CN111607227B - Three-dimensional nano carbon/polyimide composite aerogel material and preparation method and application thereof - Google Patents
Three-dimensional nano carbon/polyimide composite aerogel material and preparation method and application thereof Download PDFInfo
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Abstract
The application discloses a preparation method of a three-dimensional nano carbon/polyimide composite aerogel material, the three-dimensional nano carbon/polyimide composite aerogel material prepared by the method, and application of the three-dimensional nano carbon/polyimide composite aerogel material in a pressure sensor. The preparation method comprises the working procedures of modifying the nano-carbon material, preparing a modified nano-carbon/polyimide precursor solution, preparing three-dimensional nano-carbon/polyimide precursor aerogel, imidizing at low temperature by microwave and the like which are sequentially carried out.
Description
Technical Field
The application relates to the technical field of nano materials, in particular to a three-dimensional carbon/polyimide composite aerogel material and a preparation method and application thereof.
Background
Polyimide (PI) is a high-performance special polymer, has excellent thermal stability, mechanical properties, electrical insulation and chemical resistance, and is widely applied to the technical fields of aerospace, microelectronics, mechanical manufacturing and the like at present. With the rapid development of flexible electronic technology, conventional microelectronic devices face many new requirements and challenges, such as: the sensing material used for preparing the flexible sensor in the flexible wearable electronic equipment needs to meet excellent performances such as high flexibility, high sensitivity, strong durability and the like.
The sensing materials used to prepare conventional sensors are mainly aerogel materials with a pore structure, such as: the nano carbon aerogel material is complex in preparation process and long in time consumption, and the nano carbon aerogel material serving as a conductive material has mechanical brittleness in a certain direction, so that the requirements of flexible wearable electronic equipment cannot be met. In order to meet the requirements of flexible wearable electronic equipment, a nano carbon/polyimide composite aerogel material is produced, has the advantages of excellent mechanical property and heat insulation property, ideal flexibility, high porosity, high specific surface area, controllable structure and the like, and is one of ideal materials for preparing flexible sensors in the flexible wearable electronic equipment.
At present, graphene/polyimide aerogel is mostly researched in nanocarbon/polyimide composite aerogel materials, but due to the fact that strong van der waals force action exists between two-dimensional sheets of graphene, agglomeration phenomenon is easy to occur, negative effects on microwave absorption, heat conduction and charge conduction are caused, and therefore application of the graphene/polyimide aerogel in the field of flexible electronics is limited.
In addition, the preparation method of the graphene/polyimide aerogel comprises an imidization process, wherein the imidization process is usually a chemical imidization method or a thermal imidization method, and the chemical imidization method has the defects of difficult control of a reaction process, high catalyst toxicity, environmental friendliness and the like; the thermal imidization is a method in which imidization is carried out at a high temperature (300 to 400 ℃) for a long time, and has problems of high energy consumption, easy damage to a heat-labile element, and the like. For the thermal imidization method, there is a method of adding an imidization accelerator to lower the curing temperature of polyimide to achieve low-temperature imidization, but uneven dispersion of the residual accelerator may cause a decrease in mechanical properties and/or structural defects of the prepared material.
Disclosure of Invention
Aiming at the problems in the prior art, the application provides a preparation method of a nano-carbon/polyimide composite aerogel material, a three-dimensional nano-carbon/polyimide composite aerogel material prepared by the method, and application of the three-dimensional nano-carbon/polyimide composite aerogel material in a flexible circuit substrate.
In a first aspect, the present application provides a method for preparing a nanocarbon/polyimide composite aerogel material, comprising the following steps:
preparing a modified nano carbon material;
preparing a modified nano carbon/polyimide precursor solution by using the modified nano carbon material and the polyimide precursor as raw materials;
sequentially freezing and drying the modified nano carbon/polyimide precursor solution to prepare three-dimensional nano carbon/polyimide precursor aerogel; and
and (2) performing microwave imidization on the three-dimensional nano carbon/polyimide precursor aerogel to prepare the three-dimensional nano carbon/polyimide composite aerogel material, wherein the microwave imidization temperature is not more than 230 ℃, and the reaction time is 1-30 min.
In some embodiments, the preparing of the modified nanocarbon material comprises the steps of: and oxidizing the nano carbon material to prepare an oxidized nano carbon material, wherein the nano carbon material is graphene, a carbon nano tube or nano carbon black.
In some embodiments, the preparing the modified nanocarbon material further comprises the steps of: and carrying out silane modification on the oxidized nano carbon material to prepare the oxidized nano carbon material modified by the silane coupling agent.
In some embodiments, said silane modifying said oxidized nanocarbon material comprises the steps of:
adding a silane coupling agent and a catalyst into the solution for oxidizing the nano carbon material, and fully reacting to obtain a mixture; and
and filtering the mixture, washing the filtrate, and drying to obtain the oxidized nano carbon material modified by the silane coupling agent.
In some embodiments, the preparing the modified nanocarbon/polyimide precursor solution comprises the steps of:
adding the modified nano carbon material into a first solvent, and fully and uniformly dispersing to prepare a first mixed solution;
adding diamine into the first mixed solution, and fully dissolving to prepare a second mixed solution;
adding dianhydride into the second mixed solution, and reacting to obtain a third mixed solution;
adding a second solvent serving as an extracting agent into the third mixed solution, collecting a lower-layer precipitate after extraction and separation, washing the precipitate, and drying to obtain a solid modified nano carbon/polyimide precursor; and
and fully dissolving the alkaline amine compound and the solid modified nano carbon/polyimide precursor into water to prepare the modified nano carbon/polyimide precursor solution.
In some embodiments, the first solvent is one or more of N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-dimethylformamide, tetramethylurea, dimethyl sulfoxide, and hexamethylphosphoric triamide; the second solvent is one or more of water, methanol and acetonitrile.
In some embodiments, the preparing the three-dimensional nanocarbon/polyimide precursor aerogel comprises the steps of:
pouring the modified nano carbon/polyimide precursor solution into a mold, and then freezing to prepare a three-dimensional nano carbon/polyimide precursor wet gel; and
and drying the three-dimensional nano carbon/polyimide precursor wet gel to prepare the three-dimensional nano carbon/polyimide precursor aerogel.
In a second aspect, the present application provides a three-dimensional nanocarbon/polyimide composite aerogel material, which is prepared by the preparation method of the nanocarbon/polyimide composite aerogel material described in the first aspect.
In some embodiments, the material of the nanocarbon is graphene, carbon nanotubes or carbon black.
In a third aspect, the present application provides a use of the three-dimensional nanocarbon/polyimide composite aerogel material described in the second aspect in a pressure sensor.
The application relates to a three-dimensional carbon/polyimide composite aerogel material, a preparation method and application thereof, and the three-dimensional carbon/polyimide composite aerogel material has the following technical effects:
the preparation method of the three-dimensional nano carbon/polyimide composite aerogel material has the advantages that: 1. the surface of the nano-carbon material is subjected to functional modification, wherein the functional modification is oxidation treatment and silane coupling agent modification, so that the agglomeration phenomenon of the nano-carbon material in an organic solvent can be avoided, the interaction between the nano-carbon material and polyimide precursor resin is enhanced, and the microwave-thermal conversion efficiency is improved. 2. The surface modified nano carbon material is introduced in an in-situ polymerization manner, so that the method is simple, convenient and efficient; 3. the microwave imidization mode is adopted to carry out imidization process, low-temperature and high-efficiency imidization is realized, 100 percent of imidization rate can be achieved only by keeping for 10min in a microwave environment at 230 ℃, and the microwave imidization process has the characteristics of time saving, energy saving, environmental protection and high product performance, and is controllable in the microwave imidization reaction process.
The three-dimensional nano carbon/polyimide composite aerogel material can bear 90% of compressive strain, can rapidly recover the original state, has excellent thermal stability, chemical stability, pressure-resistance effect, flexibility and mechanical stability, can be applied to the technical fields of flexible electronics and microelectronics, and is particularly suitable for being used as a material for preparing a pressure sensor in flexible wearable electronic equipment.
Drawings
The technical solution and other advantages of the present application will become apparent from the detailed description of the embodiments of the present application with reference to the accompanying drawings.
Fig. 1 is a schematic flow chart of a preparation method of a three-dimensional nanocarbon/polyimide composite aerogel material according to an embodiment of the present application.
Fig. 2 is a schematic diagram of a pressure sensor in an embodiment of the present application.
Figure 3 is a schematic cross-sectional view of the sensing mechanism of figure 2.
Fig. 4 is a scanning electron microscope cross-sectional view of the three-dimensional graphene/polyimide composite aerogel material in example 1 of the present application.
Fig. 5 is a scanning electron microscope image of the three-dimensional structure of the three-dimensional graphene/polyimide composite aerogel material in example 1 of the present application.
Fig. 6 is an infrared spectrum of the three-dimensional graphene/polyimide composite aerogel material according to example 1 of the present application.
Fig. 7 is a graph of a pressure-rebound test result of the three-dimensional graphene/polyimide composite aerogel material in example 1 of the present application, wherein A, B, C and D represent pressure-deformation curves of the three-dimensional graphene/polyimide composite aerogel material at set deformation amounts of 90%, 80%, 50%, and 30%, respectively.
FIG. 8 is a Scanning Electron Microscope (SEM) cross-sectional view of a three-dimensional carbon nanotube/polyimide composite aerogel material according to example 9 of the present application.
Fig. 9 is a scanning electron microscope image of the three-dimensional structure of the three-dimensional carbon nanotube/polyimide composite aerogel material according to example 9 of the present application.
Fig. 10 is an infrared spectrum of the three-dimensional carbon nanotube/polyimide composite aerogel material according to example 9 of the present application.
Fig. 11 is a graph of the pressure-rebound testing result of the three-dimensional carbon nanotube/polyimide composite aerogel material in example 9 of the present application, wherein E, F and G represent pressure-deformation curves of the three-dimensional carbon nanotube/polyimide composite aerogel material at set deformation amounts of 80%, 50% and 30%, respectively.
FIG. 12 is a scanning electron microscope cross-sectional view of a three-dimensional nano carbon black/polyimide composite aerogel material according to example 10 of the present application.
FIG. 13 is a scanning electron microscope image of the three-dimensional structure of the three-dimensional nano carbon black/polyimide composite aerogel material in example 10 of the present application.
FIG. 14 shows an IR spectrum of a three-dimensional nano carbon black/polyimide composite aerogel material according to example 10 of the present application.
Fig. 15 is a graph of the pressure-rebound testing results of the three-dimensional nano carbon black/polyimide composite aerogel material in example 10 of the present application, wherein H, I and J represent the pressure-deformation curves of the three-dimensional nano carbon black/polyimide composite aerogel material at set deformation amounts of 80%, 50% and 30%, respectively.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It is to be understood that the embodiments described are only a few embodiments of the present application and not all embodiments. All other embodiments, which can be made by those skilled in the art without any inventive step based on the embodiments in the present application, shall fall within the protection scope of the present application.
In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed in a particular orientation, and be operated in a particular manner, and are not to be construed as limiting the present application. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise.
In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; may be mechanically connected, may be electrically connected or may be in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.
In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may comprise direct contact of the first and second features, or may comprise contact of the first and second features not directly but through another feature in between. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. "beneath," "under" and "beneath" a first feature includes the first feature being directly beneath and obliquely beneath the second feature, or simply indicating that the first feature is at a lesser elevation than the second feature.
The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application. Moreover, the present application may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, examples of various specific processes and materials are provided herein, but one of ordinary skill in the art may recognize applications of other processes and/or use of other materials.
In the foregoing embodiments, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In a first aspect, an embodiment of the present application provides a method for preparing a three-dimensional nanocarbon/polyimide composite aerogel material, including the following steps:
s1, preparing the modified nano carbon material.
Specifically, the nano carbon material is graphene, a carbon nano tube or nano carbon black.
In some embodiments, the preparing of the modified nanocarbon material comprises the steps of: and carrying out oxidation treatment on the nano carbon material to prepare an oxidized nano carbon material.
When the nano carbon material is graphene, the graphene is oxidized by adopting an improved Hummers method to prepare a graphene oxide aqueous solution. The improved Hummers method specifically comprises the following steps: firstly, under the ice-bath condition of 0 +/-5 ℃, a proper amount of graphene and concentrated H are added into a glass bottle 2 SO 4 (ii) a Then adding NaNO under the condition of constant stirring 3 And KMnO 4 Reacting for 0.5-1.5 h; then, keeping the temperature for 0.5 to 1.5 hours under the condition of 35 +/-5 ℃ water bath; adding deionized water or distilled water at 45 + -5 deg.C, and adding H 2 O 2 Obtaining a first mixture; centrifuging the first mixture, removing supernatant to collect precipitate, wherein the precipitate is solid graphene oxide; and finally, washing the solid graphene oxide for multiple times until the pH value is neutral, and fully dispersing the solid graphene oxide with the neutral pH value in deionized water or distilled water by ultrasonic waves to prepare a graphene oxide aqueous solution.
When the nano carbon material is a carbon nano tube, the carbon nano tube is oxidized by adopting a mixed acid oxidation method to prepare an oxidized carbon nano tube aqueous solution. The mixed acid oxidation method hasThe body is as follows: firstly, a proper amount of carbon nanotube powder is added into a 250mL round-bottom flask, and then a proper amount of concentrated H is added into the round-bottom flask at room temperature 2 SO 4 Stirring for 15-60 min; then, concentrated HNO was added thereto 3 Said concentrated HNO 3 In a volume of said concentrated H 2 SO 4 Stirring for 1/3 of the volume of the mixture at the temperature of between 40 and 80 ℃ for 1 to 5 hours to obtain a second mixture; then, adding a proper amount of distilled water or deionized water into the second mixture, and then carrying out filtering operation, wherein the filtered substance is the solid carbon oxide nano tube; and finally, repeating washing and filtering operations on the solid carbon oxide nanotubes until the pH of the solid carbon oxide nanotubes is neutral, and fully dispersing the solid carbon oxide nanotubes with neutral pH in distilled water or deionized water by ultrasonic waves to prepare the carbon oxide nanotube aqueous solution.
When the nano carbon material is nano carbon black, oxidizing by using an oxidant, and selecting concentrated HNO 3 Or H 2 O 2 As oxidant, prepare the oxidized nano carbon black water solution. The method specifically comprises the following steps: firstly, adding a proper amount of nano carbon black powder into a 250mL round-bottom flask, and then adding a proper amount of concentrated HNO into the round-bottom flask at room temperature 3 Or H 2 O 2 Stirring and reacting for 5-24 h at 50-80 ℃ to obtain a third mixture; then, adding a proper amount of distilled water or deionized water into the third mixture, and then carrying out filtering operation, wherein the filtered substance is the solid oxidized nano carbon black; and finally, repeatedly washing and filtering the solid oxidized nano carbon black until the pH value of the solid oxidized nano carbon black is neutral, and fully dispersing the solid oxidized nano carbon black with neutral pH value in distilled water or deionized water by ultrasonic waves to prepare the oxidized nano carbon black aqueous solution.
Preferably, the mass ratio of the oxidant (concentrated nitric acid or hydrogen peroxide) to the nano carbon black is 1:1-8.
In some embodiments, the preparing the modified nanocarbon material further comprises the steps of: and carrying out silane modification on the oxidized nano carbon material to prepare the oxidized nano carbon material modified by the silane coupling agent. After the oxidized nano carbon material is modified by silane, the dispersibility of the oxidized nano carbon material in an organic solvent is obviously improved, so that the agglomeration phenomenon is avoided.
Under mild conditions, the modification reaction of a silane coupling agent on the oxidized nano carbon material is promoted by a catalyst, and the oxidized nano carbon material is not subjected to silane modification by the silane coupling agent under acidic or alkaline conditions, so that the condition that the oxygen-containing groups of the oxidized nano carbon material are damaged by acid or alkali is effectively avoided, and the negative influence on the dispersing performance of the oxidized nano carbon material in an organic solvent is caused.
Specifically, a proper amount of silane coupling agent is added into an aqueous solution of an oxidized nano carbon material (such as an aqueous solution of graphene oxide, or an aqueous solution of carbon nano tubes, or an aqueous solution of oxidized nano carbon black), and the mixture reacts for 12 to 36 hours at a temperature of between 0 and 25 ℃ under the action of a catalyst, and then the oxidized nano carbon material modified by the silane coupling agent is prepared by sequentially carrying out the procedures of filtering, washing the filtrate and freeze-drying the filtrate.
The catalyst is a mixture of N-hydroxysuccinimide (NHS) and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride (EDC. HCL). Preferably, the mass ratio of the NHS to the EDC-HCL is 1:1, and the mass ratio of the NHS to the EDC-HCL to the graphene oxide aqueous solution is 1.
The silane coupling agent is one or more of gamma-aminopropyldimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropylmethyldimethoxysilane, gamma-glycidoxypropylmethyldimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryloxypropyltrimethoxysilane, dimethoxymethyl-3-piperidinylpropylsilane, diethoxy-3-glycidoxypropylmethylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (beta-methoxyethoxysilane, N- (3-diethoxymethylsilylpropyl) succinimide, N- [3- (triethoxysilyl) propyl ] anthranilic acid, benzophenone-3,3 '-bis (N- [ 3-triethoxysilyl ] propylamide) -3252 zxft 52' -dicarboxylic acid, benzene-1,4-bis (N- [ 3-triethoxysilyl ] propylamide) -25 zxft 3425-dicarboxylic acid, 3- (triethoxysilyl) propylsuccinic anhydride and N-phenylaminopropyl-trimethoxysilane.
Preferably, the mass of the aqueous solution of the silane coupling agent and the oxidized nanocarbon material is 1.
And S2, preparing a modified nano carbon/polyimide precursor solution from the modified nano carbon material and the polyimide precursor.
Specifically, the raw materials of the polyimide precursor are diamine and dianhydride. Preferably, the molar ratio of the diamine to the dianhydride is 0.9 to 1:1.
Preferably, the diamine is selected from: 4,4 '-diaminodiphenyl ether, 1,3-bis (4' -aminophenoxy) benzene, 4,4 '-diamino-2,2' -bistrifluoromethylbiphenyl, or an alkyldiamine compound.
Preferably, the dianhydride is selected from: pyromellitic dianhydride, 2,3,3',4' -diphenylether tetracarboxylic dianhydride, 4,4' - (hexafluoroisopropylidene) diphthalic anhydride or 3,3',4,4' -benzophenone tetracarboxylic dianhydride.
In some embodiments, the preparing the modified nanocarbon/polyimide precursor solution comprises the steps of:
s2.1, adding the modified nano carbon material into a first solvent, and fully and uniformly dispersing to prepare a first mixed solution.
Specifically, the first solvent is an anhydrous polar organic solvent, and the modified nanocarbon material is sufficiently dispersed in the first solvent by ultrasonic waves.
In some embodiments, the first solvent is one or more of N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-dimethylformamide, tetramethylurea, dimethyl sulfoxide, and hexamethylphosphoric triamide; the second solvent is one or more of water, methanol and acetonitrile.
And 2.2, adding diamine into the first mixed solution, and fully dissolving to prepare a second mixed solution.
And S2.3, adding dianhydride into the second mixed solution, and reacting to obtain a third mixed solution.
Specifically, under the protection atmosphere of nitrogen, adding dianhydride into the second mixed solution, and continuously stirring for 4-12 h to enable the dianhydride and the diamine to fully react to obtain the polyimide precursor (polyamic acid).
In some embodiments, the dianhydride is added in two portions, namely: dividing the dianhydride into two parts with equal quantity, firstly adding one part into the second mixed solution, and adding the other part at intervals of 10-20 min. The purpose of adding dianhydride in two times is as follows: the polyimide polymerization process is controlled, and the problem that the dianhydride is input too fast to cause uneven molecular weight of the polymer or cause implosion is prevented.
And S2.4, adding a second solvent serving as an extracting agent into the third mixed solution, collecting a lower-layer precipitate after extraction and separation, washing the precipitate, and drying to obtain the solid modified nano carbon/polyimide precursor.
In particular, the second solvent is used to extract the nanocarbon/polyimide precursor from the first solvent. And (3) repeatedly washing and filtering the precipitate by using the second solvent, and then drying the filtrate obtained in the last filtering operation to obtain the solid modified nano carbon/polyimide precursor.
In some embodiments, the filtrate can be dried using an oven, hot plate, blower, or the like, and can also be dried using infrared drying or vacuum drying. Preferably, the drying temperature is 40-80 ℃, and the drying time is 12-24 h.
In some embodiments, the second solvent is one or more of water, methanol, and acetonitrile.
And S2.5, sufficiently dissolving an alkaline amine compound and the solid modified nano carbon/polyimide precursor into water to prepare the modified nano carbon/polyimide precursor solution.
Specifically, the water is deionized water. The basic amine compound is added for the purpose of: the basic amine compound reacts with the polyimide precursor (i.e. polyamic acid) to form a salt compound, so that the solid modified nanocarbon/polyimide precursor can be dissolved in water.
In some embodiments, the basic amine compound is one or more of triethylamine, diamine, diethylenetriamine, polyethyleneimine, and pyridine.
And S3, sequentially freezing and drying the modified nano carbon/polyimide precursor solution to prepare the three-dimensional nano carbon/polyimide precursor aerogel.
In some embodiments, the freezing and drying processes are sequentially performed on the modified nano carbon/polyimide precursor solution, and the method comprises the following steps:
s3.1, pouring the modified nano carbon/polyimide precursor solution into a mold, and then freezing to obtain the three-dimensional nano carbon/polyimide precursor wet gel.
Specifically, the mold filled with the modified nanocarbon/polyimide precursor solution is placed in a refrigerator, so that the modified nanocarbon/polyimide precursor solution is frozen and molded.
And S3.2, drying the three-dimensional nano carbon/polyimide precursor wet gel to prepare the three-dimensional nano carbon/polyimide precursor aerogel.
Specifically, the drying mode is a freeze drying method. Preferably, the freezing temperature is-196 ℃ to-18 ℃, the drying temperature is room temperature, the drying vacuum degree is 1 Pa to 50Pa, and the drying time is 24h to 48h.
And S4, performing microwave imidization on the three-dimensional nano carbon/polyimide precursor aerogel to obtain the three-dimensional nano carbon/polyimide composite aerogel material, wherein the microwave imidization temperature is not more than 230 ℃, and the reaction time is 1-30 min.
In some embodiments, the three-dimensional nanocarbon/polyimide precursor aerogel is placed in a microwave oven, and is subjected to microwave imidization at 230 ℃ for 10min to achieve 100% imidization rate, and then is cooled to room temperature to obtain the three-dimensional nanocarbon/polyimide aerogel.
In a second aspect, an embodiment of the present application provides a three-dimensional nanocarbon/polyimide composite aerogel material, which is prepared by the preparation method of the three-dimensional nanocarbon/polyimide composite aerogel material described in the first aspect.
The three-dimensional nano carbon/polyimide composite aerogel material can bear 90% of compressive strain, can quickly recover the original state, has excellent thermal stability, chemical stability, pressure-resistance effect, flexibility and mechanical stability, can be applied to the technical fields of flexible electronics and microelectronics, can be used for preparing electronic devices such as flexible circuit substrates, flexible batteries, supercapacitors, sensors, brakes and the like, can also be used as carbon biological tissue supports, ultralight mechanical damping porous materials and ultralight heat insulation/sound insulation porous materials, and is particularly suitable for being used as a material for preparing pressure sensors in flexible wearable electronic equipment. The flexible circuit substrate may be: a Thin-film transistor (TFT) array substrate in a flexible display panel, a flexible substrate of an Organic Light-Emitting Diode (OLED) display panel, a flexible substrate or a flexible insulating layer in a semiconductor microchip, and the like.
In a third aspect, the present application provides a use of the three-dimensional nanocarbon/polyimide composite aerogel material described in the second aspect in a pressure sensor. The three-dimensional nano carbon/polyimide composite aerogel material can be used as a sensing material in a pressure sensor.
For example: as shown in fig. 2 and 3, a pressure sensor includes: induction mechanism 1 and signal of telecommunication measuring mechanism 2, signal of telecommunication measuring mechanism 2 pass through wire 3 with induction mechanism 1 electric connection. The sensing mechanism 1 includes a first electrode 11, an aerogel layer 12, and a second electrode 13, which are stacked in sequence. First electrode 11 with between the aerogel layer 12, and second electrode 13 with all be equipped with electrically conductive silver glue between the aerogel layer 12, the material of aerogel layer 12 does three-dimensional nanometer carbon polyimide composite aerogel material. And leads 3 are respectively led out from the first electrode 11 and the second electrode 13 to realize the electrical connection between the induction mechanism 1 and the electric signal measuring mechanism 2, and the electric signal measuring device 2 is used for measuring the resistance value of the induction mechanism 1.
In the embodiment of the application, the imidization rate of the three-dimensional nano carbon/polyimide composite aerogel material is calculated by the following formula (1):
imidization rate (%) = S 1380 /S 1500 ×100％(1)
In the above formula (1), S 1380 Comprises the following steps: after microwave imidization treatment, the absorption peak area of C-C stretching vibration on the imide ring of polyimide, S 1500 Comprises the following steps: and after microwave imidization treatment, the absorption peak area of C-C stretching vibration on an imide ring of the polyimide. Wherein, the S 1380 And said S 1500 All obtained by infrared spectroscopy.
In the embodiment of the application, a universal testing machine is used for carrying out pressure-resilience test on the three-dimensional nano carbon/polyimide composite aerogel material, and the method specifically comprises the following steps: firstly, compressing the three-dimensional nano carbon/polyimide composite aerogel material to a set deformation amount by using a universal testing machine, wherein the compression speed is 0.5-1 mm/min; and then, reversely releasing the three-dimensional nano carbon/polyimide composite aerogel material to the initial position before compression at a release speed which is the same as the compression speed, thereby obtaining a pressure-deformation curve in the process.
The present application will be described in further detail below by way of specific examples and comparative examples, which set forth the gist of the present application, but the present application is not limited to these examples. In the following examples, the "parts" are "parts by mass".
Example 1: preparation of three-dimensional graphene/polyimide composite aerogel material
The embodiment provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, wherein the preparation method comprises the following steps:
s1, preparing a modified graphene material, wherein the modified graphene material is a silane coupling agent modified graphene oxide material.
Preparing a graphene oxide aqueous solution: first, a glass vial was charged with 4g of graphene and 120mL of concentrated H under an ice bath at 0 deg.C 2 SO 4 (ii) a Then under the condition of constant stirringTo which 2g of NaNO was added 3 And 20g of KMnO 4 Reacting for 1h; then, keeping for 1h under the condition of 35 ℃ water bath; then, deionized water was added thereto at 45 ℃ until 500mL, and then 30% by mass of H was added 2 O 2 Obtaining a first mixture; centrifuging the first mixture at the rotating speed of 9500r/min, removing supernatant to collect precipitate, wherein the precipitate is solid graphene oxide; and finally, washing the solid graphene oxide by using HCl with the mass fraction of 5% and deionized water in sequence until the pH of the solid graphene oxide is 7.0, and fully dispersing the solid graphene oxide with the pH of 7.0 in the deionized water by ultrasonic waves to prepare a graphene oxide aqueous solution with the concentration of 1 mg/mL.
Preparing a graphene oxide material modified by a silane coupling agent: firstly, taking 50mL of graphene oxide aqueous solution with the concentration of 1mg/mL, adding 1g of NHS, 1g of EDC & HCL and 250mg of vinyl triethoxysilane into the graphene oxide aqueous solution, and reacting for 24 hours at 10 ℃ to obtain a reaction mixture; then, filtering the reaction mixture to obtain a filtrate which comprises a silane coupling agent modified graphene oxide material; and finally, washing the filtrate by using distilled water to remove unreacted substances, and then performing a freeze-drying process to prepare the solid silane coupling agent modified graphene oxide material.
S2, preparing a modified graphene/polyimide precursor solution from the silane coupling agent modified graphene oxide material and a polyimide precursor.
Specifically, the polyimide precursor is prepared from diamine and dianhydride, wherein the diamine is 1,3-bis (4' -aminophenoxy) benzene, and the dianhydride is pyromellitic dianhydride.
The preparation of the modified graphene/polyimide precursor solution comprises the following steps:
s2.1, adding 0.2g of the graphene oxide material modified by the silane coupling agent and 18.5g of N-methyl-2-pyrrolidone into a flask at room temperature, and carrying out ultrasonic treatment for 30min to fully disperse the graphene oxide material modified by the silane coupling agent into the N-methyl-2-pyrrolidone to prepare a first mixed solution.
S2.2, adding 1.4915g of 1,3-bis (4' -aminophenoxy) benzene into the first mixed solution, and fully dissolving to prepare a second mixed solution.
And S2.3, adding the pyromellitic dianhydride of which the total amount is 1.1151g into the second mixed solution twice (at an interval of 15 min) under the protection of nitrogen, and stirring for 5 hours to fully react to prepare a third mixed solution.
And S2.4, adding deionized water serving as an extracting agent into the third mixed solution, collecting a lower-layer precipitate after extraction and separation, repeatedly washing and filtering the precipitate by using the deionized water, and drying a filtrate obtained in the last filtering operation by using a 60-DEG C drying oven for 24 hours to obtain the solid modified graphene/polyimide precursor.
S2.5, fully dissolving 0.5g of solid modified graphene/polyimide precursor and 0.1g of triethylamine in 10g of deionized water to prepare a modified graphene/polyimide precursor solution with the mass fraction of 1%.
And S3, sequentially freezing and drying the modified graphene/polyimide precursor solution with the mass fraction of 1% to prepare the three-dimensional graphene/polyimide precursor aerogel.
Specifically, firstly, the modified graphene/polyimide precursor solution with the mass fraction of 1% is poured into a mold, and then the mold is placed in a refrigerator at the temperature of-20 ℃ for freezing to prepare the three-dimensional graphene/polyimide precursor wet gel.
And then, freeze-drying the three-dimensional graphene/polyimide precursor wet gel, wherein the freezing temperature is-196 ℃, the drying temperature is room temperature, the drying vacuum degree is 10Pa, and the drying time is 48h to obtain the three-dimensional graphene/polyimide precursor aerogel.
And S4, placing the three-dimensional graphene/polyimide precursor aerogel in a microwave oven, performing microwave imidization for 10min at 230 ℃, and then cooling to room temperature to obtain the three-dimensional graphene/polyimide composite aerogel material.
The cross-sectional scanning electron microscope image and the three-dimensional structure scanning electron microscope image of the three-dimensional graphene/polyimide composite aerogel are respectively shown in fig. 4 and fig. 5. The prepared three-dimensional graphene/polyimide composite aerogel material is subjected to infrared spectrum testing, the testing result is shown in fig. 6, and the testing result shows that the three-dimensional graphene/polyimide precursor is kept for 10min in a microwave environment at 230 ℃, so that the imidization rate can reach 100%.
The prepared three-dimensional graphene/polyimide composite aerogel material is subjected to a pressure-rebound test, the test result is shown in fig. 7, and the test result shows that the three-dimensional graphene/polyimide composite aerogel material can bear 90% of compressive strain and can be rapidly recovered to the original state.
Example 2: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, and the preparation method is different from that of example 1 only in that: the "microwave imidization at 230 ℃ for 10min" in step S4 was replaced by "microwave imidization at 200 ℃ for 10min".
Example 3: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, which is different from example 1 only in that: the step S4 of "microwave imidization at 230 ℃ for 10min" was replaced by "microwave imidization at 180 ℃ for 10min".
Example 4: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, and the preparation method is different from that of example 1 only in that: the step S4 of "microwave imidization at 230 ℃ for 10min" was replaced by "microwave imidization at 150 ℃ for 10min".
Example 5: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, which is different from example 1 only in that: the step S4 of "microwave imidization at 230 ℃ for 10min" was replaced by "microwave imidization at 120 ℃ for 10min".
Example 6: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, which is different from example 1 only in that: the step S4 of "microwave imidization at 230 ℃ for 10min" was replaced by "microwave imidization at 230 ℃ for 8min".
Example 7: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, which is different from example 1 only in that: the "microwave imidization at 230 ℃ for 10min" in step S4 was replaced by "microwave imidization at 200 ℃ for 5min".
Example 8: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, which is different from example 1 only in that: the "microwave imidization at 230 ℃ for 10min" in step S4 was replaced by "microwave imidization at 200 ℃ for 3min".
Example 9: preparation of three-dimensional carbon nanotube/polyimide composite aerogel material
The embodiment provides a three-dimensional carbon nanotube/polyimide composite aerogel material and a preparation method thereof, wherein the preparation method comprises the following steps:
s1, preparing a modified carbon nanotube material, wherein the modified graphene material is a silane coupling agent modified carbon oxide nanotube material.
Preparing an aqueous solution of the carbon oxide nanotubes: first, 500mg of carbon nanotube powder was placed in a 250mL round-bottom flask, and 60mL of concentrated H was added thereto at room temperature 2 SO 4 Stirring for 30min; then, 20mL of concentrated HNO was added thereto 3 Stirring for 2h at 60 ℃ to obtain a second mixture; then, adding appropriate amount of distillation to the second mixtureWater, and then filtering to obtain a filtrate, namely the solid carbon oxide nano tube; and finally, repeatedly washing and filtering the solid carbon oxide nanotubes by using distilled water until the pH of the solid carbon oxide nanotubes is 7.0, and fully dispersing the solid carbon oxide nanotubes with the pH of 7.0 in deionized water by ultrasonic waves to prepare the carbon oxide nanotube aqueous solution with the concentration of 1 mg/mL.
Preparing a silane coupling agent modified carbon oxide nanotube material: firstly, 50mL of oxidized carbon nanotube aqueous solution with the concentration of 1mg/mL is taken, 2g of NHS, 2g of EDC & HCL and 3g of vinyl triethoxysilane are added into the aqueous solution, and the mixture is reacted for 24 hours at the temperature of 0 ℃ to obtain a reaction mixture; then, filtering the reaction mixture to obtain a filtrate comprising a silane coupling agent modified carbon oxide nanotube material; and finally, washing the filtrate by using distilled water to remove unreacted substances, and then performing a freeze-drying process to prepare the solid carbon oxide nanotube material modified by the silane coupling agent.
S2, preparing a modified carbon nanotube/polyimide precursor solution from the oxidized carbon nanotube material modified by the silane coupling agent and a polyimide precursor.
Specifically, the polyimide precursor is prepared from diamine and dianhydride, wherein the diamine is 1,3-bis (4' -aminophenoxy) benzene, and the dianhydride is pyromellitic dianhydride.
The preparation of the modified carbon nanotube/polyimide precursor solution comprises the following steps:
s2.1, adding 0.2g of the carbon oxide nanotube material modified by the silane coupling agent and 18.5g of N-methyl-2-pyrrolidone into a flask at room temperature, and carrying out ultrasonic treatment for 30min to fully disperse the carbon oxide nanotube material modified by the silane coupling agent in the N-methyl-2-pyrrolidone to prepare a first mixed solution.
S2.2, 1.4915g of 1,3-bis (4' -aminophenoxy) benzene is added to the first mixed solution and sufficiently dissolved to prepare a second mixed solution.
And S2.3, adding the pyromellitic dianhydride of which the total amount is 1.1151g into the second mixed solution twice (at an interval of 15 min) under the protection of nitrogen, and stirring for 5 hours to fully react to prepare a third mixed solution.
And S2.4, adding deionized water serving as an extracting agent into the third mixed solution, collecting the lower-layer precipitate after extraction and separation, repeatedly washing and filtering the precipitate by using the deionized water, and drying the filtrate obtained in the last filtering operation by using a 60-DEG C drying oven for 24 hours to obtain the solid modified carbon nano tube/polyimide precursor.
S2.5, fully dissolving 0.5g of solid modified carbon nano tube/polyimide precursor and 0.1g of triethylamine in 10g of deionized water to prepare a modified carbon nano tube/polyimide precursor solution with the mass fraction of 1%.
And S3, sequentially freezing and drying the modified carbon nanotube/polyimide precursor solution with the mass fraction of 1% to prepare the three-dimensional carbon nanotube/polyimide precursor aerogel.
Specifically, the modified carbon nanotube/polyimide precursor solution with the mass fraction of 1% is poured into a mold, and then the mold is placed in a refrigerator at the temperature of-20 ℃ for freezing to prepare the three-dimensional carbon nanotube/polyimide precursor wet gel.
And then, freeze-drying the three-dimensional carbon nanotube/polyimide precursor wet gel, wherein the freezing temperature is-18 ℃, the drying temperature is room temperature, the drying vacuum degree is 15Pa, and the drying time is 24 hours, so as to prepare the three-dimensional carbon nanotube/polyimide precursor aerogel.
And S4, placing the three-dimensional carbon nanotube/polyimide precursor aerogel in a microwave oven, performing microwave imidization for 10min at 230 ℃, and then cooling to room temperature to obtain the three-dimensional carbon nanotube/polyimide composite aerogel material.
The cross-sectional scanning electron microscope image and the three-dimensional structure scanning electron microscope image of the three-dimensional carbon nanotube/polyimide composite aerogel are respectively shown in fig. 8 and fig. 9. The prepared three-dimensional carbon nanotube/polyimide composite aerogel material is subjected to infrared spectrum test, the test result is shown in figure 10, and the test result shows that the three-dimensional carbon nanotube/polyimide precursor is kept for 10min in a microwave environment at 230 ℃, so that the imidization rate can reach 99.8%.
The prepared three-dimensional carbon nanotube/polyimide composite aerogel material is subjected to a pressure-rebound test, the test result is shown in fig. 11, and the test result shows that the three-dimensional carbon nanotube/polyimide composite aerogel material can bear 80% of compressive strain and can be rapidly recovered to the original state.
Example 10: preparation of three-dimensional nano carbon black/polyimide composite aerogel material
The embodiment provides a three-dimensional nano carbon black/polyimide composite aerogel material and a preparation method thereof, wherein the preparation method comprises the following steps:
s1, preparing a modified nano carbon black material, wherein the modified nano carbon black material is an oxidized nano carbon black material modified by a silane coupling agent.
Preparing an oxidized nano carbon black aqueous solution: first, 50g of carbon nanotube powder was placed in a 500mL round-bottom flask, and 300mL of H was added thereto at room temperature 2 O 2 Stirring and reacting for 20 hours at the temperature of 60 ℃ to obtain a third mixture; then, adding a proper amount of distilled water into the third mixture, and then carrying out filtering operation to obtain a filtrate, namely the solid oxidized nano carbon black; and finally, repeatedly washing and filtering the solid oxidized nano carbon black by using distilled water until the pH value of the solid oxidized nano carbon black is 7.0, and fully dispersing the solid oxidized nano carbon black with the pH value of 7.0 in deionized water by ultrasonic waves to prepare an oxidized nano carbon black aqueous solution with the concentration of 1 mg/mL.
Preparing an oxidized nano carbon black material modified by a silane coupling agent: firstly, taking 50mL of oxidized carbon nanotube aqueous solution with the concentration of 1mg/mL, adding 300g of NHS, 300g of EDC & HCL and 400g of vinyl triethoxysilane into the aqueous solution, and reacting for 12h at 25 ℃ to obtain a reaction mixture; then, filtering the reaction mixture, wherein the obtained filtrate comprises an oxidized nano carbon black material modified by a silane coupling agent; and finally, washing the filtrate by using distilled water to remove unreacted substances, and then performing a freeze-drying process to prepare the solid silane coupling agent modified oxidized nano carbon black material.
S2, preparing a modified nano carbon black/polyimide precursor solution from the oxidized nano carbon black material modified by the silane coupling agent and the raw material of the polyimide precursor.
Specifically, the polyimide precursor is prepared from diamine and dianhydride, wherein the diamine is 1,3-bis (4' -aminophenoxy) benzene, and the dianhydride is pyromellitic dianhydride.
The preparation method of the modified nano carbon black/polyimide precursor solution comprises the following steps:
s2.1, adding 0.3g of the oxidized nano carbon black material modified by the silane coupling agent and 18.5g of N-methyl-2-pyrrolidone into a flask at room temperature, and carrying out ultrasonic treatment for 30min to fully disperse the oxidized carbon nano tube material modified by the silane coupling agent into the N-methyl-2-pyrrolidone to prepare a first mixed solution.
S2.2, adding 1.4915g of 1,3-bis (4' -aminophenoxy) benzene into the first mixed solution, and fully dissolving to prepare a second mixed solution.
And S2.3, adding the pyromellitic dianhydride of which the total amount is 1.1151g into the second mixed solution twice (at an interval of 15 min) under the protection of nitrogen, and stirring for 5 hours to fully react to prepare a third mixed solution.
And S2.4, adding deionized water serving as an extracting agent into the third mixed solution, collecting the lower-layer precipitate after extraction and separation, repeatedly washing and filtering the precipitate by using the deionized water, and drying the filtrate obtained in the last filtering operation by using a 60-DEG C drying oven for 24 hours to obtain the solid modified nano carbon black/polyimide precursor.
S2.5, fully dissolving 0.5g of solid modified nano carbon black/polyimide precursor and 0.1g of triethylamine in 10g of deionized water to prepare a modified nano carbon black/polyimide precursor solution with the mass fraction of 1%.
And S3, sequentially freezing and drying the modified nano carbon black/polyimide precursor solution with the mass fraction of 1% to prepare the three-dimensional nano carbon black/polyimide precursor aerogel.
Specifically, firstly, the modified nano carbon black/polyimide precursor solution with the mass fraction of 1% is poured into a mold, and then the mold is placed in a refrigerator with the temperature of-20 ℃ for freezing to prepare the three-dimensional nano carbon black/polyimide precursor wet gel.
And then, freeze-drying the three-dimensional nano carbon black/polyimide precursor wet gel, wherein the freezing temperature is-50 ℃, the drying temperature is room temperature, the drying vacuum degree is 20Pa, and the drying time is 48h to prepare the three-dimensional nano carbon black/polyimide precursor aerogel.
And S4, placing the three-dimensional nano carbon black/polyimide precursor aerogel in a microwave oven, performing microwave imidization for 10min at 230 ℃, and then cooling to room temperature to obtain the three-dimensional nano carbon black/polyimide composite aerogel material.
The section scanning electron microscope image and the three-dimensional structure scanning electron microscope image of the three-dimensional nano carbon black/polyimide composite aerogel are respectively shown in fig. 12 and fig. 13. The infrared spectrum test is carried out on the prepared three-dimensional nano carbon black/polyimide composite aerogel material, the test result is shown in figure 14, and the test result shows that the three-dimensional nano carbon black/polyimide precursor is kept for 10min in a microwave environment at 230 ℃, so that the imidization rate can reach 99.7%.
The prepared three-dimensional carbon nanotube/polyimide composite aerogel material is subjected to a pressure-rebound test, the test result is shown in fig. 15, and the test result shows that the three-dimensional carbon nanotube/polyimide composite aerogel material can bear 80% of compressive strain and can be rapidly recovered to the original state.
Comparative example: preparation of three-dimensional graphene/polyimide composite aerogel material
This example provides a three-dimensional graphene/polyimide composite aerogel material and a preparation method thereof, which is different from example 1 only in that: the "microwave imidization at 230 ℃ for 10min" in step S4 was replaced with a conventional thermal imidization method. The traditional thermal imidization method specifically comprises the following steps: and (2) placing the three-dimensional nano carbon/polyimide precursor aerogel into a thermal imidization furnace, and setting a thermal treatment program with a temperature gradient, namely, keeping the temperature at 100 ℃ for 1h, keeping the temperature at 200 ℃ for 1h, keeping the temperature at 300 ℃ for 2h, wherein the heating rate is 10 ℃/min, so as to perform a thermal imidization procedure on the three-dimensional nano carbon/polyimide precursor aerogel.
The imidization rates of examples 1 to 10 and comparative examples are detailed in the following table 1:
table 1 is a summary of the imidization rates of examples 1 to 10 and comparative examples
| Name (R) | Imidization ratio (%) |
| Example 1 | 100 |
| Example 2 | 95.46 |
| Example 3 | 90.76 |
| Example 4 | 81.31 |
| Example 5 | 78.09 |
| Example 6 | 95.72 |
| Example 7 | 88.90 |
| Example 8 | 83.74 |
| Example 9 | 99.8％ |
| Example 10 | 99.7％ |
| Comparative example | 97.00 |
As can be seen from table 1, according to the imidization rate data of comparative example 1 and examples 2 to 8, the optimal process parameters for microwave imidization in preparing the three-dimensional graphene/polyimide composite aerogel material are as follows: the temperature of the microwave imidization is 230 ℃, and the time of the microwave imidization is 10min. Furthermore, it is clear from the imidization ratio data of examples 9 and 10 that the imidization ratio of the three-dimensional carbon nanotube/polyimide composite aerogel material and the imidization ratio of the three-dimensional carbon black/polyimide composite aerogel material are both close to 100% when they are kept in a microwave environment at 230 ℃ for 10min. Therefore, the optimal process parameters of the microwave imidization of the three-dimensional nano carbon/polyimide composite aerogel material provided by the application are determined as follows: the temperature of microwave imidization is 230 ℃, and the time of microwave imidization is 10min.
Compared with the traditional thermal imidization mode, the microwave imidization mode has obvious advantages of low temperature, high imidization degree, time saving, energy saving, environmental protection and controllable reaction process.
The three-dimensional carbon/polyimide composite aerogel material provided by the embodiment of the application, and the preparation method and the application thereof are described in detail above. The principle and the implementation of the present application are explained using specific examples, and the above description of the embodiments is only used to help understand the technical solution and the core idea of the present application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the scope of the claims of the various embodiments of the present application.
Claims (7)
1. A preparation method of a three-dimensional nano carbon/polyimide composite aerogel material is characterized by comprising the following steps:
preparing a modified nano carbon material;
preparing a modified nano carbon/polyimide precursor solution by using the modified nano carbon material and the polyimide precursor as raw materials;
sequentially freezing and drying the modified nano carbon/polyimide precursor solution to prepare three-dimensional nano carbon/polyimide precursor aerogel; and
performing microwave imidization on the three-dimensional nano carbon/polyimide precursor aerogel to prepare a three-dimensional nano carbon/polyimide composite aerogel material, wherein the microwave imidization temperature is not more than 230 ℃, and the reaction time is 1-10 min;
wherein, the preparation of the modified nano carbon material comprises the following steps:
carrying out oxidation treatment on a nano carbon material to prepare an oxidized nano carbon material, wherein the nano carbon material is graphene, a carbon nano tube or nano carbon black;
adding a silane coupling agent and a catalyst into the solution for oxidizing the nano carbon material, and fully reacting to obtain a mixture; and
filtering the mixture, washing the filtrate, and then drying to obtain the oxidized nano carbon material modified by the silane coupling agent;
wherein the mass ratio of the silane coupling agent to the solution of the oxidized nanocarbon material is 1: (0.1 to 2); the catalyst is a mixture of N-hydroxysuccinimide and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, the N-hydroxysuccinimide, 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride: the mass ratio of the solution for oxidizing the nano carbon material is 1:1: (0.02-1);
wherein the silane coupling agent is selected from one or more of gamma-aminopropyldimethoxysilane, N- (beta-aminoethyl) -gamma-aminopropylmethyldimethoxysilane, gamma-glycidoxypropylmethyldimethoxysilane, gamma-mercaptopropylmethyldimethoxysilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryloxypropyltrimethoxysilane, dimethoxymethyl-3-piperidinylpropylsilane, diethoxy-3-glycidoxypropylmethylsilane, vinyltriethoxysilane, vinyltrimethoxysilane, vinyltris (beta-methoxyethoxy) silane, N- (3-diethoxymethylsilylpropyl) succinimide, N- [3- (triethoxysilyl) propyl ] o-carbamoylbenzoic acid, benzophenone-3,3 '-bis (N- [ 3-triethoxysilyl ] propylamide) -4,4' -dicarboxylic acid, benzene-1,4-bis (N- [ 3-triethoxysilyl ] propylamide) -2,5-dicarboxylic acid, 3- (triethoxysilyl) propyltrimethoxysilane and N-phenylpropylaminopropyltrimethoxysilane.
2. The preparation method of the three-dimensional nanocarbon/polyimide composite aerogel material according to claim 1, wherein the preparation of the modified nanocarbon/polyimide precursor solution comprises the following steps:
adding the modified nano carbon material into a first solvent, and fully and uniformly dispersing to prepare a first mixed solution;
adding diamine into the first mixed solution, and fully dissolving to prepare a second mixed solution;
adding dianhydride into the second mixed solution, and reacting to obtain a third mixed solution;
adding a second solvent serving as an extracting agent into the third mixed solution, collecting a lower-layer precipitate after extraction and separation, washing the precipitate, and drying to obtain a solid modified nano carbon/polyimide precursor; and
and fully dissolving the alkaline amine compound and the solid modified nano carbon/polyimide precursor into water to prepare the modified nano carbon/polyimide precursor solution.
3. The method for preparing the three-dimensional nanocarbon/polyimide composite aerogel material according to claim 2, wherein the first solvent is one or more of N, N-dimethylacetamide, N-methyl-2-pyrrolidone, N-dimethylformamide, tetramethylurea, dimethyl sulfoxide, and hexamethylphosphoric triamide; the second solvent is one or more of water, methanol and acetonitrile.
4. The method for preparing the three-dimensional nanocarbon/polyimide composite aerogel material according to claim 1, wherein the preparation of the three-dimensional nanocarbon/polyimide precursor aerogel comprises the steps of:
pouring the modified nano carbon/polyimide precursor solution into a mold, and then freezing to prepare a three-dimensional nano carbon/polyimide precursor wet gel; and
and drying the three-dimensional nano carbon/polyimide precursor wet gel to prepare the three-dimensional nano carbon/polyimide precursor aerogel.
5. A three-dimensional nano carbon/polyimide composite aerogel material, which is prepared by the preparation method of the three-dimensional nano carbon/polyimide composite aerogel material as claimed in any one of claims 1 to 4.
6. The three-dimensional nanocarbon/polyimide composite aerogel material according to claim 5, wherein the nanocarbon is graphene, carbon nanotubes or carbon black.
7. Use of the three-dimensional nanocarbon/polyimide composite aerogel material according to claim 5 or 6 in a pressure sensor.
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