Preparation method and application of polyurethane hydrogel surface modified polyester fabric

Abstract

The application discloses a preparation method and application of polyurethane hydrogel surface modified polyester fabric. The method comprises the following steps: firstly, synthesizing a linear polyurethane polymer; then, adding a trifunctional aziridine group crosslinking agent into the linear polyurethane polymer and uniformly mixing; after that, taking polyester fabric as a base material, coating the mixed solution on the surface of the fiber, and heating to cause the carboxyl group to react with the aziridine group to obtain a polyurethane gel coating on the surface of the fiber, and the modified polyester fabric exhibits superhydrophilic and underwater superoleophobic properties. The concentration of the linear polymer can be changed to obtain a polyurethane hydrogel-polyester fabric composite film. The polyurethane hydrogel modified polyester fabric and the composite film obtained by the method have the advantages of high coating adhesion strength, oil resistance, acid and alkali resistance, abrasion resistance, high separation efficiency and the like, are oil-water separation materials capable of simultaneously separating four different surfactant stable oil-in-water emulsions and high-polarity water-in-oil emulsions, and have good application prospects in the fields of oily wastewater, oil spill in the sea, water removal in oil and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method and application of polyurethane hydrogel surface modified polyester fabric, and applies it to the field of oil-water mixture and oil-water emulsion separation treatment. BACKGROUND

[0002] With the development of industry and the increasing demand for environmental protection, oil-water separation technology has become increasingly important in many fields, such as marine oil spill treatment, chemical wastewater treatment, etc. Polyester (PET) fabric is widely used in filtration and separation fields due to its good mechanical properties, wear resistance and economy. However, the insufficient hydrophilicity of PET fabric limits its performance in oil-water separation applications. To solve this problem, this study aims to modify the PET fabric through surface coating to improve its hydrophilicity and oil-water separation effect. However, due to the weak adhesion on PET, the coating is easily detached from the substrate, resulting in the loss of surface functional properties. Therefore, it is necessary to improve the adhesion strength between the coating and the substrate.

[0003] Cation-π interaction is the interaction between positively charged cations and negatively charged electron clouds in the π system. Recently, this interaction as strong as hydrogen bonding has attracted widespread attention in the scientific community. It has been applied in multiple research fields such as chemistry, materials science, biology and synthesis. In particular, cation-π interaction has been used in underwater adhesive materials. This interaction can effectively improve the adhesion strength between the phenyl substrate and the coating with cationic groups.

[0004] In addition, polyurethane is widely used in the preparation of surface modification coatings due to its good mechanical properties, chemical resistance and film-forming properties. In addition, due to the tunability of polyurethane components, different groups can be introduced into the polyurethane segment to achieve the purpose of directional modification of the substrate surface.

[0005] The present application discloses a preparation method and application of polyurethane hydrogel surface modified polyester fabric. The polyurethane hydrogel coating prepared by the method forms a double crosslinked gel system with excellent mechanical properties through physical crosslinking of cation-π interaction and chemical crosslinking between carboxyl and aziridine groups. The polyester fabric modified by the hydrogel surface has the advantages of wear resistance, acid and alkali resistance, oil stain resistance, high separation efficiency, etc. The prepared polyurethane hydrogel-polyester fabric composite membrane has high separation efficiency for oil-in-water emulsion prepared by different types of surfactants. SUMMARY

[0006] The application aims to solve the problem of difficult separation of oil-containing wastewater such as oil-water mixture, different types of oil-in-water emulsion, water-in-oil emulsion, etc., and provides a preparation method and application of polyurethane hydrogel surface modified polyester fabric. The method uses polyester fabric as a substrate, coats a blended solution of synthesized linear polyurethane and trifunctional aziridine-based crosslinking agent on the surface of the polyester fabric, and obtains super-hydrophilic polyester fabric with polyurethane hydrogel surface modification through heating and crosslinking. The quaternary ammonium salt cation in the polyurethane hydrogel coating can form a cation-π interaction with the benzene ring in the polyester substrate, thereby enhancing the bonding strength between the coating and the polyester fabric. The polyurethane hydrogel surface modified polyester fabric obtained by the method has the advantages of oil stain resistance, acid and alkali resistance, friction resistance, high separation efficiency, etc., and can be used for the treatment of different types of oil-containing wastewater.

[0007] The method for preparing the polyurethane hydrogel surface modified polyester fabric according to the application is performed in the following steps:

[0008] a. Dry 0.002-0.007 mol of polyethylene glycol with a molecular weight of 400-2000 and 0.004 mol of dimethylol butanoic acid in a vacuum drying oven at a temperature of 110℃ for 2h respectively;

[0009] b. Mix the dried polyethylene glycol, 0.002 mol of dimethylol butanoic acid and 0.002-0.007 mol of bis(2-hydroxyethyl)dimethylammonium chloride with 20-25 ml of solvent N,N-dimethylformamide, stir under the protection of dry inert gas nitrogen at a temperature of 50-80℃ for 20-30 min, then add 13-18 μL of catalyst dibutyltin dilaurate, and gradually add 0.013-0.16 mol of toluene diisocyanate, and react for 3h to obtain a linear polyurethane prepolymer solution;

[0010] c. Add the linear polyurethane prepolymer solution obtained in step b to a mixed solution of 0.002 mol of dimethylol butanoic acid dissolved in 3-6 ml of N,N-dimethylformamide, and carry out chain extension reaction under the protection of dry inert gas nitrogen, and continue to react for 2h to obtain a linear polyurethane polymer solution;

[0011] d. Dilute the linear polyurethane solution obtained in step c to 10wt%, and uniformly blend with 1.0wt% of trifunctional aziridine-based crosslinking agent, then immerse the cleaned polyester fabric in the mixed solution for 2-4 min until the polyester fabric is completely wetted by the mixed solution, and take out and dry in an oven at a temperature of 80℃ for 3h to obtain the polyester fabric with polyurethane hydrogel surface modification.

[0012] The method obtains the polyurethane hydrogel surface modified polyester fabric, and the application of the polyester fabric in the preparation of separation of oil-water mixture, oil-in-water emulsion and water-in-oil emulsion.

[0013] The application discloses a preparation method and application of polyurethane hydrogel surface modified polyester fabric.

[0014] 1. The application crosslinks linear cationic polyurethane by a trifunctional aziridine crosslinking agent to obtain a novel polyurethane hydrogel.

[0015] 2. The application prepares a polyurethane hydrogel coating by forming physical crosslinking and chemical crosslinking through cation-π interaction, and the polyurethane hydrogel coating has excellent chemical stability, and the modified polyurethane hydrogel surface modified polyester fabric has good hydrophilic performance.

[0016] 3. The polyurethane hydrogel surface modified polyester fabric obtained by the method has high separation efficiency for oil-water mixture, oil-in-water emulsion prepared by different surfactants, and water-in-oil emulsion.

[0017] 4. The application has no negative effect on other properties of the polyester fabric during the modification of raw materials, but can improve the mechanical properties of the fabric by transferring stress between fibers. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A schematic diagram for a synthesis and preparation process of the polyurethane hydrogel is shown in the figure.

[0019] Figure 2 The figure shows underwater oil-repellent performance of the polyurethane hydrogel surface modified polyester fabric material obtained by the application, wherein a is a contact angle of an oil drop on the surface of the fabric, and b is an oil stain resistance of the fabric under water.

[0020] Figure 3 The figure shows electron microscope pictures of the polyurethane hydrogel modified polyester fabric obtained by the application under different magnifications.

[0021] Figure 4 The figure shows an oil-water separation process and effect diagram of the polyurethane hydrogel surface modified polyester fabric oil-water separation material on an oil-water mixture, wherein a is an oil-water separation process of n-hexane and water, b is a separation equipment diagram of emulsion, c is oil-in-water emulsion separation performance prepared by different types of surfactants, and d is water-in-oil emulsion separation performance. DETAILED DESCRIPTION

[0022] The application will be further described in detail below in combination with examples, but the embodiments of the application are not limited to the given examples.

[0023] Example 1

[0024] a. 0.005 mol of polyethylene glycol with a molecular weight of 400 and 0.004 mol of 2,2-dimethylbutyric acid were dried separately in a vacuum drying oven at a temperature of 110°C for 2 h to remove water;

[0025] b. 0.005 mol of polyethylene glycol, 0.002 mol of 2,2-dimethylbutyric acid, and 0.002 mol of bis(2-hydroxyethyl)dimethylammonium chloride after drying in step a were mixed with 20 ml of solvent N,N-dimethylformamide, stirred for 20 min under the protection of dry inert gas nitrogen at a temperature of 50°C, then 15 μL of catalyst dibutyltin dilaurate was added, and 0.013 mol of toluene diisocyanate was gradually added dropwise, and the reaction was carried out for 3 h to obtain a linear polyurethane prepolymer solution;

[0026] c. A mixture of 0.002 mol of 2,2-dimethylbutyric acid dissolved in 3 ml of N,N-dimethylformamide was added to the linear polyurethane prepolymer solution obtained in step b, and a chain extension reaction occurred under the protection of dry inert gas nitrogen, and the reaction was continued for 2 h to obtain a linear polyurethane polymer solution;

[0027] d. The linear polyurethane solution obtained in step c was diluted to 10 wt%, and 1.0 wt% of a trifunctional aziridine-based crosslinking agent was uniformly blended, then a clean polyester fabric was soaked in the mixed solution for 2 min until the polyester fabric was completely wetted by the mixed solution, and then taken out and laid on a Teflon plate, and placed in an oven at a temperature of 80°C for drying for 3 h to obtain a polyurethane hydrogel surface-modified polyester fabric.

[0028] The obtained polyurethane hydrogel modified polyester fabric was used for oil-water separation test, and the separation efficiency was 90.0%, and the underwater oil contact angle of the material could reach 140.5°, showing the performance of underwater oleophobicity.

[0029] Example 2

[0030] a. 0.005 mol of polyethylene glycol with a molecular weight of 1000 and 0.004 mol of 2,2-dimethylbutyric acid were dried separately in a vacuum drying oven at a temperature of 110°C for 2 h to remove water;

[0031] b. 0.005 mol of polyethylene glycol, 0.002 mol of 2,2-dimethylbutyric acid, and 0.005 mol of bis(2-hydroxyethyl)dimethylammonium chloride after drying in step a were mixed with 25 ml of solvent N,N-dimethylformamide, stirred for 25 min under the protection of dry inert gas nitrogen at a temperature of 70°C, then 15 μL of catalyst dibutyltin dilaurate was added, and 0.015 mol of toluene diisocyanate was gradually added dropwise, and the reaction was carried out for 3 h to obtain a linear polyurethane prepolymer solution;

[0032] c. To the linear polyurethane prepolymer solution obtained in step b, 0.002 mol of 2,2 dimethyl butyric acid dissolved in 5 ml of N,N-dimethylformamide was added, and chain extension reaction occurred under the protection of dry inert gas nitrogen for 2 h, to obtain a linear polyurethane polymer solution;

[0033] d. The linear polyurethane solution obtained in step c was diluted to 10 wt%, and 1.0 wt% of a trifunctional aziridine-based crosslinking agent was uniformly blended, and then the cleaned terylene fabric was immersed in the mixed solution for 2 min until the terylene fabric was completely wetted by the mixed solution, and was taken out and laid on a Teflon plate, and was placed in an oven at a temperature of 80°C for drying for 3 h, to obtain a polyurethane hydrogel surface-modified terylene fabric.

[0034] The obtained polyurethane hydrogel modified terylene fabric was used for oil-water separation test, and the separation efficiency was 99.24%, and the underwater oil contact angle of the material could reach 149.4°, showing the performance of underwater oleophobicity.

[0035] Example 3

[0036] a. 0.005 mol of polyethylene glycol with a molecular weight of 2000 and 0.004 mol of 2,2 dimethyl butyric acid were dried separately in a vacuum drying oven at a temperature of 110°C for 2 h;

[0037] b. 0.005 mol of polyethylene glycol, 0.002 mol of 2,2 dimethyl butyric acid and 0.007 mol of bis(2-hydroxyethyl)dimethylammonium chloride after drying in step a were mixed with 20 ml of solvent N,N-dimethylformamide, and stirring was performed under the protection of dry inert gas nitrogen at a temperature of 80°C for 30 min, then 18 μL of catalyst dibutyltin dilaurate was added, and 0.016 mol of toluene diisocyanate was gradually added dropwise, and reaction was performed for 3 h, to obtain a linear polyurethane prepolymer solution;

[0038] c. To the linear polyurethane prepolymer solution obtained in step b, 0.002 mol of 2,2 dimethyl butyric acid dissolved in 5 ml of N,N-dimethylformamide was added, and chain extension reaction occurred under the protection of dry inert gas nitrogen for 2 h, to obtain a linear polyurethane polymer solution;

[0039] d, the linear polyurethane solution obtained in step c is diluted to 10wt%, and uniformly blended with 1.0wt% of a tri-functional aziridine-based crosslinking agent, then the cleaned polyester fabric is soaked in the mixed solution for 2min until the polyester fabric is completely wetted by the mixed solution, and after being taken out, it is dried in an oven at a temperature of 80°C for 3h to obtain a polyurethane hydrogel surface-modified polyester fabric. The obtained polyurethane hydrogel-modified polyester fabric is used for oil-water separation test, and the separation efficiency is 97.0%, and the underwater oil contact angle of the material can reach 151.5°, showing the performance of underwater oleophobicity.

[0040] Example 4

[0041] a, 0.002 mol of polyethylene glycol with a molecular weight of 1000 and 0.004 mol of 2,2-dimethylbutyric acid are dried at a temperature of 110°C in a vacuum drying oven for 2h respectively;

[0042] b, 0.002 mol of polyethylene glycol, 0.002 mol of 2,2-dimethylbutyric acid and 0.004 mol of bis(2-hydroxyethyl)dimethylammonium chloride after drying in step a are mixed with 22ml of solvent N,N-dimethylformamide, stirred for 20min under the protection of dry inert gas nitrogen at a temperature of 60°C, then 15μL of catalyst dibutyltin dilaurate is added, and 0.015 mol of toluene diisocyanate is gradually added dropwise, and the reaction is carried out for 3h to obtain a linear polyurethane prepolymer solution;

[0043] c, 0.002 mol of 2,2-dimethylbutyric acid dissolved in 4ml of N,N-dimethylformamide is added to the linear polyurethane prepolymer solution obtained in step b, and chain extension reaction occurs under the protection of dry inert gas nitrogen, and the reaction is continued for 2h to obtain a linear polyurethane polymer solution;

[0044] d, the linear polyurethane solution obtained in step c is diluted to 10wt%, and uniformly blended with 1.0wt% of a tri-functional aziridine-based crosslinking agent, then the cleaned polyester fabric is soaked in the mixed solution for 2min until the polyester fabric is completely wetted by the mixed solution, and after being taken out, it is dried in an oven at a temperature of 80°C for 3h to obtain a polyurethane hydrogel surface-modified polyester fabric. The obtained polyurethane hydrogel-modified polyester fabric is used for different types of surfactant prepared oil-in-water emulsion and water-in-oil emulsion, and the separation efficiency reaches 94.0% or more, and the underwater oil contact angle of the material can reach 146.0° or more, showing the performance of underwater oleophobicity.

[0045] Example 5

[0046] a, 0.007 mol of polyethylene glycol with a molecular weight of 1000 and 0.004 mol of 2,2-dimethylbutyric acid are dried at a temperature of 110°C in a vacuum drying oven for 2h respectively;

[0047] b. 0.007 mol of polyethylene glycol, 0.002 mol of 2,2-dimethylbutyric acid and 0.004 mol of bis(2-hydroxyethyl)dimethylammonium chloride were mixed with 22 ml of solvent N,N-dimethylformamide, stirred for 20 min under the protection of dry inert gas nitrogen at a temperature of 60°C, then 15 μL of catalyst dibutyltin dilaurate was added, and 0.015 mol of toluene diisocyanate was gradually added dropwise, and the reaction was carried out for 3 h to obtain a linear polyurethane prepolymer solution;

[0048] c. The linear polyurethane prepolymer solution obtained in step b was mixed with 0.002 mol of 2,2-dimethylbutyric acid dissolved in 4 ml of N,N-dimethylformamide, and a chain extension reaction occurred under the protection of dry inert gas nitrogen, and the reaction was continued for 2 h to obtain a linear polyurethane polymer solution;

[0049] d. The linear polyurethane solution obtained in step c was diluted to 10 wt%, and 1.0 wt% of a trifunctional aziridine-based crosslinking agent was uniformly blended, then a clean polyester fabric was immersed in the mixed solution for 2 min until the polyester fabric was completely wetted by the mixed solution, and after taking out, it was dried in an oven at a temperature of 80°C for 3 h to obtain a polyurethane hydrogel surface-modified polyester fabric.

[0050] The obtained polyurethane hydrogel modified polyester fabric was used to prepare oil-in-water emulsions and water-in-oil emulsions with different types of surfactants, and the separation efficiency reached 96.0% or more, and the material could reach 150° or more in underwater oil contact angle, showing underwater oleophobic properties.

Claims

1. A method for surface modification of polyester fabric with polyurethane hydrogel, characterized in that... Follow these steps: a. 0.002-0.007 mol of polyethylene glycol with a molecular weight of 400-2000 and 0.004 mol of dimethylolbutyric acid were dried in a vacuum drying oven at 110℃ for 2 h to remove water. b. Mix the dried polyethylene glycol from step a, 0.002 mol of dimethylolbutyric acid, and 0.002-0.007 mol of bis(2-hydroxyethyl)dimethylammonium chloride with 20-25 ml of N,N-dimethylformamide solvent. Stir for 20-30 min under dry inert nitrogen protection at 50-80℃. Then add 13-18 µL of dibutyltin dilaurate catalyst and gradually add 0.013-0.16 mol of toluene diisocyanate. React for 3 h to obtain a linear polyurethane prepolymer solution. c. Add a mixture of 0.002 mol dihydroxymethylbutyric acid dissolved in 3-6 ml N,N-dimethylformamide to the linear polyurethane prepolymer solution obtained in step b. The chain extension reaction is carried out under the protection of dry inert nitrogen gas for 2 h to obtain a linear polyurethane polymer solution. d. Dilute the linear polyurethane solution obtained in step c to 10 wt%, and mix it uniformly with 1.0 wt% of a trifunctional aziridine crosslinking agent. Then, immerse the cleaned polyester fabric in the mixed solution for 2-4 minutes until the polyester fabric is completely wetted by the mixed solution. After taking it out, dry it in an oven at 80℃ for 3 hours to obtain a polyester fabric with polyurethane hydrogel surface modification.

2. The application of the polyurethane hydrogel surface-modified polyester fabric obtained by the method according to claim 1 in the separation of oil-water mixtures, oil-in-water emulsions, and water-in-oil emulsions.

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