A method for super-hydrophilic modification of polyamide fabric based on DES combined with multiple enzymes

Abstract

The application discloses a method for super-hydrophilic modification of polyamide fiber based on DES combined with multiple enzymes, and belongs to the technical field of functionalized textiles.The method for super-hydrophilic modification specifically comprises the following steps: immersing the polyamide fabric after refining treatment into DES for pretreatment, taking out and drying; then immersing into a protease modification solution for reaction; after the reaction is completed, washing, drying and balancing; then immersing into a mixed solution formed by laccase, TEMPO, trehalose and a buffer solution for reaction; after the reaction is completed, washing, drying, balancing and hydrophilic modification of the polyamide fabric are obtained; the super-hydrophilic modified polyamide fabric can reach a surface static contact angle of 9 degrees within 60 seconds, and the contact angle is reduced by 90.2 percent; the method has low energy consumption, is safe and environmentally friendly, and has good durability of hydrophilic modification.

Description

Technical Field

[0001] This invention relates to a method for superhydrophilic modification of nylon fabrics based on DES combined with multiple enzymes, belonging to the field of functional textile technology. Background Technology

[0002] Nylon is the world's earliest synthetic fiber, and due to its excellent performance, it is the second most produced synthetic fiber after polyester. Nylon's greatest strength and abrasion resistance are its superior properties, ranking first among all fibers. However, nylon shares the same drawbacks as polyester: poor moisture absorption and breathability. In dry environments, nylon is prone to static electricity, and short-fiber nylon fabrics are prone to pilling and fuzzing. Therefore, to further improve the performance of nylon fabrics, modification is often necessary.

[0003] Currently, commonly used methods for functionalizing nylon include: acid-base treatment, graft copolymerization modification, plasma treatment, dopamine polymerization, and enzymatic hydrolysis. Acid-base treatment significantly increases surface roughness by adding additional chemical bonds, thereby improving the hydrophilicity and reactivity of nylon fabrics; however, the use of acids and alkalis can adversely affect the tensile properties of nylon. Graft copolymerization modification typically uses acrylamide and acrylic acid graft copolymerization to enhance the hydrophilicity of nylon fabrics, but a high grafting rate significantly reduces the softness of the fabrics. Plasma treatment enhances the wettability and capillary transport of fluids through channels by increasing surface roughness and introducing hydrophilic groups; however, plasma hydrophilization requires textile companies to purchase specialized equipment, resulting in high costs. Dopamine polymerization can impart excellent hydrophilicity and antistatic effects to nylon fabrics, but the hydrophilic functionalization process is too slow. Enzymatic hydrolysis has been proven to effectively promote the hydrophilicity of nylon, and the functionalization process is relatively environmentally friendly and safe; however, the enzymatic hydrolysis effect is weak and cannot achieve the effect of superhydrophilic modification. Summary of the Invention

[0004] [Technical Issues]

[0005] Chemical methods for hydrophilic modification of nylon fabrics can affect their properties and pollute the environment; currently, enzymatic methods for hydrophilic modification of nylon fabrics have the problem of insignificant hydrophilic effects.

[0006] [Technical Solution]

[0007] To address the aforementioned issues, this invention employs a combination of DES pretreatment, protease surface modification, and laccase / TEMPO system-catalyzed oxidation of trehalose to achieve superhydrophilic modification of nylon fabrics. The method of this invention is energy-efficient, safe, environmentally friendly, and possesses a certain degree of durability; furthermore, the modified nylon fabric meets the required mechanical properties for wear.

[0008] The first objective of this invention is to provide a method for superhydrophilic modification of nylon fabrics based on deep eutectic solvent (DES) combined with protease and laccase, the method comprising the following steps:

[0009] (1) DES preprocessing

[0010] The refined nylon fabric is completely immersed in DES for pretreatment, then removed, washed, and dried to obtain the pretreated modified nylon fabric.

[0011] (2) Protease hydrolysis modification

[0012] The protease and buffer solution were mixed evenly to obtain the protease-modified solution. Then, the pretreated and modified nylon fabric obtained in step (1) was immersed in the protease-modified solution for reaction. After the reaction was completed, the fabric was washed, dried and equilibrated to obtain the protease-modified nylon fabric.

[0013] (3) Laccase / TEMPO grafting modification

[0014] Laccase, TEMPO, trehalose, and buffer solution were mixed evenly to obtain a mixed solution. Then, the nylon fabric modified by the protease obtained in step (2) was immersed in the mixed solution for reaction. After the reaction was completed, it was washed, dried, and equilibrated to obtain the superhydrophilic modified nylon fabric.

[0015] In one embodiment, the method for preparing the nylon fabric after the refining treatment in step (1) is as follows:

[0016] The nylon fabric is placed in a refining solution and treated at 50-60℃ for 1-3 hours, followed by desizing and sizing, washing, drying, and equilibration to obtain the refined nylon fabric. The concentration of soap flakes in the refining solution is 4-6 g / L, the concentration of sodium carbonate is 2-5 g / L, and the remainder is water. The bath ratio of the nylon fabric to the refining solution is 1:50-100. The washing is done with water, and the drying is done at 80-105℃. The equilibration is carried out in a constant temperature and humidity chamber (21±1℃, 65±2%) for at least 24 hours.

[0017] In one embodiment, the pretreatment in step (1) is to immerse the sample at 40-70°C for 2-8 hours with a bath ratio of 1:20-50.

[0018] In one embodiment, the DES in step (1) includes choline chloride as a hydrogen bond acceptor and one or more of citric acid, malic acid, lactic acid, glycerol and urea as a hydrogen bond donor.

[0019] In one embodiment, the DES in step (1) includes choline chloride as a hydrogen bond acceptor and citric acid or malic acid as a hydrogen bond donor.

[0020] In one embodiment, when the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is citric acid, the DES is composed of choline chloride, citric acid, and water, with a molar ratio of choline chloride, citric acid, and water of 1:2:2.62; when the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is malic acid, the DES is composed of choline chloride, malic acid, and water, with a molar ratio of choline chloride, malic acid, and water of 1:2:2.27; when the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is lactic acid, the DES has a molar ratio of choline chloride to lactic acid of 1:2; when the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is glycerol, the DES has a molar ratio of choline chloride to glycerol of 1:2; and when the hydrogen bond acceptor is choline chloride and the hydrogen bond donor is urea, the DES has a molar ratio of choline chloride to urea of ​​1:2.

[0021] In one embodiment, the protease in step (2) is pineapple stem protease, and the enzyme activity of pineapple stem protease is 23 U / mg; the buffer is phosphate buffer.

[0022] In one embodiment, the bath ratio for protease modification in step (2) is 1:20-60.

[0023] In one embodiment, the concentration of protease in the protease-modified solution in step (2) is 4-40 g / L.

[0024] In one embodiment, the reaction conditions in step (2) are: pH 5.5-8.0, reaction at 25-60°C for 1-24 hours.

[0025] In one embodiment, the cleaning in step (2) is performed by cleaning with a sodium carbonate aqueous solution (concentration of 2 g / L), followed by rinsing with water, and finally ultrasonic cleaning.

[0026] In one embodiment, the drying in step (2) is performed in an oven at 80-105°C.

[0027] In one embodiment, the equilibration in step (2) is to place the container in a constant temperature and humidity chamber (21±1℃, 65±2%) for at least 24 hours.

[0028] In one embodiment, the concentration of laccase in the mixed solution described in step (3) is 40-100 mL / L, the concentration of TEMPO is 0.1-5.0 g / L, the concentration of trehalose is 5-20 g / L, the pH of the buffer solution is 3.5-5.5, and the laccase activity is 37-45 U / mL.

[0029] In one embodiment, the buffer solution in step (3) is an acetic acid-sodium acetate buffer solution.

[0030] In one embodiment, the bath ratio of the reaction in step (3) is 1:100-250.

[0031] In one embodiment, the reaction in step (3) is carried out at a pH of 3.5-5.5 and a temperature of 45-65°C for 1.5-9 hours.

[0032] In one embodiment, the cleaning in step (3) is to first clean with anhydrous ethanol and then with water.

[0033] In one embodiment, the drying in step (3) is performed in an oven at 80-105°C.

[0034] In one embodiment, the equilibration in step (3) is to place the container in a constant temperature and humidity chamber (21±1℃, 65±2%) for at least 24 hours.

[0035] A second objective of this invention is to obtain superhydrophilic modified nylon fabrics prepared by the method described above.

[0036] A third objective of this invention is the application of the superhydrophilic modified nylon fabric described above in the preparation of functional textiles.

[0037] In one embodiment, the functional textiles include home textiles and industrial textiles.

[0038] The beneficial effects of this invention are:

[0039] (1) The present invention uses DES pretreatment, which improves the accessibility of protease to nylon and enhances the surface roughness of the fabric. Under the same enzyme concentration, the contact angle can be further reduced.

[0040] (2) The present invention utilizes protease to hydrolyze the amide bonds on the surface of nylon, which can generate more amino and carboxyl groups, so that nylon can achieve hydrophilic modification while maintaining its own advantageous properties.

[0041] (3) In this invention, the primary hydroxyl groups in the structure of trehalose are catalytically oxidized by the laccase / TEMPO system to obtain carboxyl groups; then, the amino groups on the surface of nylon undergo a dehydration condensation reaction with the carboxyl groups in the oxidized trehalose to graft trehalose onto the surface of nylon, thereby giving nylon hydrophilicity.

[0042] (4) The method of the present invention has the advantages of low energy consumption and safe and environmentally friendly processing technology, avoiding the disadvantages of strict chemical grafting reaction conditions and easy environmental pollution.

[0043] (5) The superhydrophilic modified nylon fabric prepared by the present invention can achieve a static contact angle of 9° within 60s, and the contact angle decreases by as much as 90.2%. Attached Figure Description

[0044] Figure 1The figures show the test results of the contact angle of the hydrophilic modified nylon fabric obtained in Example 1, the nylon fabric after refining treatment in Comparative Example 1, and the nylon fabric modified by only using DES pretreatment; where (a) is Comparative Example 1, (b) is Example 1, and (c) is Comparative Example 3.

[0045] Figure 2 The graph shows the ATR-FTIR test results of the nylon fabrics obtained in Comparative Example 1 and Comparative Example 3.

[0046] Figure 3 The graph shows the results of enzyme activity and product concentration tests for different incubation times of the protease in Example 3. Detailed Implementation

[0047] The preferred embodiments of the present invention are described below. It should be understood that the embodiments are for better explanation of the present invention and are not intended to limit the present invention.

[0048] The testing method involved in this invention:

[0049] 1. Contact angle test

[0050] After equilibrating the nylon fabric at one standard atmosphere (21±1℃, relative humidity 65±2%) for at least 24 hours, trim the selvage neatly and cut a 1×1cm piece. 2 The fabric was attached to a glass slide with double-sided tape and then placed on the platform of a DSA 25 contact angle measuring instrument. 10 μL of deionized water was dripped from a height of 10 mm above the fabric surface, and a photograph was taken after 1 minute to measure the contact angle. Three parallel samples were prepared for each group, and each parallel sample was measured once; the average value was taken.

[0051] 2. Quantitative analysis of hydrolysis products

[0052] The supernatant was obtained by centrifugation of the residual liquid after protease modification. 50 μL of the supernatant diluted 100 times was mixed with 1 mL of OPA reagent and reacted for 2 min. The absorbance at 340 nm was measured. 50 μL of enzyme solution and 50 μL of deionized water were used as control and blank samples, respectively. The absorbance of the reaction residue at 340 nm wavelength was measured using a TU-1900 dual-beam UV-Vis spectrophotometer. Each sample was measured 3 times.

[0053] 3. Fabric Zeta Potential Test

[0054] The changes in charge properties of the fabric before and after modification were determined using the Omni multi-angle particle size and high-sensitivity Zeta potential analyzer. First, the sample was cut into small pieces and placed in deionized water to form a mixed colloid. After sonication for 30 minutes, 1.5 mL of the suspension was taken for testing, and the Zeta potential value was recorded.

[0055] 4. Infrared spectroscopy characterization

[0056] The total reflectance infrared spectrum of the nylon fabric surface was measured using a Nicola IS 10 Fourier transform infrared spectrometer, with a scanning range of 4000-500 cm⁻¹. -1 The number of scans was 32. -1 .

[0057] 5. Wear resistance characterization

[0058] A Y522 fabric abrasion tester was used, with a 280-mesh grinding wheel and a 250g weight. The fabric sample was fixed on a 90mm diameter working disc, which rotated at a constant speed of 70 rpm. The sample moved relative to the grinding wheel, causing multi-directional wear and forming wear rings. The weight loss rate of the sample was observed under 50 cycles of friction as the evaluation criterion. Each group of samples was tested three times, and the average value was taken.

[0059] 6. Tensile breaking strength test

[0060] According to GB / T3923.1-2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength and Elongation at Break (Strip Method)", the breaking strength, elongation at break and breaking energy of nylon fabrics were tested using an HD026NS electronic fabric tensile tester. The sample size was set as a strip of 200mm × 50mm, the clamping distance was 200mm, and the tensile speed was 10mm / min.

[0061] The raw materials involved in the embodiments and comparative examples of this invention are as follows:

[0062] The nylon fabric is a plain weave fabric made of 100% nylon filament, with a fabric specification of 20D / 380T.

[0063] The enzyme activity of pineapple stem protease was 23 U / mg, purchased from Beijing Solarbio Science & Technology Co., Ltd.

[0064] The enzyme activity of laccase was 37-45 U / mL, and it was purchased from Nanjing Vickers Biotechnology Co., Ltd.

[0065] Example 1

[0066] A method for superhydrophilic modification of nylon fabrics based on DES combined with protease and laccase includes the following steps:

[0067] The nylon fabric was placed in a refining solution (5 g / L soap flakes, 2 g / L sodium carbonate, and the remainder water) at a liquor ratio of 1:100 and treated at 60°C for 60 min. Then, it was desized and sintered at a liquor ratio of 1:100, washed with water, and dried in an oven at 90°C. Finally, it was placed in a constant temperature and humidity chamber (21±1°C, 65±2%) for equilibration for 24 h to obtain the refined nylon fabric.

[0068] (1) DES preprocessing

[0069] The refined nylon fabric was immersed in DES2 at a bath ratio of 1:20. # In the (choline chloride:citric acid:water, molar ratio of 1:2:2.62) modifying reagent, the reaction was carried out at 70℃ for 4 hours. After washing with deionized water, the product was dried in an oven at 90℃ to obtain the pretreated nylon fabric.

[0070] (2) Modification with bromelain:

[0071] 3.2g of pineapple stem protease and 100mL of phosphate-sodium phosphate buffer (pH 6.0) were mixed evenly to obtain a protease-modified solution. Then, the nylon fabric pretreated in step (1) was immersed in the protease-modified solution at a bath ratio of 1:40 and reacted at pH 6.0 and 50℃ for 18h. After the reaction, it was first washed with a 2% sodium carbonate aqueous solution for 10min, then ultrasonically washed for 10min, and finally placed in a 90℃ oven for drying. It was then placed in a constant temperature and humidity chamber (21±1℃, 65±2%) for equilibration for 24h to obtain the protease-modified nylon fabric.

[0072] (3) Laccase / TEMPO grafting modification:

[0073] Mix 4 mL of laccase, 250 mg of TEMPO, 1.0 g of trehalose, and 100 mL of acetate-sodium acetate buffer (pH 4.0) to obtain a mixed solution. Then, immerse the protease-modified nylon fabric obtained in step (2) in the mixed solution at a bath ratio of 1:200 and react at pH 4.0 and 50°C for 5 h. After the reaction, wash with anhydrous ethanol for 5 min, then wash with deionized water for 5 min. After the reaction, dry the fabric in a 90°C oven and then equilibrate it in a constant temperature and humidity chamber (21±1°C, 65±2%) for 24 h to obtain the superhydrophilic modified nylon fabric.

[0074] Comparative Example 1

[0075] The nylon fabric is directly refined.

[0076] The performance of the superhydrophilic modified nylon fabric obtained in Example 1 and the refined nylon fabric used in Comparative Example 1 were tested. The test results are as follows:

[0077] Figure 1 The test results show the contact angles of the hydrophilic modified nylon fabric obtained in Example 1 and the nylon fabric after refining treatment in Comparative Example 1; where (a) is Comparative Example 1 and (b) is Example 1. Figure 1 It can be seen that the contact angle of the nylon fabric after refining treatment in Comparative Example 1 is 102°, while the contact angle of the superhydrophilic modified nylon fabric obtained in Example 1 is 9°. This shows that the contact angle was reduced by 90.2% after treatment using the method of the present invention. The number of hydrophilic groups (-COOH) on the fabric surface increased after modification treatment, and the K / S value of the dyed fabric increased to 5 times that of Comparative Example 1.

[0078] As shown in Table 1, after the same number of wear cycles, the abrasion resistance of the superhydrophilic modified nylon fabric increased by 0.6256%. The breaking strength decreased significantly, but still met the requirement of 150N in GB / T3923.1—2013 "Textiles - Tensile Properties of Fabrics - Part 1: Determination of Breaking Strength and Elongation at Break (Strip Method)," thus conforming to the mechanical properties of apparel fabrics.

[0079] Table 1. Properties of the fabrics from Example 1 and Comparative Example 1

[0080] example Comparative Example 1 Example 1 Contact angle / ° 102 9 K / S percentage 100％ 500％ Weight loss rate / % 1.6674 1.0418 Fracture strength / N 370 200

[0081] Comparative Example 2

[0082] The DES pretreatment and laccase grafting modification treatment in Example 1 were omitted, and only the fabric was subjected to protease hydrolysis treatment to obtain the modified nylon fabric.

[0083] The modified fabric was subjected to performance tests, and the results are as follows:

[0084] Table 2. Properties of fabrics from Example 1 and Comparative Examples 1-2.

[0085] example Comparative Example 1 Comparative Example 2 Example 1 Contact angle / ° 102 52 9

[0086] As can be seen from Tables 1 and 2, the static contact angle of the unmodified nylon fabric was 102°, while the static contact angle of the nylon fabric modified with protease reached 52°, a reduction of 49.0%. Comparing with Example 1, it can be seen that, using the same bromelain modification, the nylon fabric pretreated with DES showed a greater decrease in contact angle.

[0087] Comparative Example 3

[0088] The bromelain treatment and laccase grafting modification treatment in Example 1 were omitted. Only the nylon fabric after refining was subjected to choline chloride / oxalic acid DES pretreatment to obtain DES modified nylon fabric.

[0089] The modified fabric was subjected to performance tests, and the results are as follows:

[0090] Table 3. Properties of fabrics from Example 1 and Comparative Examples 1 and 3

[0091] example Comparative Example 1 Comparative Example 3 Example 1 Contact angle / ° 102 58 9

[0092] Table 3 shows that DES pretreatment alone significantly improves the hydrophilicity of the fabric; compared to DES pretreatment alone, the hydrophilicity of nylon fabric modified with a combination of DES, protease, and laccase is even more significantly improved. This indicates that DES pretreatment can assist the multi-enzyme system in effectively improving the hydrophilicity of the fabric surface.

[0093] Figure 2 The ATR-FTIR test results are for the nylon fabrics obtained in Comparative Examples 1 and 3. Figure 2 It can be known that 3348cm -1 The peak at 3171 cm⁻¹ is a characteristic peak of amino groups. -1 The double peak at 2894 cm⁻¹ is a characteristic peak of the primary amide group. -1 The peak at 1673 cm⁻¹ is a characteristic peak of the methylene group. -1 The peak at 1503 cm⁻¹ is the amide I band. -1 The peak at 3500–4000 cm⁻¹ corresponds to the amide II band. The characteristic peaks of nylon before and after modification did not significantly disappear or fluctuate, indicating that the functional groups of the fabric remained unchanged and the chemical composition was constant. However, nylon fabrics modified with DES showed differences in peak values ​​between 3500 and 4000 cm⁻¹. -1 A fluctuating absorption signal appeared within the band, and the absorption signal was enhanced. This band was formed by the superposition of absorption peaks of -OH groups. Furthermore, analysis of the absorption intensity of characteristic peaks showed that the intensity of the stretching vibration of -OH groups in the DES-modified nylon fabric was significantly higher than that in the unmodified nylon fabric. This is because the modified nylon fabric has more -OH groups. Therefore, it can be inferred that in addition to physically etching the fabric surface, DES also generated more -OH groups on the nylon surface. In summary, the significant improvement in the hydrophilicity of the nylon surface is due to the combined effect of physical etching and weak chemical modification by DES.

[0094] Table 4. Potential Data

[0095] PA (unmodified nylon fabric) Comparative Example 3 Bromelain (liquid) Zeta potential / mV -39.3 -38.8 -39.0

[0096] Table 4 shows that the zeta potential of the nylon fabric surface before modification was -39.3 mV, indicating a significant Coulombic repulsion between the fabric and bromelain in the buffer system, resulting in limited contact between the protease molecules and the fabric. After modification with choline chloride / oxalic acid, the surface potential of the nylon fabric changed to -38.8 mV, reducing the repulsion between the fabric and enzyme molecules, further promoting the adsorption of enzyme molecules on the fabric, and improving the hydrolysis effect of the protease.

[0097] Comparative Example 4

[0098] The laccase grafting modification treatment in Example 1 was omitted, and the nylon fabric modified by DES and protease was obtained.

[0099] The modified fabric was subjected to performance tests, and the results are as follows:

[0100] Table 5. Fabric properties of Example 1 and Comparative Examples 1 and 4

[0101] example Comparative Example 1 Comparative Example 4 Example 1 Contact angle / ° 102 22 9

[0102] As can be seen from Table 5, the combined modification of DES and protease plays a dominant role in the hydrophilic modification of nylon fabrics, reducing the surface contact angle of nylon fabrics by 78.4%.

[0103] Example 2

[0104] Adjust DES to DES1 in step (1) of Example 1. # DES 3 # DES 4 # DES 5 # DES 6 # Everything else remained the same as in Example 1, resulting in a hydrophilic modified nylon fabric.

[0105] Table 6. DES Preparation Ratio

[0106]

[0107] The obtained hydrophilic modified fabric was subjected to performance tests, and the test results are as follows:

[0108] Table 7.

[0109] example Example 1 DES1# <![CDATA[DES 3 # ]]> <![CDATA[DES 4 # ]]> <![CDATA[DES 5 # ]]> <![CDATA[DES 6 # ]]> Contact angle / ° 9 ≈0 18 25 22 25 Fracture strength / N 200 / 350 370 375 375

[0110] As can be seen from Table 7: except for nylon fabrics modified with choline chloride / oxalic acid that completely lose their mechanical properties, DES 2 # The hydrophilic modification effect is most obvious on nylon fabrics, and superhydrophilic modification can be achieved.

[0111] Example 3

[0112] The reaction time of bromelain with nylon fabric in step (2) of Example 1 was adjusted from 18h to 6h and 24h. Other parameters and conditions remained the same as in Example 1, and hydrophilic modified nylon fabric was obtained.

[0113] The obtained hydrophilic modified fabric was subjected to performance tests, and the test results are as follows:

[0114] Table 8. Contact angles of fabrics from Examples 1 and 3 and Comparative Example 1

[0115] Reaction time / h Comparative Example 1 6 24 Example 1(18) Contact angle / ° 102 38 7 9

[0116] Figure 3 This study examines the relationship between protease reaction time, hydrolysis product concentration, and enzyme activity. Initially, the concentration of free amino groups in nylon fabric hydrolyzed by BM increased rapidly with increasing reaction time. However, the increase in product concentration reached an inflection point after 18 hours. Further extending the reaction time resulted in a slower increase in free amino group concentration. This indicates that BM has a significant effect on nylon. However, because the enzyme cannot break through the highly crystalline structure of the nylon surface, its accessibility to internal amide bonds is low. As the reaction time increases, the number of hydrolyzable amide bonds on the nylon surface decreases, and the increase in free amino group concentration slows down. Figure 3 Similarly, it can be seen that the activity of BM enzyme gradually decreased over time, with the remaining enzyme activity dropping to 49.2% of the original enzyme activity at 6 hours, and reaching the inflection point of enzyme activity decrease at 18 hours, which coincides with the inflection point of free amino concentration increase. The decrease in enzyme activity also leads to a decrease in the catalytic efficiency of BM, resulting in a slower trend in the increase of hydrolysis product concentration.

[0117] As can be seen from Table 8, with the increase of protease reaction time, the contact angle of nylon fabric shows a trend of first decreasing and then leveling off. When the reaction time is 18h, the contact angle reaches the turning point, which is consistent with the trend of changes in the enzyme activity of bromelain and the concentration of hydrolysis products.

[0118] Comparative Example 5

[0119] The bath ratio in the DES modification reaction in step (1) of Example 1 was adjusted from 1:20 to 1:30, 1:40 and 1:50, while the other steps remained the same as in Example 1, to obtain hydrophilic modified nylon fabric.

[0120] The obtained hydrophilic modified fabric was subjected to performance tests, and the test results are as follows:

[0121] Table 9

[0122] Bath ratio Comparative Example 1 Example 1 1:30 1:40 1:50 Contact angle / ° 102 9 18 15 12

[0123] As can be seen from Table 9, with the increase of the liquor ratio during the DES modification process, the change in the contact angle of the nylon fabric shows a trend of first decreasing and then leveling off. When the liquor ratio is 1:20, the static contact angle of the fabric surface is the lowest.

[0124] Comparative Example 6

[0125] The temperature in the DES modification reaction in step (1) of Example 1 was adjusted from 70°C to 40°C, 50°C and 60°C, while other parameters and conditions remained the same as in Example 1, to obtain hydrophilic modified nylon fabric.

[0126] The obtained hydrophilic modified fabric was subjected to performance tests, and the test results are as follows:

[0127] Table 9. Properties of fabrics from Example 1 and Comparative Examples 1 and 6

[0128] Temperature / °C Comparative Example 1 Example 1 (70) 40 50 60 Contact angle / ° 102 9 43 33 29

[0129] As can be seen from Table 9, as the temperature increases during the DES modification process, the contact angle of the nylon fabric decreases rapidly at around 60℃. When the reaction temperature is 70℃, the static contact angle of the fabric surface is the lowest. This is because the glass transition temperature of nylon fabric is around 60℃. The higher the temperature, the more intense the movement of the nylon macromolecular chain segments, and the easier it is for DES to enter the molecular chain, resulting in a more obvious modification effect on nylon.

[0130] Example 4

[0131] The concentration of laccase in step (3) of Example 1 was adjusted from 40 mL / L to 20 mL / L, 60 mL / L, 80 mL / L, and 100 mL / L, while other parameters remained the same as in Example 1, to obtain hydrophilic modified nylon fabric.

[0132] The obtained hydrophilic modified fabric was subjected to performance tests, and the test results are as follows:

[0133] Table 10. Properties of fabrics from Examples 1 and 4 and Comparative Example 1

[0134] example Comparative Example 1 Example 1 (40 mL / L) 20mL / L 60mL / L 80mL / L 100mL / L Contact angle / ° 102 9 25 10 6 9

[0135] As shown in Table 10, in the initial stage of the reaction, the contact angle of the modified nylon fabric surface decreased with increasing laccase concentration. Further increasing the enzyme concentration gradually leveled off the contact angle change, reaching 10° at a concentration of 60 mL / L, achieving a superhydrophilic effect. This is because with increasing laccase concentration, the oxidation degree of the primary hydroxyl groups of trehalose increased, converting aldehyde groups to carboxyl groups. However, in a reaction system with low moisture content, the amide dehydration condensation reaction between carboxyl and amino groups could not be achieved, leading to a decrease in grafting rate and a weakened modification effect.

[0136] Example 5

[0137] The superhydrophilic modified nylon fabric obtained in Example 1 was first washed with anhydrous ethanol for 5 min, then washed with deionized water for 5 min, and then ultrasonically cleaned for 10 min; then it was placed in an oven at 105℃ for drying and placed in a constant temperature and humidity chamber (21±1℃, 65±2%) for equilibration for 24 h.

[0138] The hydrophilic modified nylon fabric obtained after washing was subjected to performance tests, and the test results are as follows:

[0139] Table 10. Properties of the fabrics from Examples 1 and 5

[0140] example Example 1 Example 5 Contact angle / ° 9 12

[0141] As can be seen from Table 10, the nylon fabric can still maintain good hydrophilicity after several washes, and the hydrophilic modification has good durability.

[0142] The embodiments provided above are not intended to limit the scope of the invention, nor are the described steps intended to limit the order of execution. Any obvious modifications made to the invention by those skilled in the art based on existing common knowledge also fall within the scope of protection defined in the claims of this invention.

Claims

1. A method for super-hydrophilic modification of polyamide fabric based on deep eutectic solvent (DES) combined with multiple enzymes, characterized in that, The method includes the following steps: (1) DES preprocessing The refined nylon fabric is completely immersed in DES for pretreatment, then removed, washed, and dried to obtain the pretreated modified nylon fabric. The DES is composed of choline chloride, citric acid and water, with a molar ratio of choline chloride, citric acid and water of 1:2:2.

62. The pretreatment temperature is 70℃ and the liquor ratio is 1:20; (2) Protease hydrolysis modification The protease and buffer solution were mixed evenly to obtain the protease-modified solution. Then, the pretreated and modified nylon fabric obtained in step (1) was immersed in the protease modification solution for reaction; after the reaction was completed, it was washed, dried and balanced to obtain the protease-modified nylon fabric. The protease is pineapple stem protease, and the enzyme activity of pineapple stem protease is 23 U / mg; The concentration of protease in the protease-modified solution was 32 g / L; The reaction conditions were: pH 6.0, 50 °C for 18 h. (3) Laccase / TEMPO grafting modification Laccase, TEMPO, trehalose, and buffer solution were mixed evenly to obtain a mixed solution; then the nylon fabric modified by the protease obtained in step (2) was immersed in the mixed solution for reaction; after the reaction was completed, it was washed, dried, and equilibrated to obtain the superhydrophilic modified nylon fabric. The reaction conditions were: pH 4.0, 50 °C for 5 h. The concentration of laccase in the mixed solution is 60-100 mL / L, the concentration of TEMPO is 0.1-5 g / L, the concentration of trehalose is 5-20 g / L, and the pH of the buffer solution is 3.5-5.5; the enzyme activity of laccase is 37-45 U / mL.

2. The method of claim 1, wherein, In step (2), the buffer solution is phosphate buffer.

3. The superhydrophilic modified nylon fabric prepared by the method of claim 1 or 2.

4. The application of the superhydrophilic modified nylon fabric according to claim 3 in the preparation of functional textiles.

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