to the original cotton fabric. This nitrogen element comes from the molecular structure of the conjugated Schiff base, thus indicating that the conjugated Schiff base has been successfully grafted onto the cotton fabric. Figure 5XPS plots of cotton fabrics: (a) raw cotton fabric; (b) cotton fabric loaded with conjugated Schiff base 3.

[0055] Absorption spectroscopy analysis: The absorption spectrum of cotton fabric 3 loaded with conjugated Schiff base is as follows: Figure 6 As shown in the figure, the cotton fabric before treatment exhibits some absorption in the ultraviolet and near-infrared light bands. Ultraviolet light has a wavelength of 400–10 nm. The conjugated Schiff base contains a large π bond connected by C=N double bonds, and the delocalization of the conjugated π electrons allows for the absorption of ultraviolet light. With increasing conjugation, the absorption peak shifts towards longer wavelengths. In the UVB (280–320 nm) band, the absorbance is around 1.2, indicating strong absorption. However, in the UVA (320–400 nm) band, the absorbance decreases from 1.2 to around 0.2, showing that the treated cotton fabric has poorer absorption of long-wave ultraviolet (UVA) than medium-wave ultraviolet (UVB). In the near-infrared band of 750–2500 nm, due to the abrupt changes in the -NH2 vibration, the absorbance increases in a wave-like manner, indicating that the treated cotton fabric has a certain absorption effect on infrared radiation. As can be seen from the figure, the cotton fabric loaded with the conjugated Schiff base can effectively absorb ultraviolet and near-infrared light. Figure 6 Absorption spectra of cotton fabrics: (a) raw cotton fabric; (b) cotton fabric loaded with conjugated Schiff base 3.

[0056] Antibacterial performance analysis: Antibacterial photos of raw cotton fabric and cotton fabric with different loads of conjugated Schiff base against Escherichia coli and Staphylococcus aureus are shown below. Figure 7 and Figure 8 As shown in Table 1, the antibacterial rate of the fabric was analyzed. The antibacterial performance analysis focused on the fabric's ability to inhibit and kill bacteria such as Staphylococcus aureus and Escherichia coli. This was primarily achieved using the antibacterial mechanism of conjugated Schiff bases. The results of the antibacterial performance are shown in the table below, using Staphylococcus aureus and Escherichia coli. The antibacterial effect of the sample was evaluated by measuring the concentration of viable bacteria in the bacterial solution in the Erlenmeyer flask before and after shaking for a certain period. As shown in the table, the original cotton fabric exhibited inhibition rates of 8.23% and 6.75% against the two bacteria after 18 hours of shaking. This may be due to the hydrophilicity of cotton fabric, allowing a small number of bacteria to adhere to the fiber surface or exist in the gaps and pores between fibers. The cotton fabric loaded with conjugated Schiff bases showed inhibition rates of 69.9% and 87.15%, 92.93% and 90.35%, and 100% against Staphylococcus aureus and Escherichia coli, respectively, from low to high concentration. This is attributed to the presence of conjugated Schiff bases, whose imino groups also possess antibacterial properties. The antibacterial test results demonstrate that the antibacterial cotton fabric loaded with conjugated Schiff bases prepared in this study possesses highly efficient and significant antibacterial activity. Figure 7Antimicrobial properties of cotton fabrics against Staphylococcus aureus: (a) raw cotton fabric; (b) cotton fabric 1 loaded with conjugated Schiff base; (c) cotton fabric 2 loaded with conjugated Schiff base; (d) cotton fabric 3 loaded with conjugated Schiff base. Figure 8 Antibacterial properties of cotton fabrics against Escherichia coli: (a) raw cotton fabric; (b) cotton fabric 1 loaded with conjugated Schiff base; (c) cotton fabric 2 loaded with conjugated Schiff base; (d) cotton fabric 3 loaded with conjugated Schiff base.

[0057] Table 1 Antibacterial rate of cotton fabrics

[0058]

[0059]

[0060] UV protection performance analysis: The UV protection properties of raw cotton fabric and cotton fabrics loaded with different amounts of conjugated Schiff base are shown in Table 2. From this, we can see that the UVA and UVB transmittance of raw cotton is 15.02% and 8.16%, respectively. For cotton fabrics loaded with conjugated Schiff base, the UVA and UVB transmittances, from lowest to highest concentration, are 1.33% and 1.17%, 0.86% and 0.54%, and 0.42% and 0.25%, respectively. The UPF values ​​of the cotton fabrics before and after treatment were calculated to be 9.08, 100+, 100+, and 100+, respectively. This indicates that cotton fabrics loaded with conjugated Schiff base have a better absorption effect on ultraviolet light, possibly because the Schiff base (C=N) can pass through π-π ＊ Bond migration is used to absorb photons, converting some ultraviolet light into other forms of energy, thus achieving the effect of absorbing ultraviolet light. In addition, as the concentrations of p-phenylenediamine and glyoxal increase, the degree of conjugation increases, and the ultraviolet protection effect is improved.

[0061] Table 2 UVA and UVB transmittance and UPF of cotton fabrics

[0062]

[0063] Tensile property analysis: Tensile breaking strength of raw cotton fabric and cotton fabric with different loads of conjugated Schiff base as shown in Figure 1. Figure 9 As shown in the figure, the tensile strength of a fabric is an important indicator for ensuring its basic performance in daily life and production. During chemical treatment and finishing processes, fabrics are subjected to acid and alkali reactions, as well as drying, which can cause a decrease in fabric strength. As can be seen from the figure, the warp and weft strengths of the original cotton fabric are 462.4 N and 342.6 N, respectively. After treatment, the warp and weft strengths of cotton fabrics loaded with different concentrations of conjugated Schiff alkali are 345.7 N and 256.5 N, 332.1 N and 242.1 N, and 301.9 N and 227.3 N, respectively. The strength decreases, but the decrease is not significant. Compared with the traditional padding and baking finishing process, the in-situ modified fabric retains better strength.

[0064] Crease recovery performance analysis: The acute and delayed elastic recovery angles of raw cotton fabrics and cotton fabrics with different loads of conjugated Schiff alkali are shown in Tables 3 and 4. Crease recovery is the property of a fabric to resist and recover to its original state to a certain extent after being subjected to bending deformation and creases during use. After treatment, the acute elastic recovery angle of the cotton fabric increased from 139° to 172°, showing a significant improvement.

[0065] Table 3. Quick elastic recovery angle of cotton fabrics

[0066]

[0067] Note: c indicates that p < 0.001 compared to the original cotton fabric.

[0068] Table 4. Elastic recovery angle of cotton fabrics

[0069]

[0070] Hydrophilicity analysis: The contact angles of raw cotton fabric and loaded conjugated Schiff base cotton fabric 3 are as follows: Figure 10 As shown in the figure, by measuring the contact angle using the protractor method, the contact angle of cotton fabric loaded with conjugated Schiff bases was significantly increased compared to that of raw cotton, while the change in contact angle of cotton fabrics loaded with different amounts of conjugated Schiff bases was not significant. The contact angle of raw cotton was 59°, indicating hydrophilicity; while the contact angle of cotton fabric loaded with conjugated Schiff bases was approximately 119°, indicating hydrophobicity, and the hydrophobicity was relatively good.

[0071] Electromagnetic wave shielding performance test: The electromagnetic wave shielding performance of the load conjugate Schiff alkali cotton fabric 3 was tested using the coaxial method within the set frequency band, which was set to 300000Hz-3000000000Hz, with 801 scan points.

[0072] In this invention, p-phenylenediamine was added twice at different temperatures. In the early stages of the experiment, an attempt was made to replace the p-phenylenediamine added in the second step with ethylenediamine, keeping other conditions unchanged. However, it was found that the treated cotton fabric did not have an electromagnetic wave shielding effect. In contrast, the cotton fabric prepared by the method in Example 1 did have an electromagnetic wave shielding effect. During the experiment, the first addition of p-phenylenediamine was to ensure better dissolution at room temperature, and the second addition at 65°C was to achieve the reaction conditions between p-phenylenediamine and glyoxal. An experiment was also conducted where p-phenylenediamine was added all at room temperature. The electromagnetic wave shielding performance test results showed that the electromagnetic wave shielding effect of the cotton fabric treated with a single addition of p-phenylenediamine at room temperature was not significantly different from that of ordinary cotton fabric. However, the cotton fabric prepared in Example 1 had a better electromagnetic wave shielding effect (the electromagnetic shielding effectiveness of the conjugated Schiff base-loaded cotton fabric 3 was approximately 15 dB).

[0073] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. Use of a conjugated Schiff base loaded cotton fabric in the preparation of functional cotton fabric, characterized in that: The cotton fabric has the functions of anti-ultraviolet, antibacterial, improving hydrophobicity of the cotton fabric, improving crease recovery angle of the cotton fabric and shielding electromagnetic wave, and the preparation method of the cotton fabric loaded with the conjugated Schiff base comprises the following steps, Pre-treatment of the cotton fabric: the cotton fabric is soaked in a sodium periodate aqueous solution, and a light-proof reaction is carried out, and then the cotton fabric is washed to obtain aldehyde fiber; Preparation of the cotton fabric loaded with the conjugated Schiff base: the aldehyde fiber is soaked in a p-phenylenediamine solution and a reaction is carried out at room temperature, then glyoxal and p-phenylenediamine are added and the soaking is continued by heating, the treated cotton fabric is taken out and washed and dried to obtain the cotton fabric loaded with the conjugated Schiff base; The concentration of the sodium periodate aqueous solution is 0.04-0.05 g / mL; The p-phenylenediamine solution is an ethanol solution of p-phenylenediamine, and 0.015 mol of p-phenylenediamine is added to 20 mL of ethanol to prepare the p-phenylenediamine solution; The glyoxal and p-phenylenediamine are added in the p-phenylenediamine solution, and 0.0297 mol of glyoxal and 0.018 mol of p-phenylenediamine are added. The reaction is carried out at room temperature, and the reaction time is 2-3 h; the soaking is continued by heating, and the soaking is carried out at 60-65 ℃ for 4-4.5 h.

2. Use according to claim 1, characterized in that: In the pre-treatment of the cotton fabric, the cotton fabric is first soaked in an aqueous solution of ethylene glycol and then washed with water.

3. Use according to claim 1 or 2, characterized in that: The light-proof reaction is carried out at a temperature of 35-40 ℃ for 4-4.5 h.

4. Use according to claim 1 or 2, characterized in that: The washing and drying are carried out by washing with ethanol and then drying in an oven at 50-60 ℃.

5. The use according to claim 1, characterized in that: The antibacterial property includes resistance to Escherichia coli and Staphylococcus aureus.

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