CN108342902B - A kind of superhydrophilic polymer microsphere and its preparation method and superhydrophilic fabric prepared by the same - Google Patents

Abstract

The invention discloses a super-hydrophilic polymer microsphere, a preparation method thereof and a super-hydrophilic fabric prepared from the super-hydrophilic polymer microsphere. The micro-morphology of the surface of the microsphere can be controlled by controlling the process conditions such as the concentration of the solvent and the solution selected during the preparation of the spraying solution, the electrostatic spraying voltage and the receiving distance, and the microsphere prepared by the method has a micron-nano composite structure surface, high surface roughness and large specific surface area, so that the microsphere has super-hydrophilicity. The preparation method of the microsphere provided by the invention is simple and convenient in process, strong in controllability and suitable for industrial production, popularization and application.

Description

A kind of superhydrophilic polymer microsphere and preparation method thereof and superhydrophilic microsphere prepared therefrom fabric

technical field

The invention relates to a superhydrophilic polymer microsphere, a preparation method thereof and a superhydrophilic fabric prepared therefrom. The use of polyethylene glycol and poly(ω-caprolactone) block copolymer (PEG-b-PCL) As raw material, microspheres are prepared by electrostatic spraying method, the product can be used for coating, and belongs to the field of polymer processing and material surface treatment.

Background technique

Polymer microspheres have unique characteristics of low density and high specific surface area, so they have strong development potential and good application prospects. In particular, polymer microspheres with biodegradability and bioaffinity have received continuous attention and research. They are widely used in immobilization, affinity chromatography, drug release, microscopic separation, microcarriers, etc.

At present, many techniques can be used to prepare polymer microspheres, such as interfacial polymerization, emulsion polymerization, suspension polymerization, interfacial deposition, phase separation, spray drying, electrostatic spraying, etc. Among them, electrostatic spraying is a convenient and concise method to prepare polymer nano- and micro-microspheres. It is a method of forming microspheres with the help of a high-voltage electrostatic field. The size of the microspheres or particles prepared by this method can reach several micrometers or even nanometers. If the polymer liquid is a high-viscosity polymer solution or melt with good fiber-forming properties, the liquid stream does not split into fine polymer droplets in the electric field, but forms continuous fibers, which is called electrospinning. It has been extensively studied. In contrast, there are relatively few reports on the preparation of microspheres and microparticles by electrostatic spraying.

In previous reports, many polymer materials, such as polylactic acid (PLA), polylactic acid-glycolic acid polymer (PLGA), polystyrene (PS) and polycaprolactone (PCL), have been developed by electrostatic spraying. Prepared into solid, hollow, porous, core-shell microspheres. In recent years, PCL electrospinning and microsphere products have been used for biological tissue scaffolds, drug delivery and embedding. As absorbable polymer materials, PCL and its modified polymers are one of the most common electrostatic spray materials.

However, as a microcarrier, the surface wettability of the microspheres has a great influence on its adhesion to cells and the sustained release of the load. While PCL is inherently hydrophobic, nanofibers or microspheres directly prepared from PCL are also hydrophobic.

In addition, compared with natural fibers such as cotton, wool, and silk, chemical fibers have the characteristics of low production cost and superior mechanical properties. However, the textiles prepared therefrom have low equilibrium moisture absorption rate, poor moisture absorption and perspiration performance, and are easily uncomfortable to wear due to the accumulation of static electricity. In this regard, an effective solution is to perform hydrophilic finishing on textiles.

Commonly used hydrophilic finishing agents are polyacrylates and polyurethanes. Among them, the introduction of polar groups into the polyacrylic acid copolymer can provide hydrophilicity on the surface of the fiber, and the hydrophilic polyurethane finishing agent can be used as a soft segment by introducing hydrophilic polyethylene glycol into the polyurethane system. The surface of the fiber forms a film to provide a hydrophilic finish with good durability.

At present, polyurethane-based hydrophilic finishing agents have been industrialized abroad, such as ElastronW-11 and Enicat M-4 of Japan's First Pharmaceutical Company. The durability is still lower than 10s, which shows that the finishing has good washing resistance. However, the hydrophilic performance index provided by such hydrophilic functional additives is still as high as several seconds, which greatly limits the application of textiles in the field of functionalized fabrics such as water treatment.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a superhydrophilic polymer microsphere and its preparation method and application. After the PEG with hydrophilicity is blocked in the PCL molecular chain, the hydrophilicity of the copolymer is improved, and as the PEG chain increases, the hydrophilicity of the copolymer is improved. Different structures show different hydrophilicity; micro-nanocomposite microspheres are coated on the surface of the fabric by electrostatic spraying, and superhydrophilic fabrics are prepared by the superhydrophilicity provided by the composite microspheres.

The technical scheme adopted in the present invention is:

A preparation method of superhydrophilic polymer microspheres, comprising the following steps:

(1) Add carboxyl-terminated PCL and N,N'-carbonyldiimidazole into tetrahydrofuran and dissolve at room temperature; then under nitrogen protection, dropwise add the tetrahydrofuran solution of PEG; then react to obtain polyethylene glycol-poly(ω-hexane) lactone) block copolymer (PEG-b-PCL);

(2) Dissolving polyethylene glycol-poly(ω-caprolactone) block copolymer in chlorinated alkane solvent, stirring and dissolving to prepare a spray stock solution; finally, the spray stock solution is prepared into a super-affinity by electrostatic spraying Water polymer microspheres.

In above-mentioned technical scheme, the mass ratio of described carboxyl-terminated PCL, N,N'-carbonyldiimidazole, PEG is 1: 0.1～0.2: 0.03～0.5; The number-average molecular weight of described carboxyl-terminated PCL is 20,000～120,000 , the number-average molecular weight of the PEG is 1000-5000, the reaction is 8 hours at 35°C; the mass concentration of the sprayed stock solution is 1.0%-9.2%; the processing temperature during the electrostatic spraying is 10-35 ℃, the humidity is 45%-75%, the applied voltage is 8-25kV, the flow rate is 0.6 mL·h ^- 1-3mL·h ^-1 , the receiving distance is 10-25cm, and the drum rotation rate is 10-100 rpm.

In the above-mentioned technical scheme, when the sprayed stock solution is prepared into super-hydrophilic microspheres by means of electrostatic spraying, the surface of the substrate is coated with adhesive, and then the substrate is wound and fixed on the roller device of the electrostatic sprayer, and the adhesive is applied. The layer is facing outward, ready to receive the microspheres, suck the electrostatically sprayed stock solution prepared above into the syringe, put it into the propelling pump, then adjust the processing temperature and humidity, set a certain applied voltage, flow rate and receiving distance, static electricity on the surface of the substrate Spray coated microspheres to obtain superhydrophilic microspheres. The base material is metal or plastic, one of plate or sheet material, or fabric; the adhesive is one of polyurethane, polyacrylate or silicone adhesive, and the adhesive is diluted to the quality The concentration is 1%~5%.

A preparation method of superhydrophilic fabric, comprising the steps:

(1) Add carboxyl-terminated PCL and N,N'-carbonyldiimidazole into tetrahydrofuran and dissolve at room temperature; then under nitrogen protection, dropwise add the tetrahydrofuran solution of PEG; then react to obtain polyethylene glycol-poly(ω-hexane) lactone) block copolymer;

(2) Dissolving the polyethylene glycol-poly(ω-caprolactone) block copolymer into a chlorinated alkane solvent, stirring and dissolving to prepare a spray stock solution;

(3) Dip and roll the fabric in the water-based adhesive to obtain a liquid-saturated fabric;

(4) Using the liquid-filled fabric as a receiver, the sprayed stock solution is sprayed onto the surface of the liquid-filled fabric by electrostatic spraying to obtain a microsphere-coated fabric;

(5) drying the coated fabric to obtain a superhydrophilic fabric.

In the above technical solution, the number-average molecular weight of the carboxyl-terminated PCL is 20,000-120,000, the number-average molecular weight of the PEG is 1,000-5,000, and the reaction is performed at 35° C. for 8 hours.

In the above technical scheme, the chlorinated alkane solvent is one of chloroform, dichloromethane, carbon tetrachloride, and dichloroethane; the mass concentration of the sprayed stock solution is 1.0% to 9.2%.

In the above technical scheme, the fabric is one of cotton, polyester, silk, and aramid or any blended fabric thereof; the water-based adhesive is one of polyacrylate emulsion or polyurethane emulsion, and the water-based adhesive is The mass concentration of the agent is 1%-10%; the liquid-carrying rate of the liquid-carrying fabric is 90%-120%.

In the above technical scheme, the processing temperature during the electrostatic spraying is 10-35°C, the humidity is 45%-75%, the applied voltage is 8-25kV, and the flow rate is 0.6 mL·h ^-1 -3 mL·h ^-1 , The receiving distance is 10-25 cm, and the rotation rate of the drum is 10-100 rpm; in the microsphere-coated fabric, the average particle size of the microspheres is 5.0-10.0 μm.

In the above technical solution, the drying temperature is 40-80° C., and the drying time is 1-24 h.

The invention discloses a super-hydrophilic fabric prepared according to the above-mentioned preparation method of the super-hydrophilic fabric; or a super-hydrophilic polymer microsphere prepared according to the above-mentioned preparation method of the super-hydrophilic polymer microsphere. And the application of the above-mentioned superhydrophilic polymer microspheres in the preparation of superhydrophilic fabrics.

The preparation method of the superhydrophilic fabric of the present invention can be expressed as follows:

(1) Preparation of spray stock solution

By weight, weigh 0.1~1 part of polyethylene glycol-poly(ω-caprolactone) block copolymer (PEG-b-PCL), put it into a container, add 9.9 parts of chlorinated alkane solvent, and stir It is completely dissolved and prepared into a certain concentration of spray stock solution.

(2) Fabric prepreg

The fabric is pre-dipped and rolled in water-based adhesive to maintain a certain liquid rate, and then the fabric is wound and fixed on the drum device of the electrospinning machine, ready to receive microspheres.

(3) Electrostatic spray

The electrostatic spray stock solution prepared above was sucked into the syringe and put into the propelling pump. Subsequently, the processing temperature and humidity were adjusted, and a certain applied voltage, flow rate and receiving distance were set, and the coated microspheres were electrostatically sprayed on the surface of the fabric.

(4) Bonding treatment

The microsphere-coated fabric is dried at a certain temperature, so that the adhesive is cross-linked and cured, and the microspheres are bonded on the fabric to obtain a coated finishing fabric.

(5) Test the wettability and hydrophilic time of the fabric.

0.5 μL of distilled water was dropped onto the surface of the finished fabric with a micro-syringe, and the wetting time was recorded. Test 5 times at different parts, and take the average value as the hydrophilic time. Water conductivity test: Cut out 3 fabric samples with a size of 2.5cm×30cm. Prepare 0.5% potassium dichromate aqueous solution and keep the liquid temperature at 27±2℃. Immerse the lower end of the spline in 0.5% potassium dichromate aqueous solution for 30 min, and then take out the spline. Measure the penetration height of the strip. The average value of the 3 splines is taken to obtain the wool effect value of the fabric.

The mechanism of the present invention is as follows: (1) Controlling the molecular structure of the block copolymer with amphiphilic properties in the electrostatic spraying stock solution, utilizing the difference in the hydrophilicity of the two blocks during the drying process of the droplets to cause microphase separation to generate a rough spherical surface . (2) Polyethylene glycol with a number average molecular weight of 1000~5000 is connected to the PCL segment to form a block polymer. The moderate PEG chain length can not only provide sufficient hydrophilicity, but also ensure that PEG and the same The macromolecular PCL undergoes an esterification reaction. (3) Using a lower mass concentration of the electrostatic spraying stock solution and a lower flow rate of the spraying liquid, and applying a higher applied voltage, the sprayed polymer solution forms secondary droplets and sub-secondary droplets, so as to obtain the spraying liquid drop. (4) The chlorinated alkane solvent used has a low boiling point and is easy to evaporate, so the sprayed droplets are completely dried during the falling process, and finally microsphere particles are obtained.

The preparation method and application of the superhydrophilic polymer microsphere disclosed in the invention. The process of preparing the microspheres is simple, and the particle size and surface morphology of the obtained microspheres are controllable.

Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are:

(1) In the selected PEG-modified PCL molecule, due to the embedded PEG segment with a certain chain length, during the process of droplet falling and drying into a sphere, the intrinsically hydrophobic PCL chain and the intrinsically hydrophilic PEG segment will form a microphase. Separation, in which PEG is more inclined to aggregate at the air end, while PCL chains are more inclined to diffuse inwards, producing bumps and pits on the surface of the microspheres, respectively, forming nano-secondary structures with wrinkled morphologies.

(2) The average particle size of the hydrophilic microspheres prepared by the present invention is 5.0-10.0 μm, which belongs to micron-level spherical particles, and can be used for substrate coating to obtain a micron-level primary structure. The composite surface with both micron primary structure and nanometer secondary structure has high surface roughness and large specific surface area, so it has super hydrophilicity.

(3) When the microspheres are coated on the surface of the fabric, the adhesive used is a water-based adhesive, so a large amount of water dispersant will not evaporate during the rotation of the drum and will be cross-linked and cured in advance. After electrostatic spray reception, drying is used to cross-link and cure the adhesive, which binds the microspheres to the fiber surface of the fabric, providing durability.

(4) The microsphere preparation method provided by the present invention has the advantages of simple process and strong controllability, and is suitable for industrial production and popularization and application.

Description of drawings

Fig. 1 is the schematic diagram of the electrostatic spraying microsphere and coating used in the embodiment of the present invention;

Fig. 2 is the statistic diagram of the average particle size of microspheres prepared by the embodiment of the present invention;

3 is a microscopic topography diagram of the microspheres prepared in the embodiment of the present invention and the comparative example;

FIG. 4 is a topography diagram of a superhydrophilic fabric prepared in an embodiment of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

In the present invention, the hydrophilic modified block copolymer is used as a treatment agent, and the hydrophilicity of the polymer is utilized to coat the fabric by electrostatic spraying. Control the low mass concentration of the electrostatic spraying stock solution, the low spraying liquid flow rate, and apply a high applied voltage to make the sprayed polymer solution form secondary droplets and secondary droplets, so that microphase separation occurs. The surface of the fabric produces a coating of spherical particles with a rough surface. The use of hydrophilic particles with high specific surface area to provide superhydrophilicity on the fabric surface.

Example 1

10.1 g of carboxyl-terminated PCL with a number-average molecular weight of 80,000, 1.62 g of N,N'-carbonyldiimidazole (CDI) and 100 mL of tetrahydrofuran (THF) were added to a 250 mL three-necked flask, and dissolved at room temperature. Under nitrogen protection, 1.2 g of PEG-1000 was dissolved in 40 g of tetrahydrofuran (THF), and added dropwise to a three-necked flask through a constant temperature and constant pressure funnel, and the dropwise addition was completed in 2 hours. After the addition, the reaction was carried out at 35°C for 8 hours. After the reaction, the reaction solution was poured into 160 g of petroleum ether, and the white solid was separated out by anti-solvent method, and 9.6 g of block-modified PCL product PEG1000-b-PCL was obtained by filtration. :1) Wash the mixed solution 4 times with 300 g each time, and then wash it with deionized water 4 times with 600 g each time, put the obtained product in a vacuum oven, and bake it at 37°C for 24 hours for use.

Weigh 0.3 g of PEG1000-b-PCL, transfer it to a round-bottomed flask, add 9.7 g of chloroform, stir to dissolve completely, and prepare an electrostatic spray stock solution with a mass concentration of 3%. Inhale the prepared electrospray stock solution into the syringe, put it into the propelling pump, and then adjust the temperature in the device to 18±1℃ and the humidity to 65%. The applied voltage was adjusted to 12.5kV, the flow rate was 0.6mL·h ^-1 , and the receiving distance was 15cm.

Dilute the polyacrylate emulsion adhesive with distilled water to a solid content of 2wt%, and then pre-dilute the polyester fabric in the diluted adhesive for two dips and two rollings to keep the liquid rate at 115-120%. The polyester fabric was wound and fixed on the drum device to receive the microspheres, and the receiving time was 3 h. After receiving, the polyester fabric was dried in a drying oven at 50°C for 24 hours, so that the adhesive was cross-linked and cured, and the average particle size of the microspheres was 5.293±0.623 μm. A polyacrylate-coated aluminum plate can also be used to receive the microspheres, and the resulting microspheres are similar to the fabric acceptance.

Wetting test: drop 0.5 μL of distilled water onto the surface of the finished fabric with a micro-syringe, and record the wetting time. Test 5 times at different parts and take the average value. The wetting time was measured to be 1 s, and the fabric showed superhydrophilicity.

Water conductivity test: Cut out 3 fabric samples with a size of 2.5cm×30cm. Prepare 0.5% potassium dichromate aqueous solution and keep the liquid temperature at 27±2℃. Immerse the lower end of the spline in 0.5% potassium dichromate aqueous solution for 30 min, and then take out the spline. Measure the penetration height of the strip. The average value of the 3 splines was taken to obtain a wool value of 16.7 cm for the fabric.

Air permeability test: YG461E-III automatic air permeability tester (produced by Ningbo Textile Instrument Co., Ltd.) was used to test the air permeability of the coated fabric. The pressure during the test was 100Pa, and the area of the cloth sample was 20cm ² . The average value of 4 tests was taken. The air permeability of the coated fabric was measured to be 115.5 mm/s. Compared with the unfinished fabric (air permeability of 115.7 mm/s), the air permeability of the coated fabric did not decrease.

Example 2

11.6 g of carboxyl-terminated PCL with a number average molecular weight of 100,000, 1.62 g of N,N'-carbonyldiimidazole (CDI) and 110 mL of tetrahydrofuran (THF) were added to a 250 mL three-necked flask, and dissolved at room temperature. Under nitrogen protection, 4.1 g of PEG-4000 was dissolved in 40 g of tetrahydrofuran (THF), and added dropwise to a three-necked flask through a constant temperature and constant pressure funnel, and the dropwise addition was completed in 2 hours. After the addition, the reaction was carried out at 35°C for 8 hours. After the reaction, the reaction solution was poured into 180 g of petroleum ether, and a white solid was separated out by anti-solvent method, and 13.7 g of block-modified PCL product PEG4000-b-PCL were obtained by filtration. :1) Wash the mixed solution 4 times, each time using 350 g, and then wash it 4 times with deionized water, using 700 g each time, put the obtained product in a vacuum oven, and bake it at 37 °C for 24 hours for use.

Weigh 0.5 g of PEG1000-b-PCL, transfer it to a round-bottomed flask, add 10.0 g of dichloromethane, stir to dissolve completely, and prepare an electrostatic spray stock solution with a mass concentration of 4.8%. Inhale the prepared electrospray stock solution into a 10mL syringe, put it into the propelling pump, and then adjust the temperature in the device to 20±1℃, and the humidity to 65%. The applied voltage was adjusted to 12.5kV, the flow rate was 1.0 mL·h ^-1 , and the receiving distance was 15cm.

The polyurethane emulsion adhesive is diluted with distilled water to a solid content of 2wt%, and the polyester fabric is pre-dipped and rolled in the diluted adhesive to keep the liquid rate at 115-120%. The fabric was wound and fixed on the drum device to receive the sprayed microspheres. The receiving time was 70 min. After receiving, the polyester fabric was dried in a drying oven at 45 °C for 24 h to make the adhesive cross-linked and cured. The particle size of the microspheres was 5.9153±0.568 μm.

According to the wettability test in Example 1, the wetting time was measured to be 0.5s, and the fabric was instantly wetted, showing super hydrophilicity. The measured gross value was 17.6 cm; the air permeability test was carried out according to the method in Example 1, and the average value was taken for 4 tests, and the measured air permeability of the coated fabric was 117.8 mm/s.

Example 3

11.7 g of carboxyl-terminated PCL with a number-average molecular weight of 100,000, 1.62 g of N,N'-carbonyldiimidazole (CDI) and 110 mL of tetrahydrofuran (THF) were added to a 250 mL three-necked flask, and dissolved at room temperature. Under nitrogen protection, 2.4 g of PEG-2000 was dissolved in 35 g of tetrahydrofuran (THF), and added dropwise to a three-necked flask through a constant temperature and constant pressure funnel, and the dropwise addition was completed in 1 hour. After the addition, the reaction was carried out at 35°C for 8 hours. After the reaction, the reaction solution was poured into 150 g of petroleum ether, and the white solid was separated out by anti-solvent method, and 11.0 g of block-modified PCL product PEG3000-b-PCL was obtained by filtration. :1) Wash the mixed solution 4 times, each time using 250 g, and then wash it 4 times with deionized water, using 500 g each time, put the obtained product in a vacuum oven, and bake it at 37 ℃ for 24 hours, for use.

Weigh 0.5 g of PEG2000-b-PCL, transfer it to a round-bottomed flask, add 9.5 g of chloroform, stir to dissolve completely, and prepare an electrostatic spray stock solution with a mass concentration of 5.0%. Inhale the prepared electrospray stock solution into a 10mL syringe, put it into the propelling pump, and then adjust the temperature in the device to 20±1℃, and the humidity to 65%. The applied voltage was adjusted to 12.0kV, the flow rate was 1.6 mL·h ^-1 , and the receiving distance was 12cm.

The polyester fabric is pre-dipped and rolled in the binder (solid content of polyacrylate emulsion is 5wt%) to keep the liquid rate at 115-120%, and then the polyester fabric is wound and fixed on the roller device to receive the sprayed microspheres , the receiving time is 60min. After receiving, the polyester fabric is dried in a drying oven at 45℃ for 24 hours, so that the adhesive is cross-linked and cured. The average particle size of the microspheres is 7.252±0.487 μm.

According to the wettability test in Example 1, the measured wetting time was 1 s, and the fabric was instantly wetted, showing super hydrophilicity. The measured gross value is 16.9cm. Air permeability test: YG461E-III automatic air permeability tester (produced by Ningbo Textile Instrument Co., Ltd.) was used to test the air permeability of the coated fabric. The pressure during the test was 100Pa, and the area of the cloth sample was 20cm ² . The average value of 4 tests was taken. The measured air permeability of the coated fabric is 116.9mm/s

Example 4

The preparation process of PEG2000-b-PCL is the same as that in Example 3.

Weigh 0.5 g of PEG2000-b-PCL, transfer it to a round-bottomed flask, add 9.5 g of chloroform, stir to dissolve completely, and prepare an electrostatic spray stock solution with a mass concentration of 5.0%. Inhale the prepared electrospray stock solution into a 10mL syringe, put it into the propelling pump, and then adjust the temperature in the device to 20±1℃, and the humidity to 65%. The applied voltage was adjusted to 10.0kV, the flow rate was 2.0 mL·h ^-1 , and the receiving distance was 18cm.

The polyester fabric is pre-dipped and rolled in the binder (solid content of polyacrylate emulsion 3wt%) to maintain the liquid rate of 115-120%, and then the polyester fabric is wound and fixed on the drum device to receive the sprayed microspheres. The receiving time was 60 min. After receiving, the polyester fabric was dried in a drying oven at 45 °C for 24 h to make the adhesive cross-linked and cured. The average particle size of the microspheres was 8.439±0.665 μm.

According to the wettability test in Example 1, the measured wetting time was 0 s, and the fabric was instantly wetted, showing super-hydrophilicity. The measured gross value was 18.1 cm. Air permeability test: YG461E-III automatic air permeability tester (produced by Ningbo Textile Instrument Co., Ltd.) was used to test the air permeability of the coated fabric. The pressure during the test was 100Pa, and the area of the cloth sample was 20cm ² . The average value of 4 tests was taken. The air permeability of the coated fabric was measured to be 114.2 mm/s.

Example 5

The preparation process of PEG2000-b-PCL is the same as that in Example 3.

Weigh 0.3 g of PEG2000-b-PCL, transfer it to a round-bottomed flask, add 9.7 g of chloroform, stir to dissolve completely, and prepare an electrostatic spray stock solution with a mass concentration of 3.0%. Inhale the prepared electrospray stock solution into a 10mL syringe, put it into the propelling pump, and then adjust the temperature in the device to 20±1℃, and the humidity to 65%. The applied voltage was adjusted to 15.0kV, the flow rate was 3.0 mL·h ^-1 , and the receiving distance was 15cm.

The polyester fabric is pre-dipped and rolled in the adhesive (polyurethane emulsion solid content of 5wt%) to keep the liquid rate at 115-120%, and then the polyester fabric is wound and fixed on the drum device to receive the sprayed microspheres, and the receiving time After receiving, the polyester fabric was dried at 45 °C for 24 h in a drying oven to make the adhesive cross-linked and cured, and the average particle size of the microspheres was 9.672±0.745.

According to the wettability test in Example 1, the measured wetting time was 0 s, and the fabric was instantly wetted, showing super-hydrophilicity. The measured gross value was 18.4 cm. Air permeability test: YG461E-III automatic air permeability tester (produced by Ningbo Textile Instrument Co., Ltd.) was used to test the air permeability of the coated fabric. The pressure during the test was 100Pa, and the area of the cloth sample was 20cm ² . The average value of 4 tests was taken. The air permeability of the coated fabric was measured to be 118.1 mm/s.

Comparative Example 1

11.0 g of carboxyl-terminated PCL with a number average molecular weight of 100,000, 1.62 g of N,N'-carbonyldiimidazole (CDI) and 110 mL of tetrahydrofuran (THF) were added to a 250-mL three-necked flask, and dissolved at room temperature. Under nitrogen protection, 0.6 g of PEG-400 was dissolved in 20 g of tetrahydrofuran (THF), and added dropwise to a three-necked flask through a constant temperature and constant pressure funnel, and the dropwise addition was completed in 1 hour. After the addition, the reaction was carried out at 35°C for 8 hours. After the reaction was completed, the reaction solution was poured into 150 g of petroleum ether, and the white solid was separated out by anti-solvent method, and 9.1 g of block-modified PCL product PEG400-b-PCL was obtained by filtration. :1) Wash the mixed solution 4 times, each time using 200 g, and then wash it 4 times with deionized water, using 400 g each time, put the obtained product in a vacuum oven, and bake it at 37 °C for 24 hours, for use.

Weigh 0.5 g of PEG1000-b-PCL, transfer it to a round-bottomed flask, add 9.5 g of chloroform, stir to dissolve completely, and prepare an electrostatic spray stock solution with a mass concentration of 5.0%. Inhale the prepared electrospray stock solution into a 10mL syringe, put it into the propelling pump, and then adjust the temperature in the device to 20±1℃, and the humidity to 65%. The applied voltage was adjusted to 12.5kV, the flow rate was 1.0 mL·h ^-1 , and the receiving distance was 15cm.

The polyester fabric is pre-dipped and rolled in the binder (solid content of polyacrylate emulsion 2wt%) to keep the liquid rate at 115-120%, and then the polyester fabric is wound and fixed on the drum device to receive the sprayed microspheres. The particle size of the microspheres is 5.613±0.654μm, the surface of the microspheres is smooth, and there is no micro-nano structure. After receiving, the polyester fabric was dried in a drying oven at 45 °C for 24 h, so that the adhesive was cross-linked and cured. According to the wettability test in Example 1, the wetting time was measured to be 7s, and the fabric showed poor hydrophilicity. The measured gross value is 6.2cm.

FIG. 1 is a schematic diagram of the electrostatic spraying microspheres and coatings used in the embodiment of the present invention. The polymer solution in the syringe is pushed by the pump into the high-voltage electric field, and under the action of the high-voltage electric field, the original solution is sprayed to form droplets. Microspheres on the surface of nanocomposite structures.

Fig. 2 is a statistical diagram of the average particle size of the microspheres prepared according to Examples 1 to 5 of the present invention, the average particle size of the microspheres obtained in Example 1 is 5.293±0.623 μm, and the average particle size of the microspheres in Example 2 is 5.9153 μm ±0.568 μm, the average particle size of the microspheres in Example 3 was 7.252±0.487 μm, the average particle size of the microspheres in Example 4 was 8.439±0.665 μm, and the average particle size of the microspheres in Example 5 was 9.672±0.745.

3 is a microscopic topography diagram of the microspheres prepared according to Examples 1 to 5 of the present invention and Comparative Example 1. The surface of the microspheres prepared by the embodiment of the present invention has wrinkles, all showing a micro-nano composite structure. The average particle size of the proportional microspheres is 5.613±0.654 μm, and the surface of the microspheres is smooth.

4 is a microscopic topography diagram of a coated fabric prepared according to Examples 1 to 3 of the present invention, wherein abc corresponds to Example 1, Example 2, and Example 3, respectively.

The present invention utilizes the amphiphilic property of polyethylene glycol-poly(ω-caprolactone) block copolymer to form spherical particles of micro-nano composite structure with rough surface during the molding process; , The adhesive used is a water-based adhesive, so a large amount of water dispersant will not evaporate during the rotation of the drum and will not be cross-linked and cured in advance. After electrostatic spray reception, drying is used to cross-link and cure the adhesive, which binds the microspheres to the fiber surface of the fabric, providing durability.

Claims (3)

1. A preparation method of super-hydrophilic fabric is characterized by comprising the following steps:

(1) adding carboxyl-terminated PCL and N, N' -carbonyldiimidazole into tetrahydrofuran, and dissolving at room temperature; then, under the protection of nitrogen, dripping a tetrahydrofuran solution of PEG; then reacting to obtain a polyethylene glycol-poly (omega-caprolactone) block copolymer;

(2) dissolving a polyethylene glycol-poly (omega-caprolactone) block copolymer into a chloroalkane solvent, stirring and dissolving to prepare a spray stock solution;

(3) soaking and rolling the fabric in a water-based adhesive for two times to obtain a fabric with liquid;

(4) spraying the spraying stock solution to the surface of the fabric with the liquid by taking the fabric with the liquid as a receiver in an electrostatic spraying manner to obtain a fabric with a microsphere coating;

(5) drying the coated fabric to obtain a super-hydrophilic fabric;

the number average molecular weight of the carboxyl-terminated PCL is 2-12 ten thousand, the number average molecular weight of the PEG is 1000-5000, and the reaction is carried out for 8 hours at 35 ℃;

the processing temperature during electrostatic spraying is 10-35 ℃, the humidity is 45-75%, the applied voltage is 8-25 kV, and the flow rate is 0.6 mL.h^-1～3 mL· h^-1The receiving distance is 10-25 cm, and the rotation speed of the roller is 10-100 revolutions per minute; in the fabric with the microsphere coating, the average particle size of the microspheres is 5.0-10.0 μm.

2. The method of claim 1, wherein the chlorinated alkane solvent is one of chloroform, dichloromethane, carbon tetrachloride and dichloroethane; the mass concentration of the spraying stock solution is 1.0-9.2%.

3. The method for preparing the super-hydrophilic fabric according to claim 1, wherein the fabric is one of cotton, terylene, silk and aramid fiber or any blended fabric thereof; the water-based adhesive is one of polyacrylate emulsion or polyurethane emulsion, and the mass concentration of the water-based adhesive is 1-10%; the liquid carrying rate of the liquid carrying fabric is 90-120%; the drying temperature is 40-80 ℃, and the drying time is 1-24 hours.

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