A high-temperature-resistant porous membrane material and a preparation method thereof

Abstract

The application relates to a high-temperature-resistant porous membrane material and a preparation method thereof, and belongs to the technical field of wave-absorbing material preparation. The application aims to solve the problem of insufficient wave-absorbing capacity of an electromagnetic wave-absorbing material, and the method is as follows: a high-temperature-resistant nanofiber is prepared by an electrostatic spinning process and is heat-treated at high temperature; the nanofiber is blended with a polymer, and a composite fiber with high orientation of nanofibers is prepared by spinning; the composite fiber is bundled and is subjected to pressurized pyrolysis treatment at high temperature to obtain an oriented nanofiber bundle; a wave-absorbing particle modified silicone resin nanoemulsion is prepared by using a one-step emulsion method; the oriented nanofiber bundle is soaked in the wave-absorbing particle modified silicone resin nanoemulsion, is taken out after sufficient soaking and is dried; step-by-step temperature rising curing is carried out according to a modified silicone resin curing process to obtain a porous nanocolumn. The method greatly improves the wave-absorbing capacity. The porous membrane is not only heat-insulating but also high-temperature-resistant and high in wave-absorbing capacity, and is very widely applicable.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wave-absorbing material preparation, and particularly relates to a high-temperature-resistant porous membrane material and a preparation method thereof. BACKGROUND

[0002] In today's rapidly developing technology, electromagnetic waves are increasingly widely used and have penetrated into all aspects of our lives. However, electromagnetic waves, while bringing convenience, also bring many challenges, such as electromagnetic radiation pollution, electromagnetic interference, etc. With the explosive growth of electronic devices and wireless communication facilities, electromagnetic pollution is becoming increasingly serious, not only affecting the daily operation of equipment, but also posing a threat to human production activities. Therefore, how to effectively absorb and reduce the negative effects of electromagnetic waves has become an important issue in the current scientific research field. In the field of aerospace, low-density, high-temperature-resistant wave-absorbing materials are particularly important.

[0003] Low-density, high-temperature-resistant electromagnetic wave-absorbing film is a special film material that is lightweight, high-strength, and can work stably at high temperatures and effectively absorb electromagnetic waves. The development of this film combines the wisdom of material science, electromagnetics, chemistry, and other disciplines. Its preparation process involves complex chemical reactions and physical processes, and by precisely controlling the proportion of raw materials and reaction conditions, wave-absorbing films with excellent performance can be prepared. In the composition of high-temperature-resistant electromagnetic wave-absorbing film, micro-nano array structure and wave-absorbing filler are the core components. On the one hand, the multi-level reflection of the micro-nano array structure is used to improve the absorption of electromagnetic waves; on the other hand, the physical wave-absorbing and structural design of the wave-absorbing filler are used to achieve high-efficiency absorption of wide-band electromagnetic waves by adjusting the dielectric constant and flash characteristics. In addition, electromagnetic wave-absorbing film also has the characteristics of high absorption, good compatibility, and large dielectric loss, so that electromagnetic waves are effectively converted into heat and electricity inside the film layer and are consumed through electronic scattering, energy conduction, or low-frequency electromagnetic radiation.

[0004] In addition to excellent wave-absorbing performance, electromagnetic wave-absorbing film also has excellent high-temperature resistance. It can remain stable at high temperatures up to 1500℃ without falling off or cracking, ensuring the long-term effective wave-absorbing function of the coating. This feature makes high-temperature-resistant electromagnetic wave-absorbing film have broad application prospects in high-temperature equipment, aerospace vehicles, and other fields. With the continuous development of technology, high-temperature-resistant electromagnetic wave-absorbing coating and its coating technology will continue to be optimized and improved. In the future, we can expect this coating to be applied in more fields to bring more convenience and safety to people's lives. At the same time, we should also pay attention to the new problems and challenges that may arise in the application process and continuously explore solutions to promote the continuous progress and development of this technology. SUMMARY

[0005] The application aims to solve the problem of insufficient wave absorption capability of electromagnetic wave absorption materials, and provides a high-temperature-resistant porous film material and a preparation method thereof. The method constructs a nano array light trap, uses a new nano array porous film as a carrier, loads high wave absorption materials in the regular and ordered nano channels, adjusts electromagnetic parameters, improves impedance matching degree and dispersity, so as to obtain a light and efficient wave absorption film material. On one hand, the light reflection on the film surface is weakened, and on the other hand, the light entering the nano hole is reflected and absorbed on the hole surface for multiple times, so that the wave absorption characteristic is greatly enhanced.

[0006] To achieve the above-mentioned purpose, the technical scheme adopted by the application is as follows:

[0007] The application provides a preparation method of a high-temperature-resistant porous film material.

[0008] (1) A high-temperature-resistant fiber precursor is prepared by an electrostatic spinning process, and the fiber precursor is heat treated at high temperature to obtain a high-temperature-resistant nano fiber.

[0009] (2) The high-temperature-resistant nano fiber is blended with a polymer (the proportion of the polymer is 60% to 99.99%), and a composite fiber with highly oriented nano fibers is prepared by spinning.

[0010] (3) The composite fiber is bundled and subjected to pressurized pyrolysis treatment at high temperature to obtain an oriented nano fiber bundle.

[0011] (4) A wave absorption particle modified silicone resin nano emulsion is prepared by a one-step emulsion method.

[0012] (5) The oriented nano fiber bundle is soaked in the wave absorption particle modified silicone resin nano emulsion, and after sufficient adsorption and infiltration, the oriented nano fiber bundle is taken out and dried.

[0013] (6) Stepwise temperature rising curing is performed according to a modified silicone resin curing process, so that a porous nano column body with a rough surface and magnetism is obtained.

[0014] (7) The porous nano column body is cut according to the required size to obtain a shock-resistant and high-temperature-resistant wave absorption porous film.

[0015] Further, in step (1), the high-temperature-resistant fiber is one or a combination of glass fiber, basalt fiber, asbestos fiber, metal fiber, boron nitride fiber, ceramic fiber, carbon fiber and graphite fiber.

[0016] Further, in step (1), the electrostatic spinning condition is that the spinning liquid concentration is 0.5% to 30%, and the voltage is 1 to 100 kV. The spinning liquid is a mixture of high-temperature-resistant fiber precursor particles and a solvent. The solvent is one or a mixture of dimethyl sulfoxide, tetrahydrofuran, ethanol, methanol, acetic acid, who, ethylene glycol, acetone, acetonitrile, phenol and methyl sulfonic acid.

[0017] Further, in step (1), the temperature of the heat treatment is 20-3000 DEG C, and the time is 0.1-72 h.

[0018] Further, in step (2), the polymer is one or more of polyethylene, polypropylene, polyethylene terephthalate, phenolic resin, epoxy resin, polyurethane, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene glycol, polyamide, and cellulose.

[0019] Further, in step (2), the high-temperature-resistant nanofiber and the polymer are blended by solvent blending or melt blending, and correspondingly, if melt blending is adopted, the spinning is melt spinning; if solution blending is adopted, the spinning is solution spinning; the temperature of the melt blending is 50-400 DEG C.

[0020] Still further, in step (2), the solvent of the solvent blending is one or a mixture of acetone, ethanol, methanol, ethylene glycol, acetonitrile, dimethyl sulfoxide, N, N-dimethylformamide, dichloromethane, chloroform, phenol, and paraffin oil. Most of the solvent blending does not need to be heated, but some systems need to be heated, and the highest temperature does not exceed 260 DEG C.

[0021] Further, in step (3), the high-temperature and high-pressure pyrolysis treatment condition is that the pressure is 0.1-20 MPa, the temperature is 20-1000 DEG C, and the time is 0.1-24 h; in step (6), the stepwise heating and curing is specifically that the curing is carried out at 200-300 DEG C for 1-3 h, at 400-500 DEG C for 1-2 h, and at 600-800 DEG C for 0.1-1 h.

[0022] Further, in step (4), the one-step emulsion method condition is that the wave-absorbing particle modified silicone resin is added to a water phase containing 10 wt% emulsifier and 15 wt% dispersant at a speed of 1-10 drops per second, the stirring speed is 100-10000 rpm, and the stirring time is 1-60 minutes; the concentration of the wave-absorbing particle modified silicone resin is 0.5-50 wt%.

[0023] Further, in step (4), the wave-absorbing particle is one or more of graphite, graphene, carbon black, carbon fiber, carbon nanotube, ferrite, iron oxide, magnetic iron nanomaterial, silicon carbide, conductive polymer, chiral material, and plasmonic material. The wave-absorbing particle is dispersed by high-speed stirring with the organic silicone resin, and the mass ratio is 5:95-45:55, so that the wave-absorbing particle modified silicone resin is obtained.

[0024] A high-temperature-resistant porous membrane material prepared by the preparation method.

[0025] The present application has the following beneficial effects over the prior art:

[0026] (1) The method can prepare highly ordered nanowire array structure, greatly improving the wave absorption capacity.

[0027] (2) The porous membrane not only has heat insulation, but also has high temperature resistance, strong wave absorption capacity, and very wide application.

[0028] (3) Through the programmed arrangement and sintering treatment of nanowires, the preparation of special-shaped curved surface membrane materials can be simply realized, greatly reducing the quality problems caused by traditional cutting and polishing, and saving costs.

[0029] (4) The process is simple and feasible, and easy to mass produce. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a schematic diagram of a precursor structure;

[0031] Figure 2 is a schematic diagram of a precursor structure obtained by electrospinning;

[0032] Figure 3 is a schematic diagram of nanofibers obtained by high temperature treatment;

[0033] Figure 4 is a schematic diagram of nanofiber / polymer blend;

[0034] Figure 5 is a schematic diagram of nanofiber / polymer fiber;

[0035] Figure 6 is a schematic diagram of nanofiber / polymer fiber bundle;

[0036] Figure 7 is a schematic diagram of nanofiber / polymer bundle fiber high temperature pyrolysis structure;

[0037] Figure 8 is a schematic diagram of high temperature pyrolysis bundle fiber surface attached magnetic particle structure;

[0038] Figure 9 is a schematic diagram of wave absorbing block to membrane material segmentation;

[0039] Figure 10 is a ceramic nanofiber morphology diagram in Example 1;

[0040] Figure 11 is a ceramic nanofiber / polymer composite fiber internal structure diagram in Example 1;

[0041] Figure 12 is a ceramic nanofiber / polymer composite fiber bundle structure diagram in Example 1;

[0042] Figure 13Figure 1 is a morphology diagram of the ceramic nanofiber / polymer composite fiber bundle after being attached with the wave-absorbing particles in Example 1;

[0043] Figure 14 Figure 4 is a surface morphology diagram of the ceramic film after being cut in Example 1. DETAILED DESCRIPTION

[0044] The technical solutions in the present application will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application. The specific conditions not mentioned in the embodiments are carried out according to the conventional conditions or the conditions suggested by the manufacturers. The reagents or instruments not mentioned by the manufacturers are all conventional products that can be purchased in the market.

[0045] Example 1

[0046] (1) 90 g of aluminum powder and 10 g of aluminum chloride were added into 200 g of deionized water, and the mixture was stirred and refluxed at a temperature of 60-100 ℃. 5 g of cryolite was added, and the stirring was continued for 12-48 hours. The obtained solution was aged at a temperature of 50-120 ℃ until the viscosity reached 1-5000 Pa·s, thereby obtaining an electrospinning precursor. The aluminum oxide ceramic fiber precursor was prepared by an electrospinning process under a voltage of 20 kV, and the fiber precursor was heat-treated at 1300 ℃ for 3 h to obtain high-temperature-resistant nanofibers, as shown in Figure 1. Figure 10

[0047] (2) The ceramic fibers were blended with polyethylene terephthalate (mass ratio 20:80), and the ceramic fiber highly oriented polyethylene terephthalate composite fiber was prepared by melt spinning at 285 ℃.

[0048] (3) The ceramic fiber highly oriented polyethylene terephthalate composite fiber was bundled, and the pressure was 5 MPa, the temperature was 800 ℃, and the pyrolysis time was 4 h, thereby obtaining an oriented ceramic nanofiber bundle, as shown in Figure 3. Figure 12

[0049] (4) 10 g of iron oxide particle modified silicone resin (mass ratio 5:95) was added dropwise into an aqueous phase containing 10 wt% emulsifier and 15 wt% dispersant at a speed of 2 drops per second, and the stirring speed was 2000 revolutions per minute for 30 minutes, thereby obtaining an iron oxide particle modified silicone resin emulsion.

[0050] (5) The oriented ceramic nanofiber bundle was soaked in the iron oxide particle modified silicone resin emulsion, and after adsorbing and infiltrating for 0.4 h, it was taken out and dried under the conditions of normal pressure, 120 ℃, and 2 h.

[0051] ​​(6) according to the modified silicone resin curing process step curing, step curing conditions for, 220 ℃ curing 2h, 450 ℃ curing 1.5h, 700 ℃ curing 0.3h, get the surface rough, and the magnetic porous nanocolumn, such as Figure 13 shown;

[0052] (7) porous nanocolumns according to the required size cutting, get the impact, high temperature resistant wave absorbing porous film, such as Figure 14

[0053] The thickness direction of the obtained wave absorbing porous film is 123 MPa at room temperature, 54 MPa at 800 ℃, 82.3% porosity, 30 MHz-18 GHz≥15 dB, and high temperature resistance≥1000 ℃.

[0054] Example 2:

[0055] (1) in 320g deionized water, add 50g boron trioxide and 10g tricalcium phosphate, the mixed solution is stirred at 60-100 ℃ temperature under reflux, namely electrostatic spinning precursor. With 10g alumina, 4.8h ammonium chloride blending, under the voltage of 12kV, through the electrostatic spinning process preparation alumina boron nitride fiber precursor, the fiber precursor is treated in ammonia gas, 300 ℃ treatment 2h, 800 ℃ treatment 3h, 1300 ℃ heat treatment 3h get high temperature resistant boron nitride nanofiber;

[0056] (2) boron nitride fiber and polyethylene blending (mass ratio 25:75), in 170 ℃ through melt spinning preparation boron nitride fiber highly oriented polyethylene composite fiber;

[0057] (3) boron nitride fiber highly oriented polyethylene composite fiber bundle, 3MPa pressure, temperature 800 ℃, pyrolysis 4h, get oriented boron nitride nanofiber bundle;

[0058] (4) 10g iron oxide particles modified silicone resin (mass ratio 5:95) is added to the water phase containing 10wt% emulsifier, 15wt% dispersant at the speed of 2 drops per second, the stirring speed is 2000r / min, and the stirring time is 30 minutes, to get the iron oxide particles modified silicone resin emulsion;

[0059] (5) the oriented boron nitride nanofiber bundle is soaked in the iron oxide particle modified silicone resin emulsion, and the adsorption infiltration is 0.4h, then it is taken out and dried, and the drying conditions are normal pressure, 120 ℃, 2h;

[0060] (6) according to the modified silicone resin curing process step curing, step curing conditions for, 220 ℃ curing 2h, 450 ℃ curing 1.5h, 700 ℃ curing 0.3h, get the surface rough, and the magnetic porous nanocolumn, such as​

[0061] (7) The porous nanocolumns are cut according to the required size to obtain the shock-resistant and high-temperature-resistant wave-absorbing porous film.

[0062] The obtained wave-absorbing porous film has a thickness direction normal temperature compressive strength of 77 MPa, an 800℃ compressive strength of 24 MPa, a porosity of 89.1%, a wave-absorbing property of 30MHz-18GHz≥11dB, and a high-temperature resistance of ≥1260℃.

Claims

1. A method of making a high temperature resistant porous membrane material, characterized by: The method is: (1) A high-temperature resistant fiber precursor is prepared by an electrospinning process, and the fiber precursor is heat-treated at high temperature to obtain a high-temperature resistant nanofiber; the high-temperature resistant nanofiber is one or a combination of glass fiber, basalt fiber, asbestos fiber, metal fiber, boron nitride fiber, ceramic fiber, carbon fiber, and graphite fiber; (2) The high-temperature resistant nanofiber is blended with a polymer, and the polymer accounts for 60% to 80%, and a nanofiber highly oriented composite fiber is prepared by spinning; (3) The composite fiber is bundled and subjected to pressurized pyrolysis treatment at high temperature to obtain an oriented nanofiber bundle; (4) A wave-absorbing particle modified silicone resin nanoemulsion is prepared by a one-step emulsion method; the one-step emulsion method is as follows: the wave-absorbing particle modified silicone resin is added dropwise into an aqueous phase containing 10 wt% emulsifier and 15 wt% dispersant at a speed of 1 to 10 drops per second; wherein the wave-absorbing particle is dispersed by high-speed stirring with the organic silicone resin to obtain the wave-absorbing particle modified silicone resin; (5) The oriented nanofiber bundle is soaked in the wave-absorbing particle modified silicone resin nanoemulsion, and after sufficient adsorption and infiltration, it is taken out and dried; (6) Stepwise temperature rising curing is performed according to a modified silicone resin curing process to obtain a porous nanocolumn.

2. The method of claim 1, wherein: In step (1), the electrospinning conditions are as follows: the concentration of the spinning solution is 0.5% to 30%, and the voltage is 12 to 20 kV.

3. The method of claim 1, wherein the method further comprises: In step (1), the temperature of the heat treatment is 1300 to 3000℃, and the time is 3h.

4. The method of claim 1, wherein the method further comprises: In step (2), the polymer is one or more of polyethylene, polypropylene, polyethylene terephthalate, phenolic resin, epoxy resin, polyurethane, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene glycol, and polyamide.

5. The method of claim 1, wherein the method further comprises: In step (2), the high-temperature resistant nanofiber is blended with the polymer by solution blending or melt blending; correspondingly, if melt blending is adopted for blending, the spinning is melt spinning; if solution blending is adopted for blending, the spinning is solution spinning; the temperature of the melt blending is 170 to 400℃.

6. The method of claim 1, wherein: In step (3), the pressurized pyrolysis treatment conditions are as follows: the pressure is 3 to 20 MPa, the temperature is 800 to 1000℃, and the time is 4 to 24h; in step (6), the stepwise temperature rising curing is as follows: curing at 200 to 300℃ for 1 to 3h, curing at 400 to 500℃ for 1 to 2h, and curing at 600 to 800℃ for 0.1 to 1h.

7. The method of claim 1, wherein the method further comprises: In step (4), the stirring speed is 100 to 10000 revolutions per minute, and the stirring time is 1 to 60 minutes; the concentration of the wave-absorbing particle modified silicone resin is 0.5 to 50 wt%.

8. The method of claim 1, wherein the method further comprises: In step (4), the wave-absorbing particle is one or more of graphite, graphene, carbon black, carbon fiber, carbon nanotube, ferrite, silicon carbide, chiral material, and plasmonic material.

9. A high-temperature resistant porous membrane material prepared by the preparation method of any one of claims 1 to 8.

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