Protective fabric with flame-retardant and antibacterial functions and preparation method thereof

Abstract

The invention provides a protective fabric with flame-retardant and antibacterial functions and a preparation method thereof.The protective fabric comprises a flame-retardant fabric layer and a flame-retardant aerogel layer from the inner layer to the surface layer, the flame-retardant fabric layer is made of chitosan modified polyester fabric, and the flame-retardant aerogel layer is made of PVA / MXene aerogel. Chitosan spinning solutions of different concentrations are adopted to coat polyester yarns in a layered electrostatic spinning mode, a chitosan modified polyester yarn layer of a gradient structure is formed, the fabric is endowed with excellent antibacterial and heat insulation performance, after the fabric makes contact with a fire source, a protection barrier is formed through the synergistic effect of chitosan, phytic acid and MXene, combustible gas is diluted, and the high-flame-retardant effect is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of protective fabrics, in particular to a protective fabric with flame-retardant and antibacterial functions and a preparation method thereof. BACKGROUND

[0002] With the development of social economy and the improvement of living consumption level, consumers' demand for wearing fabrics has upgraded to multifunctional and high-performance. Polyester fabric has the characteristics of high strength and high modulus, light resistance, wear resistance, stable physical and chemical properties, easy processing, etc., and is an important material for home wear fabric. However, the limiting oxygen index of polyester fabric is only about 21%, which is in the category of flammable, and it is easy to melt and drip and release a large amount of heat during combustion, which poses a serious safety hazard. Therefore, the study of flame-retardant polyester fabric has become an important direction to expand its application performance.

[0003] At present, the most common method for improving the flame retardance of polyester fabric is to use flame retardants for surface coating. This method is low in cost and simple in process. However, the surface coating has poor durability and is easy to be lost during washing, which cannot achieve long-term protection. In addition, the poor moisture absorption and air permeability of polyester fabric itself, and the coating of flame retardants often reduce the wearing comfort. Traditional flame-retardant modification has single function and poor performance in antibacterial and heat insulation. In addition, the structure design of existing protective fabrics is mostly simple superposition, and there is lack of synergistic effect between functional layers, which makes it difficult to fully exert the comprehensive performance of the material. Therefore, there is an urgent need for a multifunctional polyester protective fabric that is environmentally friendly, durable and has synergistic effect between components. SUMMARY

[0004] The technical problem to be solved is to provide a protective fabric with flame-retardant and antibacterial functions and a preparation method thereof. The polyester yarn is coated with a gradient chitosan electrospun film, and then woven to obtain a protective fabric with antibacterial function and high flame-retardant performance.

[0005] Technical scheme: A protective fabric with flame-retardant and antibacterial functions comprises a flame-retardant fabric layer and a flame-retardant aerogel layer from the inner layer to the surface layer. The flame-retardant fabric layer is a chitosan modified polyester fabric, and the flame-retardant aerogel layer is a PVA / MXene aerogel. The flame-retardant fabric layer is made of a gradient chitosan electrospun film coated polyester yarn and woven into a plain weave.

[0006] Preferably, the gradient chitosan electrospun film coated polyester yarn has a porosity that decreases from the inside to the outside of the polyester yarn.

[0007] The above-mentioned preparation method of the chitosan modified polyester fabric comprises the following steps: S11. treating the surface of the polyester yarn with NaOH; S12. Dissolve chitosan of different qualities in the same mass of acetic acid solution to prepare three groups of spinning solutions with different concentrations, which are respectively ABC groups, the concentration of chitosan in group A is 2-4wt%, the concentration of chitosan in group B is 6-8wt%, and the concentration of chitosan in group C is 10-12wt%, wherein, in the solution of group C, phytic acid is added and stirred uniformly, and the mass ratio of phytic acid to chitosan is 1:1-4; S13. The spinning solution prepared in step S12 is electrospun by using an auxiliary electrode self-polymerization method to coat the polyester yarn prepared in step S11, and the spinning sequence from inside to outside is group A, group B and group C, thereby forming a chitosan nanofiber layer with a gradient structure; S14. The collected chitosan modified polyester yarn is dried in an oven to remove excess acetic acid solution; S15. The dried chitosan modified polyester yarn is woven into a fabric, and the fabric structure of the fabric is plain weave.

[0008] The above-mentioned method for preparing a functional fabric comprises the following steps: S1. Dissolve LiF in an HCl solution to obtain a mixed solution, then add Ti3AlC2 to the mixed solution for etching, collect the precipitate after etching, and freeze-dry to obtain MXene nanosheets; S2. Prepare a PVA solution with a concentration of 4-6wt%, add MXene nanosheets to the solution at a ratio of 1:1-10 to PVA, and disperse under the assistance of high-power ultrasonic waves; S3. Add a silane coupling agent dropwise to the uniformly dispersed solution, and obtain a PVA / MXene aerogel precursor hydrogel after uniform stirring; S4. Coat the hydrogel prepared in step S3 on the surface of the fabric, pre-freeze after standing and aging, and then freeze-dry to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0009] Preferably, the linear density of the polyester yarn in step S11 is 70-80D, and the number of fiber filaments is 36-48f.

[0010] Preferably, in step S13, the spinning voltage of electrospinning is 15-20kV, the pushing speed is 0.3-1.0mL / h, the collection distance is 10-20cm, the collection speed is 50-200rpm, the temperature is 22-25℃, and the relative humidity is 40-60%.

[0011] Preferably, in step S15, the warp density of the plain weave structure is 40-60 threads / cm, and the weft density is 30-50 threads / cm.

[0012] Preferably, the amount of LiF added in step S1 is 3-3.2 g, the volume of HCl solution is 40-45 mL, the molar concentration of HCl solution is 9-12 mol / L, the amount of Ti3AlC2 added is 2-2.5 g, the etching temperature is 40-45℃, and the etching time is 24-48 h.

[0013] Preferably, in step S2, the ultrasonic frequency for high-power ultrasonic-assisted dispersion is 40-50 kHz, and the power is 300-400 W; in step S4, the pre-freezing temperature is -80 to -90℃, the freeze-drying temperature is -50 to -60℃, and the freeze-drying time is 36-48 h.

[0014] Preferably, in step S3, the silane coupling agent is one or more of methyltrimethoxysilane, aminopropyltriethoxysilane, and vinyltrimethoxysilane, and the amount of silane coupling agent added is 0.1-1 wt% of the solution mass.

[0015] Beneficial effects: The protective fabric with flame-retardant and antibacterial functions has the following advantages: The protective fabric of the present application is woven by modifying the polyester yarn with chitosan and phytic acid electrospinning, and a PVA / MXene aerogel flame-retardant layer is compounded on the surface layer. When heated, chitosan and phytic acid decompose cooperatively to generate free radicals, which capture active free radicals generated in the flame gas phase to inhibit the chain combustion reaction of combustible gas and dilute the combustible components in the flame zone. At the same time, a carbon layer is formed on the surface of the polyester. In a high-temperature environment, MXene in the aerogel layer is oxidized to form a TiO2 shielding layer, which forms a ceramic dense barrier with the decomposition products of phytic acid, further blocking the conduction of heat and oxygen to achieve high flame-retardant effect.

[0016] The present application adopts the auxiliary electrode self-polymerization electrospinning technology to gradiently coat the chitosan nanofiber on the surface-treated polyester yarn. By controlling the concentration of chitosan spinning solution, the chitosan nanofiber is electrospun in stages from low concentration to high concentration, so that a coating layer with a pore gradient structure is formed on the surface of the polyester yarn from the inside to the outside. The inner layer is formed by low-concentration chitosan spinning solution, the nanofiber diameter is small, and the porosity is high, which is beneficial to heat insulation. The outer layer is formed by high-concentration chitosan spinning solution, the fiber diameter is thick, the arrangement is more dense and continuous, and the integrity and mechanical stability of the surface layer of the yarn are enhanced. Chitosan has natural antibacterial properties. After being electrospun into a nanofiber structure with high specific surface area, the contact area with microorganisms increases, which can effectively inhibit the adhesion and reproduction of bacteria, and endow the polyester yarn with excellent and durable antibacterial properties.

[0017] The silane coupling agent is introduced in the preparation process of the aerogel layer, and after hydrolysis, the intermediate containing active silanol groups is condensed with PVA and the -OH on the surface of MXene to construct a stable organic-inorganic synergistic cross-linking network structure, which effectively supports the three-dimensional skeleton structure during the drying process of the aerogel to improve the anti-shrinkage and anti-collapse ability, and at the same time enhances the flexibility and mechanical strength of the aerogel, so that it has excellent heat insulation and flame retardant properties, and good bending and fitting properties, which significantly improves the comfort and durability of the protective fabric during wearing. DETAILED DESCRIPTION

[0018] The application will be further described in conjunction with the following examples, which are illustrative of the application but not limited to the following examples: Example 1

[0019] A preparation method of a protective fabric with flame-retardant and antibacterial functions, comprising the following steps: S1. Dissolve 3g of LiF in 45mL of 12mol / L HCl solution, stir at room temperature for 20min to obtain a mixed solution, then add 2.5g of Ti3AlC2 to the LiF / HCl mixed solution, stir at 45℃ for 24h, collect the precipitate and wash to neutral, freeze-dry to obtain MXene nanosheets; S2. Prepare a PVA solution with a concentration of 4wt%, add MXene nanosheets to the solution, the ratio of MXene nanosheets to PVA is 1:10, and disperse under the assistance of high-power ultrasound with a ultrasonic frequency of 50kHz and a power of 300W; S3. Add methyltrimethoxysilane dropwise in the uniformly dispersed solution, the addition amount is 0.5wt% of the mass of the solution, and after stirring uniformly, a PVA / MXene aerogel precursor hydrogel is obtained; S4. Coating the hydrogel prepared in step S3 on the surface of the chitosan modified polyester fabric, standing for 1h, then pre-freezing at-90℃ for 1h, and freeze-drying at-50℃ for 48h to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0020] Preparation of the chitosan modified polyester fabric: S11. Place the polyester yarn with a specification of 80D / 48f in a NaOH solution with a concentration of 5wt%, the bath ratio is 1:50, continuously stir at a low speed in a constant temperature water bath at 60℃ for 30min, after treatment, wash with water several times to remove residual alkali and dry; S12. Dissolve chitosan of different qualities in the same mass of 3wt% acetic acid solution to prepare three groups of spinning solutions with different concentrations, which are respectively ABC groups, the chitosan concentration of group A is 2.5wt%, the chitosan concentration of group B is 6wt%, and the chitosan concentration of group C is 10wt%, wherein, in the solution of group C, phytic acid is added and stirred uniformly, and the mass ratio of phytic acid to chitosan is 1:4; S13. The three groups of chitosan spinning solutions in step S12 are respectively electrospun by auxiliary electrode self-polymerization method, and are coated on the polyester yarn treated in step S11 in turn, and the spinning sequence from inside to outside is group A, group B and group C in turn, to construct a gradient chitosan nanofiber layer with decreasing porosity from inside to outside. During the electrospinning process, the polyester yarn is driven by the motor to rotate at high speed and move along the axial direction, the electrospinning of the spinning solution injector is perpendicular to the movement direction of the polyester, the applied voltage is 18kV, the pushing speed of the spinning solution is set to 0.6mL / h, the collection distance between the injection needle and the collection roller is 15cm, the rotation speed of the collection roller is 60rmp, and the environmental temperature is 23℃, and the relative humidity is controlled at 60%; S14. The collected chitosan modified polyester yarn is dried in a 50℃ oven to remove excess acetic acid solution; S15. The dried chitosan modified polyester yarn is woven into a fabric, and the fabric structure of the fabric is plain weave, the warp density is 40 roots / cm, and the weft density is 50 roots / cm.

[0021] Example 2

[0022] A method for preparing a protective fabric with flame-retardant and antibacterial functions, comprising the following steps: S1. Dissolve 3.2g of LiF in 40mL of 9mol / L HCl solution, stir for 20min at room temperature to obtain a mixed solution, then add 2g of Ti3AlC2 to the LiF / HCl mixed solution, stir at 40℃ for 48h, wash the precipitate to neutral, and freeze-dry to obtain MXene nanosheets; S2. Prepare a 4wt% PVA solution, add MXene nanosheets to the solution, and disperse under the assistance of high-power ultrasound with a frequency of 50kHz and a power of 300W; S3. Add methyltrimethoxysilane dropwise in the uniformly dispersed solution, and the addition amount is 1wt% of the mass of the solution, and after stirring uniformly, a PVA / MXene aerogel precursor hydrogel is obtained; S4. The hydrogel prepared in step S3 is coated on the surface of the chitosan-modified polyester fabric, and after standing and aging for 1 h, it is pre-frozen at -80℃ for 1 h, and then freeze-dried at -60℃ for 36 h to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0023] Preparation of the chitosan-modified polyester fabric: S11. Polyester yarn with a specification of 70D / 36f is placed in a NaOH solution with a concentration of 5wt%, with a bath ratio of 1:50, and is continuously stirred at a low speed in a constant-temperature water bath at 60℃ for 30 min. After the treatment is completed, the residual alkali solution is removed by washing multiple times and the yarn is dried; S12. Chitosan with different masses is dissolved in 3wt% acetic acid solutions with the same mass to prepare three groups of spinning solutions with different concentrations, which are referred to as groups A, B and C. The chitosan concentration in group A is 3.5wt%, the chitosan concentration in group B is 6wt%, and the chitosan concentration in group C is 10wt%. In the solution in group C, phytic acid is added and stirred uniformly, and the mass ratio of phytic acid to chitosan is 1:3; S13. The three groups of chitosan spinning solutions in step S12 are electrospun by using an auxiliary electrode self-polymerization method, and are coated on the polyester yarn treated in step S11 in sequence. The spinning sequence from the inside to the outside is group A, group B and group C in sequence, thereby constructing a gradient chitosan nanofiber layer with a porosity that decreases in sequence from the inside to the outside. During the electrospinning process, the polyester yarn is rotated at a high speed and moves along the axial direction under the drive of a motor, and a spinning solution injector is perpendicular to the movement direction of the polyester yarn to electrospin the spinning solution. The applied voltage is 18kV, the pushing speed of the spinning solution is set to 0.6mL / h, the collection distance between the injection needle and the collection roller is 15cm, the rotation speed of the collection roller is 60rmp, and the environmental temperature is 23℃ with a relative humidity controlled at 60%; S14. The collected chitosan-modified polyester yarn is dried in a 50℃ oven to remove the excess acetic acid solution; S15. The dried chitosan-modified polyester yarn is woven into a fabric. The fabric has a plain weave structure, with a warp density of 60 roots / cm and a weft density of 30 roots / cm.

[0024] Example 3

[0025] A method for preparing a protective fabric with both flame-retardant and antibacterial functions, comprising the following steps: S1. 3.2g of LiF is dissolved in 40mL of 9mol / L HCl solution, stirred at room temperature for 20min to obtain a mixed solution, then 2g of Ti3AlC2 is added to the LiF / HCl mixed solution, stirred at 45℃ for 24h, the precipitate is washed to neutral, and freeze-dried to obtain MXene nanosheets; S2. A solution with a concentration of 4wt% PVA was prepared, and MXene nanosheets were added to the solution, with a ratio of MXene nanosheets to PVA of 1:10. The solution was dispersed under the assistance of high-power ultrasound with a frequency of 50 kHz and a power of 300 W; S3. Methyltrimethoxysilane was added dropwise to the uniformly dispersed solution, with an addition amount of 0.1wt% of the mass of the solution. After stirring uniformly, a PVA / MXene aerogel precursor hydrogel was obtained; S4. The hydrogel prepared in step S3 was coated on the surface of the chitosan-modified polyester fabric. After standing for 1h, pre-freezing was performed at -80℃ for 1h. After freeze-drying at -60℃ for 36h, a flame-retardant aerogel layer with a porous three-dimensional network structure was formed on the surface of the fabric, and a protective fabric was obtained.

[0026] The preparation of the chitosan-modified polyester fabric is as follows: S11. Polyester yarn with a specification of 75D / 36f was placed in a NaOH solution with a concentration of 5wt%, with a bath ratio of 1:50. The treatment was performed in a constant-temperature water bath at 60℃ for 30min with continuous low-speed stirring. After the treatment, the residual alkali was removed by multiple water washes, and the yarn was dried. S12. Chitosan with different masses was dissolved in the same mass of a 3wt% acetic acid solution to prepare three groups of spinning solutions with different concentrations. The spinning solutions were respectively groups A, B, and C. The chitosan concentration of group A was 4wt%, the chitosan concentration of group B was 8wt%, and the chitosan concentration of group C was 12wt%. In the solution of group C, phytic acid was added and stirred uniformly, with a mass ratio of phytic acid to chitosan of 1:3. S13. The three groups of chitosan spinning solutions in step S12 were respectively electrospun using the auxiliary electrode self-polymerization method, and were coated on the polyester yarn treated in step S11. The spinning sequence from the inside to the outside was group A, group B, and group C. A gradient chitosan nanofiber layer with a decreasing porosity from the inside to the outside was constructed. During the electrospinning process, the polyester yarn was rotated at a high speed and moved along the axial direction under the drive of the motor. The electrospinning of the spinning solution was performed vertically to the movement direction of the polyester yarn. The applied voltage was 18kV, the pushing speed of the spinning solution was set to 0.6mL / h, the collection distance between the injection needle and the collection roller was 15cm, the rotation speed of the collection roller was 60rmp, and the environmental temperature was 23℃ with a relative humidity of 60%. S14. The collected chitosan-modified polyester yarn was dried in a 50℃ oven to remove excess acetic acid solution. S15. The dried chitosan-modified polyester yarn was woven into a fabric. The fabric organization structure of the fabric was plain weave, with a warp density of 60 roots / cm and a weft density of 50 roots / cm.

[0027] Example 4

[0028] A method for preparing a protective fabric with both flame-retardant and antibacterial functions, comprising the following steps: S1. Dissolve 3.2 g of LiF in 40 mL of 9 mol / L HCl solution and stir at room temperature for 20 min to obtain a mixed solution, then add 2 g of Ti3AlC2 to the LiF / HCl mixed solution, stir and react at 45℃ for 24 h, collect the precipitate, wash to neutral, freeze-dry to obtain MXene nanosheets; S2. Prepare a PVA solution with a concentration of 4wt%, add MXene nanosheets to the solution, the ratio of MXene nanosheets to PVA is 1:5, and disperse under the assistance of high-power ultrasound with a ultrasonic frequency of 50 kHz and a power of 300 W; S3. Add methyltrimethoxysilane to the uniformly dispersed solution, the addition amount is 0.5wt% of the mass of the solution, and after stirring uniformly, a PVA / MXene aerogel precursor hydrogel is obtained; S4. Coating the hydrogel prepared in step S3 on the surface of the chitosan modified polyester fabric, standing for 1h, pre-freezing for 1h in a-80℃ environment, and freeze-drying at-60℃ for 36h to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0029] The preparation of the chitosan modified polyester fabric is as follows: S11. Put the polyester yarn with a specification of 75D / 36f into a NaOH solution with a concentration of 5wt%, the bath ratio is 1:50, and continuously stir at a low speed in a 60℃ constant temperature water bath for 30 min, then wash the residual alkali solution multiple times and dry; S12. Dissolve different amounts of chitosan in the same amount of 3wt% acetic acid solution to prepare three groups of spinning solutions with different concentrations, the spinning solutions are respectively ABC groups, the chitosan concentration of group A is 2.5wt%, the chitosan concentration of group B is 6wt%, and the chitosan concentration of group C is 10wt%, wherein, in the solution of group C, add phytic acid and stir uniformly, the mass ratio of phytic acid to chitosan is 1:3; S13. Electrospun the three groups of chitosan spinning solutions in step S12 by auxiliary electrode self-polymerization method, and coated on the polyester yarn treated in step S11 in turn, the spinning sequence from inside to outside is group A, group B, and group C in turn, to construct a gradient chitosan nanofiber layer with decreasing porosity from inside to outside, during the electrospinning process, the polyester yarn rotates at a high speed under the drive of the motor and moves along the axial direction, the electrospinning of the spinning solution injector is perpendicular to the movement direction of the polyester, the applied voltage is 18kV, the pushing speed of the spinning solution is set to 0.6mL / h, the collection distance between the injection needle and the collection roller is 15cm, the rotation speed of the collection roller is 60rmp, and the environmental temperature is 23℃, and the relative humidity is controlled at 60%; S14. The collected chitosan modified polyester yarn is placed in a 50℃ oven to dry, removing excess acetic acid solution; S15. The dried chitosan modified polyester yarn is woven into a fabric, and the fabric has a plain weave structure with a warp density of 55 threads / cm and a weft density of 45 threads / cm.

[0030] Example 5

[0031] A method for preparing a protective fabric with flame-retardant and antibacterial functions, comprising the following steps: S1. Dissolve 3.2 g of LiF in 40 mL of 9 mol / L HCl solution and stir at room temperature for 20 min to obtain a mixed solution, then add 2 g of Ti3AlC2 to the LiF / HCl mixed solution, stir at 45℃ for 24 h, collect the precipitate, wash to neutral, and freeze-dry to obtain MXene nanosheets; S2. Prepare a 6wt% PVA solution, add MXene nanosheets to the solution, and disperse the MXene nanosheets and PVA at a ratio of 1:10 under the assistance of high-power ultrasound at a frequency of 50 kHz and a power of 300 W; S3. Add methyltrimethoxysilane dropwise to the uniformly dispersed solution at an amount of 0.5wt% of the solution mass, and obtain a PVA / MXene aerogel precursor hydrogel after uniform stirring; S4. Coat the hydrogel prepared in step S3 on the surface of the chitosan modified polyester fabric, stand for 1 h, then pre-freeze at -80℃ for 1 h, and freeze-dry at -60℃ for 36 h to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0032] wherein the chitosan modified polyester fabric is prepared as follows: S11. Place polyester yarn with a specification of 75D / 36f in a 5wt% NaOH solution, with a bath ratio of 1:50, and continuously stir at a low speed in a 60℃ constant temperature water bath for 30 min, then wash with water multiple times to remove residual alkali and dry; S12. Dissolve chitosan with different masses in 3wt% acetic acid solutions with the same mass to prepare three groups of spinning solutions with different concentrations, namely groups A, B and C, wherein the chitosan concentration of group A is 2.5wt%, the chitosan concentration of group B is 6wt%, and the chitosan concentration of group C is 10wt%; in the solution of group C, add phytic acid and stir uniformly, and the mass ratio of phytic acid to chitosan is 1:3; S13. The three groups of chitosan spinning solution in step S12 are respectively electrospun by auxiliary electrode self-polymerization method, and are coated on the polyester yarn treated in step S11 in turn, and the spinning sequence from inside to outside is A group, B group and C group in turn, to construct a gradient chitosan nanofiber layer with decreasing porosity from inside to outside. During the electrospinning process, the polyester yarn is driven by the motor to rotate at high speed and move along the axial direction, the electrospinning of the spinning solution injector is perpendicular to the movement direction of the polyester, the applied voltage is 18kV, the spinning solution injection speed is set to 0.6mL / h, the collection distance between the injection needle and the collection roller is 15cm, the collection roller rotating speed is 60rmp, and the environmental temperature is 23℃ with the relative humidity controlled at 60%; S14. The collected chitosan modified polyester yarn is dried in a 50℃ oven to remove excess acetic acid solution; S15. The dried chitosan modified polyester yarn is woven into a fabric, and the fabric structure of the fabric is plain weave with a warp density of 55 / cm and a weft density of 45 / cm.

[0033] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the chitosan electrospun film coated on the polyester yarn has no gradient; A preparation method of a protective fabric with flame-retardant and antibacterial functions, comprising the following steps: S1. Dissolve 3.2g of LiF in 40mL of 9mol / L HCl solution, stir at room temperature for 20min to obtain a mixed solution, then add 2g of Ti3AlC2 to the LiF / HCl mixed solution, stir at 45℃ for 24h, collect the precipitate and wash to neutral, freeze-dry to obtain MXene nanosheets; S2. Prepare a PVA solution with a concentration of 4wt%, add MXene nanosheets to the solution, and the ratio of MXene nanosheets to PVA is 1:10, disperse under the assistance of high-power ultrasound with a ultrasonic frequency of 50kHz and a power of 300W; S3. Add methyltrimethoxysilane to the uniformly dispersed solution, the addition amount is 0.5wt% of the mass of the solution, and after stirring uniformly, a PVA / MXene aerogel precursor hydrogel is obtained; S4. The hydrogel prepared in step S3 is coated on the surface of the chitosan modified polyester fabric, and after standing for 1h, it is pre-frozen at-80℃ for 1h, and then freeze-dried at-60℃ for 36h to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0034] The preparation of the chitosan modified polyester fabric is as follows: S11. Place the 75D / 36f polyester yarn in a 5wt% NaOH solution with a bath ratio of 1:50, and continuously stir at low speed in a 60℃ constant temperature water bath for 30 minutes. After treatment, wash with water several times to remove residual alkali and dry. S12. Dissolve the same chitosan in the same mass of 3wt% acetic acid solution to prepare two groups of spinning solutions with a chitosan concentration of 10wt%. The spinning solutions are group A and group C, respectively. Group A does not add other components. Phytic acid is added to the solution of group C and stirred evenly. The mass ratio of phytic acid to chitosan is 1:4. S13. The two groups of chitosan spinning solutions from step S12 are electrospun using the auxiliary electrode self-polymerization method, and then sequentially coated onto the polyester yarn treated in step S11. The spinning order from the inside to the outside is group A and group C. The applied voltage is 18kV, the spinning solution feed speed is set to 0.6mL / h, the collection distance between the jet needle and the collecting roller is 15cm, the collecting roller speed is 60rpm, the ambient temperature is 23℃, and the relative humidity is controlled at 60%. S14. Place the collected chitosan-modified polyester yarn in a 50°C oven to dry and remove excess acetic acid solution; S15. The dried chitosan-modified polyester yarn is woven into a fabric, wherein the fabric structure is plain weave, with a warp density of 55 threads / cm and a weft density of 45 threads / cm.

[0035] Comparative Example 2 The difference between Comparative Example 2 and Example 4 is that the chitosan attachment methods are different; A method for preparing a protective fabric with both flame-retardant and antibacterial functions includes the following steps: S1. Dissolve 3.2 g of LiF in 40 mL of 9 mol / L HCl solution and stir for 20 min at room temperature to obtain a mixed solution. Then add 2 g of Ti3AlC2 to the LiF / HCl mixed solution and stir at 45 °C for 24 h. Collect the precipitate, wash until neutral, and freeze-dry to obtain MXene nanosheets. S2. Prepare a 4wt% PVA solution, add MXene nanosheets to the solution, the ratio of MXene nanosheets to PVA is 1:5, and disperse under high-power ultrasonic assistance at a frequency of 50kHz and a power of 300W. S3. Add methyltrimethoxysilane dropwise to a uniformly dispersed solution at a concentration of 0.5 wt% of the solution mass, and stir until homogeneous to obtain a PVA / MXene aerogel precursor hydrogel. S4. The hydrogel prepared in step S3 is coated on the surface of the chitosan-modified polyester fabric, and after standing for 1 h, pre-freezing is performed at -80℃ for 1 h, and then freeze-drying is performed at -60℃ for 36 h to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0036] The chitosan-modified polyester fabric is prepared as follows: S11. Polyester yarn with a specification of 75D / 36f is placed in a NaOH solution with a concentration of 5wt%, and the bath ratio is 1:50. The treatment is performed in a constant-temperature water bath at 60℃ for 30 min with continuous low-speed stirring. After the treatment, the residual alkali solution is removed by multiple water washing, and then the yarn is dried. S12. Different amounts of chitosan are dissolved in the same amount of 3wt% acetic acid solution to prepare three groups of solutions with different concentrations. The solutions are respectively denoted as groups A, B and C. The chitosan concentration of group A is 2.5wt%, the chitosan concentration of group B is 6wt%, and the chitosan concentration of group C is 10wt%. In the solution of group C, phytic acid is added and stirred uniformly, and the mass ratio of phytic acid to chitosan is 1:3. S13. The polyester yarn obtained in step S11 is sequentially immersed in the three groups of chitosan solutions in step S12, and the immersion is performed at room temperature for 15 min. After taking out, the yarn is gently squeezed to remove excess liquid, and then dried in an oven at 60℃ to obtain chitosan-impregnated polyester yarn.

[0037] S14. The dried chitosan-impregnated polyester yarn is woven into a fabric. The fabric has a plain weave structure, and the warp density is 55 threads / cm and the weft density is 45 threads / cm.

[0038] Comparative Example 3 The difference between Comparative Example 3 and Example 4 is that the flame-retardant aerogel layer does not contain MXene. A method for preparing a protective fabric with both flame-retardant and antibacterial functions, comprising the following steps: S1. A PVA solution with a concentration of 4wt% is prepared, and methyltrimethoxysilane is added dropwise at an amount of 0.5wt% of the solution mass. After stirring uniformly, a PVA aerogel precursor hydrogel is obtained. S2. The hydrogel prepared in step S3 is coated on the surface of the chitosan-modified polyester fabric, and after standing for 1 h, pre-freezing is performed at -80℃ for 1 h, and then freeze-drying is performed at -60℃ for 36 h to form a flame-retardant aerogel layer with a porous three-dimensional network structure on the surface of the fabric, thereby obtaining a protective fabric.

[0039] The chitosan-modified polyester fabric is prepared as follows: S11. Place the 75D / 36f polyester yarn in a 5wt% NaOH solution with a bath ratio of 1:50, and continuously stir at low speed in a 60℃ constant temperature water bath for 30 minutes. After treatment, wash with water several times to remove residual alkali and dry. S12. Different masses of chitosan were dissolved in the same mass of 3wt% acetic acid solution to prepare three groups of solutions with different concentrations, namely A, B, and C. Group A had a chitosan concentration of 2.5wt%, Group B had a chitosan concentration of 6wt%, and Group C had a chitosan concentration of 10wt%. Phytic acid was added to the Group C solution and stirred evenly. The mass ratio of phytic acid to chitosan was 1:3. S13. The three chitosan spinning solutions from step S12 are electrospun using the auxiliary electrode self-polymerization method, and sequentially coated onto the polyester yarn treated in step S11. The spinning order from the inside to the outside is group A, group B, and group C, constructing a gradient chitosan nanofiber layer with decreasing porosity from the inside to the outside. During the electrospinning process, the polyester yarn rotates at high speed and moves along the axial direction under the drive of the motor. The spinning solution injector is perpendicular to the polyester movement direction for electrospinning. The applied voltage is 18kV, the spinning solution propulsion speed is set to 0.6mL / h, the collection distance between the injection needle and the collection roller is 15cm, the collection roller speed is 60rpm, the ambient temperature is 23℃, and the relative humidity is controlled at 60%. S14. Place the collected chitosan-modified polyester yarn in a 50°C oven to dry and remove excess acetic acid solution; S15. The dried chitosan-modified polyester yarn is woven into a fabric, wherein the fabric structure is plain weave, with a warp density of 55 threads / cm and a weft density of 45 threads / cm.

[0040] Comparative Example 4 The difference between Comparative Example 4 and Example 4 is that the polyester fabric was not modified with chitosan; A method for preparing a protective fabric with both flame-retardant and antibacterial functions includes the following steps: S1. Dissolve 3.2 g of LiF in 40 mL of 9 mol / L HCl solution and stir for 20 min at room temperature to obtain a mixed solution. The solution was prepared by adding 2g of Ti3AlC2 to a mixed solution of LiF / HCl, stirring at 40℃ for 48h, collecting the precipitate, washing it until neutral, and freeze-drying it to obtain MXene nanosheets. S2. Prepare a 4wt% PVA solution, add MXene nanosheets to the solution, the ratio of MXene nanosheets to PVA is 1:5, and disperse under high-power ultrasonic assistance at a frequency of 50kHz and a power of 300W. S3. Add vinyltrimethoxysilane dropwise in the uniformly dispersed solution, the amount of addition is 0.5wt% of the mass of the solution, and after stirring uniformly, a PVA / MXene aerogel precursor hydrogel is obtained; S4. The hydrogel prepared in step S3 is coated on the surface of the chitosan-modified polyester fabric, and after standing for 1h, pre-freezing for 1h in an environment of-80℃, and freeze-drying for 36h at-60℃, a flame-retardant aerogel layer with a porous three-dimensional network structure is formed on the surface of the fabric, and a protective fabric is obtained.

[0041] The polyester fabric is prepared as follows: S11. The polyester yarn with a specification of 75D / 36f is placed in a NaOH solution with a concentration of 5wt%, the bath ratio is 1:50, and the treatment is carried out in a constant temperature water bath at 60℃ for 30min with continuous low-speed stirring, and after the treatment is completed, the residual alkali is removed by washing multiple times and the yarn is dried; S12. The dried chitosan-modified polyester yarn is woven into a fabric, and the fabric structure of the fabric is plain weave, the warp density is 55 roots / cm, and the weft density is 45 roots / cm.

[0042] Comparative Example 5 The difference between Comparative Example 5 and Example 4 is that the protective fabric does not have a flame-retardant aerogel layer; A method for preparing a protective fabric with both flame-retardant and antibacterial functions, comprising the following steps: S11. The polyester yarn with a specification of 75D / 36f is placed in a NaOH solution with a concentration of 5wt%, the bath ratio is 1:50, and the treatment is carried out in a constant temperature water bath at 60℃ for 30min with continuous low-speed stirring, and after the treatment is completed, the residual alkali is removed by washing multiple times and the yarn is dried; S12. Chitosan with different masses is dissolved in 3wt% acetic acid solutions with the same mass to prepare three groups of spinning solutions with different concentrations, and the spinning solutions are respectively ABC groups, the chitosan concentration of group A is 2.5wt%, the chitosan concentration of group B is 6wt%, and the chitosan concentration of group C is 10wt%, wherein, in the solution of group C, phytic acid is added and stirred uniformly, and the mass ratio of phytic acid to chitosan is 1:3; S13. The three groups of chitosan spinning solutions in step S12 are respectively electrospun by auxiliary electrode self-polymerization method, and are coated on the polyester yarn treated in step S11 in sequence, and the spinning sequence from inside to outside is group A, group B, and group C in sequence, thereby constructing a gradient chitosan nanofiber layer with decreasing porosity from inside to outside, and in the electrospinning process, the polyester yarn rotates at high speed under the drive of the motor and moves along the axial direction, the electrospinning of the spinning solution injector is perpendicular to the movement direction of the polyester, the applied voltage is 18kV, the pushing speed of the spinning solution is set to 0.6mL / h, the collection distance between the spraying needle and the collection roller is 15cm, the rotation speed of the collection roller is 60rmp, and the environmental temperature is 23℃, and the relative humidity is controlled at 60%. S14. The collected chitosan modified polyester yarn is dried in a 50℃ oven to remove excess acetic acid solution; S15. The dried chitosan modified polyester yarn is woven into a fabric, and the fabric has a plain weave structure with a warp density of 55 threads / cm and a weft density of 45 threads / cm.

[0043] Table 1 Porosity test and thermal conductivity test of electrospun membrane

[0044] The present application forms a high-porosity nanofiber structure on the surface of the polyester yarn by electrospinning, effectively inhibits heat convection and heat conduction, and constructs a chitosan nanofiber layer with decreasing porosity from the inside to the outside through the concentration gradient of the spinning solution. The gradient structure further delays heat transfer, forms multiple thermal resistance barriers, and significantly improves the thermal insulation performance of the fabric.

[0045] Table 2 Washable antibacterial test

[0046] The present application constructs a chitosan nanofiber crosslinked network by electrospinning method, improves the fixation and stability of the chitosan antibacterial layer on the surface of the fabric, and realizes long-term maintenance of antibacterial activity. Compared with the fabric treated by traditional immersion method, the fabric modified by electrospinning method has good antibacterial rate retention after multiple washing, which shows that the present application has significant advantages in washable antibacterial aspect.

[0047] Table 3 Flame retardant performance test

[0048] In the present application, chitosan and phytic acid synergistically generate free radicals at high temperature to capture active free radicals generated in the gas phase of the flame to inhibit the chain combustion reaction of flammable gas and dilute the combustible components in the flame area. At the same time, a carbon layer is formed on the surface of polyester. In a high temperature environment, MXene in the aerogel layer is oxidized to a TiO2 shielding layer, and a ceramic dense barrier is formed with the decomposition products of phytic acid, which structurally blocks the transmission of heat and oxygen, achieving excellent flame retardant effect.

[0049] Note: 1. The porosity test refers to the standard GB / T 42697-2023; 2. The thermal conductivity test refers to the standard GB / T 11048-2018; 3. The antibacterial test refers to the standard GB / T 20944.3-2008, the standard washing method is normal temperature washing in a household washing machine, 5 minutes of washing is 1 time, the detergent dosage is 2g / L, and the standard strain is Staphylococcus aureus and Escherichia coli; 4. Limiting oxygen index test reference standard 《GB / T 5454-1997》 5. Vertical burning test reference standard 《GB / T 5455-2014》

[0050] Obviously, the above embodiments are only examples for clearly illustrating, but not limitation to the embodiments. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description. Here, it is not necessary and also impossible to enumerate all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A protective fabric with both flame retardant and antibacterial functions: the protective fabric comprises a flame retardant fabric layer and a flame retardant aerogel layer from the inner layer to the outer layer, the flame retardant fabric layer is a chitosan-modified polyester fabric, the flame retardant aerogel layer is a PVA / MXene aerogel, and the flame retardant fabric layer is made by plain weaving polyester yarn coated with a gradient chitosan electrospun film.

2. The protective fabric according to claim 1, characterized in that: The gradient chitosan electrospun film coating polyester yarn has a progressively decreasing porosity from the inside to the outside of the polyester yarn.

3. The protective fabric according to claim 1, characterized in that: The preparation method of the chitosan-modified polyester fabric includes the following steps: S11. Treat the surface of polyester yarn with NaOH; S12. Different masses of chitosan are dissolved in the same mass of acetic acid solution to prepare three groups of spinning solutions with different concentrations. The spinning solutions are divided into groups A, B, and C. Group A has a chitosan concentration of 2-4 wt%, Group B has a chitosan concentration of 6-8 wt%, and Group C has a chitosan concentration of 10-12 wt%. Phytic acid is added to the solution of Group C and stirred evenly. The mass ratio of phytic acid to chitosan is 1:1-4. S13. The spinning solution prepared in step S12 is electrospun using the auxiliary electrode self-polymerization method and coated onto the polyester yarn prepared in step S11. The spinning sequence from the inside to the outside is group A, group B, and group C, forming a chitosan nanofiber layer with a gradient structure. S14. Place the collected chitosan-modified polyester yarn in an oven to dry and remove excess acetic acid solution; S15. The dried chitosan-modified polyester yarn is woven into a fabric, wherein the fabric structure of the fabric is plain weave.

4. The method for preparing the protective fabric according to claim 1, characterized in that, Includes the following steps: S1. LiF was dissolved in HCl solution to obtain a mixed solution, and then Ti3AlC2 was added to the mixed solution for etching. After etching, the precipitate was collected and freeze-dried to obtain MXene nanosheets. S2. Prepare a PVA solution with a concentration of 4~6wt%, add MXene nanosheets to the solution at a ratio of 1:1~10 to PVA, and disperse under high-power ultrasonic assistance; S3. Add silane coupling agent dropwise to a uniformly dispersed solution, stir until homogeneous, and obtain PVA / MXene aerogel precursor hydrogel; S4. The hydrogel prepared in step S3 is coated on the surface of the fabric, allowed to stand and age, then pre-frozen and freeze-dried to form a fire-retardant gel layer with a porous three-dimensional network structure on the surface of the fabric, thus obtaining the protective fabric.

5. The protective fabric according to claim 3, characterized in that: In step S11, the linear density of the polyester yarn is 70~80D and the number of fiber filaments is 36~48f.

6. The protective fabric according to claim 3, characterized in that: In step S13, the electrospinning voltage is 15~20kV, the feed speed is 0.3~1.0mL / h, the collection distance is 10~20cm, the collection speed is 50~200rpm, the temperature is 22~25℃, and the relative humidity is 40~60%.

7. The protective fabric according to claim 3, characterized in that: In step S15, the warp density of the plain weave structure is 40-60 threads / cm, and the weft density is 30-50 threads / cm.

8. The method for preparing the protective fabric according to claim 4, characterized in that: In step S1, the amount of LiF added is 3~3.2g, the volume of HCl solution is 40~45mL, the molar concentration of HCl solution is 9~12mol / L, the amount of Ti3AlC2 added is 2~2.5g, the etching temperature is 40~45℃, and the etching time is 24~48h.

9. The method for preparing the protective fabric according to claim 4, characterized in that: In step S2, the ultrasonic frequency of the high-power ultrasonic-assisted dispersion is 40~50kHz and the power is 300~400W. In step S4, the pre-freezing temperature is -80~-90℃, the freeze-drying temperature is -50~-60℃, and the freeze-drying time is 36~48h.

10. The method for preparing the protective fabric according to claim 4, characterized in that: In step S3, the silane coupling agent is one or more of methyltrimethoxysilane, aminopropyltriethoxysilane, and vinyltrimethoxysilane, and the amount of the silane coupling agent added is 0.1 to 1 wt% of the solution mass.

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