CN110438586B

CN110438586B - Preparation method of super-hydrophobic porous fiber with oriented pore structure, product and application

Info

Publication number: CN110438586B
Application number: CN201810421225.2A
Authority: CN
Inventors: 柏浩; 邵子钰
Original assignee: Zhejiang University ZJU
Current assignee: Zhejiang University ZJU
Priority date: 2018-05-04
Filing date: 2018-05-04
Publication date: 2020-11-17
Anticipated expiration: 2038-05-04
Also published as: CN110438586A

Abstract

The invention relates to a preparation method of super-hydrophobic porous fiber with an oriented pore structure, a product and application, wherein the preparation method comprises the following steps: preparing a spinning solution; spinning the spinning solution, directionally freezing during spinning, and collecting frozen fibers; freezing the fiber to remove ice crystals; and carrying out surface super-hydrophobic treatment on the porous fiber. According to the invention, the porous fiber with the oriented pore structure is obtained by combining directional freezing and solution spinning, and then the surface super-hydrophobic treatment is carried out on the porous fiber, so that the porous fiber has excellent heat insulation and super-hydrophobic properties.

Description

Preparation method of super-hydrophobic porous fiber with oriented pore structure, product and application

Technical Field

The invention relates to the field of preparation of porous fibers, in particular to a preparation method, a product and application of a super-hydrophobic porous fiber with an oriented pore structure.

Background

Directional freezing is a method that uses temperature gradients to influence and control the movement and assembly of raw materials to obtain oriented structure porous materials. In recent years, various porous materials with oriented structures are successfully prepared by utilizing a directional freezing method. Deville et al (s.deville, e.saiz, a.p.tomsia, Biomaterials 2006,27,5480) successfully produced hydroxyapatite scaffold materials, the presence of oriented structures giving such materials greater compressive strength than other structures. The graphene/cellulose composite scaffold material prepared by Wicklein et al (b.wicklein, a.kocjan, g.salazar-Alvarez, f.carosio, g.camino, m.antonietti, l.bergstrom, nat.nanotechnol.2014,10,27791) by using the directional freezing method has better heat insulation and flame retardant properties because of the oriented structure.

However, the conventional directional freezing method cannot realize continuous large-scale preparation due to the limitation of a mold, and the application of the directional freezing method to the preparation of porous fibers is severely limited for the occasions requiring large-scale continuous preparation of porous fibers. In addition, even with the directional freezing method, the prepared material itself often does not have superhydrophobic properties.

The super-hydrophobic phenomenon is a common phenomenon in nature, the surfaces of a plurality of plant leaves represented by lotus leaves are super-hydrophobic surfaces, water is beaded on the surfaces of the plant leaves, and the plant leaves can roll off under the action of gravity when inclined, so that the plant leaves have a self-cleaning effect, and the phenomenon is called as the lotus leaf effect. Generally, a surface with a water contact angle of more than 150 degrees and a rolling angle of less than 10 degrees is called a super-hydrophobic surface, and the super-hydrophobic surface can be constructed in a way of constructing a surface with a micro-nano rough structure or reducing surface energy and the like.

The super-hydrophobic fabric is a functional fabric developed on the basis of super-hydrophobic surface research, can be used as protective clothing, waterproof cloth and the like due to good self-cleaning, antifouling, water repellency and other properties, and has important application in the fields of industry, medical treatment and the like.

The hydrophobic capacity of the super-hydrophobic fiber and fabric is closely related to the surface roughness and the surface energy thereof, and at present, the method for obtaining the super-hydrophobic fiber and fabric mainly comprises the following steps:

(1) and coating the surface of the fabric with nanoparticles. This method obtains a superhydrophobic fiber or fabric mainly by dipping the fiber or fabric in a solution containing nanoparticles or spraying the solution containing nanoparticles on the surface of the fiber or fabric. The nanoparticles commonly adopted by the method comprise nano silicon dioxide, nano titanium dioxide and the like, and the main purpose is to construct a rough micro-nano structure on the surface of the fiber or fabric so as to improve the hydrophobic property of the surface of the fiber or fabric.

(2) And coating a low-surface-energy coating on the surface of the fiber or the fabric. The method mainly makes the surface of the fiber or the fabric have lower surface energy by dip coating, vapor deposition and the like, thereby obtaining the fiber or the fabric with the super-hydrophobic surface.

Therefore, it is urgently needed to develop a new process for preparing porous fiber having oriented pore structure with super-hydrophobic property.

Disclosure of Invention

The invention aims to provide a preparation method of a super-hydrophobic porous fiber with an oriented pore structure, which aims to overcome the defects of the prior art, and the preparation method is characterized in that the porous fiber with the oriented pore structure is obtained by combining directional freezing and solution spinning, and then the surface super-hydrophobic treatment is carried out on the porous fiber, so that the porous fiber has excellent heat insulation and super-hydrophobic properties.

The technical scheme provided by the invention is as follows:

a method of making a superhydrophobic porous fiber having an oriented pore structure comprising:

preparing a spinning solution;

spinning the spinning solution, directionally freezing during spinning, and collecting frozen fibers;

freezing the fiber to remove ice crystals;

and carrying out surface super-hydrophobic treatment on the porous fiber.

The porous fiber prepared by the technical scheme has excellent heat insulation and super-hydrophobic properties. After the spinning solution is extruded from the extrusion pump, the nucleation and growth of ice crystals are oriented in the extrusion direction due to the influence of the temperature gradient, and an oriented pore structure is formed. Meanwhile, as the system is subjected to micro-phase separation, the raw materials are extruded and compressed in gaps among the ice crystals by the ice crystals. After the freezing is completed, removing the ice crystal to obtain the porous fiber which uses the ice crystal as a template and has an oriented pore structure. And then carrying out surface superhydrophobic treatment on the obtained porous fiber with the oriented pore structure to obtain the superhydrophobic porous fiber with the oriented pore structure.

The preparation method of the super-hydrophobic porous fiber with the oriented pore structure comprises the following steps:

1) preparing a natural polymer solution for spinning; the natural polymer solution comprises one or more of sodium carboxymethylcellulose solution, starch solution, chitosan solution and fibroin solution;

2) carrying out solution spinning on the natural polymer solution, carrying out directional freezing during spinning, and collecting frozen fibers;

3) freeze drying the frozen fiber to remove ice crystals to obtain porous fiber with an oriented pore structure;

4) and performing surface super-hydrophobic treatment on the porous fiber to obtain the super-hydrophobic porous fiber with an oriented pore structure.

Preferably, the sodium carboxymethyl cellulose solution is a sodium carboxymethyl cellulose aqueous solution, and the mass fraction of the sodium carboxymethyl cellulose solution is 1% -10%. Preparation of sodium carboxymethyl cellulose solution: dissolving sodium carboxymethylcellulose powder in water to prepare sodium carboxymethylcellulose solution.

Preferably, the starch solution is a starch aqueous solution, and the mass fraction of the starch solution is 1-10%. Preparation of starch solution: dissolving water-soluble starch powder in water to prepare starch solution.

Preferably, the chitosan solution is a chitosan acetic acid solution; the concentration of the chitosan solution is 20-60 mg/ml. Preparation of chitosan solution: dissolving chitosan powder in acetic acid solution to prepare chitosan solution, wherein the mass concentration of the acetic acid solution is 0.5-1.5%.

Preferably, the preparation of the fibroin solution: shearing natural silkworm cocoons, boiling and drying in a sodium carbonate solution, dissolving in a lithium bromide solution, and preparing a fibroin solution after complete dialysis; the mass fraction of the fibroin solution is 1% -30%.

Preferably, the natural polymer solution comprises a chitosan solution and a fibroin solution, wherein the mass ratio of fibroin to chitosan is 8-10: 1.

(1) preparing an emulsion to be polymerized; the emulsion to be polymerized comprises a resin monomer, a free radical polymerization initiator, a reactive emulsifier and a thickening agent, or the emulsion to be polymerized comprises a prepolymer, a free radical polymerization initiator, a reactive emulsifier and a thickening agent, or the emulsion to be polymerized comprises a self-emulsifying prepolymer, a free radical polymerization initiator and a thickening agent;

(2) carrying out emulsion spinning on the emulsion to be polymerized, carrying out directional freezing during spinning, and collecting frozen fibers;

(3) the frozen fiber is subjected to polymerization reaction in a low-temperature environment;

(4) unfreezing and drying the frozen fiber to obtain porous resin fiber with an oriented pore structure;

(5) and carrying out surface super-hydrophobic treatment on the porous resin fiber to obtain the super-hydrophobic porous fiber with an oriented pore structure.

Preferably, the emulsion to be polymerized comprises, in parts by weight: 10-30 parts of resin monomer or prepolymer, 1-5 parts of free radical polymerization initiator, 1-10 parts of reactive emulsifier and 1-10 parts of thickener.

Preferably, the emulsion to be polymerized comprises, in parts by weight: 5-40 parts of self-emulsifying prepolymer, 1-5 parts of free radical polymerization initiator and 1-10 parts of thickening agent.

The resin monomer in the present invention is a resin monomer that can undergo radical polymerization. Preferably, the resin monomer is one or more selected from styrene, methyl methacrylate, butyl acrylate, acrylic acid, ethyl methacrylate and butyl methacrylate.

Preferably, the prepolymer is selected from an epoxy acrylate prepolymer or an acrylated polycarbonate prepolymer.

Preferably, the self-emulsifying prepolymer is selected from water-based polyurethane acrylate or water-based epoxy acrylate.

The thickener in the invention is mainly used for thickening and thickening the emulsion so as to enable the emulsion to be polymerized to carry out emulsion spinning. Preferably, the thickener is selected from nanoclay or sodium hydroxypropyl cellulose.

The reactive emulsifier of the present invention can be an emulsifier which can emulsify a resin monomer or a prepolymer and can copolymerize with the resin monomer or the prepolymer under specific conditions such as ultraviolet irradiation and high-energy radiation. The reactive emulsifier can be selected from emulsifier ER series (such as ER-10), SR series (such as SR-10), NE series (such as NE-10), SE series (such as SE-10N), COPS-2 (2-acrylamido-2-methylpropane sulfonic acid sodium salt), HE-1012 (Henan chemical). Preferably, the reactive emulsifier is selected from one or more of ER-10, SR-10, NE-10, SE-10N, 2-acrylamide-2-methyl sodium propane sulfonate and HE-1012.

The radical polymerization initiator in the present invention includes organic peroxide initiators, inorganic peroxide initiators, azo initiators, redox initiators and other types of photoinitiators. Preferably, the radical polymerization initiator in step 1) is selected from benzoyl peroxide and N, N-dimethyl benzamide, tert-butyl hydroperoxide and trioctyl tertiary amine, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 1-hydroxycyclohexyl phenyl ketone or 2-hydroxy-4' - (2-hydroxyethoxy) -2-methyl phenylpropyl ketone.

Preferably, the emulsion to be polymerized further comprises a crosslinking agent; the cross-linking agent is selected from one or more of ethylene glycol dimethacrylate, divinyl benzene, diisocyanate and N, N-methylene bisacrylamide.

Preferably, the temperature of the low-temperature environment is-40 to-10 ℃. Further preferably-20 ℃.

Preferably, the self-emulsifying prepolymer is water-based polyurethane acrylate, the free radical polymerization initiator is 2-hydroxy-2-methyl-1-phenyl-1-acetone, and the polymerization reaction is carried out under the irradiation of ultraviolet light.

Preferably, the drying is vacuum drying at 30-60 ℃. Because the resin fiber has small hydrophilicity and high strength, the resin fiber does not need vacuum freeze drying after freezing, only needs vacuum drying at 30-60 ℃ after thawing, and does not cause the collapse of the pore canal structure.

i, preparing polyamic acid salt hydrogel;

II, carrying out solution spinning on the polyamic acid salt hydrogel, carrying out directional freezing during spinning, and collecting frozen fibers;

III, freeze drying the frozen fiber to remove ice crystals to obtain porous fiber with an oriented pore structure;

IV, carrying out thermal imidization on the porous fiber to obtain polyimide porous fiber;

and (V) performing surface superhydrophobic treatment on the polyimide porous fiber to obtain the superhydrophobic porous fiber with an oriented pore structure.

Preferably, the mass fraction of the polyamic acid salt hydrogel is 3-20%. More preferably 5 to 15%.

The polyamic acid salt hydrogel in the present invention can be prepared by the prior art. Preferably, the preparation of the polyamic acid salt hydrogel comprises:

1.1) dissolving 4,4' -diaminodiphenyl ether in dimethylacetamide, adding pyromellitic dianhydride and triethylamine for reaction to obtain polyamic acid salt solid;

1.2) mixing the polyamic acid salt solid with triethylamine and water to obtain polyamic acid salt hydrogel.

Further preferably, the preparation of the polyamic acid salt hydrogel specifically comprises:

1.1) dissolving 4,4' -diaminodiphenyl ether in dimethylacetamide, adding pyromellitic dianhydride and triethylamine, mixing and stirring to obtain polyamic acid salt solution; pouring the polyamic acid salt solution into water for separation, washing, freezing and drying to obtain polyamic acid salt solid;

1.2) mixing and stirring the polyamic acid salt solid, triethylamine and water, and standing to obtain polyamic acid salt hydrogel.

Preferably, the thermal imidization refers to: and (3) carrying out three-stage heating and three-stage constant temperature treatment on the porous fiber, wherein the heating and the constant temperature treatment are alternately carried out.

Further preferably, the thermal imidization specifically includes: heating to 90-110 deg.C at room temperature at 1-3 deg.C/min, and maintaining for 25-35 min; heating to 190-210 ℃ at a speed of 1-3 ℃/min, and keeping for 25-35 min; heating to 290 ℃ and 310 ℃ at the speed of 1-3 ℃/min, and keeping the temperature for 55-65 min.

Preferably, the surface superhydrophobic treatment comprises: dip coating, vapor deposition or wet chemical deposition. The surface of the porous fiber is added with a super-hydrophobic coating, so that the porous fiber has super-hydrophobic properties, and water or other liquid can be beaded on the surface of the fabric and can roll off by gravity when the fabric is inclined.

The dip coating method is preferably: immersing the porous fiber into a nano silicon dioxide sol, a nano titanium dioxide sol, a fluoro-silane solution such as 1H,1H,2H, 2H-perfluorooctyltriethoxysilane or 1H,1H,2H, 2H-perfluorodecyltriethoxysilane, a mixed solution of fluoro-silane such as 1H,1H,2H, 2H-perfluorooctyltriethoxysilane or 1H,1H,2H, 2H-perfluorodecyltriethoxysilane and nano titanium dioxide, a super-hydrophobic coating solution such as a mixed solution of fluoro-silane such as 1H,1H,2H, 2H-perfluorooctyltriethoxysilane or 1H,1H,2H, 2H-perfluorodecyltriethoxysilane and nano silicon dioxide, and drying for 5-30 min.

The vapor deposition method is preferably: and (3) placing the porous fiber in a fluorosilane atmosphere such as 1H,1H,2H, 2H-perfluorooctyltriethoxysilane or 1H,1H,2H, 2H-perfluorodecyltriethoxysilane for deposition for 8-12H.

The wet chemical deposition method is preferably: co-hydrolyzing tetraethoxysilane such as tetraethoxysilane and 1H,1H,2H, 2H-perfluorooctyl triethoxysilane or 1H,1H,2H, 2H-perfluorodecyl triethoxysilane to obtain super-hydrophobic solution, immersing the porous fiber in the super-hydrophobic solution for 5-30min, or spin-coating or spray-coating the super-hydrophobic solution on the surface of the fiber, and then drying; or immersing the porous fiber in mixed acetone or DMF solution of poly (vinylidene fluoride-co-hexafluoropropylene) and fluorosilane such as 1H,1H,2H, 2H-perfluorooctyltriethoxysilane or 1H,1H,2H, 2H-perfluorodecyltriethoxysilane for 5-30min, and drying.

Preferably, the directional freezing specifically comprises: extruding the spinning solution from an extrusion pump, and then passing through a low-temperature copper ring for directional freezing; the temperature of the low-temperature copper ring is-120-0 ℃.

The invention provides the super-hydrophobic porous fiber with the oriented pore structure, which is prepared by the preparation method. The diameter of the porous fiber is 100 to 1000 μm, and the pore diameter is 10 to 100 μm.

The invention provides application of the super-hydrophobic porous fiber with the oriented pore structure in preparation of a water-proof and oil-proof fabric material. The porous fiber is further subjected to surface super-hydrophobic treatment, so that the porous fiber has super-hydrophobic property, can be beaded and fall by gravity when liquid such as water falls on the surface of a fabric, reduces the pollution of the liquid to the fabric, has the functions of self-cleaning, stain resistance, water repellency and the like, can be widely applied to wearable fabrics, and has wide development prospect.

The invention provides application of the super-hydrophobic porous fiber with the oriented pore structure as a heat insulation material.

Compared with the prior art, the invention has the beneficial effects that:

(1) the preparation method is simple, can be used for continuous large-scale preparation, is suitable for industrial amplification application, and can be used for designing different materials according to actual requirements.

(2) The preparation method can prepare the porous fiber with different pore diameters by adjusting the temperature of the directional freezing, and in addition, the pore diameter, the porosity and the pore appearance of the porous structure of the fiber can be adjusted in a large range.

(3) According to the invention, the porous fiber with the oriented pore structure is obtained by combining directional freezing and solution spinning, and then the surface super-hydrophobic treatment is carried out on the porous fiber, so that the porous fiber has excellent heat insulation and super-hydrophobic properties.

Drawings

FIG. 1 is a schematic diagram of an apparatus for the directional freeze-spinning process of the present invention;

FIG. 2 is an optical diagram of a porous fiber prepared in example 1;

FIG. 3 is a Micro-CT plot of porous fibers prepared in example 1;

FIG. 4 is an SEM image of a porous fiber prepared in example 2;

FIG. 5 is an SEM image of a porous fiber prepared in example 6;

FIG. 6 is an SEM photograph of a porous resin fiber prepared in example 7;

FIG. 7 is an SEM photograph of a porous resin fiber prepared in example 9;

FIG. 8 is an SEM image of a porous fiber prepared in example 12;

FIG. 9 is an infrared image of a porous fibrous woven fabric prepared in example 12;

FIG. 10 is a temperature statistic of the porous fiber woven fabric prepared in example 12 with a hot stage substrate;

FIG. 11 is an SEM image of a porous fiber prepared in example 13;

fig. 12 is an SEM image of the porous fiber prepared in example 14.

Detailed Description

The invention will be further illustrated with reference to specific examples:

the schematic diagram of the directional freezing-spinning apparatus used in the example is shown in fig. 1, wherein the upper part is an extrusion apparatus 1, the mixed solution is extruded by the extrusion apparatus 1, and then passes through a low-temperature copper ring 2, the copper ring 2 is connected with a cold source (not shown), and the bottom part is a motor collecting device 3. The right side of FIG. 1 is an enlarged view of the mixed solution after freeze-spinning.

Example 1

(1) Shearing 4.5g of natural silkworm cocoon, boiling and drying in 1% sodium carbonate solution, dissolving in 20ml of 9mol/ml lithium bromide solution, dialyzing for 24h, and preparing into a fibroin solution with the mass fraction of 22.5%.

0.5g of chitosan powder is dissolved in 10ml of 1 percent acetic acid solution, and the chitosan powder is stirred for 30min at the rotating speed of 800rpm/min to be uniformly mixed to prepare chitosan solution with the concentration of 50 mg/ml.

Uniformly mixing 20ml of fibroin solution and 10ml of chitosan solution, centrifuging to remove bubbles to obtain uniform solution, wherein the mass ratio of fibroin to chitosan is 9: 1.

(2) And (3) placing the mixed solution into an injector, extruding the solution through an extrusion pump, placing a copper ring into a low-temperature reaction bath (-100 ℃), passing the solution through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(3) And (3) freeze-drying the frozen fiber obtained in the step (2) for 24h to remove the solvent, so as to obtain the porous fiber with an oriented porous structure, wherein the optical photo of the porous fiber is shown in FIG. 2. And the porous fiber was subjected to Micro-CT characterization, as shown in fig. 3, indicating that the porous fiber had an oriented pore structure.

(4) And (4) placing the porous fiber obtained in the step (3) in an atmosphere of 1H,1H,2H, 2H-perfluorooctyltriethoxysilane, and carrying out vapor deposition for 12H to obtain the super-hydrophobic porous fiber.

(5) The super-hydrophobic porous fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 151.5 degrees, and the contact angle of the silicone oil on the surface of the fabric is 150.3 degrees.

Example 2

After 20ml of fibroin solution and 10ml of chitosan solution are uniformly mixed, centrifuging to remove bubbles to obtain uniform solution, wherein the mass ratio of fibroin to chitosan is 9: 1.

(2) placing the mixed solution into an injector, extruding the solution through an extrusion pump, placing a copper ring into a low-temperature reaction bath (respectively-40, -60, -80 and-100 ℃), passing the solution through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(3) And (3) freeze-drying the frozen fiber obtained in the step (2) for 24h to remove the solvent, so as to obtain the porous fiber with an oriented porous structure. SEM characterization was performed on the porous fibers obtained at different temperatures in this example, as shown in fig. 4, illustrating that the porous fibers have an oriented pore structure.

(4) Dissolving 1.25g of poly (vinylidene fluoride-co-hexafluoropropylene) and 0.75mL of 1H,1H,2H, 2H-perfluorooctyltriethoxysilane in 50mL of acetone, and stirring at 50 ℃ for 30min to obtain a super-hydrophobic coating solution;

(5) and (3) immersing the porous fiber obtained in the step (3) into the super-hydrophobic coating solution obtained in the step (4) for 5min, and then drying at 130 ℃ for 30min to obtain the super-hydrophobic porous fiber.

(6) The super-hydrophobic porous fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 150.8 degrees, and the contact angle of the silicone oil on the surface of the fabric is 150.2 degrees.

Example 3

(2) and (3) placing the mixed solution into an injector, extruding the solution through an extrusion pump, placing a copper ring into a low-temperature reaction bath (the temperature is-100 ℃), passing the solution through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(3) And (3) freeze-drying the frozen fiber obtained in the step (2) for 24h to remove the solvent, so as to obtain the porous fiber with an oriented porous structure.

(4) And (4) immersing the porous fiber obtained in the step (3) into nano silica sol for 5min, and drying at 130 ℃ for 30min to obtain the super-hydrophobic porous fiber.

(5) The super-hydrophobic porous fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 152.1 degrees, and the contact angle of the silicone oil on the surface of the fabric is 150.8 degrees.

Example 4

(1) 0.2g of sodium carboxymethylcellulose powder is dissolved in 10ml of deionized water, and after complete dissolution, a sodium carboxymethylcellulose solution with the mass fraction of 2% is prepared.

(2) Putting the solution into an injector, extruding the solution through an extrusion pump, putting a copper ring into a low-temperature reaction bath, wherein the temperature of the copper ring is-90 ℃, enabling the solution to pass through the copper ring for freezing-spinning, and collecting the frozen fiber by using a motor.

(5) The super-hydrophobic porous fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 153.1 degrees and the contact angle of the silicone oil on the surface of the fabric is 150.0 degrees.

Example 5

(1) 0.3g of water-soluble starch powder is dissolved in 10ml of deionized water, and after complete dissolution, a starch solution with the mass fraction of 3% is prepared.

(4) And (4) immersing the porous fiber obtained in the step (3) into nano titanium dioxide sol for 5min, and drying at 130 ℃ for 30min to obtain the super-hydrophobic porous fiber.

(5) The super-hydrophobic porous fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 150.1 degrees and the contact angle of the silicone oil on the surface of the fabric is 151.2 degrees.

Example 6

(1) 0.6g of chitosan powder is dissolved in 10ml of 1 percent acetic acid solution, and the chitosan powder is stirred for 30min at the rotating speed of 800rpm/min to be uniformly mixed to prepare chitosan solution with the concentration of 60 mg/ml.

(2) Placing the mixed solution in an injector, extruding the solution by an extrusion pump, placing a copper ring in a low-temperature reaction bath (the temperature is-90 ℃ respectively), enabling the solution to pass through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(3) And (3) freeze-drying the frozen fibers obtained in the step (2) for 24h to remove the solvent, so as to obtain porous fibers, wherein the porous fibers have an oriented porous structure as shown in figure 5.

(4) And (4) soaking the porous fiber obtained in the step (3) into a mixed solution of 1H,1H,2H, 2H-perfluorooctyltriethoxysilane and nano titanium dioxide for 5min, and drying at 130 ℃ for 30min to obtain the super-hydrophobic porous fiber.

(5) The super-hydrophobic porous fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 154.2 degrees, and the contact angle of the silicone oil on the surface of the fabric is 152.1 degrees.

Example 7

(1) 0.15g of benzoyl peroxide was dissolved in 6ml of methyl methacrylate and mixed well. 0.7g of ER-10 is dissolved in 14ml of deionized water to be uniformly mixed, and then the ER-10 solution with the mass fraction of 5% is prepared. And uniformly mixing the methyl methacrylate mixed solution with the ER-10 solution to prepare methyl methacrylate emulsion with the volume fraction of 30%.

1.2g of crosslinking agent ethylene glycol dimethacrylate was added to the above emulsion and mixed well. 0.8g of nanoclay was added to the above methyl methacrylate emulsion and mixed well. 70 mu l N of N-dimethyl benzamide is added into the emulsion and evenly mixed, and then air bubbles are removed by centrifugation.

(2) And (3) placing the emulsion in an injector, extruding the solution through an extrusion pump, placing a copper ring in a low-temperature reaction bath (-100 ℃), passing the solution through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(3) The collected fibers were placed in a refrigerator at-20 ℃ for 24 h.

(4) And (4) drying the frozen fiber obtained in the step (3) in a vacuum oven at 45 ℃ for 3h to obtain the porous resin fiber with an oriented pore structure as shown in figure 6. And a thermal conductivity test was performed, the thermal conductivity was 61.3mW/(m × K).

(5) And (3) placing the porous resin fiber obtained in the step (4) in an atmosphere of 1H,1H,2H, 2H-perfluorooctyltriethoxysilane, and carrying out vapor deposition for 12H to obtain the super-hydrophobic porous resin fiber.

(6) The super-hydrophobic porous resin fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 152.4 degrees, and the contact angle of the silicone oil on the surface of the fabric is 150.3 degrees.

Example 8

(1) 0.10g of benzoyl peroxide was dissolved in 4ml of methyl methacrylate and mixed well. 0.8g of ER-10 is dissolved in 16ml of deionized water to be uniformly mixed, so as to prepare an ER-10 solution with the mass fraction of 5%. And uniformly mixing the methyl methacrylate mixed solution with the ER-10 solution to prepare a methyl methacrylate emulsion with the volume fraction of 20%.

0.8g of crosslinking agent ethylene glycol dimethacrylate was added to the above emulsion and mixed well. 0.53 g of nanoclay was added to the above methyl methacrylate emulsion and mixed well. 50 mu l N of N-dimethyl benzamide is added into the emulsion and evenly mixed, and then air bubbles are removed by centrifugation.

(3) The collected fibers were placed in a refrigerator at-20 ℃ for 24 h.

(4) And (4) placing the frozen fiber obtained in the step (3) in a vacuum oven at 45 ℃ for 3h for drying to obtain porous resin fiber with an oriented pore structure, and performing a thermal conductivity test, wherein the thermal conductivity is 56.7mW/(m × K).

(5) And (3) soaking the porous resin fiber obtained in the step (4) into a 1H,1H,2H, 2H-perfluorodecyl triethoxysilane solution for 5min, and drying at 130 ℃ for 30min to obtain the super-hydrophobic porous resin fiber.

(6) The super-hydrophobic porous resin fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 152.6 degrees, and the contact angle of the silicone oil on the surface of the fabric is 151.3 degrees.

Example 9

(1) Taking 5ml of aqueous polyurethane acrylate emulsion (mass fraction is 40%), adding 15ml of deionized water, diluting into 10% aqueous polyurethane acrylate emulsion, and mixing uniformly.

0.2g of 2-hydroxy-2-methyl-1-phenyl-1-propanone was dissolved in 20ml of aqueous urethane acrylate emulsion (10%) and mixed well. To the above emulsion was added 0.4g of ethylene glycol dimethacrylate and mixed well. Adding 0.8 nanometer clay into the emulsion to realize thickening, and centrifuging to remove bubbles after uniform mixing.

(3) The collected fibers were placed in a-20 ℃ freezer and irradiated with uv light for 7 h.

(4) And (4) drying the frozen fiber obtained in the step (3) in a vacuum oven at 45 ℃ for 3h to obtain the porous resin fiber with an oriented pore structure as shown in figure 7. And a thermal conductivity test was performed, the thermal conductivity was 45.8mW/(m × K).

(6) Weaving super-hydrophobic porous resin fibers into a fabric, and measuring the contact angle of liquid such as water, silicone oil and the like on the surface of the fabric by using a contact angle meter, wherein the test result shows that the contact angle of the water on the surface of the fabric is 150.8 degrees, and the contact angle of the silicone oil on the surface of the fabric is 151.2 degrees

Example 10

(1) 3ml of methyl methacrylate are mixed homogeneously with 3ml of butyl acrylate. 0.15g of benzoyl peroxide was dissolved in 6ml of the above mixture and mixed well. 0.7g of ER-10 is dissolved in 14ml of deionized water to be uniformly mixed to prepare an ER-10 solution with the mass fraction of 5 wt%. And uniformly mixing the methyl methacrylate mixed solution with the ER-10 solution to prepare a mixed emulsion of methyl methacrylate/butyl acrylate with the volume fraction of 30%.

1.2g of crosslinking agent ethylene glycol dimethacrylate was added to the above emulsion and mixed well. 0.8g of nanoclay was added to the above methyl methacrylate/butyl acrylate mixed emulsion and mixed well. 70 mu l N of N-dimethyl benzamide is added into the emulsion and evenly mixed, and then air bubbles are removed by centrifugation.

(3) The collected fibers were placed in a refrigerator at-20 ℃ for 24 h.

(4) And (4) placing the frozen fiber obtained in the step (3) in a vacuum oven at 45 ℃ for 3h for drying to obtain porous resin fiber with an oriented pore structure, and performing a thermal conductivity test, wherein the thermal conductivity is 50.3mW/(m × K).

(6) Weaving super-hydrophobic porous resin fibers into a fabric, and measuring the contact angle of liquid such as water, silicone oil and the like on the surface of the fabric by using a contact angle meter, wherein the test result shows that the contact angle of the water on the surface of the fabric is 155.0 degrees, and the contact angle of the silicone oil on the surface of the fabric is 152.4 degrees

Example 11

(1) 0.10g of t-butyl hydroperoxide was dissolved in 4ml of methyl methacrylate and mixed well. 0.8g of ER-10 is dissolved in 16ml of deionized water to be uniformly mixed, so as to prepare an ER-10 solution with the mass fraction of 5%. And uniformly mixing the methyl methacrylate mixed solution with the ER-10 solution to prepare a methyl methacrylate emulsion with the volume fraction of 20%.

0.8g of crosslinking agent ethylene glycol dimethacrylate was added to the above emulsion and mixed well. 0.53 g of nanoclay was added to the above methyl methacrylate emulsion and mixed well. Add 50. mu.l trioctyl tertiary amine into the above emulsion, mix well, remove the bubble by centrifugation.

(3) The collected fibers were placed in a refrigerator at-20 ℃ for 24 h.

(4) And (4) placing the frozen fiber obtained in the step (3) in a vacuum oven at 45 ℃ for 3h for drying to obtain porous resin fiber with an oriented pore structure, and performing a thermal conductivity test, wherein the thermal conductivity is 60.2mW/(m × K).

(5) 1.25g of poly (vinylidene fluoride-co-hexafluoropropylene) and 0.75mL of 1H,1H,2H, 2H-perfluorodecyltriethoxysilane were dissolved in 50mL of acetone, and stirred at 50 ℃ for 30min to obtain a superhydrophobic coating solution;

(6) and (3) immersing the porous resin fiber obtained in the step (4) into the super-hydrophobic coating solution obtained in the step (5) for 5min, and drying at 130 ℃ for 30min to obtain the super-hydrophobic porous resin fiber.

(7) Weaving super-hydrophobic porous resin fibers into a fabric, and measuring the contact angle of liquid such as water, silicone oil and the like on the surface of the fabric by using a contact angle meter, wherein the test result shows that the contact angle of the water on the surface of the fabric is 154.1 degrees, and the contact angle of the silicone oil on the surface of the fabric is 152.8 degrees

Example 12

(1) 8.0096g of ODA (4, 4' -diaminodiphenyl ether) and 95.57g of DMAc (dimethylacetamide) were sufficiently stirred, and when ODA was completely dissolved, 8.8556g of PMDA (pyromellitic dianhydride) and 4.0476g of TEA (triethylamine) were then added, and mixed and stirred for 4 hours to give a viscous pale yellow PAS (polyamic acid salt) solution. The PAS solution was slowly poured into water, washed, and freeze-dried to obtain a pale yellow PAS solid.

(2) 5g of TEA (triethylamine) and 90g of deionized water were added to 5g of PAS, and the obtained suspension was continuously stirred for several hours, mixed uniformly and then left to stand for 24 hours to obtain a PAS hydrogel with a mass fraction of 5%.

(3) And (2) placing the polyamic acid salt hydrogel with the mass fraction of 5% in an injector, extruding the hydrogel through an extrusion pump, placing a copper ring in a low-temperature reaction bath (-100 ℃), spinning through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(4) Freeze-drying the frozen fiber obtained in the step (3) for 24 hours to remove ice crystals, so as to obtain porous fiber with an oriented pore structure;

(5) carrying out thermal imidization on the porous fiber, specifically heating to 100 ℃ at room temperature at a speed of 2 ℃/min, and keeping for 30 min; heating to 200 deg.C at 2 deg.C/min, and maintaining for 30 min; and (3) heating to 300 ℃ at the speed of 2 ℃/min, keeping the temperature for 60min to obtain the polyimide porous fiber, and performing SEM characterization, wherein as shown in figure 8, the porous fiber has an oriented pore structure, and the pore diameter is 50-100 microns.

(6) 5mL of tetraethoxysilane and 0.5mL of 1H,1H,2H, 2H-perfluorooctyltriethoxysilane were dissolved in 25mL of ethanol, and 6mL of 28% NH was added₃·H₂Dissolving O in 25mL of ethanol, mixing the two solutions at room temperature, stirring the two solutions uniformly, and then carrying out ultrasonic treatment for 30min to obtain the super-hydrophobic coating solution.

(7) And (4) spraying the super-hydrophobic coating solution obtained in the step (6) on the porous fiber obtained in the step (5), drying at room temperature and further curing at 110 ℃ to obtain the super-hydrophobic porous fiber.

(8) Weaving super-hydrophobic porous fibers into a fabric, and measuring the contact angle of liquid such as water, silicone oil and the like on the surface of the fabric by using a contact angle meter, wherein the test result shows that the contact angle of the water on the surface of the fabric is 151.3 degrees, and the contact angle of the silicone oil on the surface of the fabric is 151.2 degrees

(9) The heat-insulating properties of the woven high-temperature heat-insulating flame-retardant fabric were tested. The fabric was placed on the same hot table for comparison. A series of infrared images were obtained when the heat stage was heated from 50 c to 220 c, with five representative images when the heat stage temperature was 50 c, 100 c, 150 c, 200 c, 220 c, respectively, as shown in fig. 9, the infrared images giving the background temperature of the substrate and the average temperature of the fabric surface. Fig. 10 shows statistics of the temperature of the base of the heat station and the temperature of the surface of the fabric, and the larger the temperature difference, the better the heat insulation performance.

Example 13

(2) 5g of TEA (triethylamine) and 85g of deionized water were added to 10g of PAS, and the obtained suspension was continuously stirred for several hours, mixed uniformly and then left to stand for 24 hours to obtain a PAS hydrogel with a mass fraction of 10%.

(3) And (2) placing the polyamic acid salt hydrogel with the mass fraction of 10% in an injector, extruding the hydrogel through an extrusion pump, placing a copper ring in a low-temperature reaction bath (-80 ℃), spinning through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(5) carrying out thermal imidization on the porous fiber, specifically heating to 100 ℃ at room temperature at a speed of 2 ℃/min, and keeping for 30 min; heating to 200 deg.C at 2 deg.C/min, and maintaining for 30 min; heating to 300 deg.C at 2 deg.C/min, and maintaining for 60min to obtain polyimide porous fiber with oriented porous structure, with SEM photograph shown in FIG. 11.

(6) And (3) placing the porous fiber obtained in the step (5) in an atmosphere of 1H,1H,2H, 2H-perfluorooctyltriethoxysilane, and carrying out vapor deposition for 12H to obtain the super-hydrophobic porous fiber.

(7) Weaving super-hydrophobic porous fibers into a fabric, and measuring the contact angle of liquid such as water, silicone oil and the like on the surface of the fabric by using a contact angle meter, wherein the test result shows that the contact angle of the water on the surface of the fabric is 153.2 degrees, and the contact angle of the silicone oil on the surface of the fabric is 151.3 degrees

Example 14

(3) And (2) placing the polyamic acid salt hydrogel with the mass fraction of 5% in an injector, extruding the hydrogel through an extrusion pump, placing a copper ring in a low-temperature reaction bath (-40 ℃), spinning through the copper ring to perform a freezing-spinning process, and collecting the frozen fiber by using a motor.

(5) carrying out thermal imidization on the porous fiber, specifically heating to 100 ℃ at room temperature at a speed of 2 ℃/min, and keeping for 30 min; heating to 200 deg.C at 2 deg.C/min, and maintaining for 30 min; heating to 300 deg.C at 2 deg.C/min, and maintaining for 60min to obtain polyimide porous fiber with oriented porous structure, with SEM photograph as shown in FIG. 12.

(7) The super-hydrophobic porous fiber is woven into a fabric, a contact angle of liquid such as water, silicone oil and the like on the surface of the fabric is measured by using a contact angle meter, and the test result shows that the contact angle of the water on the surface of the fabric is 153.2 degrees, and the contact angle of the silicone oil on the surface of the fabric is 154.2 degrees.

Claims

1. A preparation method of super-hydrophobic porous fiber with an oriented pore structure is characterized by comprising the following steps:

(1) preparing an emulsion to be polymerized; the emulsion to be polymerized comprises a resin monomer, a free radical polymerization initiator, a reactive emulsifier and a thickening agent, or the emulsion to be polymerized comprises a prepolymer, a free radical polymerization initiator, a reactive emulsifier and a thickening agent, or the emulsion to be polymerized comprises a self-emulsifying prepolymer, a free radical polymerization initiator and a thickening agent; the free radical polymerization initiator is a redox initiator or a photoinitiator; the redox initiator is selected from benzoyl peroxide and N, N-dimethyl benzamide, tert-butyl hydroperoxide and trioctyl tertiary amine;

(3) the frozen fiber is subjected to polymerization reaction in a low-temperature environment; the temperature of the low-temperature environment is-40 to-10 ℃;

(4) unfreezing and drying the frozen fiber to obtain porous resin fiber with an oriented pore structure; the directional freezing specifically comprises: extruding the spinning solution from an extrusion pump, and then passing through a low-temperature copper ring in a low-temperature reaction bath for directional freezing; the temperature of the low-temperature copper ring is-120-0 ℃;

2. A preparation method of super-hydrophobic porous fiber with an oriented pore structure is characterized by comprising the following steps:

i, preparing polyamic acid salt hydrogel;

II, carrying out solution spinning on the polyamic acid salt hydrogel, carrying out directional freezing during spinning, and collecting frozen fibers; the directional freezing specifically comprises: extruding the spinning solution from an extrusion pump, and then passing through a low-temperature copper ring in a low-temperature reaction bath for directional freezing; the temperature of the low-temperature copper ring is-120-0 ℃;

3. The method of preparing superhydrophobic porous fiber with oriented pore structure of claim 1 or 2, wherein the surface superhydrophobic treatment comprises: dip coating, vapor deposition or wet chemical deposition.

4. A superhydrophobic porous fiber having an oriented pore structure prepared by the preparation method as claimed in any one of claims 1 or 2.

5. Use of the superhydrophobic porous fiber having an oriented pore structure according to claim 4 in the preparation of a water and oil repellent textile material.

6. Use of the superhydrophobic porous fiber having an oriented pore structure according to claim 4 as a thermal insulation material.