Preparation method of composite structure Ti3C2Tx / polyimide film capable of resisting atomic oxygen erosion

Abstract

The invention discloses a preparation method of a composite structure Ti3C2Tx / polyimide film capable of resisting atomic oxygen erosion. The preparation method comprises the following steps: by taking a two-dimensional material Ti3C2Tx as an atomic oxygen resisting material, firstly, preparing a homogeneous Ti3C2Tx / polyamide acid-based membrane by utilizing a blade coating technology; and forming a Ti < 3 > C < 2 > T < x > / polyamide acid coating with high Ti < 3 > C < 2 > T < x > content on the Ti < 3 > C < 2 > T < x > / polyamide acid base film to obtain the Ti < 3 > C < 2 > T < x > / polyamide acid film with a composite structure. And finally, carrying out gradient heat treatment on the composite structure Ti3C2Tx / polyamide acid film, and carrying out cross-linking reaction on polyamide acid to generate polyimide, so as to obtain the atomic oxygen erosion resistant composite structure Ti3C2Tx / polyimide film. The preparation method is simple in preparation process, short in time, rapid in forming and controllable in process, and the prepared composite structure Ti3C2Tx / polyimide film is good in mechanical property and has excellent atomic oxygen corrosion resistance.

Description

Technical Field

[0001] The present invention belongs to the field of nanocomposite materials, and specifically relates to a preparation method of a composite structure Ti 3 C 2 T x / polyimide film resistant to atomic oxygen erosion. Background Art

[0002] In the low Earth orbit environment, high-flux atomic oxygen has strong oxidizing properties and will strongly erode the polyimide material on the surface of spacecraft, resulting in the breaking of its chemical bonds, mass loss, and a significant decline in mechanical properties, thus threatening the safe operation of spacecraft. At present, with the rapid development of aerospace technology, how to effectively improve the atomic oxygen erosion resistance of polyimide has become an important technical challenge that urgently needs to be overcome in the scientific research field.

[0003] Currently, the commonly used protection method at home and abroad is surface coating protection of polyimide. Oxides with excellent atomic oxygen resistance are deposited on the surface of polyamide to achieve the effect of resisting atomic oxygen erosion. Taking inorganic coatings as an example, Gotlib-Vainstein et al. deposited SiO 2 inert protective layers on the surface of polyimide, effectively preventing the erosion of atomic oxygen on polyimide (ACS Applied Materials&Interfaces, 2015, 7, 3539-3546). However, once cracks or peeling occur in the protective coating, atomic oxygen will have a strong "undercutting" effect on polyimide. At the same time, the method of matrix modification is used to add graphene to the polyimide matrix to improve the ability to resist atomic oxygen corrosion (Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2021, 629, 127398.). However, it takes a certain amount of time to form a passivation layer by this method, and increasing the content of graphene will lead to a significant decline in the mechanical properties of polyimide.

[0004] At the same time, currently, the means of protecting polyimide from atomic oxygen usually adopt methods such as liquid-phase deposition method, hot-pressing process deposition method, and sol-gel method to achieve. However, the above preparation processes are relatively complex, require a long time for preparation, and have poor controllability. Summary of the Invention

[0005] Aiming at the deficiencies of the prior art, the technical problem to be solved by the present invention is to provide a preparation method of a composite structure Ti 3 C 2 T x / polyimide film resistant to atomic oxygen erosion.

[0006] The technical solution of the present invention to solve the above technical problems is to provide a preparation method of a composite structure Ti 3 C 2 T x / polyimide film, characterized in that the method comprises the following steps:

[0007] Step 1: Mix the polyamic acid solution and the Ti 3 C 2 T x nanosheet suspension evenly to obtain a first film-forming solution;

[0008] Step 2: Knife-coat the first film-forming solution of Step 1 on a smooth heat-conducting substrate, and continuously heat to remove the solvent in the first film-forming solution; after the first film-forming solution loses fluidity, continue to knife-coat the first film-forming solution of Step 1 on this first film-forming solution; repeat the knife-coating and heating processes several times; after the last knife-coating is completed, continuously heat until the first film-forming solution of the last knife-coating loses fluidity, and form a Ti 3 C 2 T x / polyamic acid-based film on the smooth heat-conducting substrate;

[0009] Step 3: Mix the polyamic acid solution and the Ti 3 C 2 T x nanosheet suspension evenly to obtain a second film-forming solution; using the Ti 3 C 2 T x / polyamic acid-based film of Step 2 as the substrate, knife-coat the second film-forming solution on the Ti 3 C 2 T x / polyamic acid-based film, continuously heat to completely remove the solvents in the first film-forming solution and the second film-forming solution, and form a Ti 3 C 2 T x / polyamic acid coating on the Ti 3 C 2 T x / polyamic acid film, and obtain a composite structure Ti 3 C 2 T x / polyamic acid film;

[0010] Step 4: Gradient heat-treat the composite structure Ti 3 C 2 T x / polyamic acid film obtained in Step 3, the polyamic acid undergoes a cross-linking reaction to generate polyimide, and obtain a composite structure Ti 3 C 2 T x / polyimide film resistant to atomic oxygen erosion.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] (1) The present invention uses the layered two-dimensional material Ti 3 C 2 T x as the anti-atomic oxygen material. First, a homogeneous Ti 3 C 2 T x / polyamic acid-based film is prepared by using the doctor blade technique; then a Ti 3 C 2 T x / polyamic acid-based film with a high Ti 3 C 2 T x content Ti 3 C 2 T x / polyamic acid coating is formed to obtain a composite structure Ti 3 C 2 T x / polyamic acid film; finally, the composite structure Ti 3 C 2 T x / polyamic acid film is subjected to gradient heat treatment, and the polyamic acid undergoes a cross-linking reaction between layers and within layers to generate polyimide, obtaining a composite structure Ti 3 C 2 T x / polyimide film that resists atomic oxygen erosion.

[0013] (2) The preparation process of the present invention is simple, takes a short time, enables rapid prototyping, and the process is controllable. The prepared composite structure Ti 3 C 2 T x / polyimide film has good mechanical properties and excellent anti-atomic oxygen erosion performance.

[0014] (3) Starting from the perspective of structural design, in the composite structure of the present invention, a low content of Ti 3 C 2 T x is added through the method of matrix modification to form the bottom Ti 3 C 2 T x / polyamic acid-based film, and a thin layer of Ti 3 C 2 T x with a high Ti 3 C 2 T x / polyamic acid coating. A single matrix modification will expose a large amount of polyimide to direct contact with atomic oxygen, providing holes for subsequent erosion; a single coating will crack and lose its atomic oxygen protection ability. The present invention gives full play to the advantages of anti-atomic oxygen erosion of both matrix modification protection and coating protection methods. The top and the substrate are not prone to cracking, and a high content of Ti in the top coating 3 C 2 T x can achieve a good effect of resisting atomic oxygen erosion.

[0015] (4) The composite structure Ti 3 C 2 T x / polyimide film prepared by the present invention has good mechanical properties, and its tensile strength is 130 - 160 MPa. Using a ground atomic oxygen simulation device to irradiate the composite structure Ti 3 C 2 T x / polyimide film, when the atomic oxygen fluence is 2.14×10 20 atoms / cm 2 ², the atomic oxygen erosion rate of the composite structure Ti 3 C 2 T x / polyimide film is 7 - 25% of that of the polyimide film, showing excellent anti-atomic oxygen erosion performance. Before and after atomic oxygen erosion, the surface morphology and roughness change of the composite structure Ti 3 C 2 T x / polyimide film is significantly less than that of the polyimide film. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 are the stress-strain diagrams of the polyimide film of Comparative Example 1 and the homogeneous Ti 3 C 2 T x / polyimide film of Comparative Example 2, and the composite structure Ti 3 C 2 T x / polyimide films of Example 1, Example 2, Example 3 and Example 4 of the present invention;

[0017] Figure 2 is the cross-sectional SEM image (magnification: 5000 times) of the polyimide film of Comparative Example 1 of the present invention;

[0018] Figure 3 is the homogeneous Ti 3 C 2 T xCross-sectional SEM image of the polyimide film (magnification: 5000 times);

[0019] Figure 4 This is the composite structure Ti of Example 3 of the present invention 3 C 2 T x Cross-sectional SEM image of the polyimide film (magnification: 5000 times);

[0020] Figure 5 This is the surface SEM image of the polyimide film of Comparative Example 1 of the present invention before being eroded by atomic oxygen (magnification: 5000 times);

[0021] Figure 6 This is the surface SEM image of the polyimide film of Comparative Example 1 of the present invention after being eroded by atomic oxygen (magnification: 5000 times);

[0022] Figure 7 This is the homogeneous Ti of Comparative Example 2 of the present invention 3 C 2 T x Surface SEM image of the polyimide film before being eroded by atomic oxygen (magnification: 5000 times);

[0023] Figure 8 This is the homogeneous Ti of Comparative Example 2 of the present invention 3 C 2 T x Surface SEM image of the polyimide film after being eroded by atomic oxygen (magnification: 5000 times);

[0024] Figure 9 This is the composite structure Ti of Example 3 of the present invention 3 C 2 T x Surface SEM image of the polyimide film before being eroded by atomic oxygen (magnification: 5000 times);

[0025] Figure 10 This is the composite structure Ti of Example 3 of the present invention 3 C 2 T x Surface SEM image of the polyimide film after being eroded by atomic oxygen (magnification: 5000 times);

[0026] Figure 11 This is the atomic force microscopy image of the polyimide film of Comparative Example 1 of the present invention before being eroded by atomic oxygen;

[0027] Figure 12 This is the atomic force microscopy image of the polyimide film of Comparative Example 1 of the present invention after being eroded by atomic oxygen;

[0028] Figure 13 Homogeneous Ti of Comparative Example 2 of the present invention 3 C 2 T x Atomic force microscopy image of the TiC / T polyimide film before being eroded by atomic oxygen;

[0029] Figure 14 Homogeneous Ti of Comparative Example 2 of the present invention 3 C 2 T x Atomic force microscopy image of the TiC / T polyimide film after being eroded by atomic oxygen;

[0030] Figure 15 Composite structure Ti of Example 3 of the present invention 3 C 2 T x Atomic force microscopy image of the TiC / T polyimide film before being eroded by atomic oxygen;

[0031] Figure 16 Composite structure Ti of Example 3 of the present invention 3 C 2 T x Atomic force microscopy image of the TiC / T polyimide film after being eroded by atomic oxygen. Detailed implementation manners

[0032] The following are specific embodiments of the present invention. The specific embodiments are only used to further illustrate the present invention in detail and do not limit the protection scope of the claims of the present invention.

[0033] The present invention provides a method for preparing a composite structure TiC / T polyimide film (hereinafter referred to as the method), which is characterized in that the method comprises the following steps: 3 C 2 T x / polyimide film, and preferably, step 1 is specifically: mixing the polyamic acid solution and the TiC nanosheet suspension evenly, and then adding a solvent to dilute to a required concentration to obtain the first film-forming solution; the solvent is the solvent in the polyamic acid solution and the TiC nanosheet suspension.

[0034] Step 1, mixing a polyamic acid solution and a TiC (titanium carbide) nanosheet suspension evenly to obtain a first film-forming solution; 3 C 2 T x (titanium carbide) nanosheet suspension evenly to obtain a first film-forming solution;

[0035] Preferably, step 1 is specifically: mixing the polyamic acid solution and the TiC 3 C 2 T x nanosheet suspension evenly, and then adding a solvent to dilute to a required concentration to obtain the first film-forming solution; the solvent is the solvent in the polyamic acid solution and the TiC 3 C 2 T x nanosheet suspension.

[0036] Preferably, in step 1, the polyamic acid solution is a DMAC or DMF solution of polyamic acid, and the Ti 3 C 2 T x solution is a DMAC or DMF solution of Ti 3 C 2 T x .

[0037] Preferably, in step 1, in the first film-forming solution, the mass of Ti 3 C 2 T x is 1-4% (preferably 1%) of the mass of polyamic acid, and the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid is 12-15 wt% (preferably 12.5 wt%).

[0038] Step 2: Knife-coat the first film-forming solution of step 1 on a smooth heat-conducting substrate, and continuously heat to remove the solvent in the first film-forming solution; after the first film-forming solution loses fluidity, knife-coat the first film-forming solution of step 1 on this first film-forming solution again; repeat the knife-coating and heating processes several times; after the last knife-coating is completed, continuously heat until the first film-forming solution of the last knife-coating loses fluidity, and form a Ti 3 C 2 T x / polyamic acid-based film on the smooth heat-conducting substrate;

[0039] Preferably, step 2 is specifically: lay the smooth heat-conducting substrate flat on a knife coater, set the knife-coating parameters; then when the temperature of the heating table rises to the heating temperature, knife-coat the first film-forming solution of step 1 on the smooth heat-conducting substrate, and continuously heat to remove the solvent in the first film-forming solution; after the first film-forming solution loses fluidity, knife-coat the first film-forming solution of step 1 on this first film-forming solution again; repeat the knife-coating and heating processes several times; after the last knife-coating is completed, continuously heat until the first film-forming solution of the last knife-coating loses fluidity, and form a Ti 3 C 2 T x / polyamic acid-based film on the smooth heat-conducting substrate.

[0040] Preferably, in step 2, the knife-coating parameters are: the height of the knife is 250-400 μm, the heating temperature is 60-90 °C, and the forward rate is 9-12 mm / s.

[0041] Preferably, in step 2, the knife-coating and heating processes are repeated 3-5 times, and the time interval between each knife-coating is 5-8 min.

[0042] Preferably, in step 2, the smooth heat-conducting substrate is made of stainless steel.

[0043] Preferably, in step 2, before scraping coating, the smooth heat-conducting substrate is first treated with a release agent. Specifically, polytetrafluoroethylene release agent is sprayed on the surface of the smooth heat-conducting substrate, and then heat treatment is carried out to reduce the adhesion between the substrate and the film; the temperature of the heat treatment is 220 - 250 °C, and the time is 25 - 40 min, preferably carried out in an oven.

[0044] Preferably, in step 2, Ti 3 C 2 T x / polyamic acid-based film has a thickness of 20 - 40 μm.

[0045] Step 3: Mix the polyamic acid solution and the Ti 3 C 2 T x nanosheet suspension evenly to obtain a second film-forming solution; using the Ti 3 C 2 T x / polyamic acid-based film in step 2 as the substrate, after adjusting the Ti 3 C 2 T x / polyamic acid-based film to a suitable height with a feeler gauge, scrape and coat the second film-forming solution on the Ti 3 C 2 T x / polyamic acid-based film, continuously heat to completely remove the solvents in the first film-forming solution and the second film-forming solution, and form a high-Ti 3 C 2 T x / polyamic acid coating on the Ti 3 C 2 T x content Ti 3 C 2 T x / polyamic acid film; 3 C 2 T x / polyamic acid film;

[0046] Preferably, in step 3, the polyamic acid solution uses a DMAC or DMF solution of polyamic acid, and the Ti 3 C 2 T x solution uses a DMAC or DMF solution of Ti 3 C 2 T x .

[0047] Preferably, in step 3, in the second film-forming solution, the mass of Ti 3 C 2 T x accounts for Ti 3 C2 T x is 10 to 100% (preferably 10%, 40%, 70% and 100%) of the sum of the mass of TiC and polyamic acid, and Ti 3 C 2 T x and the sum of the mass fractions of polyamic acid is 0.2 to 0.5 wt%.

[0048] Preferably, in step 3, a feeler gauge with a thickness of 60 to 75 μm is placed on both sides of the smooth heat-conducting substrate, and the appropriate position is adjusted.

[0049] Preferably, in step 3, when scraping the second film-forming solution, a wire bar is used instead of a scraper for scraping.

[0050] Preferably, in step 3, the time for continuously heating to completely remove the solvent is 20 to 30 min.

[0051] Preferably, in step 3, the high-content Ti 3 C 2 T x / polyamic acid coating has a thickness of 1 to 3 μm.

[0052] Step 4: Gradient heat-treat the composite structure Ti 3 C 2 T x / polyamic acid film, and the polyamic acid undergoes a cross-linking reaction to form polyimide, obtaining a composite structure Ti 3 C 2 T x / polyimide film resistant to atomic oxygen erosion.

[0053] Preferably, in step 4, the process of gradient heat treatment is: first treat at 70 to 85 °C for 5 to 8 h, then treat at 150 to 180 °C for 30 to 45 min, and finally treat at 200 to 260 °C for 10 to 25 min.

[0054] Preferably, in step 4, the gradient heat treatment is carried out in a drying oven.

[0055] Preferably, step 4 further includes: before gradient heat treatment, turn off the heating of the heating plate of the doctor coater, and cool the composite structure Ti 3 C 2 T x / polyamic acid film to room temperature.

[0056] Preferably, step 4 further includes: after gradient heat treatment, cool to room temperature, and remove the composite structure Ti 3 C 2 T x / polyimide film resistant to atomic oxygen erosion from the smooth heat-conducting substrate.

[0057] Example 1:

[0058] (1) Mix 4.8 g of polyamic acid DMAC solution (25 wt%) and 0.6 g of Ti 3 C 2 T x nanosheet DMAC suspension (2 wt%) evenly, then add 4.6 g of DMAC for dilution, and adjust the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid to 12 wt%, where the mass of Ti 3 C 2 T x is 1% of the mass of polyamic acid, to obtain the first film-forming solution;

[0059] (2) Spray the release agent on the surface of the smooth heat-conducting substrate, and perform heat treatment at 220 °C in an oven for 25 min; then lay the smooth heat-conducting substrate treated with the release agent flat on the doctor coater, and adjust the doctor height of the doctor coater to 250 μm, the heating temperature to 60 °C, and the forward rate to 9 mm / s; when the temperature of the heating table rises to the heating temperature, scrape the first film-forming solution onto the smooth heat-conducting substrate, and continuously heat to remove the solvent in the first film-forming solution; after the first film-forming solution loses fluidity, scrape the first film-forming solution on top of this first film-forming solution; repeat the scraping and heating processes 3 times, with a 5-min interval between each scraping; after the last scraping is completed, continue heating until the first film-forming solution of the last scraping loses fluidity, and form a Ti 3 C 2 T x / polyamic acid-based film with a thickness of 20 μm on the smooth heat-conducting substrate;

[0060] (3) Mix the polyamic acid solution and the Ti 3 C 2 T x nanosheet suspension evenly to obtain the second film-forming solution, where the mass of Ti 3 C 2 T x accounts for 10% of the sum of the mass of Ti 3 C 2 T x and polyamic acid, and the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid is 0.2 wt%; using the Ti 3 C 2 T x / polyamic acid-based film as the substrate, use a feeler gauge with a thickness of 60 μm to place the Ti 3 C 2 T xAfter adjusting the polyamic acid-based film to the appropriate height, a wire bar is used to scrape and coat the second film-forming solution on the Ti 3 C 2 T x / polyamic acid-based film, and continuously heated for 20 min to completely remove the solvents in the first film-forming solution and the second film-forming solution. A Ti 3 C 2 T x / polyamic acid-based film with a thickness of 1 μm is formed on the Ti 3 C 2 T x / polyamic acid coating to obtain a composite structure Ti 3 C 2 T x / polyamic acid film;

[0061] (4) Turn off the heating of the heating plate and cool to room temperature; then place the smooth heat-conducting substrate with the attached composite structure Ti 3 C 2 T x / polyamic acid film in a blast drying oven, first treat it at 70 °C for 5 h, then at 150 °C for 30 min, and finally at 200 °C for 10 min. The polyamic acid undergoes a cross-linking reaction to form polyimide; after cooling to room temperature, the film after gradient heat treatment is removed from the smooth heat-conducting substrate to obtain a composite structure Ti 3 C 2 T x / polyimide film.

[0062] After testing, the tensile strength of the composite structure Ti 3 C 2 T x / polyimide film is 153 MPa. When the atomic oxygen fluence is 2.14×10 20 atoms / cm 2 , the atomic oxygen erosion rate of the composite structure Ti 3 C 2 T x / polyimide film is 0.64×10 -24 cm 3 / atom, which is 24% of the polyimide film in Comparative Example 1. Before and after atomic oxygen erosion, the surface morphology and roughness change little.

[0063] Example 2:

[0064] (1) Mix 4.8 g of polyamic acid DMAC solution (25 wt%) and 1.2 g of Ti 3 C 2 T x nanosheet DMAC suspension (2 wt%) evenly, and then add 3.4 g of DMAC for dilution. The Ti3 C 2 T x The sum of the mass fractions of C and polyamic acid is adjusted to 13 wt%, where the mass of Ti 3 C 2 T x is 2% of the mass of the polyamic acid, obtaining a first film-forming solution;

[0065] (2) Spray a release agent on the surface of a smooth heat-conducting substrate and perform heat treatment at 230 °C for 30 min in an oven; then lay the smooth heat-conducting substrate treated with the release agent flat on a knife coater, adjust the height of the knife of the knife coater to 300 μm, the heating temperature to 70 °C, and the advancing rate to 10 mm / s; when the temperature of the heating table rises to the heating temperature, scrape the first film-forming solution onto the smooth heat-conducting substrate and continuously heat to remove the solvent in the first film-forming solution; after the first film-forming solution loses fluidity, scrape the first film-forming solution continuously on this first film-forming solution; repeat the scraping and heating processes 4 times, with a 6-min interval for each scraping; after the last scraping is completed, continuously heat until the first film-forming solution of the last scraping loses fluidity, and form a Ti 3 C 2 T x / polyamic acid-based film with a thickness of 26 μm on the smooth heat-conducting substrate;

[0066] (3) Mix the polyamic acid solution and the Ti 3 C 2 T x nanosheet suspension evenly to obtain a second film-forming solution, where the mass of Ti 3 C 2 T x accounts for 40% of the sum of the mass of Ti 3 C 2 T x and the polyamic acid, and the sum of the mass fractions of Ti 3 C 2 T x and the polyamic acid is 0.3 wt%; using the Ti 3 C 2 T x / polyamic acid-based film as the substrate, use a feeler gauge with a thickness of 65 μm to adjust the Ti 3 C 2 T x / polyamic acid-based film to a suitable height, and then use a wire bar to scrape the second film-forming solution onto the Ti 3 C 2 T x / polyamic acid-based film, continuously heat for 24 min to completely remove the solvents in the first film-forming solution and the second film-forming solution, and form a film on the Ti 3 C 2 T x / A Ti with a thickness of 1.6 μm is formed on the polyamic acid-based film 3 C 2 T x / a polyamic acid coating to obtain a composite structure Ti 3 C 2 T x / polyamic acid film;

[0067] (4) Turn off the heating of the heating plate and cool to room temperature; then place the smooth heat-conducting substrate with the composite structure Ti 3 C 2 T x / polyamic acid film into a blast drying oven. First, treat it at 75 °C for 6 h, then at 160 °C for 35 min, and finally at 220 °C for 15 min. The polyamic acid undergoes a cross-linking reaction to form polyimide; after cooling to room temperature, remove the composite film after gradient heat treatment from the smooth heat-conducting substrate to obtain a composite structure Ti 3 C 2 T x / polyimide film.

[0068] After testing, the tensile strength of the composite structure Ti 3 C 2 T x / polyimide film is 145 MPa. When the atomic oxygen fluence is 2.14×10 20 atoms / cm 2 , the atomic oxygen erosion rate of the composite structure Ti 3 C 2 T x / polyimide film is 0.23×10 -24 cm 3 / atom, which is 8.4% of the polyimide film in Comparative Example 1. Before and after atomic oxygen erosion, the surface morphology and roughness change little.

[0069] Example 3:

[0070] (1) Mix 4.8 g of polyamic acid DMAC solution (25 wt%) and 1.8 g of Ti 3 C 2 T x nanosheet DMAC suspension (2 wt%) evenly, and then add 2 g of DMAC for dilution. Adjust the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid to 14 wt%, where the mass of Ti 3 C 2 T x is 3% of the mass of polyamic acid to obtain the first film-forming solution;

[0071] (2) Spray the release agent on the surface of the smooth heat-conducting substrate and heat-treat it in an oven at 240 °C for 35 min; then lay the smooth heat-conducting substrate treated with the release agent flat on the doctor blade coater, and adjust the height of the doctor blade of the doctor blade coater to 350 μm, the heating temperature to 80 °C, and the forward rate to 11 mm / s; when the temperature of the heating table rises to the heating temperature, scrape the first film-forming solution onto the smooth heat-conducting substrate and continuously heat to remove the solvent in the first film-forming solution; after the first film-forming solution loses fluidity, scrape the first film-forming solution on top of this first film-forming solution; repeat the scraping and heating process 5 times, with a 7-min interval between each scraping; after the last scraping is completed, continuously heat until the first film-forming solution of the last scraping loses fluidity, and form a Ti film with a thickness of 32 μm on the smooth heat-conducting substrate. 3 C 2 T x / polyamic acid-based film;

[0072] (3) Mix the polyamic acid solution and the Ti 3 C 2 T x nanosheet suspension evenly to obtain the second film-forming solution, where the mass of Ti 3 C 2 T x accounts for 70% of the sum of the masses of Ti 3 C 2 T x and polyamic acid, and the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid is 0.4 wt%; using the Ti 3 C 2 T x / polyamic acid-based film as the substrate, use a feeler gauge with a thickness of 70 μm to adjust the Ti 3 C 2 T x / polyamic acid-based film to the appropriate height, and then use a wire bar to scrape the second film-forming solution onto the Ti 3 C 2 T x / polyamic acid-based film, and continuously heat for 26 min to completely remove the solvents in the first film-forming solution and the second film-forming solution, and form a Ti 3 C 2 T x / polyamic acid coating with a thickness of 2.4 μm on the Ti 3 C 2 T x / polyamic acid film to obtain the composite structure Ti 3 C 2 T x / polyamic acid film;

[0073] (4) Turn off the heating of the heating plate and cool it to room temperature; then place the smooth heat-conducting substrate with the composite structure Ti 3 C 2 T x / polyamic acid film in a forced-air drying oven, first treat it at 80 °C for 7 h, then at 170 °C for 40 min, and finally at 240 °C for 20 min. The polyamic acid undergoes a cross-linking reaction to form polyimide; after cooling to room temperature, remove the composite film after gradient heat treatment from the smooth heat-conducting substrate to obtain the composite structure Ti 3 C 2 T x / polyimide film.

[0074] After testing, the tensile strength of the composite structure Ti 3 C 2 T x / polyimide film is 136 MPa. When the atomic oxygen fluence is 2.14×10 20 atoms / cm 2 , the atomic oxygen erosion rate of the composite structure Ti 3 C 2 T x / polyimide film is 0.20×10 -24 cm 3 / atom, which is 7.5% of the polyimide film in Comparative Example 1. Before and after atomic oxygen erosion, the surface morphology and roughness change less.

[0075] Example 4:

[0076] (1) Mix 4.8 g of polyamic acid DMAC solution (25 wt%) and 2.4 g of Ti 3 C 2 T x nanosheet DMAC suspension (2 wt%) evenly, then add 0.8 g of DMAC for dilution, and adjust the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid to 15 wt%, where the mass of Ti 3 C 2 T x is 4% of the mass of polyamic acid to obtain the first film-forming solution;

[0077] (2) Spray the mold release agent on the surface of the smooth heat-conducting substrate and heat-treat it in an oven at 250 °C for 40 min. Then, lay the smooth heat-conducting substrate treated with the mold release agent flat on the knife coater, and adjust the height of the knife of the knife coater to 400 μm, the heating temperature to 90 °C, and the forward rate to 12 mm / s. When the temperature of the heating table rises to the heating temperature, scrape the first film-forming solution onto the smooth heat-conducting substrate and continuously heat to remove the solvent in the first film-forming solution. After the first film-forming solution loses fluidity, scrape the first film-forming solution on top of this first film-forming solution. Repeat the scraping and heating process 5 times, with an 8-min interval between each scraping. After the last scraping is completed, continuously heat until the first film-forming solution from the last scraping loses fluidity, and form a Ti film with a thickness of 40 μm on the smooth heat-conducting substrate. 3 C 2 T x / polyamic acid-based film;

[0078] (3) Mix the polyamic acid solution and the Ti 3 C 2 T x nanosheet suspension evenly to obtain the second film-forming solution, where the mass of Ti 3 C 2 T x accounts for 100% of the sum of the masses of Ti 3 C 2 T x and polyamic acid, and the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid is 0.5 wt%. Using the Ti 3 C 2 T x / polyamic acid-based film as the substrate, use a feeler gauge with a thickness of 75 μm to adjust the Ti 3 C 2 T x / polyamic acid-based film to the appropriate height, and then use a wire bar to scrape the second film-forming solution onto the Ti 3 C 2 T x / polyamic acid-based film, and continuously heat for 30 min to completely remove the solvents in the first and second film-forming solutions, and form a Ti 3 C 2 T x / polyamic acid coating with a thickness of 3 μm on the Ti 3 C 2 T x / polyamic acid film to obtain the composite structure Ti 3 C 2 T x / polyamic acid film;

[0079] (4) Turn off the heating of the heating plate and cool it to room temperature; then place the smooth heat-conducting substrate with the composite structure Ti 3 C 2 T x / polyamic acid film into a forced-air drying oven. First, treat it at 85 °C for 8 h, then at 180 °C for 45 min, and finally at 260 °C for 25 min. The polyamic acid undergoes a cross-linking reaction to form polyimide; after cooling to room temperature, remove the composite film after gradient heat treatment from the smooth heat-conducting substrate to obtain the Ti 3 C 2 T x / polyamic acid film resistant to atomic oxygen erosion.

[0080] After testing, the tensile strength of the composite structure Ti 3 C 2 T x / polyimide is 132 MPa. When the atomic oxygen fluence is 2.14×10 20 atoms / cm 2 ², the atomic oxygen erosion rate of the composite structure Ti 3 C 2 T x / polyimide film is 0.28×10 -24 ⁻⁶ cm 3 / atom, which is 10% of the polyimide film in Comparative Example 1. Before and after atomic oxygen erosion, the surface morphology and roughness change little.

[0081] Comparative Example 1:

[0082] (1) Scrape a 25 wt% DMAC solution of 4.8 g of polyamic acid on a smooth heat-conducting substrate. The moving speed of the scraper is 12 mm / s, the height of the scraper is 400 μm, the temperature of the heating plate is 90 °C, and after scraping, continuously heat for 30 min to remove the organic solvent to form a polyamic acid film on the surface of the smooth heat-conducting substrate;

[0083] (2) Turn off the heating of the heating plate and cool it to room temperature; then place the smooth heat-conducting substrate with the polyamic acid film into a forced-air drying oven. First, treat it at 85 °C for 8 h, then at 180 °C for 45 min, and finally at 260 °C for 25 min. The polyamic acid undergoes a cross-linking reaction to form polyimide; after cooling to room temperature, remove the film after gradient heat treatment from the smooth heat-conducting substrate to obtain a polyimide film.

[0084] After testing, the tensile strength of this polyimide film is 160 MPa. When the atomic oxygen fluence is 2.14×10 20 atoms / cm 2 ², the atomic oxygen erosion rate of this polyimide film is 2.68×10 -24 ⁻⁶ cm3 / atom. Before and after atomic oxygen erosion, the surface morphology presents a blanket-like shape and a large change in roughness.

[0085] Comparative Example 2:

[0086] (1) Mix 4.8 g of polyamic acid DMAC solution (25 wt%) and 2.4 g of Ti 3 C 2 T x nanosheet DMAC suspension (2 wt%) evenly. Add 0.8 g of DMAC to dilute the solution, and adjust the sum of the mass fractions of Ti 3 C 2 T x and polyamic acid to 15 wt%. Among them, the mass of Ti 3 C 2 T x is 4% of the mass of polyamic acid to obtain the first film-forming solution

[0087] (2) Spray the release agent on the surface of the smooth heat-conducting substrate, and heat-treat it in an oven at 250 °C for 40 min; then lay the smooth heat-conducting substrate treated with the release agent flat on the knife coater, and adjust the height of the knife of the knife coater to 400 μm, the heating temperature to 90 °C, and the forward rate to 12 mm / s; when the temperature of the heating table rises to the heating temperature, scrape the first film-forming solution onto the smooth heat-conducting substrate, and continuously heat to remove the solvent in the first film-forming solution; after the first film-forming solution loses fluidity, scrape the first film-forming solution on this first film-forming solution again; repeat the scraping and heating process 5 times, with an interval of 8 min each time; after the last scraping is completed, continuously heat until the first film-forming solution of the last scraping loses fluidity, and form a Ti 3 C 2 T x / polyamic acid film with a thickness of 40 μm on the smooth heat-conducting substrate;

[0088] (3) Turn off the heating of the heating plate and cool to room temperature; then put the smooth heat-conducting substrate with the homogeneous Ti 3 C 2 T x / polyamic acid film into a blast drying oven, first treat it at 85 °C for 8 h, then treat it at 180 °C for 45 min, and finally treat it at 260 °C for 25 min. The polyamic acid undergoes a cross-linking reaction to form polyimide; after cooling to room temperature, remove the composite film after gradient heat treatment from the smooth heat-conducting substrate to obtain a homogeneous Ti 3 C 2 T x / polyimide film.

[0089] After testing, the homogeneous Ti 3 C 2 Tx The tensile strength of the polyimide film is 148 MPa. When the atomic oxygen fluence is 2.14×10 20 atoms / cm 2 , the atomic oxygen erosion rate of the homogeneous Ti 3 C 2 T x / polyimide film is 0.56×10 -24 cm 3 / atom, which is 21% of the polyimide film of Comparative Example 1. Before and after atomic oxygen erosion, the surface morphology and roughness change little.

[0090] It can be seen from Figure 1 that the tensile strength and elongation at break of the composite structure Ti 3 C 2 T x / polyimide film decrease with the increase of the Ti 3 C 2 T x content in the coating.

[0091] It can be seen from Figure 2 , Figure 3 and Figure 4 by comparison that the spin coating technique successfully distributes Ti 3 C 2 T x uniformly in the polyimide matrix.

[0092] It can be seen from Figure 5 and Figure 6 by comparison that atomic oxygen has a strong erosion effect on the polyimide film.

[0093] It can be seen from Figure 7 and Figure 8 by comparison that atomic oxygen has an obvious erosion effect on the homogeneous Ti 3 C 2 T x / polyimide film.

[0094] It can be seen from Figure 9 and Figure 10 by comparison that atomic oxygen has a small erosion effect on the composite structure Ti 3 C 2 T x / polyimide film.

[0095] It can be seen from Figure 11 and Figure 12 by comparison that atomic oxygen erosion causes a sharp increase in the surface roughness of the polyimide film.

[0096] It can be seen from Figure 13 and Figure 14It can be seen from the comparison that atomic oxygen has a greater impact on the surface roughness of the homogeneous Ti 3 C 2 T x / polyimide film.

[0097] From Figure 15 and Figure 16 It can be seen from the comparison that atomic oxygen has a smaller impact on the surface roughness of the composite structure Ti 3 C 2 T x / polyimide film.

[0098] Matters not described in the present invention are applicable to the prior art.

Claims

1. A composite structure Ti3C2T3 that is resistant to ionized oxygen corrosion x / A method for preparing a polyimide film, characterized in that: The method comprises the following steps: Step 1: Mix polyamic acid solution and Ti3C2T x The nanosheet suspension is mixed evenly to obtain a first film-forming solution; Step 2: scrape the first film-forming liquid of step 1 onto a smooth thermally conductive substrate, and continue to heat to remove the solvent in the first film-forming liquid; after the first film-forming liquid loses fluidity, continue to scrape the first film-forming liquid of step 1 onto the first film-forming liquid; repeat the scraping and heating process several times; after the last scraping is completed, continue to heat until the last scraped first film-forming liquid loses fluidity, and Ti3C2T x / Polyamic acid based film; Step 3: Mix the polyamic acid solution and Ti3C2T x The nanosheet suspension is mixed evenly to obtain the second film-forming solution; the Ti3C2T x / polyamic acid based film as the substrate, the second film-forming liquid is scraped onto the Ti3C2T x / polyamic acid-based film, continuous heating to completely remove the solvent in the first film-forming liquid and the second film-forming liquid, on the Ti3C2T x Ti3C2T / Polyamic acid based film x / polyamic acid coating to obtain a composite structure Ti3C2T x / polyamic acid film; Step 4: The composite structure Ti3C2T obtained in step 3 x The polyamic acid film is subjected to gradient heat treatment, and the polyamic acid undergoes a cross-linking reaction to generate polyimide, thereby obtaining a composite structure Ti3C2T3 that is resistant to ion oxygen corrosion. x / polyimide film.

2. The composite structure Ti3C2T3 that is resistant to ionized oxygen corrosion according to claim 1 x / A method for preparing a polyimide film, characterized in that: In step 1, in the first film-forming solution, Ti3C2T x The mass of Ti3C2T is 1-4% of the mass of polyamic acid. x The sum of the mass fractions of polyamide acid and polyamic acid is 12-15wt%.

3. The composite structure Ti3C2T3 that is resistant to ionized oxygen corrosion according to claim 1 x / A method for preparing a polyimide film, characterized in that: Step 2 is specifically as follows: laying a smooth thermally conductive substrate flat on a blade coater and setting the coating parameters; then when the temperature of the heating platform rises to the heating temperature, coating the first film-forming liquid of step 1 on the smooth thermally conductive substrate, and continuously heating to remove the solvent in the first film-forming liquid; after the first film-forming liquid loses fluidity, continuing to coat the first film-forming liquid of step 1 on the first film-forming liquid; repeating the coating and heating process several times; after the last coating is completed, continuously heating until the last coating of the first film-forming liquid loses fluidity, and forming Ti3C2T on the smooth thermally conductive substrate. x / Polyamic acid based film.

4. The composite structure Ti3C2T3 resistant to ionized oxygen corrosion according to claim 1 or 3 x / A method for preparing a polyimide film, characterized in that: In step 2, the scraping parameters are: scraper height is 250-400 μm, heating temperature is 60-90° C., and forward speed is 9-12 mm / s; In step 2, the scraping and heating process is repeated 3 to 5 times, and the time interval between each scraping is 5 to 8 minutes.

5. The composite structure Ti3C2T3 resistant to ionized oxygen corrosion according to claim 1 or 3 x / A method for preparing a polyimide film, characterized in that: In step 2, before coating, the smooth thermally conductive substrate is first treated with a release agent, specifically: a polytetrafluoroethylene release agent is sprayed on the surface of the smooth thermally conductive substrate, and then heat treated to reduce the adhesion between the substrate and the film; the heat treatment temperature is 220-250° C., and the time is 25-40 minutes.

6. The composite structure Ti3C2T3 resistant to ionized oxygen corrosion according to claim 1 or 3. x / A method for preparing a polyimide film, characterized in that: In step 2, Ti3C2T x / The thickness of the polyamic acid-based film is 20 to 40 μm.

7. The composite structure Ti3C2T3 that is resistant to ionized oxygen corrosion according to claim 1 x / A method for preparing a polyimide film, characterized in that: In step 3, in the second film-forming solution, Ti3C2T x The mass of Ti3C2T x 10-100% of the sum of the mass of Ti3C2T x The sum of the mass fractions of polyamide acid and polyamic acid is 0.2-0.5wt%.

8. The composite structure Ti3C2T3 that is resistant to ionized oxygen corrosion according to claim 1 x / A method for preparing a polyimide film, characterized in that: In step 3, when scraping the second film-forming solution, a wire rod is used instead of a scraper for scraping; In step 3, the heating is continued for 20 to 30 minutes to completely remove the solvent.

9. The composite structure Ti3C2T3O3 resisting to ion oxygen corrosion according to claim 1 x / A method for preparing a polyimide film, characterized in that: In step 3, high content Ti3C2T x / The thickness of the polyamic acid coating is 1 to 3 μm.

10. The composite structure Ti3C2T3 that is resistant to ionized oxygen corrosion according to claim 1 x / A method for preparing a polyimide film, characterized in that: In step 4, the gradient heat treatment process is: first treat at 70-85°C for 5-8h, then treat at 150-180°C for 30-45min, and finally treat at 200-260°C for 10-25min; Step 4 also includes: after the gradient heat treatment, cooling to room temperature, and treating the composite structure Ti3C2T x / Polyimide film is removed from the smooth thermally conductive substrate.

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