A method and system for preparing and grounding a deep charge-discharge resistant polyetherimide composite dielectric

Abstract

The application belongs to the technical field of spacecraft space radiation shielding, and discloses a polyetherimide composite medium preparation and grounding configuration method and system with deep layer charge-discharge resistance, which comprises the following steps: preparing long rod-shaped zinc oxide nanoparticles; preparing polyetherimide-based composite material film samples, polyetherimide-based composite material sheet samples and polyetherimide-based composite material special-shaped structural members; and applying the samples to grounding configuration in a space radiation environment. The application provides a complete PEI / ZnO composite material preparation process and grounding configuration method, which mainly comprises the preparation of long rod-shaped zinc oxide nanoparticle dopants, the preparation of thin film and sheet-shaped PEI / ZnO composite materials, the preparation of special-shaped PEI / ZnO composite material members, and corresponding grounding configuration methods. Finally, the deep layer charge-discharge resistance of the prepared PEI / ZnO composite material is verified through a vacuum electron radiation experiment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of spacecraft space radiation shielding, and particularly relates to a polyetherimide composite medium preparation method and grounding configuration method and system with deep charge and discharge resistance. BACKGROUND

[0002] Space charged particle radiation is an important environmental factor that seriously threatens space activities on the spacecraft orbit, and the influence of the space radiation environment on the spacecraft is called space radiation effect. The main influences are total dose effect, single particle effect and charge and discharge effect. Among them, the deep charge and discharge effect of dielectric under the action of high-energy electrons is the most serious. Deep charge and discharge of dielectric refers to that high-energy electrons (0.1-10 MeV) penetrate the shielding layer and the surface of dielectric, deposit in the interior of dielectric, and because of the high resistivity of insulating materials, the charge release rate is much smaller than the charge deposition rate, so the electric charge in the dielectric interior continuously accumulates, thereby causing local electric field concentration. When the electric field generated by the deposited electric charge exceeds the breakdown threshold of the material, an electrostatic discharge phenomenon will occur. Spacecraft dielectric deep charge and discharge will cause insulation dielectric degradation, and even insulation failure; meanwhile, the electromagnetic pulse generated by electrostatic discharge will cause abnormal operation of spacecraft electronic equipment, and in severe cases, directly cause spacecraft sensitive electronic devices to breakdown, threatening the safe operation of spacecraft.

[0003] Currently, the deep charge and discharge protection of space medium is mainly realized by adding a shielding layer, and the shielding layer material is generally aluminum. The protection of aluminum plate can prevent or reduce high-energy electrons from entering the interior of spacecraft medium material, which mainly depends on the thickness of the aluminum shielding layer. Generally, the best aluminum shielding layer thickness is determined by simulating calculation according to the actual orbit of the spacecraft, the energy spectrum of high-energy electrons and the corresponding electron flux, so as to realize the protection of dielectric deep charge and discharge. The disadvantage of this method is that the setting of aluminum shielding layer outside the spacecraft will increase the overall mass of the spacecraft, thereby causing the launch cost to increase dramatically; in addition, for thick insulation dielectric (such as centimeter level), the accumulated charge in the interior is not easy to release, and at a lower charge density, dielectric charge and discharge phenomenon is easy to occur, so the required aluminum shielding thickness is larger, which further increases the launch mass of the spacecraft. On the other hand, with the development of high-voltage and high-power spacecraft, the required insulation dielectric thickness is also increasing, so it is urgent to develop a new method for dielectric deep charge and discharge protection.

[0004] Polyetherimide (PEI) is a kind of spacecraft medium material with excellent performance. It maintains the excellent high-temperature resistance and thermal stability of polyimide (PI), and also has excellent mechanical properties, chemical stability, outstanding flame retardance and low smoke density. In addition, it has excellent electrical properties, high dielectric strength and radiation resistance. Due to its excellent insulation properties, the electrical conductivity is at the level of 5.0*10 -18 S / m, the charges deposited in the interior thereof are not easy to release under electronic radiation, and are more likely to cause charge accumulation, thereby causing deep layer charging and discharging of the medium. At present, the improvement research on polyetherimide medium mainly focuses on its mechanical, frictional and dielectric properties, and there is little research on its deep layer charging and discharging resistance under electronic radiation.

[0005] The prior art has the following technical problems:

[0006] (1) The current deep layer charging and discharging protection of the spacecraft medium is mainly realized by adding an aluminum shielding layer, which increases the overall mass of the spacecraft, thereby causing a sharp increase in launch cost.

[0007] (2) With the development of high-voltage and high-power spacecraft, the thickness of the required insulating medium is also increasing. The accumulated charges in the thick insulating medium (such as centimeter level) are not easy to release, and the charging and discharging of the medium is easy to occur under a lower deposited charge density. If the traditional aluminum shielding is used, the thickness of the shielding aluminum plate required is larger, further increasing the launch mass of the spacecraft.

[0008] (3) There is little research on the deep layer charging and discharging protection of the polyetherimide medium, and there is no feasible method for improving the deep layer charging and discharging resistance of the polyetherimide medium.

[0009] (4) The grounding configuration of the medium is crucial in the deep layer charging and discharging protection of the medium, and the current method does not give a clear grounding configuration method of the polyetherimide medium. SUMMARY

[0010] In view of the problems existing in the prior art, the present application provides a polyetherimide composite medium with deep layer charging and discharging resistance and a grounding configuration method and system.

[0011] The present application is realized as follows: a polyetherimide composite medium with deep layer charging and discharging resistance and a grounding configuration method, the method comprising:

[0012] S1: preparing long rod-shaped zinc oxide nanoparticles.

[0013] S2: preparing polyetherimide-based composite film sample, polyetherimide-based composite sheet sample, polyetherimide-based composite special-shaped structure.

[0014] S3: applying the sample to a grounding configuration in a space radiation environment.

[0015] Further, the S1 specifically comprises:

[0016] (1) A certain amount of zinc nitrate hexahydrate is weighed by an electronic balance and placed in a beaker 1; a corresponding amount of sodium hydroxide is weighed and put into the beaker 1, wherein the molar ratio of zinc nitrate hexahydrate to sodium hydroxide is 1:15; a certain amount of deionized water is added into the beaker 1; the solution is magnetically stirred at room temperature for 30 min to obtain a clear and transparent solution, and the pH value of the solution is measured.

[0017] (2) The above solution is transferred into a stainless steel reaction kettle with a polytetrafluoroethylene liner, sealed, and reacted in an oven at 150°C for 8h.

[0018] (3) The above reaction kettle is taken out and naturally cooled to room temperature, and the solution in the reaction kettle is filtered to obtain a white precipitate; the white precipitate is washed with deionized water and anhydrous ethanol several times, and then transferred into a watch glass and dried in an oven at 80°C for 10h to obtain and collect the product.

[0019] Further, in the S2, the preparation of the polyetherimide-based composite film sample specifically comprises:

[0020] A scraping method and a hot-pressing annealing method are used to prepare a PEI / ZnO composite dielectric film.

[0021] Raw materials and reagents: polyetherimide (PEI) particles, SABIC-Saudi Basic Industries Corporation, Ultem1000, density 1.27g / cm 3 , Tg217°; 1-methyl-2-pyrrolidone (NMP), analytical pure, National Pharmaceutical Group Chemical Reagent Co., Ltd.; long rod-shaped zinc oxide nanopowder, self-made.

[0022] The specific process is as follows:

[0023] (1) A certain amount of PEI particles to be processed and self-made long rod-shaped zinc oxide powder are respectively placed in a 150°C convection oven and dried for 10 hours.

[0024] (2) The self-made long rod-shaped zinc oxide powder is weighed according to the set volume fraction, and is put into a beaker containing 50ml of NMP solution; the beaker is placed in an ultrasonic machine, and ultrasonic oscillation is performed for 40min until the zinc oxide powder is uniformly dispersed in the NMP solution.

[0025] (3) Weigh the corresponding mass of PEI particles with a balance, add them to the above dispersed mixed solution, and place the beaker on a magnetic stirrer. Heat through an oil bath and keep at 60°C for 12h of stirring until the PEI particles are completely dissolved in the mixed solution. Then place the beaker containing the mixed solution in a vacuum drying oven and stand for 12h until there are no bubbles in the solution.

[0026] (4) Take out the mixed solution after standing, pour it on a clean glass substrate that has been preheated to 60°, and use a film spreading scraper to evenly coat the mixed solution on the glass plate. Place the glass plate in a vacuum oven at 60°C for 12h of heat preservation, and then heat it to 220° for 4h to remove the NMP solvent. After natural cooling, perform demolding treatment in deionized water to obtain the prepared PEI / ZnO composite dielectric film.

[0027] (5) After the above prepared film is dried, heat treatment is performed in a vacuum oven to remove residual solvent. Specifically, first heat to 120°C for 5h, then heat to 200°C for 6h, and finally cool to room temperature naturally.

[0028] Further, in S2, the polyetherimide-based composite sheet sample is prepared, specifically including:

[0029] The direct melt blending method is used for preparation. The melt blending method is a method that utilizes the solubility of PEI, heats it above its viscous flow temperature, and then uses a twin-screw extruder, a two-roll open mill, a closed mixer, and other mixing equipment to fully blend the polymer matrix and fillers. Finally, the composite material is obtained by cooling, granulation, or crushing. With the strong shearing force of the mixing equipment, the polymer and fillers in the molten state can be well mixed, thereby obtaining the composite material.

[0030] (1) Take an appropriate amount of PEI particles to be processed and self-made long rod-shaped zinc oxide powder and place them in a convection oven at 150°C for 10 hours of drying.

[0031] (2) Weigh the corresponding mass of dried PEI particles and long rod-shaped zinc oxide powder with a balance according to the set proportion, mix them, and wait for use.

[0032] (3) Use a small closed mixer in the laboratory, set the mixing temperature, rotor speed, mixing time, and other parameters, and then start heating.

[0033] (4) After the mixer reaches the set temperature, start the rotor and put in the prepared PEI / zinc oxide mixture.

[0034] (5) After mixing is completed, take out the mixed material and use a flat vulcanizing machine to press the mixed material into a sheet-shaped sample of the required size.

[0035] Further, in S2, the preparation of the polyetherimide-based composite profiled structure is specifically as follows:

[0036] (1) Take the appropriate amount of PEI particles to be processed and self-made long rod-shaped zinc oxide powder and place them in a convection oven at 150°C for drying for 10 hours.

[0037] (2) Weigh the corresponding amount of dried PEI particles and long rod-shaped zinc oxide powder according to the set ratio using a balance, mix them together, and then use them.

[0038] (3) Use a small-scale closed mixing machine in the laboratory, set the mixing temperature, rotor speed, mixing time, and other parameters, and then start heating.

[0039] (4) After the mixing machine reaches the set temperature, start the rotor and put in the prepared PEI / zinc oxide mixture.

[0040] (5) After the mixing is completed, take out the mixed material and use the mold casting method to prepare the required profiled structure.

[0041] Further, S3 specifically includes:

[0042] (1) Grounding configuration method for thin film or sheet-shaped sample.

[0043] Sample grounding configuration method: The thin film or sheet-shaped sample needs to be plated with copper or pasted with a copper foil on one side of the sample, leaving a 3mm margin on the edge of the sample; at the same time, a specially designed wire is used for grounding.

[0044] The specially designed wire is composed of two copper foil patches with conductive glue and a section of braided copper wire. The size of the copper foil patch is set according to the area of the copper-plated side of the thin film or sheet-shaped sample, generally set to 1 / 4 of the area; the length of the braided copper wire is cut according to the actual application scenario and assembled with the copper foil patch. After assembly, one copper foil patch is pasted in the center of the sample, and the other copper foil patch is fixed to the grounding point, and then a multimeter is used to measure the resistance between the two ends to ensure reliable grounding.

[0045] (2) Grounding configuration method for profiled structure.

[0046] The profiled structure needs to be configured according to the actual installation location and purpose. The structure that only serves as a support should refer to the grounding configuration method of the thin film or sheet-shaped sample and paste the copper foil at the position where it is convenient to paste the copper foil and reliably ground through the specially designed wire. For the structure that serves as insulation and support, the insulation performance of the structure should be considered first, and on the basis of not affecting the insulation performance of the structure, the copper foil is pasted at the position where it is convenient to paste the copper foil on the grounding side and reliably grounded through the specially designed wire.

[0047] Another object of the present application is to provide a polyetherimide composite medium preparation and grounding configuration system with deep charge-discharge resistance based on the polyetherimide composite medium with deep charge-discharge resistance, which comprises:

[0048] A nanoparticle module for preparing long rod-shaped zinc oxide nanoparticles.

[0049] A polyetherimide-based composite material preparation module connected with the nanoparticle module for preparing polyetherimide-based composite material film samples, polyetherimide-based composite material sheet samples, and polyetherimide-based composite material special-shaped structural parts.

[0050] A grounding configuration module connected with the polyetherimide-based composite material preparation module for grounding configuration of samples in a space radiation environment.

[0051] In combination with the above technical solutions and solved technical problems, the technical solution to be protected by the present application has the following advantages and positive effects:

[0052] Firstly, in the prior art, polymer composites often exhibit problems such as decreased dielectric properties, poor structural stability, insufficient radiation resistance, and the like under deep charge-discharge and high radiation environments. These problems limit the application of the materials in high-performance electronic components and harsh environments. For example, traditional polymer matrix materials are prone to increased dielectric loss, reduced mechanical strength, and material aging in high electric fields, high temperatures, or radiation environments, resulting in decreased system reliability. Meanwhile, during deep charge-discharge cycles, existing materials are also prone to phenomena such as dielectric degradation and charge accumulation, further affecting their performance and lifespan.

[0053] 1. Improved dielectric properties.

[0054] The present application forms a composite dielectric material by uniformly dispersing long rod-shaped zinc oxide nanoparticles in a polyetherimide (PEI) matrix. The introduction of zinc oxide nanoparticles significantly improves the dielectric constant and withstand voltage of the composite material, enabling it to maintain a low dielectric loss under high electric fields. This improvement enables the composite material to exhibit more stable electrical characteristics in high-performance electronic components, making it suitable for a wider range of industrial application scenarios.

[0055] 2. Enhanced structural stability.

[0056] Using processes such as melt blending and mold casting, the composite material of the present application exhibits excellent mechanical properties under high temperature and high pressure conditions. The tensile strength, impact resistance, and structural integrity of the material are significantly improved, enabling it to remain stable for a long time in harsh environments. This advancement expands the application of the material in aerospace, military equipment, and high-demand industrial fields.

[0057] 3. Improved radiation resistance.

[0058] The zinc oxide nanoparticles in the application not only improve the dielectric properties of the material, but also significantly enhance the radiation resistance of the composite material. In a space radiation environment, the material can effectively resist the impact of high-energy particles and avoid performance degradation and material aging caused by radiation. This feature makes the material of the application particularly suitable for aerospace and military electronic devices to resist harsh radiation environments.

[0059] 4. Improved deep charge and discharge performance.

[0060] The application of the composite material in the ground configuration significantly improves the safety and durability of the system. The material exhibits excellent anti-aging ability during deep charge and discharge, avoiding problems such as charge accumulation and dielectric degradation. By extending the charge and discharge cycle life, the material of the application can effectively reduce maintenance costs and improve the overall operating efficiency of the equipment.

[0061] The application introduces long rod-shaped zinc oxide nanoparticles into the polyetherimide matrix, not only solving a number of key problems in the prior art, but also making significant technical progress in dielectric properties, structural stability, radiation resistance, and deep charge and discharge performance. These advances make the material of the application have a wide application prospect in high-demand industrial applications and extreme environments.

[0062] From the results, we can see:

[0063] (1) Under the same radiation conditions, the number of static discharge and the peak discharge current of the prepared PEI / ZnO composite sample are less than those of the unmodified PEI pure sample within the same radiation time.

[0064] (2) When the electron beam current is 5 μA, compared with the PEI pure sample, the number of static discharge of the PEI / ZnO composite sample prepared by the application is reduced by 103 times, with a decrease of 89.6%.

[0065] (3) When the electron beam current is 10 μA, compared with the PEI pure sample, the number of static discharge of the PEI / ZnO composite sample prepared by the application is reduced by 232 times, with a decrease of 88.2%; fully proving that the PEI / ZnO composite sample prepared by the application has excellent deep charge and discharge performance.

[0066] Second, the expected income and business value of the technical scheme of the application after transformation are: the application provides a feasible method for improving the deep charging and discharging performance of PEI medium, and the prepared PEI / ZnO composite sample is verified by real radiation test. Compared with the pure PEI sample, the number of electrostatic discharge is greatly reduced under the same radiation environment, and the discharge current amplitude is also significantly reduced, and the deep charging and discharging performance is excellent. The technical scheme proposed in the application can be applied to the deep charging and discharging protection of spacecraft medium, can effectively reduce the required aluminum shielding layer thickness, reduce the launch mass of the spacecraft, reduce the launch cost, has excellent commercial value, and the expected income is good.

[0067] The technical scheme of the application fills the technical blank in the industry at home and abroad: the application starts from the spacecraft medium body, improves the deep charging and discharging performance of the medium body by doping modification, especially for PEI medium, and there is no research in this regard at present. The application provides a new route for the deep charging and discharging protection of spacecraft medium, and is innovative.

[0068] Third, the technical problems and technical progress solved by the parameters of the application.

[0069] Parameters:

[0070] 1. Preparation parameters of zinc oxide nanoparticles:

[0071] The molar ratio of zinc nitrate hexahydrate to sodium hydroxide is 1:15.

[0072] React at 150 DEG C for 8 hours.

[0073] The drying temperature is 80 DEG C, and the time is 10 hours.

[0074] 2. Preparation parameters of polyetherimide-based composite film:

[0075] PEI particles and long rod-shaped zinc oxide powder are dried at 150 DEG C for 10 hours.

[0076] The stirring temperature is 60 DEG C, and the time is 12 hours.

[0077] The doctoring temperature is 60 DEG C, the vacuum oven temperature is 220 DEG C, and the holding time is 4 hours.

[0078] Heat treatment process: 120 DEG C for 5 hours, 200 DEG C for 6 hours.

[0079] 3. Preparation parameters of polyetherimide-based composite film and special-shaped structure:

[0080] PEI and long rod-shaped zinc oxide powder are dried at 150 DEG C for 10 hours.

[0081] The mixing temperature, rotor speed and time are set according to the material properties (the specific parameters depend on the actual equipment and materials).

[0082] The mold casting method is used for the molding of special-shaped structural parts.

[0083] Technical problems to be solved:

[0084] The existing polymer composite material often faces problems such as decrease in dielectric performance, poor structural stability, and insufficient anti-radiation ability in deep charging and discharging and high radiation environment. The present application introduces long rod-shaped zinc oxide nanoparticles into the polyetherimide (PEI) matrix, significantly improves the anti-deep charging and discharging performance and anti-radiation ability of the composite material, and solves the reliability problem of the material when used in harsh environment.

[0085] Significant technical progress:

[0086] 1. Improve dielectric performance.

[0087] By introducing long rod-shaped zinc oxide nanoparticles, the present application significantly improves the dielectric performance of the polyetherimide-based composite material by taking advantage of its high dielectric constant and good dispersibility. Especially under high electric field and high temperature conditions, the material can maintain stable dielectric constant and low dielectric loss, and is suitable for high-performance electronic components.

[0088] 2. Enhance structural stability.

[0089] The composite material sheets and special-shaped structural parts prepared by melt blending and mold casting have uniform structure and superior mechanical properties, and can still maintain good structural stability under high temperature and high pressure environment. The mechanical strength and impact resistance of the material are significantly improved, making it suitable for severe engineering applications.

[0090] 3. Improve anti-radiation performance.

[0091] By introducing zinc oxide nanoparticles into the polymer matrix, the composite material of the present application exhibits excellent anti-radiation ability, especially in space radiation environment, the material can effectively resist the impact of high-energy particles, and the electrical and physical properties of the material are not affected. This progress makes it have wide application prospect in the fields of aerospace, military electronic equipment, etc.

[0092] 4. Anti-deep charging and discharging performance.

[0093] The application of the composite material prepared by the present application in the grounding configuration can significantly improve the safety and stability of the system. The material shows good anti-electric aging performance in deep charging and discharging cycle, avoids the performance degradation problem caused by charge accumulation and dielectric degradation, and prolongs the service life of the equipment. BRIEF DESCRIPTION OF DRAWINGS

[0094] Figure 1 is a flow chart of a polyetherimide composite medium preparation and grounding configuration method with deep charge and discharge resistance provided by the embodiment of the present application.

[0095] Figure 2 is a grounding configuration diagram of a thin film or sheet sample provided by the embodiment of the present application.

[0096] Figure 3 is a special wire structure diagram provided by the embodiment of the present application.

[0097] Figure 4 is a grounding configuration diagram of a sheet PEI / ZnO composite sample provided by the embodiment of the present application.

[0098] Figure 5 is a high-energy electron radiation test wiring diagram provided by the embodiment of the present application.

[0099] Figure 6 is a sheet PEI / ZnO composite sample with completed grounding configuration provided by the embodiment of the present application. DETAILED DESCRIPTION

[0100] In order to make the objectives, technical solutions and advantages of the present application clearer and more comprehensible, the present application will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0101] As shown in Figure 1 , the embodiment of the present application provides a polyetherimide composite medium preparation and grounding configuration method with deep charge and discharge resistance, which comprises:

[0102] S1: preparing long rod-shaped zinc oxide nanoparticles.

[0103] S2: preparing a polyetherimide-based composite material thin film sample, a polyetherimide-based composite material sheet sample, and a polyetherimide-based composite material special-shaped structure.

[0104] S3: applying the sample to grounding configuration in a space radiation environment.

[0105] The S1 specifically comprises:

[0106] (1) An appropriate amount of zinc nitrate hexahydrate is weighed and placed in a beaker 1; an appropriate amount of sodium hydroxide corresponding to the mass is weighed and added to the beaker 1, wherein the molar ratio of zinc nitrate hexahydrate to sodium hydroxide added is 1:15; an appropriate amount of deionized water is added to the beaker 1; the solution is magnetically stirred at room temperature for 30 min to obtain a clear and transparent solution, and the pH value of the solution is measured.

[0107] (2) The above solution was transferred to a stainless steel reactor with a Teflon liner, sealed, and reacted in an oven at 150°C for 8h.

[0108] (3) The reactor was removed and allowed to cool to room temperature naturally. The solution in the reactor was filtered to obtain a white precipitate. The white precipitate was washed with deionized water and anhydrous ethanol several times, and then was transferred to a watch glass and dried in an oven at 80°C for 10h to obtain and collect the product.

[0109] In S2, the polyetherimide-based composite film sample was prepared, specifically including:

[0110] A scraping method and a hot-pressing annealing method were used to prepare the PEI / ZnO composite dielectric film.

[0111] Raw materials and reagents: polyetherimide (PEI) particles, SABIC-Saudi Basic Industries Corporation, Ultem1000, density 1.27g / cm 3 , Tg217°; 1-methyl-2-pyrrolidone (NMP), analytical pure, National Pharmaceutical Group Chemical Reagent Co., Ltd.; long rod-shaped zinc oxide nanopowder, self-made.

[0112] The specific process is as follows:

[0113] (1) A proper amount of PEI particles to be processed and self-made long rod-shaped zinc oxide powder were respectively placed in a convection oven at 150°C and dried for 10h.

[0114] (2) The corresponding mass of self-made long rod-shaped zinc oxide powder was weighed according to the set volume fraction and was put into a beaker containing 50mL of NMP solution. The beaker was placed in an ultrasonic machine and ultrasonic oscillation was performed for 40min until the zinc oxide powder was uniformly dispersed in the NMP solution.

[0115] (3) The corresponding mass of PEI particles was weighed by a balance and was added to the above dispersed mixed solution. The beaker was placed on a magnetic stirrer and was heated by an oil bath and kept at 60°C for stirring for 12h until the PEI particles were completely dissolved in the mixed solution. Then the beaker containing the mixed solution was placed in a vacuum drying box and was left for 12h until there was no bubble in the solution.

[0116] (4) The mixed solution after standing was taken out and was cast on a clean glass substrate which had been preheated to 60°. A film-coating scraper was used to uniformly coat the mixed solution on the glass plate. The glass plate was placed in a vacuum oven at 60°C for 12h and was then heated to 220° for 4h to remove the NMP solvent. After natural cooling, a film was removed in deionized water, and the prepared PEI / ZnO composite dielectric film was obtained.

[0117] (5) After the prepared film is dried, heat treatment is performed in a vacuum oven to remove residual solvent, specifically, first heated to 120°C for 5h, then heated to 200°C for 6h, and finally naturally cooled to room temperature.

[0118] In S2, the polyetherimide-based composite sheet sample is prepared, specifically including:

[0119] The direct melt blending method is used for preparation. The melt blending method is a method that utilizes the solubility of PEI, heats it to above its viscous flow temperature, and then uses a twin-screw extruder, a two-roll open mill, a closed mixing machine and other mixing equipment to fully blend the polymer matrix and fillers. Finally, the composite material is obtained by cooling, granulation or crushing. With the strong shearing force of the mixing equipment, the polymer and fillers in the molten state can be well mixed, thereby obtaining the composite material.

[0120] (1) Take an appropriate amount of PEI particles to be processed and self-made long rod-shaped zinc oxide powder and place them in a convection oven at 150°C for drying for 10 hours.

[0121] (2) Weigh the corresponding mass of dried PEI particles and long rod-shaped zinc oxide powder according to the set proportion with a balance, mix them and wait for use.

[0122] (3) Use a small closed mixing machine in the laboratory, set the mixing temperature, rotor speed, mixing time and other parameters, and then start heating.

[0123] (4) After the mixing machine reaches the set temperature, start the rotor and put in the prepared PEI / zinc oxide mixture.

[0124] (5) After the mixing is completed, take out the mixed material, and then use a flat vulcanizing machine to press the mixed material into a sheet-shaped sample of the required size.

[0125] In S2, the polyetherimide-based composite sheet sample is prepared, specifically including:

[0126] (1) Take an appropriate amount of PEI particles to be processed and self-made long rod-shaped zinc oxide powder and place them in a convection oven at 150°C for drying for 10 hours.

[0127] (2) Weigh the corresponding mass of dried PEI particles and long rod-shaped zinc oxide powder according to the set proportion with a balance, mix them and wait for use.

[0128] (3) Use a small closed mixing machine in the laboratory, set the mixing temperature, rotor speed, mixing time and other parameters, and then start heating.

[0129] (4) After the mixing machine reaches the set temperature, start the rotor and put in the prepared PEI / zinc oxide mixture.

[0130] (5) After the mixing is completed, the mixed material is taken out and the required irregular structural parts are prepared by mold casting method.

[0131] S3 specifically includes:

[0132] (1) Grounding configuration method for thin film or sheet-like specimens.

[0133] Sample grounding configuration method: For thin film or sheet-shaped samples, copper plating or copper foil adhesion should be performed on one side of the sample first, leaving a 3mm margin at the edge of the sample; if Figure 2 As shown, a special grounding conductor is used; the structure of the special conductor is as follows: Figure 3 As shown.

[0134] The specially designed conductor consists of two copper foil patches with conductive adhesive and a section of braided copper wire. The size of the copper foil patches is determined based on the area of ​​the copper-plated side of the thin film or sheet sample, typically set to 1 / 4 of its area. The length of the braided copper wire is cut according to the actual application scenario and assembled with the copper foil patches. After assembly, one copper foil patch is attached to the center of the sample, and the other end of the copper foil patch is fixed to the grounding point. Then, a multimeter is used to measure the resistance at both ends to ensure reliable grounding.

[0135] (2) Grounding configuration method for irregular structural components.

[0136] Irregularly shaped structural components need to be configured according to the actual installation location and purpose. For structural components that only serve a supporting function, the grounding configuration method should be the same as that for thin film or sheet-like specimens. Copper foil should be pasted in a location where it is easy to paste copper foil and reliably grounded through a special wire. For structural components that serve an insulating and supporting function, the insulation performance of the structural components should be considered first. Without affecting the insulation performance of the structural components, copper foil should be pasted in a location where it is easy to paste copper foil on the grounding side and reliably grounded through a special wire.

[0137] This invention provides a system for preparing and grounding a polyetherimide composite dielectric with deep charge-discharge resistance, based on the aforementioned method for preparing and grounding the polyetherimide composite dielectric with deep charge-discharge resistance. The system includes:

[0138] Nanoparticle module for preparing long rod-shaped zinc oxide nanoparticles.

[0139] A polyetherimide-based composite material preparation module, connected to a nanoparticle module, is used to prepare polyetherimide-based composite film samples, polyetherimide-based composite sheet samples, and polyetherimide-based composite irregular structural parts.

[0140] The grounding configuration module is connected to the polyetherimide-based composite material preparation module, and the sample is used for grounding configuration in a space radiation environment.

[0141] The present application takes flaky PEI / ZnO composite material as an example, and details the preparation process and grounding configuration.

[0142] 1.1, Preparation of long rod-shaped zinc oxide nanoparticles.

[0143] (1) Take 5.9496 g (0.02 mol) of zinc nitrate hexahydrate and place it in a 100 mL beaker 1; then take 11.9991 g (0.30 mol) of sodium hydroxide and put it into beaker 1; the molar ratio of added zinc nitrate hexahydrate to sodium hydroxide is 1:15; add 50 mL of deionized water to beaker 1; magnetically stir at room temperature for 30 min to obtain a clear transparent solution, and measure the pH value of the solution.

[0144] (2) Transfer the above solution to a 100 mL polytetrafluoroethylene-lined stainless steel reaction kettle, seal, and react in a 150°C oven for 8h.

[0145] (3) Take out the above reaction kettle and cool it to room temperature naturally, filter the solution in the reaction kettle, and obtain white precipitate; wash it with deionized water and anhydrous ethanol several times, then transfer the white precipitate to a watch glass and dry it in an 80°C oven for 10h to obtain and collect the product.

[0146] (4) Repeat the above preparation process to collect a total of 100g of product for use.

[0147] 1.2, Preparation of PEI / ZnO composite material flake sample.

[0148] (1) Take 500g of PEI particles, wash them several times with deionized water and anhydrous ethanol, dry them, then place them in a 150°C convection oven and dry them for 10 hours; take 50g of self-made long rod-shaped zinc oxide powder, place it in a 150°C convection oven and dry it for 10 hours.

[0149] (2) Pour the dried PEI particles and long rod-shaped zinc oxide powder into a beaker and pre-mix, then stir them evenly with a glass rod and wait for use.

[0150] (3) Use a small-scale closed mixer in the laboratory to mix, set the mixing temperature to 300°C, the rotor speed to 60 revolutions per minute, and the mixing time to 15 minutes, then start heating.

[0151] (4) After the mixer reaches the set temperature, start the rotor and put in the prepared PEI / zinc oxide mixture.

[0152] (5) After mixing is completed, take out the mixed material, and then use a flat vulcanizing machine to press the mixed material into a flaky sample of the desired size. In this example, it is pressed into a circular sample with a thickness of 1mm and a diameter of 100mm.

[0153] 1.3, Preparation of pure PEI sheet sample as a control group.

[0154] (1) Take 500 g of PEI particles, wash several times with deionized water and anhydrous ethanol, dry, and then place in a convection oven at 150°C for 10 hours.

[0155] (2) Pour the dried PEI particles into a beaker and wait to use.

[0156] (3) Use a laboratory small-scale closed mixer to mix, set the mixing temperature to 300°C, the rotor speed to 60 rpm, and the mixing time to 15 min, and then start heating.

[0157] (4) After the mixer reaches the set temperature, start the rotor and add the prepared PEI particles.

[0158] (5) After mixing is complete, remove the mixed material and use a flat vulcanizing machine to press the mixed material into a sheet-shaped sample of the desired size. In this example, it is pressed into a circular sample with a thickness of 1 mm and a diameter of 100 mm.

[0159] 1.4, Ground configuration method.

[0160] One side of the circular sample is covered with a copper foil with conductive glue, leaving a 3 mm margin at the edge of the sample, and leaving a space without copper foil, as shown in Figure 4 ; At the same time, a special lead wire is used for grounding, and the structure of the special lead wire is shown in Figure 3 .

[0161] As shown in Figure 4 , the special lead wire is composed of two copper foil patches with conductive glue and a section of braided copper wire. The two copper foil patches are both circular with a diameter of 25 mm. Copper foil patch 1 is pasted at the center of the sample, and copper foil patch 2 is pasted and fixed to the grounding surface. After installation, the resistance between the two ends is measured with a multimeter to ensure reliable connection and good grounding.

[0162] Both the prepared PEI / ZnO composite sheet sample and the pure PEI sheet sample are treated according to the above grounding configuration method.

[0163] 1.5, Medium charge and discharge performance test.

[0164] In order to verify the deep charge and discharge resistance performance of the prepared PEI / ZnO sample, a high-energy electron radiation experimental chamber is used to conduct a comparative radiation experiment on the PEI / ZnO composite sample and the PEI pure sample under the same radiation conditions. The deep charge and discharge resistance performance of the sample is directly represented by measuring the number of static discharges of each sample under electron radiation. The high-energy electron radiation experimental chamber used is shown in Figure 5 .

[0165] The radiation test connection diagram is shown in Figure 5 The sample is placed in a vacuum test chamber with a vacuum degree < 5 x 10 -4 Pa, and a high-energy electron gun is placed directly above the working plane, and the electrons are incident from top to bottom. The parameters of the high-energy electron generator are as follows: electron beam current 0.2~100μA, initial electron energy: 0.3~0.5MeV, and limit vacuum 1 x 10 -6 Pa.

[0166] The working platform below the radiation source is a grounded copper plate with a size of 470mm x 350mm, and above the copper plate is a columnar platform made of polytetrafluoroethylene, on which the sample to be tested is placed. The test sample is irradiated from the front and grounded from the back, and the lead wire on the back of the sample is grounded through a 50Ω measuring resistor. An oscilloscope is used to collect the voltage signal across the measuring resistor.

[0167] After the radiation starts, as the radiation time increases, electrons continuously accumulate inside the sample, and the deposited charge electric field continuously strengthens. When the electric field strength exceeds the breakdown threshold of the sample material, dielectric electrostatic discharge will be triggered, and the corresponding discharge waveform can be collected by measuring the voltage signal on the 50Ω resistor and recording the number of discharges.

[0168] The completed ground configuration of the sheet-shaped PEI / ZnO composite sample is shown in Figure 6 .

[0169] Experimental results:

[0170] (1) Set the electron beam current to 5μA, and measure the electrostatic discharge waveform and discharge times of the two samples within 20min after the beam current is stabilized.

[0171] (2) Set the electron beam current to 10μA, and measure the electrostatic discharge waveform and discharge times of the two samples within 20min after the beam current is stabilized.

[0172] Table 1 Comparison results of high-energy electron radiation on two samples

[0173]

[0174] From the results, it can be seen that under the same radiation conditions, in the same radiation time, the number of electrostatic discharge and the discharge current peak of the prepared PEI / ZnO composite sample are less than those of the unmodified PEI pure sample. When the electron beam current is 5 μA, compared with the PEI pure sample, the number of electrostatic discharge of the PEI / ZnO composite sample prepared in the application is reduced by 103 times, and the reduction amplitude is as high as 89.6%; when the electron beam current is 10 μA, compared with the PEI pure sample, the number of electrostatic discharge of the PEI / ZnO composite sample prepared in the application is reduced by 232 times, and the reduction amplitude is as high as 88.2%; which fully proves that the PEI / ZnO composite sample prepared in the application has excellent deep charge and discharge resistance.

[0175] The above merely illustrates the specific implementation of the present application, but the protection scope of the present application is not limited to this, any modification, equivalent replacement and improvement within the technical range disclosed in the present application and within the spirit and principle of the present application should be covered in the protection scope of the present application.

Claims

1. Use of a polyetherimide composite material having resistance to deep charge-discharge in a ground configuration in a space radiation environment, characterized in that, The application relates to a method for preparing a polyetherimide-based composite material, and belongs to the technical field of composite materials. The method comprises the following steps: S1, preparing long rod-shaped zinc oxide nanoparticles; S2, preparing a polyetherimide-based composite material film sample, a polyetherimide-based composite material sheet sample and a polyetherimide-based composite material special-shaped structure; S3, applying the sample to a grounding configuration in a space radiation environment. The method for preparing the long rod-shaped zinc oxide nanoparticles in the step S1 comprises the following steps: (1) a proper amount of zinc nitrate hexahydrate is weighed by an electronic balance and placed in a beaker 1; a corresponding amount of sodium hydroxide is weighed and put into the beaker 1, wherein the molar ratio of the zinc nitrate hexahydrate to the sodium hydroxide is 1:15; a proper amount of deionized water is added into the beaker 1; the solution is stirred by a magnetic force at normal temperature for 30 min to obtain a clear and transparent solution, and the pH value of the solution is measured; (2) the solution is transferred into a stainless steel reaction kettle with a polytetrafluoroethylene lining, sealed and reacted in an oven at 150 DEG C for 8 h; (3) the reaction kettle is taken out and naturally cooled to room temperature, the solution in the reaction kettle is filtered to obtain white precipitates; the white precipitates are washed with deionized water and anhydrous ethanol for several times, then are transferred into a watch glass and dried in an oven at 80 DEG C for 10 h to obtain and collect the product; In the step S2, the polyetherimide-based composite material film sample is prepared, and the preparation specifically comprises the following steps: The PEI / ZnO composite dielectric film is prepared by using a scraping coating method and a hot-pressing annealing method, and the specific process is as follows: (1) a proper amount of PEI particles and long rod-shaped zinc oxide nanoparticles to be processed are respectively placed in a convection oven at 150 DEG C and dried for 10 h; (2) a corresponding amount of long rod-shaped zinc oxide nanoparticles is weighed according to the set volume fraction, and is put into a beaker containing 50 mL of 1-methyl-2-pyrrolidone solution; the beaker is placed in an ultrasonic machine, and ultrasonic oscillation is carried out for 40 min until the zinc oxide powder is uniformly dispersed in the 1-methyl-2-pyrrolidone solution; (3) a corresponding amount of PEI particles is weighed by a balance and added into the above dispersed mixed solution, and the beaker is placed on a magnetic stirrer, heated by an oil bath and stirred at 60 DEG C for 12 h until the PEI particles are completely dissolved in the mixed solution, then the beaker containing the mixed solution is placed in a vacuum drying box and statically placed for 12 h until there is no air bubble in the solution; (4) the statically placed mixed solution is taken out, poured on a clean glass substrate which has been preheated to 60 DEG C, and the mixed solution is uniformly coated on the glass substrate by using a film spreading scraper, then the glass substrate is placed in a vacuum oven at 60 DEG C and kept for 12 h, and then is heated to 220 DEG C and kept for 4 h to remove the 1-methyl-2-pyrrolidone solvent, after natural cooling, the film is removed in deionized water to obtain the prepared PEI / ZnO composite dielectric film; (5) after the prepared film is dried, the film is heat-treated in a vacuum oven to remove residual solvents, specifically, the temperature is first increased to 120 DEG C and kept for 5 h, then is increased to 200 DEG C and kept for 6 h, and finally is naturally cooled to room temperature; In the step S2, the polyetherimide-based composite material sheet sample is prepared, and the preparation specifically comprises the following steps: (1) Take the appropriate amount of PEI particles and long rod-shaped zinc oxide nanoparticles to be processed and place them in a convection oven at 150 DEG C for 10 hours; (2) The corresponding mass of dried PEI particles and long rod-shaped zinc oxide nanoparticles is weighed by a balance according to the set proportion, and then mixed and used; (3) A small closed mixer for laboratory is used, and the mixing parameters such as mixing temperature, rotor speed and mixing time are set, and then heating is started; (4) After the mixer reaches the set temperature, start the rotor and put in the prepared PEI / zinc oxide mixture; (5) After mixing, take out the mixed material, and then use a flat vulcanizing machine to press the mixed material into a thin sheet-shaped sample of the required size.

2. Use of the polyetherimide composite material with deep-discharge resistance according to claim 1 in the grounding configuration in the space radiation environment, characterized by that, In S2, the preparation of a polyetherimide-based composite special-shaped structure is specifically as follows: (1) Take the appropriate amount of PEI particles and long rod-shaped zinc oxide nanoparticles to be processed and place them in a convection oven at 150 DEG C for 10 hours; (2) The corresponding mass of dried PEI particles and long rod-shaped zinc oxide nanoparticles is weighed by a balance according to the set proportion, and then mixed and used; (3) A small closed mixer for laboratory is used, and the mixing parameters such as mixing temperature, rotor speed and mixing time are set, and then heating is started; (4) After the mixer reaches the set temperature, start the rotor and put in the prepared PEI / zinc oxide mixture; (5) After mixing, take out the mixed material, and then use a flat vulcanizing machine to press the mixed material into a thin sheet-shaped sample of the required size.

3. Use of the polyetherimide composite material with resistance to deep-discharge and charge according to claim 1 in the grounding configuration in the space radiation environment, characterized by the fact that, S3 specifically includes: (1) Grounding configuration method of thin film or sheet-shaped sample: The sample grounding configuration method is that the thin film or sheet-shaped sample needs to be plated with copper or pasted with copper foil on one side of the sample, and a 3mm margin is left empty at the edge of the sample; At the same time, a special lead wire is used for grounding; The special lead wire is composed of two copper foil patches with conductive glue and a section of braided copper wire, wherein the size of the copper foil patch is set according to the area of the copper-plated side of the thin film or sheet-shaped sample, and is generally set to 1 / 4 of the area; The length of the braided copper wire is cut according to the actual application scene, and is assembled with the copper foil patch; After assembly, one copper foil patch is pasted at the center of the sample, and the other end of the copper foil patch is fixed at the grounding point, and then a multimeter is used to measure the resistance of both ends to ensure reliable grounding; (2) Grounding configuration method of special-shaped structure The special-shaped structure needs to be configured according to the actual installation position and purpose, and the structure only serving as support should refer to the grounding configuration method of the thin film or sheet-shaped sample, and the copper foil is pasted at the position convenient for pasting the copper foil and reliably grounded through the special lead wire; For the structure serving as insulation and support, the insulation performance of the structure should be considered first, and on the basis of not affecting the insulation performance of the structure, the copper foil is pasted at the position convenient for pasting the copper foil at the grounding side and reliably grounded through the special lead wire.

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