Graphene oxide / nano-carboxyl chitosan in-situ grafted fabric and preparation method thereof

Abstract

The application discloses graphene oxide / nano-carboxyl chitosan in-situ grafting fabric and a preparation method thereof. Graphene oxide is dissolved in N-methyl imidazole hydrogen sulfate ionic liquid ([Hmim]HSO4), and under the action of ultrasonic waves, nano-carboxyl chitosan dispersion liquid is added dropwise to react with graphene oxide sheet layers to obtain graphene oxide / nano-carboxyl chitosan composite. Then, the graphene oxide / nano-carboxyl chitosan composite is subjected to in-situ grafting reaction with fabric in N-methyl imidazole hydrogen sulfate ionic liquid through microwave radiation to obtain graphene oxide / nano-carboxyl chitosan in-situ grafting fabric. The application has the advantages of simple preparation process, controllable reaction condition, fast in-situ grafting reaction rate, no use of chemical cross-linking agent and additive, and the like. The prepared modified fabric has the advantages of significantly enhanced antibacterial activity, ultraviolet resistance and wrinkle resistance, good function durability, green environmental protection, and wide market prospect.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method of graphene oxide / nano-carboxyl chitosan in-situ grafted fabric and belongs to the technical field of textile functional finishing. BACKGROUND

[0002] In 2004, Geim prepared graphene by mechanical exfoliation, which has excellent electrical conductivity, thermal conductivity, mechanical properties and excellent electron mobility. As an ideal reinforcing agent for polymer materials, graphene is widely used in functional phases and reinforcing phases in composite materials. In recent years, there have been a large number of reports on the compounding of graphene and its derivatives with polymer matrices at home and abroad. The commonly used polymer matrix materials at present include polystyrene (PS), polyaniline (PANI), polyvinyl alcohol (PVA) and the like. The incorporation of graphene into polymer fiber materials can improve the tensile strength, impact toughness and thermal stability thereof. As one of the derivatives of graphene, graphene oxide not only has excellent physical and chemical properties of graphene, but also contains a large number of oxygen-containing functional groups on the surface, such as carboxyl, hydroxyl, carbonyl and epoxy groups, has good dispersibility and chemical reactivity. The unique structure and excellent performance of graphene oxide have become the focus of research and are widely used in supercapacitors, sensing, biomedicine and other fields. In recent years, with the continuous research on graphene-based materials, people are also constantly exploring the application of graphene materials in textiles. It is found that the application of graphene materials in textile fabrics can endow the fabrics with properties such as antistatic, antibacterial, antibacterial, anti-ultraviolet, sensing and bulletproof performance [Ren Y L, Song H, Jiang Z Y, et al. Properties and research progress of graphene. Journal of Mudanjiang Normal University (Natural Science Edition), 2017(3): 43-46]. These properties make graphene materials a research hotspot in the textile field and are expected to have a more profound development in textiles.

[0003] Chitosan is widely present in nature and is obtained by deacetylation of chitin. Chitin, as the raw material of chitosan, is the second most abundant natural polysaccharide after cellulose. Chitosan has good antibacterial properties and is harmless to the human body. Many researchers have modified fabrics using this property. Chitosan has a regular molecular chain and good crystallization properties due to the strong intramolecular and intermolecular hydrogen bonding. However, it is difficult to dissolve in water, alkali or organic solvents, and can only be dissolved in acid. Most acid solutions have strong volatility and strong corrosivity, which inhibits the application of chitosan. In addition, chitosan has a large molecular weight, and after coating on the fabric, a thin film is formed on the surface, affecting the hand feeling and making the fabric less breathable, resulting in discomfort when wearing. In recent years, the development of nanomaterials has expanded the use of chitosan. Nanochitosan has smaller particle size, significantly improved adsorption capacity and chemical reaction activity, and is more easily attached to the surface of the fabric. The nanoscale size allows nanochitosan to enter the interior of the fabric to achieve functional filling without affecting the excellent wearing properties of the fabric.

[0004] Currently, there are many studies reporting the preparation of graphene oxide and chitosan composite materials. Chen Shuhua et al. dispersed graphene oxide and chitosan in DMF, reacted in N2 atmosphere, and then prepared GO-g-CS by the action of phosphoric acid and ethanol [Chen Shuhua, Ren Zimo, Sun Tingting. Preparation and performance of chitosan / chitosan grafted graphene oxide composite aerogel [J]. China Plastics, 2022, 36(9): 32-37]. Shi Xuejuan et al. used N-hydroxysuccinimide (NHS) and 1-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride (EDC) as crosslinking agents to prepare graphene composite materials [Shi Xuejuan, Zhang Wenjing, Yao Yuan, et al. Adsorption of pesticides in water by graphene oxide-chitosan composite material [J]. Journal of Hebei University of Science and Technology, 2022, 36(2): 54-62]. Invention patent CN114213718A discloses a preparation method of oxidized chitosan-oxidized graphene, which uses crosslinking agent 1-ethyl-(3-dimethylaminopropyl)-3-ethyl carbodiimide hydrochloride and catalyst N-hydroxysuccinimide to prepare the composite material. The above preparation steps of graphene oxide / chitosan composite material are complex, the yield of the product is low, the cost is high, and a large amount of catalyst and crosslinking agent is used. Some materials are toxic to the human body and the environment, causing environmental pollution. At the same time, there is a lack of chemical crosslinking between the composite materials, and the stability is poor, limiting the application.

[0005] The application adds nanometer carboxyl chitosan dispersion liquid drop to the graphene oxide [Hmim]HSO4 ionic liquid solution under the action of ultrasonic waves, and makes the carboxyl and hydroxyl on the graphene oxide sheet layer form chemical bonds such as amide bond and hemiacetal bond with the amino and aldehyde group of nanometer carboxyl chitosan respectively through acid ionic liquid catalytic reaction, so as to obtain graphene oxide / nanometer carboxyl chitosan composite. The prepared composite has good stability, high reaction activity and large specific surface area, can be directly grafted with cellulose or protein fiber fabric, and obtains the textile with multiple functions such as antibacterial, anti-ultraviolet, antistatic, wrinkle resistance, good human affinity, green environmental protection, wide market prospect, and the ionic liquid as the solvent and reaction medium has strong stability, high catalytic reaction activity and easy recycling. SUMMARY

[0006] The application aims to provide a preparation method of graphene oxide / nanometer carboxyl chitosan in-situ grafted fabric, so as to improve the comprehensive performance of the fabric such as anti-ultraviolet, antibacterial, softness, moisture absorption and air permeability, wearing comfort and human affinity.

[0007] In order to achieve the above-mentioned purpose, the application adopts the following technical scheme:

[0008] The preparation method of graphene oxide / nanometer carboxyl chitosan in-situ grafted fabric is characterized in that: graphene oxide is dissolved in N-methyl imidazole hydrogen sulfate ionic liquid ([Hmim]HSO4), nanometer carboxyl chitosan dispersion liquid is added dropwise under the action of ultrasonic waves to make the graphene oxide sheet layer and the nanometer carboxyl chitosan chemically react to obtain graphene oxide / nanometer carboxyl chitosan composite, then the graphene oxide / nanometer carboxyl chitosan composite and the fabric are subjected to in-situ grafting reaction in the N-methyl imidazole hydrogen sulfate ionic liquid through microwave irradiation, so as to obtain graphene oxide / nanometer carboxyl chitosan in-situ grafted fabric.

[0009] Further, the graphene oxide / nanometer carboxyl chitosan composite is prepared according to the following steps:

[0010] The nanometer carboxyl chitosan is stirred and dissolved in acetic acid solution with a volume concentration of 2%, and a nanometer carboxyl chitosan dispersion solution with a mass concentration of 0.2-1.0% is prepared; the graphene oxide is dissolved in N-methyl imidazole hydrogen sulfate ionic liquid (the pH thereof is preferably 3.4-4.6) at 80-90°C to obtain a graphene oxide ionic liquid solution; the nanometer carboxyl chitosan dispersion solution is added dropwise into the graphene oxide ionic liquid solution under the action of 100-260W ultrasonic waves within 6-10min, and then ultrasonic chemical reaction is carried out for 1-2h, so that the graphene oxide sheet layer and the nanometer carboxyl chitosan particles form chemical bonds such as amide bonds and hemiacetal bonds, and then high-speed centrifugation is carried out for 15-20min (the rotation speed of centrifugation is preferably 10000-12500rpm) and vacuum freeze drying is carried out for 24-48h, to obtain a graphene oxide / nanometer carboxyl chitosan composite. The mass ratio of the graphene oxide to the nanometer carboxyl chitosan is 0.125-0.8:1. The nanometer carboxyl chitosan has an aldehyde group content at C6 of 28.15-41.69%, a carboxyl group content at C2 and C3 of 19.57-40.92%, a deacetylation degree of 83.61-90.73%, a solubility in water of 11.94-22.86g / 100mL, and an isoelectric point pH of 5.5-5.7, and the structural formula thereof is as follows:

[0011]

[0012] Preferably, the graphene oxide is prepared by a modified Hummers method, has a graphene oxide crystal plane spacing of 0.883-0.894nm, a sheet layer thickness of ≤1nm, a carboxyl group content of 3.73-3.95mmol / g, and a specific surface area of ≥462m 2 / g, and the structural formula thereof is as follows:

[0013]

[0014] The fabric described in the application is a cellulose fiber fabric, a protein fiber fabric, a blended fabric of cellulose fiber and polyester fiber, or a blended fabric of protein fiber and polyester fiber.

[0015] The preparation method of the graphene oxide / nanometer carboxyl chitosan in-situ grafted fabric described in the application specifically comprises the following steps:

[0016] (1) the fabric after scouring or degumming is added into N-methyl imidazole hydrogen sulfate ionic liquid (the pH thereof is preferably 4.5-5.0), and is swelled at 30-40°C using an ultrasonic probe (the power of the ultrasonic probe is preferably 60-100W) for 20-30min, and the operation is repeated for 2-3 times, and then the fabric is immersed in anhydrous ethanol for 2-4h to remove the ionic liquid, to obtain an activated fabric;

[0017] (2) the graphene oxide / nano carboxyl chitosan complex is dissolved in N-methyl imidazole bisulfate ionic liquid (the pH thereof is preferably 4.2-4.8) to prepare a reaction solution with a mass concentration of 0.2%-0.8%; the activated fabric of step (1) is added into the reaction solution (the bath ratio of the activated fabric to the reaction solution is set to 1 g: 20-30 mL), and stirring reaction is carried out under microwave irradiation conditions (the microwave irradiation power is preferably 320-680 W, and the microwave irradiation temperature is preferably 25-40 °C) for 20-90 min to obtain the fabric after grafting reaction;

[0018] (3) the fabric after grafting reaction is padded 2-3 times to make the pick-up rate of the fabric 65-95%, and then is put into a heat setting machine for pre-drying at 30-40 °C for 15-20 min, heating to 100 °C for baking for 8-12 min, and finally drying at 60 °C for 2-3 h, and then washing and air-drying to obtain the graphene oxide / nano carboxyl chitosan in-situ grafted fabric.

[0019] Preferably, in step (3), the heating method of the heat setting machine is intermittent heating, and after each 10 °C increase, the heating is paused for 1 min, wherein the heating rate is 5 °C / min.

[0020] By optimizing the mass ratio of graphene oxide to nano carboxyl chitosan, the pH of N-methyl imidazole bisulfate ionic liquid, the ultrasonic treatment time, the microwave irradiation reaction temperature and time, a series of functional fabrics with different grafting rates of graphene oxide / nano carboxyl chitosan complex can be obtained.

[0021] Compared with the prior art, the preparation principle and beneficial effects of the graphene oxide / nano carboxyl chitosan in-situ grafted fabric in the present application are as follows:

[0022] 1. In the present application, the graphene oxide is prepared by the improved Hummers method, and compared with the traditional Hummers method, nitric acid and sodium nitrate are not used, thereby avoiding the generation of harmful gases such as NO2 during the reaction process and improving the safety of the reaction; and the high-temperature reaction stage is not required, and the steps of graphene oxide intercalation, oxidation and exfoliation can be realized under low-temperature conditions, thereby greatly shortening the reaction time, improving the preparation efficiency, obtaining graphene oxide with high carboxyl content, fewer defects, regular structure and small thickness, and large specific surface area.

[0023] 2. In the present application, the crosslinking of graphene oxide and nano carboxyl chitosan is carried out in N-methyl imidazole bisulfate ionic liquid, and the [HSO4] － ion in the N-methyl imidazole bisulfate ([Hmim]HSO4) acidic ionic liquid ionizes H +The amino group of the nanometer carboxyl chitosan can be positively charged to increase the contact and nucleophilic reaction probability with the carboxyl in the graphene oxide sheet; and the pH of the N-methyl imidazole hydrogen sulfate ionic liquid is lower than the pH at the isoelectric point (5.5-5.7) of the nanometer carboxyl chitosan, so that the nanometer carboxyl chitosan particles have positive charges, greatly enhancing the electrostatic attraction between the nanometer carboxyl chitosan particles and the negative electric group carboxyl, hydroxyl and epoxy group in the graphene oxide, promoting the nanometer carboxyl chitosan particles to enter the middle of the graphene oxide sheet and realizing the uniform combination between the two, and improving the stability of the composite material. The middle part of the graphene oxide contains a large number of epoxy groups, so that the material presents the characteristics of edge hydrophilic and middle hydrophobic. The ultrasonic wave promotes the reaction of the nanometer carboxyl chitosan and the oxygen-containing functional groups on the edge of the graphene oxide, accelerates the ring-opening reaction rate of the amino group of the nanometer carboxyl chitosan and the epoxy group in the graphene oxide, and improves the yield of the reaction product of the composite. After the nanometer carboxyl chitosan is compounded, the surface energy of the graphene oxide is reduced, the hydrophilicity of the middle part of the sheet is improved, the dispersion effect is improved, and the defect that the graphene oxide is prone to sheet adhesion due to the large specific surface area is effectively prevented, so that the graphene oxide / nanometer carboxyl chitosan composite material has a uniform structure, strong adsorption capacity and easy grafting reaction with the fabric.

[0024] 3. The graphene oxide / nanometer carboxyl chitosan composite is vacuum freeze-dried in the application, the water in the composite is frozen below the freezing point to become ice, and then the ice crystals are sublimated to become vapor under higher vacuum to remove the water. The composite after vacuum freeze-drying retains the original chemical composition and physical properties, so that the graphene oxide sheet in the composite has good dispersibility and does not stick, and has a larger specific surface area; and the carboxyl chitosan particles in the composite are not aggregated and are uniformly distributed, which is beneficial to the grafting reaction of the graphene oxide / nanometer carboxyl chitosan composite with the fabric; at the same time, the energy consumption of the vacuum freeze-drying method is significantly lower than that of other drying methods.

[0025] 4. The fabric is swelled in the N-methyl imidazole hydrogen sulfate ionic liquid in the application, the hydrogen bond interaction between the fiber molecules is weakened, which is beneficial to the catalytic grafting reaction of the graphene oxide / nanometer carboxyl chitosan composite penetrating into the reaction sites inside the fiber, shortens the reaction time, improves the grafting efficiency, and enhances the bonding strength of the graphene oxide / nanometer carboxyl chitosan on the fabric; at the same time, the cavitation effect of the ultrasonic probe in the liquid forms cavities, and the instantaneous high temperature and high pressure generated by the vibration and violent explosion of the cavities can make part of the water molecules pyrolyze to form ·OH free radicals and ·H atoms, so that the active groups on the surface of the fabric increase, and the reaction accessibility and grafting rate of the polar groups such as amino, carboxyl and aldehyde groups in the activated fabric and the graphene oxide / nanometer carboxyl chitosan composite are improved.

[0026] 5. The application is to dip the fabric in N-methyl imidazole hydrogen sulfate ionic finishing solution under microwave irradiation. The microwave irradiation has the advantages of fast heating speed, short reaction time and good uniformity. The composite particles can fully contact with the active sites of the fabric, which significantly accelerates the grafting rate of ionic liquid catalyst, effectively avoids the easy agglomeration and uneven dispersion of nanoparticles caused by long time treatment, makes the composite material uniformly grafted on the surface of the fabric, and solves the problems of long reaction period, low grafting reaction rate, easy aggregation of nanoparticles in the finishing solution and uneven distribution on the fabric surface in the traditional water bath heating reaction process. At the same time, the pH of the reaction medium N-methyl imidazole hydrogen sulfate ionic liquid is 4.2-4.8, which is greater than the isoelectric point pH (about 3.5-4.2) of silk, so that the silk fabric presents negative electricity, which can significantly increase the electrostatic attraction and grafting reaction efficiency of the positively charged graphene oxide / nano carboxyl chitosan composite to the negatively charged silk, cotton and other cellulose fabrics, thereby greatly improving the grafting rate of the composite on the fabric and the antibacterial, anti-ultraviolet and anti-wrinkle properties.

[0027] 6. Graphene oxide has sharp edges due to the lamellar structure, can physically cut bacteria, destroy the cell membrane of bacteria, reduce the membrane potential or make electrolyte leak to inhibit bacterial growth. The nano carboxyl chitosan surface carries positive electricity, is easy to have electrostatic action with the negatively charged groups on the surface of fungus, bacteria and virus cells, and the small size effect makes the nano carboxyl chitosan particles more easily contact with bacteria, thereby changing the fluidity and permeability of the cell membrane, blocking the entry of nutrients into the cell to cause the death of the bacteria, or damaging the integrity of the cell wall to make the cell wall tend to dissolve, causing the leakage of proteins and other components in the cell, and promoting cell apoptosis. The graphene oxide / nano carboxyl chitosan composite can exert its respective advantages, has double antibacterial activity, and achieves long-lasting and efficient antibacterial effect after chemical grafting with the fabric, and has wide application.

[0028] 7. The graphene oxide / nano carboxyl chitosan composite can absorb ultraviolet rays with a wavelength less than 281 nm and reflect long-wave ultraviolet rays with a wavelength greater than 281 nm, which can effectively improve the problems of aging and mechanical mechanics decline of traditional textiles caused by ultraviolet radiation, and the lamellar graphene oxide is firmly chemically crosslinked on the fabric surface through the nano carboxyl chitosan, which significantly enhances the wrinkle resistance of the fabric.

[0029] 8. The preparation process of the application is simple, easy to operate, low in cost and good in controllability of reaction conditions, does not use any crosslinking agent and auxiliary agent, is green and environment-friendly, the prepared graphene oxide / nano carboxyl chitosan in-situ grafted fabric has soft hand feeling, moisture absorption and air permeability, good skin friendliness, and high-efficiency and long-lasting antibacterial, anti-ultraviolet, anti-wrinkle and other functional properties, and has great market potential. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1is the modification mechanism of graphene oxide / nano carboxyl chitosan in-situ grafting silk fabric of the application.

[0031] Figure 2 is the infrared spectrum of graphene oxide / nano carboxyl chitosan in-situ grafting silk fabric in item 1 of the application. DETAILED DESCRIPTION

[0032] In order to have a better understanding of the technical features, objectives and beneficial effects of the application, the application will be further described below in combination with the drawings and specific examples, but the application is not limited to the following examples.

[0033] I. Preparation of graphene oxide / nano carboxyl chitosan in-situ grafting fabric

[0034] Example 1

[0035] The nano carboxyl chitosan used in this example has the following characteristics: the content of aldehyde group at C6 position is 30.59%, the content of carboxyl group at C2 and C3 positions is 24.65%, the degree of deacetylation is 86.31%, the solubility in water is 15.05 g / 100 mL, and the isoelectric point pH is about 5.7.

[0036] The graphene oxide used in this example is prepared by a modified Hummers method, and has the following characteristics: the interplanar spacing is 0.891 nm, the sheet thickness is 0.95 nm, the carboxyl content is 3.77 mmol / g, and the specific surface area is 475 m 2 / g.

[0037] The graphene oxide / nano carboxyl chitosan composite of this example is prepared according to the following steps: the nano carboxyl chitosan is stirred and dissolved in an acetic acid solution with a volume concentration of 2% to prepare a nano carboxyl chitosan dispersion with a mass concentration of 0.4%; the graphene oxide is dissolved in an N-methyl imidazole hydrogen sulfate ionic liquid with pH = 3.8 at 80°C to obtain an ionic liquid solution of graphene oxide; the nano carboxyl chitosan dispersion is added dropwise into the ionic liquid solution of graphene oxide under the action of 150W ultrasonic waves within 8 minutes, and then ultrasonic chemical reaction is carried out for 1 hour, so that chemical bonds such as amide bonds and hemiacetal bonds are formed between the graphene oxide sheets and the nano carboxyl chitosan particles; high-speed centrifugation (speed of 12000 rpm) is carried out for 18 minutes, and vacuum freeze-drying is carried out for 36 hours to obtain the graphene oxide / nano carboxyl chitosan composite. The mass ratio of graphene oxide to nano carboxyl chitosan is 0.2:1.

[0038] The finishing method of this example utilizes the prepared graphene oxide / nano carboxyl chitosan composite to graft the fabric in-situ, which includes the following steps:

[0039] (1) The scoured cotton fabric was added to N-methyl imidazole bisulfate ionic liquid with pH = 4.6, swelled at 35℃ for 25 min using an ultrasonic probe (70W) for 3 times, then immersed in anhydrous ethanol for 3h to remove the ionic liquid to obtain the activated cotton fabric.

[0040] (2) The prepared graphene oxide / nano carboxyl chitosan complex was dissolved in N-methyl imidazole bisulfate ionic liquid with pH = 4.3 to prepare a reaction solution with a mass concentration of 0.4%. The activated cotton fabric of step (1) was added to the reaction solution (bath ratio of cotton fabric to reaction solution was 1g:20mL), and the grafted fabric was obtained after stirring and reacting in the microwave irradiation condition of power 400W and temperature 30℃ for 60min.

[0041] (3) The grafted fabric was padded for 3 times to make the fabric have a pick-up rate of 80%, then put into a heat setting machine (intermittent heating, pause for 1min after each temperature rise of 10℃, heating rate was 5℃ / min) for pre-drying at 30℃ for 20min, then baking at 100℃ for 10min, and finally drying at 60℃ for 2h, washed with clean water and dried to obtain the graphene oxide / nano carboxyl chitosan in-situ grafted cotton fabric (sample 13).

[0042] For comparison, the following samples were also prepared in this example:

[0043] Sample 11: raw cotton fabric.

[0044] Sample 12: the grafted fabric obtained after steps (1) and (2) in the finishing method described above in this example, then pre-drying at 30℃ for 20min in an oven, baking at 100℃ for 10min, and finally drying at 60℃ for 2h, washed with clean water and dried to obtain the graphene oxide / nano carboxyl chitosan in-situ grafted cotton fabric.

[0045] The mechanical properties, wrinkle recovery, antibacterial rate against Staphylococcus aureus and Escherichia coli, antibacterial washability, and anti-ultraviolet performance and anti-ultraviolet washability of samples 11-13 were tested according to the standards of GB / T 3923.1-2013 "Textile Fabric Tensile Properties", GB / T 3819-1997 "Determination of Wrinkle Recovery of Textile Fabrics", GB / T 20944.3-2008 "Evaluation of Antibacterial Properties of Textiles Part 3: Oscillation Method", and GB / T 18830-2009 "Evaluation of Anti-Ultraviolet Properties of Textiles". The test results are shown in Table 1.

[0046] Table 1 Physicochemical properties of graphene oxide / nano carboxyl chitosan in-situ grafted cotton fabric

[0047]

[0048] From Table 1, it can be seen that, compared with the cotton fabric (sample 11), the breaking strength, antibacterial property and ultraviolet resistance of the graphene oxide / nano-carboxyl chitosan in-situ grafted cotton fabric (samples 12 and 13) are obviously improved. The graphene oxide / nano-carboxyl chitosan can undergo a hemiacetal reaction with the cotton fabric, and is firmly combined on the fabric surface, thereby greatly improving the physical and chemical properties of the cotton fabric. The crease recovery of the fabric represents the recovery performance of the fabric after being creased under external force, and is an important factor affecting the serviceability and appearance of the fabric. From the table, it can be seen that, after the graphene oxide / nano-carboxyl chitosan is grafted on the cotton fabric, the crease recovery angle of the cotton fabric is significantly improved, reaching 190.3°. After 50 times of washing, the antibacterial rate of the modified cotton fabric (sample 13) is still above 86.9%, and the UPF value is maintained at 61.85%, indicating that the functionality of the compound modified cotton fabric is durable. In addition, compared with the sample 12 treated by oven drying (the whiteness and air permeability are reduced by 24.38% and 22.69%, respectively), the grafting rate, breaking strength, moisture regain and whiteness of the sample 13 treated by the heat setting machine are higher, and the air permeability is only slightly reduced (only reduced by 4.24%), indicating that the graphene oxide / nano-carboxyl chitosan compound grafted on the surface of the cotton fabric is uniformly distributed, and will not be aggregated into a film on the surface of the fabric, and the service comfort is good.

[0049] Example 2

[0050] The nano-carboxyl chitosan used in this example has the following characteristics: the content of aldehyde group at C6 position is 34.28%, the content of carboxyl group at C2 and C3 positions is 30.23%, the degree of deacetylation is 88.21%, the solubility in water is 17.96 g / 100 mL, and the isoelectric point pH is about 5.7.

[0051] The graphene oxide used in this example is prepared by a modified Hummers method, and has the following characteristics: the interplanar spacing is 0.887 nm, the sheet thickness is 0.91 nm, the carboxyl content is 3.81 mmol / g, the specific surface area is 492 m 2 / g

[0052] The graphene oxide / nano-carboxyl chitosan composite of the present embodiment is prepared by the following steps: nano-carboxyl chitosan is stirred and dissolved in an acetic acid solution with a volume concentration of 2%, and a nano-carboxyl chitosan dispersion with a mass concentration of 0.6% is prepared; graphene oxide is dissolved in an N-methyl imidazole bisulfate ionic liquid with pH = 4.0 at 80°C to obtain a graphene oxide ionic liquid solution; the nano-carboxyl chitosan dispersion is added dropwise into the graphene oxide ionic liquid solution under the action of an ultrasonic wave with a power of 180 W within 8 min, and then ultrasonic chemical reaction is performed for 2 h, so that chemical bonds such as amide bonds and hemiacetal bonds are formed between graphene oxide layers and nano-carboxyl chitosan particles; high-speed centrifugation (at a speed of 12000 rpm) is performed for 18 min, and vacuum freeze-drying is performed for 36 h, to obtain the graphene oxide / nano-carboxyl chitosan composite. The mass ratio of graphene oxide to nano-carboxyl chitosan is 0.4:1.

[0053] The present embodiment uses the prepared graphene oxide / nano-carboxyl chitosan composite to graft a fabric in situ, and the finishing method includes the following steps:

[0054] (1) The degummed silk fabric is added into an N-methyl imidazole bisulfate ionic liquid with pH = 5.0, and is swelled using an ultrasonic wave probe (80 W) at 35°C for 25 min, which is repeated for 3 times, and then the ionic liquid is removed by immersing the fabric in anhydrous ethanol for 3 h to obtain an activated silk fabric.

[0055] (2) The prepared graphene oxide / nano-carboxyl chitosan composite is dissolved in an N-methyl imidazole bisulfate ionic liquid with pH = 4.5 to prepare a reaction solution with a mass concentration of 0.6%. The activated silk fabric of step (1) is added into the reaction solution (the bath ratio of the silk fabric to the reaction solution is 1 g:20 mL), and is stirred under the conditions of microwave radiation with a power of 460 W and a temperature of 40°C for 60 min to obtain a grafted fabric.

[0056] (3) The grafted fabric is padded 3 times to make the pick-up rate of the fabric reach 90%, and then is placed into a heat setting machine (intermittent heating, pause for 1 min after each temperature rise of 10°C, and the heating rate is 5°C / min) for pre-drying at 35°C for 20 min, heating to 100°C for baking for 10 min, and finally drying at 60°C for 2 h, and then is washed with clean water and dried to obtain a graphene oxide / nano-carboxyl chitosan in-situ grafted silk fabric (sample 24).

[0057] For comparison, the following samples are also prepared in the present embodiment:

[0058] Sample 21: silk fabric.

[0059] Sample 22: The unactivated silk fabric was treated by step (2) in the finishing method described above in this example, then pre-dried at 35℃ for 20 min in an oven, baked at 100℃ for 10 min, and finally dried at 60℃ for 2 h, washed with clean water and air-dried, to obtain graphene oxide / nano carboxyl chitosan in-situ grafted silk fabric.

[0060] Sample 23: The fabric after grafting reaction obtained by steps (1) and (2) in the finishing method described above in this example, was pre-dried at 35℃ for 20 min in an oven, baked at 100℃ for 10 min, and finally dried at 60℃ for 2 h, washed with clean water and air-dried, to obtain graphene oxide / nano carboxyl chitosan in-situ grafted silk fabric.

[0061] The mechanical properties, wrinkle recovery, antibacterial rate against Staphylococcus aureus and Escherichia coli, antibacterial washing resistance, and anti-ultraviolet performance and anti-ultraviolet washing resistance of samples 21-24 were tested according to GB / T 3923.1-2013 Textiles-Determination of tensile properties of fabrics, GB / T 3819-1997 Textiles-Determination of the crease recovery properties of fabrics, GB / T 20944.3-2008 Evaluation of antibacterial properties of textiles-Part 3: Shake flask method, and GB / T 18830-2009 Evaluation of the anti-UV properties of textiles. The test results are shown in Table 2.

[0062] Table 2 Physicochemical properties of graphene oxide / nano carboxyl chitosan in-situ grafted silk fabric

[0063]

[0064] As can be seen from Table 2, compared with the silk fabric (sample 21), the breaking strength, antibacterial property, wrinkle resistance and ultraviolet resistance of the graphene oxide / nano carboxyl chitosan in-situ grafted silk fabric (samples 22-24) are obviously improved. The graphene oxide / nano carboxyl chitosan can occur hemiacetal reaction with the silk and firmly combine on the surface of the silk fabric, thereby significantly improving the physical and chemical properties of the silk fabric. The crease recovery of the fabric represents the recovery performance of the fabric after being creased under external force and is an important factor affecting the service performance and appearance of the fabric. As can be seen from the table, the crease recovery angle of the graphene oxide / nano carboxyl chitosan in-situ grafted silk fabric is obviously improved compared with the original silk fabric, reaching 201.2°. After 50 times of washing, the antibacterial rate of the modified silk fabric (sample 24) is still above 92.2% and the UPF value is maintained at 91.78%, indicating that the antibacterial and ultraviolet resistance performance of the graphene oxide / nano carboxyl chitosan modified silk fabric is efficient and durable. In addition, compared with the sample 23 treated by the oven drying (the whiteness and air permeability are reduced by 31.51% and 42.23%, respectively), the grafting rate, breaking strength, moisture regain and whiteness of the sample 24 treated by the heat setting machine are higher and the air permeability is less reduced (only reduced by 8.71%), indicating that the graphene oxide / nano carboxyl chitosan complex grafted on the surface of the silk fabric is uniformly distributed and will not be crosslinked into a film on the surface of the fabric, thereby being comfortable to wear.

[0065] Example 3

[0066] The nano carboxyl chitosan used in this example has the following characteristics: the content of aldehyde group at C6 position is 34.28%, the content of carboxyl group at C2 and C3 positions is 30.23%, the degree of deacetylation is 88.21%, the solubility in water is 17.96 g / 100 mL, and the isoelectric point pH is about 5.7.

[0067] The graphene oxide used in this example is prepared by the improved Hummers method and has the following characteristics: the interplanar spacing is 0.887 nm, the sheet thickness is 0.91 nm, the content of carboxyl group is 3.81 mmol / g, and the specific surface area is 492 m 2 / g.

[0068] The graphene oxide / nano-carboxyl chitosan composite of the present embodiment is prepared by the following steps: nano-carboxyl chitosan is stirred and dissolved in acetic acid solution with a volume concentration of 2%, and a nano-carboxyl chitosan dispersion with a mass concentration of 0.6% is prepared; graphene oxide is dissolved in N-methyl imidazole bisulfate ionic liquid with pH = 4.0 at 80°C to obtain a graphene oxide ionic liquid solution; the nano-carboxyl chitosan dispersion is added dropwise into the graphene oxide ionic liquid solution under the action of 180W ultrasonic wave within 8 min, and then ultrasonic chemical reaction is carried out for 2h, so that chemical bonds such as amide bonds and hemiacetal bonds are formed between graphene oxide layers and nano-carboxyl chitosan particles; high-speed centrifugation (12000 rpm) is carried out for 18 min and vacuum freeze-drying is carried out for 36h to obtain the graphene oxide / nano-carboxyl chitosan composite. The mass ratio of graphene oxide to nano-carboxyl chitosan is 0.4:1.

[0069] The finishing method of in-situ grafting of fabric by using the prepared graphene oxide / nano-carboxyl chitosan composite of the present embodiment includes the following steps:

[0070] (1) The scoured 30% polyester fiber / 70% silk blended fabric is added into N-methyl imidazole bisulfate ionic liquid with pH = 4.8, and is swelled at 40°C for 25 min using an ultrasonic probe (90W), which is repeated for 3 times, and then the ionic liquid is removed by immersing in anhydrous ethanol for 3h to obtain the activated blended fabric.

[0071] (2) The prepared graphene oxide / nano-carboxyl chitosan composite is dissolved in N-methyl imidazole bisulfate ionic liquid with pH = 4.6 to prepare a reaction solution with a mass concentration of 0.6%. The activated polyester fiber / silk blended fabric of step (1) is added into the reaction solution (the bath ratio of polyester fiber / cotton blended fabric to the reaction solution is 1g:25mL), and is stirred under the microwave irradiation conditions of power 540W and temperature 40°C for 60 min to obtain the fabric after grafting reaction.

[0072] (3) The blended fabric after grafting reaction is padded for 3 times to make the fabric have a pick-up rate of 90%, and then is put into a heat setting machine (intermittent heating, pause for 1 min after each temperature rise of 10°C, and the heating rate is 5°C / min), and is pre-dried at 40°C for 20 min, and then is baked at 100°C for 10 min, and finally is dried at 60°C for 3h, and is washed and dried to obtain the graphene oxide / nano-carboxyl chitosan in-situ grafted polyester fiber / silk blended fabric (sample 34).

[0073] For comparison, the following samples are also prepared in the present embodiment:

[0074] Sample 31: 30% polyester fiber / 70% silk blended fabric.

[0075] Sample 32: The unactivated polyester fiber / silk blended fabric was treated by step (2) in the finishing method described above in this example, then pre-dried at 40°C for 20 min in an oven, baked at 100°C for 10 min, finally dried at 60°C for 3 h, washed with clean water and air-dried, to obtain graphene oxide / nano carboxyl chitosan in-situ grafted silk fabric.

[0076] Sample 33: The grafted fabric obtained by steps (1) and (2) in the finishing method described above in this example was pre-dried at 40°C for 20 min in an oven, baked at 100°C for 10 min, finally dried at 60°C for 3 h, washed with clean water and air-dried, to obtain graphene oxide / nano carboxyl chitosan in-situ grafted polyester fiber / silk blended fabric.

[0077] The mechanical properties, wrinkle recovery, antibacterial rate against Staphylococcus aureus and Escherichia coli, antibacterial washing resistance, anti-ultraviolet performance and anti-ultraviolet washing resistance of samples 31-34 were tested according to GB / T 3923.1-2013 Textiles - Determination of tensile properties of fabrics, GB / T 3819-1997 Textiles - Determination of the crease recovery properties of fabrics, GB / T 20944.3-2008 Evaluation of antibacterial properties of textiles - Part 3: shaking method, and GB / T 18830-2009 Evaluation of anti-UV properties of textiles, etc. The test results are shown in Table 3.

[0078] Table 3 Physicochemical properties of graphene oxide / nano carboxyl chitosan in-situ grafted polyester fiber / silk blended fabric

[0079]

[0080] As can be seen from Table 3, compared with the polyester fiber / silk blended fabric (sample 31), the breaking strength, antibacterial property, wrinkle resistance and ultraviolet resistance of the graphene oxide / nano carboxyl chitosan in-situ grafted blended fabric (samples 32-34) are obviously improved. The graphene oxide / nano carboxyl chitosan can undergo a hemiacetal reaction with the blended fabric and firmly combine on the surface of the blended fabric, thereby significantly improving the physical and chemical properties of the blended fabric. The crease recovery of the blended fabric represents the recovery performance of the fabric after being creased under external force and is an important factor affecting the serviceability and appearance of the fabric. As can be seen from the table, the crease recovery angle of the graphene oxide / nano carboxyl chitosan in-situ grafted blended fabric is obviously improved compared with the original blended fabric and reaches 175.4°. After 50 times of washing, the antibacterial rate of the modified blended fabric (sample 34) is still above 90.2% and the UPF value remains at 69.26%, indicating that the antibacterial and ultraviolet resistance of the composite modified blended fabric are highly efficient and durable. In addition, compared with the sample 33 treated by oven drying (the whiteness and air permeability are reduced by 24.68% and 30.72%, respectively), the grafting rate, breaking strength, moisture regain and whiteness of the sample 34 treated by the heat setting machine are higher and the air permeability is reduced by a smaller amount (only by 4.40%), indicating that the graphene oxide / nano carboxyl chitosan composite grafted on the surface of the blended fabric is uniformly distributed and will not form a film on the surface of the blended fabric, thereby providing good service comfort.

[0081] Example 4

[0082] The nano carboxyl chitosan used in this example has the following characteristics: the content of aldehyde group at C6 position is 38.14%, the content of carboxyl group at C2 and C3 positions is 31.82%, the degree of deacetylation is 82.25%, the solubility in water is 21.82 g / 100 mL, and the isoelectric point pH is about 5.7.

[0083] The graphene oxide used in this example is prepared by a modified Hummers method and has the following characteristics: the interplanar spacing is 0.884 nm, the sheet thickness is 0.85 nm, the carboxyl group content is 3.90 mmol / g, and the specific surface area is 493 m 2 / g.

[0084] The graphene oxide / nano-carboxyl chitosan composite of the present embodiment is prepared by the following steps: nano-carboxyl chitosan is stirred and dissolved in acetic acid solution with a volume concentration of 2%, and a nano-carboxyl chitosan dispersion with a mass concentration of 0.4% is prepared; graphene oxide is dissolved in N-methyl imidazole bisulfate ionic liquid with pH = 4.2 at 85°C to obtain a graphene oxide ionic liquid solution; the nano-carboxyl chitosan dispersion is added dropwise into the graphene oxide ionic liquid solution under the action of 150W ultrasonic wave within 8min, and then ultrasonic chemical reaction is carried out for 1h, so that chemical bonds such as amide bonds and hemiacetal bonds are formed between graphene oxide layers and nano-carboxyl chitosan particles; high-speed centrifugation (speed: 11000rpm) is carried out for 15min, and vacuum freeze-drying is carried out for 40h, to obtain the graphene oxide / nano-carboxyl chitosan composite. The mass ratio of graphene oxide to nano-carboxyl chitosan is 0.6:1.

[0085] The finishing method of the present embodiment for grafting fabrics in situ by using the prepared graphene oxide / nano-carboxyl chitosan composite includes the following steps:

[0086] (1) The scoured 30% polyester fiber / 70% viscose blended fabric is added into N-methyl imidazole bisulfate ionic liquid with pH = 4.8, and is swelled at 35°C for 25min using an ultrasonic probe (90W), and the operation is repeated for 3 times, and then the ionic liquid is removed by immersing in anhydrous ethanol for 3h to obtain the activated polyester fiber / viscose blended fabric;

[0087] (2) The prepared graphene oxide / nano-carboxyl chitosan composite is dissolved in N-methyl imidazole bisulfate ionic liquid with pH = 4.5 to prepare a reaction solution with a mass concentration of 0.6%; the activated polyester fiber / viscose blended fabric of step (1) is added into the reaction solution (bath ratio of polyester fiber / viscose blended fabric to reaction solution is 1g:30mL), and stirring reaction is carried out under the conditions of microwave radiation with a power of 500W and a temperature of 40°C for 70min, to obtain the fabric after grafting reaction.

[0088] (3) The fabric after grafting reaction is padded for 3 times to make the pick-up rate of the fabric reach 95%, and then is put into a heat setting machine (intermittent heating, pause for 1min after each temperature rise of 10°C, and the heating rate is 5°C / min), and is pre-dried at 40°C for 15min, and then is heated to 100°C for 12min, and finally is dried at 60°C for 3h, and is washed and dried, to obtain the graphene oxide / nano-carboxyl chitosan in-situ grafted polyester fiber / viscose blended fabric (sample 43).

[0089] For comparison, the following samples are also prepared in the present embodiment:

[0090] Sample 41: 30% polyester fiber / 70% viscose blended fabric.

[0091] Sample 42: The grafted fabric after step (1) and (2) in the above finishing method of this example was obtained, then pre-dried in an oven at 40℃ for 15 min, baked at 100℃ for 12 min, and finally dried at 60℃ for 3 h, washed with clean water and air-dried to obtain graphene oxide / nano carboxyl chitosan in-situ grafted polyester fiber / viscose blended fabric.

[0092] The mechanical properties, wrinkle recovery, antibacterial rate against Staphylococcus aureus and Escherichia coli, antibacterial washability, and anti-UV performance and anti-UV washability of samples 41-43 were tested according to GB / T 3923.1-2013 Textiles - Determination of tensile properties of fabrics, GB / T 3819-1997 Textiles - Determination of the crease recovery properties of fabrics, GB / T 20944.3-2008 Evaluation of antibacterial properties of textiles - Part 3: shaking method, and GB / T 18830-2009 Evaluation of anti-UV properties of textiles, etc. The test results are shown in Table 4.

[0093] Table 4 Physicochemical properties of graphene oxide / nano carboxyl chitosan in-situ grafted polyester fiber / viscose blended fabric

[0094]

[0095] As can be seen from Table 4, compared with the polyester fiber / viscose blended fabric (sample 41), the breaking strength, antibacterial property, wrinkle resistance, and anti-UV of the graphene oxide / nano carboxyl chitosan in-situ grafted blended fabric (samples 42-43) were significantly improved. Graphene oxide / nano carboxyl chitosan can undergo hemiacetal reaction with the blended fabric and firmly bind to the surface of the blended fabric, significantly improving the physicochemical properties of the blended fabric. The wrinkle recovery of the blended fabric represents the recovery performance of the fabric after being creased under external force, which is an important factor affecting the serviceability and appearance of the fabric. As can be seen from the table, the wrinkle recovery angle of the graphene oxide / nano carboxyl chitosan in-situ grafted blended fabric is significantly improved compared with the original blended fabric, reaching 169.4°. After 50 washes, the antibacterial rate of the modified blended fabric (sample 43) is still above 86.3%, and the UPF value remains at 76.39%, indicating that the antibacterial and anti-UV performance of the compound modified blended fabric is highly efficient and durable. In addition, compared with sample 42 treated by oven drying (whiteness and air permeability decreased by 28.99% and 29.67%, respectively), sample 43 treated by heat setting machine has higher grafting rate, breaking strength, moisture regain, and whiteness, and smaller decrease in air permeability (only decreased by 6.82%), indicating that the graphene oxide / nano carboxyl chitosan compound distributed uniformly on the surface of the blended fabric and did not form a film on the surface of the blended fabric, providing good service comfort.

[0096] Comparative Example 1 (without adding nano carboxyl chitosan)

[0097] The finishing method of the prepared graphene oxide grafted fabric in this example includes the following steps:

[0098] (1) The degummed silk fabric was added into N-methyl imidazole hydrogen sulfate ionic liquid with pH = 5.0, swelled for 25 min at 35℃ using an ultrasonic probe (80W), repeated for 3 times, then immersed in anhydrous ethanol for 3h to remove the ionic liquid to obtain the activated silk fabric.

[0099] (2) The graphene oxide (interplanar spacing of 0.887nm, sheet thickness of 0.91nm, carboxyl content of 3.81mmol / g, specific surface area of 492m 2 / g) was dissolved in N-methyl imidazole hydrogen sulfate ionic liquid with pH = 4.5 to prepare a reaction solution with a mass concentration of 0.6%. The activated silk fabric of step (1) was added into the reaction solution (bath ratio of silk fabric to reaction solution was 1g:20mL), and stirred for 60 min under the conditions of microwave radiation with power of 460W and temperature of 40℃ to obtain the grafted fabric after reaction.

[0100] (3) The grafted fabric after reaction was padded for 3 times to make the pick-up rate of the fabric at 90%, then put into a heat setting machine (intermittent heating, pause for 1 min after each temperature rise of 10℃, heating rate of 5℃ / min), pre-dried at 35℃ for 20 min, then baked at 100℃ for 10 min, finally dried at 60℃ for 2h, washed with clean water and dried to obtain the graphene oxide in-situ grafted silk fabric (sample 53).

[0101] The following samples were also prepared in this comparative example:

[0102] Sample 51: silk fabric.

[0103] Sample 52: the grafted fabric after reaction obtained by steps (1) and (2) in the finishing method described above in this comparative example, then pre-dried at 35℃ for 20 min in an oven, baked at 100℃ for 10 min, finally dried at 60℃ for 2h, washed with clean water and dried to obtain the graphene oxide grafted silk fabric.

[0104] The mechanical properties, wrinkle recovery, inhibition rate of Staphylococcus aureus and Escherichia coli, antibacterial washing resistance, anti-ultraviolet performance and anti-ultraviolet washing resistance of samples 51-53 were tested according to the standards of GB / T 3923.1-2013 "Textile Fabric Tensile Properties", GB / T 3819-1997 "Determination of Wrinkle Recovery of Textile Fabrics", GB / T 20944.3-2008 "Evaluation of Antibacterial Properties of Textiles Part 3: Oscillation Method", and GB / T 18830-2009 "Evaluation of Anti-Ultraviolet Properties of Textiles". The test results are shown in Table 5.

[0105] Table 5 Physicochemical properties of graphene oxide grafted silk fabric

[0106]

[0107]

[0108] As can be seen from Table 5, without the nano-carboxyl chitosan complex, the grafting rate, wrinkle recovery angle, moisture regain, whiteness, mechanical property, antibacterial property and ultraviolet resistance of the graphene oxide grafted silk fabric are all obviously decreased compared with the graphene oxide / nano-carboxyl chitosan in-situ grafted silk fabric in Example 2. The graphene oxide / nano-carboxyl chitosan complex in Example 2 can exert respective advantages, has double antibacterial activity, and the nano-carboxyl chitosan in the complex can crosslink with the silk through amide bond, hemiacetal bond, Schiff base and the like, so that more graphene oxide layers are uniformly grafted on the surface of the silk, the adhesion of the graphene oxide layers is reduced, the modified fabric has stronger and more durable functions, and the aggregation and adhesion of the graphene oxide layers are prone to occur in the process of combining the graphene oxide with the silk, and the grafting sites of the graphene oxide and the silk are less, which leads to a great decrease in the functionality and wearability of the modified silk fabric.

[0109] II. Test experiments on the samples obtained in the above examples

[0110] Test item 1: infrared spectrum characterization of graphene oxide / nano-carboxyl chitosan in-situ grafted silk fabric

[0111] The infrared spectrum of the graphene oxide / nano-carboxyl chitosan in-situ grafted silk fabric was analyzed. Three silk fabric samples were taken: the first sample was the fabric A obtained from the degummed silk fabric, the second sample was the modified fabric with a grafting rate of 5.01% obtained from the graphene oxide / nano-carboxyl chitosan in-situ grafted silk fabric according to the method of the sample 22 in Example 2, and the third sample was the modified fabric C with a grafting rate of 10.58% obtained from the graphene oxide / nano-carboxyl chitosan in-situ grafted silk fabric according to the method of Example 2. The test results are shown in Figure 2 (A)-(C), respectively.

[0112] As can be seen from Figure 2 , the strong absorption peak of the infrared spectrum A of the degummed silk fabric at 2900-3400 cm -1 is the characteristic peak of the stretching of O-H and N-H in fibroin protein, and the peaks at 1621.4 cm -1 , 1514.7 cm -1 and 1227.3 cm -1The characteristic absorption bands of amide I, amide II and amide III respectively belong to the silk fibroin. In the infrared curves B and C of the modified silk, after the graphene oxide / nano carboxymethyl chitosan is in-situ grafted to the silk fabric, the vibration peak corresponding to the beta-pyranoside bond of the nano carboxymethyl chitosan in the complex appears at 892.3cm -1 Nearby; the characteristic absorption peak of the modified silk does not change obviously compared with the amide characteristic peak of the silk fibroin, which indicates that the in-situ grafting of the graphene oxide / nano carboxymethyl chitosan does not cause damage to the secondary structure of the silk fibroin; and the C=O stretching vibration peak and the C-H stretching characteristic peak of the aldehyde group appear at 1740.6cm -1 and 2851.8cm -1 respectively, which are caused by the absorption bands of the -COOH and -CHO in the graphene oxide / nano carboxymethyl chitosan complex grafted to the surface of the silk. The C-O stretching absorption peaks of the primary and secondary hydroxyl groups of the carboxymethyl chitosan at 1032.8cm -1 , 1064.2cm -1 are also obvious, and the C-N characteristic peak of amide III at 1227.3cm -1 increases with the increase of the grafting rate of the complex, which indicates that the graphene oxide / nano carboxymethyl chitosan complex forms more amide bond combinations with the silk. Meanwhile, the hydrogen bond absorption band of the original silk moves from 3283.4cm -1 to 3274.9cm -1 and 3273.8cm -1 of the modified silk, which is because the grafting reaction of the complex and the silk fabric to some extent strengthens the intermolecular force of the silk. The infrared analysis indicates that the graphene oxide / nano carboxymethyl chitosan complex is firmly combined with the silk fabric through the grafting reaction, and the functional modified textile is obtained.

[0113] In summary, the graphene oxide / nano carboxymethyl chitosan is in-situ grafted to the fabric, the aldehyde group and the carboxyl group of the graphene oxide / nano carboxymethyl chitosan complex form semi-acetal, amide bond and other chemical bond cross-linking with the silk fabric, the graphene oxide / nano carboxymethyl chitosan is uniformly grafted to the surface of the silk fabric, and the functional textile with high grafting rate, durable and efficient antibacterial and ultraviolet resistance, safety and comfort is obtained. The in-situ grafting fabric technology of the graphene oxide / nano carboxymethyl chitosan is adopted, the process is simple, the fabric functionality is durable, the wearability is good, no chemical cross-linking agent is used, it is green and environmentally friendly, and there is no environmental burden, and the practical application prospect is huge.

[0114] The above is only a preferred embodiment of the present application, and is not used to limit the present application, any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing graphene oxide / nano-carboxyl chitosan in-situ grafted fabric, characterized in that: is prepared by dissolving graphene oxide in N-methyl imidazole hydrogen sulfate ionic liquid ([Hmim]HSO4), adding nano carboxyl chitosan dispersion solution dropwise to graphene oxide layers under the action of ultrasonic waves to produce chemical reaction, and then through microwave radiation to make graphene oxide / nano carboxyl chitosan composite and fabric in N-methyl imidazole hydrogen sulfate ionic liquid to produce in-situ grafting reaction, thereby obtaining graphene oxide / nano carboxyl chitosan in-situ grafted fabric; The graphene oxide / nano carboxyl chitosan composite is prepared by the following steps: stirring and dissolving nano carboxyl chitosan in acetic acid solution with a volume concentration of 2% to prepare nano carboxyl chitosan dispersion solution with a mass concentration of 0.2-1.0%; dissolving graphene oxide in N-methyl imidazole hydrogen sulfate ionic liquid at 80-90 ℃ to obtain graphene oxide ionic liquid solution; adding nano carboxyl chitosan dispersion solution dropwise into graphene oxide ionic liquid solution under the action of 100-260 W ultrasonic waves for 6-10 min, and then performing ultrasonic chemical reaction for 1-2 h to form chemical combination between graphene oxide layers and nano carboxyl chitosan particles; and then performing high-speed centrifugation for 15-20 min and vacuum freeze-drying for 24-48 h to obtain graphene oxide / nano carboxyl chitosan composite; the mass ratio of graphene oxide to nano carboxyl chitosan is 0.125-0.8:

1. The nano carboxyl chitosan has an aldehyde group content at C6 position of 28.15-41.69%, a carboxyl group content at C2 and C3 positions of 19.57-40.92%, a deacetylation degree of 83.61-90.73%, a solubility in water of 11.94-22.86 g / 100 mL, and an isoelectric point pH of 5.5-5.7, and has the following structural formula: The pH of the N-methyl imidazole hydrogen sulfate ionic liquid is 3.4-4.6; the rotation speed of the high-speed centrifugation is 10000-12500 rpm; the graphene oxide is prepared by a modified Hummers method, the interplanar spacing of the graphene oxide crystal face is 0.883-0.894 nm, the sheet layer thickness is ≤1 nm, the carboxyl content is 3.73-3.95 mmol / g, and the specific surface area is ≥462 m 2 / g.

2. The method for preparing graphene oxide / nano-carboxyl chitosan in-situ grafted fabric according to claim 1, characterized in that: The fabric is a cellulose fiber fabric, a protein fiber fabric, a blended fabric of cellulose fiber and polyester fiber, or a blended fabric of protein fiber and polyester fiber.

3. The method for preparing graphene oxide / nano-carboxyl chitosan in-situ grafted fabric according to claim 1, characterized in that, The method comprises the following steps: (1) adding scoured or degummed fabric into N-methyl imidazole hydrogen sulfate ionic liquid, swelling at 30-40 ℃ for 20-30 min using an ultrasonic probe, repeating 2-3 times, and then immersing in anhydrous ethanol for 2-4 h to remove the ionic liquid to obtain activated fabric; (2) dissolving the graphene oxide / nano carboxyl chitosan composite in N-methyl imidazole hydrogen sulfate ionic liquid to prepare a reaction solution with a mass concentration of 0.2%-0.8%; adding the activated fabric of step (1) into the reaction solution, and stirring under microwave radiation for 20-90 min to obtain grafted fabric; (3) padding the grafted fabric 2-3 times to make the fabric have a pick-up rate of 65-95%, and then placing the fabric into a heat setting machine to pre-dry at 30-40 ℃ for 15-20 min, to bake at 100 ℃ for 8-12 min, and finally to dry at 60 ℃ for 2-3 h, and then washing and airing to obtain graphene oxide / nano carboxyl chitosan in-situ grafted fabric.

4. The method for preparing graphene oxide / nano-carboxyl chitosan in-situ grafted fabric according to claim 3, characterized in that: In step (1), the power of the ultrasonic probe is 60-100 W.

5. The method for preparing graphene oxide / nano-carboxyl chitosan in-situ grafted fabric according to claim 3, characterized in that: In step (2), the pH of the N-methyl imidazole hydrogen sulfate ionic liquid is 4.2-4.8, the microwave radiation power is 320-680 W, and the microwave radiation temperature is 25-40 DEG C.

6. The method for preparing graphene oxide / nano-carboxyl chitosan in-situ grafted fabric according to claim 3, characterized in that: In step (2), the bath ratio of the activated fabric to the reaction solution is set to 1g:20-30 mL.

7. A graphene oxide / nano-carboxyl chitosan in-situ grafted fabric prepared by the preparation method in any one of claims 1-6.

Images