CN113105657A - High-orientation and high-power graphene heating film and preparation method and application thereof - Google Patents
High-orientation and high-power graphene heating film and preparation method and application thereof Download PDFInfo
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/18—Manufacture of films or sheets
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2379/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen, or carbon only, not provided for in groups C08J2361/00 - C08J2377/00
- C08J2379/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
- C08J2379/08—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K2201/00—Specific properties of additives
- C08K2201/002—Physical properties
- C08K2201/003—Additives being defined by their diameter
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/02—Elements
- C08K3/04—Carbon
- C08K3/042—Graphene or derivatives, e.g. graphene oxides
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- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
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Abstract
The invention relates to a preparation method of a high-orientation and high-power graphene heating film, which comprises the steps of mixing a polyamic acid solution with graphene to obtain a mixed slurry; and then casting the mixed slurry into a film, drying, performing biaxial tension, performing heat treatment, and imidizing to obtain the heating film. In the preparation process of the heating film, the polyamide chains are regularly oriented by tensile stress, the graphene fillers in the film are induced to be horizontally and directionally arranged and are lapped into a continuous electric and heat conducting network, and then the electric and heat conducting network is fixed by imidization, curing and molding. The stretching process effectively reduces the internal pores of the heating film, and the regular oriented polyimide provides support and protection for the heating medium without additional binder. The prepared heating film has the advantages of good flexibility, excellent mechanical strength, high thermal stability, high electrothermal efficiency, high heating rate, good heat transfer performance, high thermal radiation efficiency and the like, is favorable for realizing rapid heating up and uniform heat and large-area uniform heating of the heating film, and can be used for heating elements.
Description
Technical Field
The invention belongs to the technical field of electrothermal conversion devices, and particularly relates to a highly-oriented and high-power graphene heating film, and a preparation method and application thereof.
Background
In modern electric heating devices and systems, resistance wires are mostly adopted as heating elements, and the generation of central hot spots is avoided in a zone heating mode. However, the resistance wire serving as a traditional electric heating device has the problems of low heating rate, uneven temperature of a heating area and difficulty in large-area uniform temperature rise. And the use of resistance wire as a heating device is often not flexible enough, and the internal heating circuit is difficult to change, and is difficult to use in non-planar or irregular areas.
At present, aiming at various problems of a resistance wire as a heating element, a graphene resin composite film is mostly adopted to replace the resistance wire as the heating element. The graphene resin composite film combines the characteristics of easy heat conduction of graphene, good toughness and high strength of resin, and is widely applied to the field of electric heat conversion devices. The existing graphene resin composite membrane has three preparation methods:
1) the graphene film and other resin films are packaged and formed in a hot pressing mode, for example, a graphene heat-resistant electrothermal film disclosed in chinese patent CN208258106U includes a graphene electrothermal film and a temperature-resistant adhesive tape layer disposed on the graphene electrothermal film, and the graphene electrothermal film and the temperature-resistant adhesive tape layer are integrated into a whole after being cold pressed.
However, in the graphene heat-resistant electrothermal film formed by hot-press packaging, the resin used for packaging and forming has poor heat resistance, is difficult to work at high temperature (>150 ℃) for a long time, and has poor thermal conductivity, which easily causes heat accumulation or uneven heating inside the device.
2) The heating film is prepared by adopting a multilayer composite mode, for example, the heating tube comprises a metal tube base body, a high-temperature resistant insulating heat dissipation layer and a high-temperature resistant far infrared electric heating layer are sequentially arranged on the outer peripheral surface of the metal tube base body from inside to outside, the high-temperature resistant insulating heat dissipation layer is composed of polyimide and white graphene with the mass ratio of (30-32): (3-16), and the high-temperature resistant far infrared electric heating layer is composed of polyimide and graphene with the mass ratio of (30-32): (3-21). The heating film prepared in the patent is a composite film of a high-temperature-resistant insulating heat dissipation layer and a high-temperature-resistant far infrared electric heating layer.
Adopt the compound heating film that forms of high temperature resistant insulating heat dissipation layer and high temperature resistant far infrared electric heat layer, because the heat conductivility between the compound rete is different, lead to the position of generating heat inhomogeneous, the whole heating performance of complex film is relatively poor. And the heat dissipation layer and the electric heating layer are respectively formed by uniformly mixing a polyimide solution and white graphene or graphene, and coating and drying the prepared slurry. However, in this way, the white graphene or the graphene is easily dispersed unevenly in the thin film, so that the difference between the thermal conductivity and the mechanical property of different areas of the thin film is large, the difference between the thermal conductivity of the composite film layers is further increased, the heterogeneity of the heating part is increased, and the overall heating performance is further deteriorated.
3) Blending graphene and a conductive agent, mixing with resin, coating, and drying to form the graphene/resin composite material.
The heating film prepared by the method has the phenomenon of uneven distribution of the conductive components, graphene cannot be uniformly dispersed in the heat-conducting film, and the problem of agglomeration generally exists, so that the difference of heat conduction and mechanical properties of different areas of the film is large, and the film is difficult to put into practical application.
The polyimide film is a novel organic polymer film and has excellent mechanical property, electrical property, chemical stability, radiation resistance, high temperature resistance and low temperature resistance. In the production of a heat-generating element, a polyimide film is often used as one of the base materials. However, the thermal conductivity of polyimide is only 0.16W/(m.K), and other resins are often mixed for preparing heating elements, and the application in thermal energy conversion is limited. Graphene is also used in a polyimide film, for example, the high temperature resistant far infrared electrothermal layer in the chinese patent CN109673067A mentioned above is formed by uniformly mixing a polyimide solution and graphene to prepare a high temperature resistant far infrared electrothermal slurry, and coating and drying the slurry. However, in this way, the graphene is easily dispersed unevenly in the thin film, resulting in a large difference in thermal conductivity and mechanical properties in different areas of the thin film.
Therefore, in order to overcome the defects of the conventional graphene resin composite film, a composite film for a heating element, which has good thermal conductivity, good weather resistance and high mechanical strength, is required.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide an improved preparation method of a high-orientation and high-power graphene heating film, and the prepared heating film has the advantages of high and stable electric conductivity, good heat conductivity, good weather resistance and high mechanical strength.
In order to achieve the technical effects, the invention adopts the technical scheme that:
a preparation method of a high-orientation and high-power graphene heating film comprises the following steps:
(1) mixing a polyamic acid solution with graphene to obtain a mixed slurry, wherein a solvent used in the polyamic acid solution is an organic solvent;
(2) and (2) carrying out tape casting on the mixed slurry obtained in the step (1) to form a film, drying for a certain time, carrying out biaxial stretching, and carrying out imidization through heat treatment to obtain the heating film, wherein the graphene accounts for 11-20% of the total mass of the heating film.
According to some embodiments of the invention, in the step (1), the organic solvent is one or more selected from N-methylpyrrolidone, acetone, dimethylsulfoxide, pyridine, dioxane, N-dimethylformamide, N-dimethylacetamide, tetrahydrofuran, butanone, ethylene glycol and diethylene glycol.
According to some embodiments of the present invention, in the step (1), the solid content of the polyamic acid solution is 5 to 30%.
According to some embodiments of the invention, the preparation method further comprises a step of performing a polycondensation reaction of diamine and dianhydride in the presence of an organic solvent under the protection of inert gas to obtain a polyamic acid solution.
According to some specific embodiment aspects of the present invention, the specific feeding manner of the diamine and dianhydride is: diamine is dissolved in organic solvent or partial organic solvent to prepare diamine solution, dianhydride or dianhydride solution prepared from dianhydride and residual organic solvent is added into the diamine solution in batches, and polyamide acid solution is obtained through stirring reaction.
According to some example aspects of this invention, the diamine to dianhydride mass ratio is 1:1.05 to 1.2.
According to some embodiment aspects of the invention, the polycondensation reaction is carried out at-10 ℃ to 30 ℃ for 3 to 24 hours.
According to some specific embodiment aspects of the invention, the diamine is one or more of diaminodiphenylmethane (DDM), 4' -diaminodiphenyl ether (ODA), 1, 4-bis (4-amino-2-trifluoromethylphenoxy) benzene (6 FAPB).
According to some specific embodiment aspects of the invention, the dianhydride is one or more of 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride (BTDA), pyromellitic dianhydride (PMDA).
According to some embodiments of the invention, in the step (2), the drying is performed so that the mass of the solvent in the dried film is 0-80% of the total mass of the film.
Further, the drying is room temperature drying or heating at 60-150 ℃ to remove the organic solvent.
According to some embodiments of the invention, in the step (2), the stretching extends the stretched film longitudinally 1.5 to 3 times as long as the film before stretching and transversely 1.5 to 2 times as long as the film before stretching.
Further, the stretching is carried out by adopting a stretching roller, and the temperature of the stretching roller is 30-80 ℃. The stretching adopts a multistage stretching device, and the multistage stretching is beneficial to the horizontal orientation of the graphene filler and the integrity of the film.
According to some embodiments of the present invention, in the step (2), the heat treatment is performed at 150 to 300 ℃ for 2 to 6 hours.
Preferably, the graphene accounts for 11-15% of the total mass of the heating film.
According to some embodiments of the invention, the graphene has a particle size of 200nm to 50 μm and a thickness of 1 to 50 nm. Preferably, the particle size of the graphene is 10-30 μm.
According to some embodiments of the present invention, the graphene may be graphene that is commercially available in the existing market, or graphene that is prepared by an industrial method for preparing large-size graphene disclosed in publication No. CN 106554010A.
Preferably, the graphene is prepared by adopting a method disclosed in CN106554010A for industrially preparing large-size graphene, and the preparation method comprises the following steps:
A. mixing graphite and concentrated sulfuric acid to obtain a mixed solution, carrying out ultrasonic treatment on the mixed solution to simultaneously carry out chemical intercalation and mechanical stripping, wherein the solution obtained after ultrasonic treatment comprises upper-layer graphene and lower-layer concentrated sulfuric acid solution;
B. separating the obtained graphene and concentrated sulfuric acid solution;
C. and (4) washing the graphene separated in the step B with water, and filtering and drying to obtain the graphene.
Further, in the step A, the volume ratio of the mass of the graphite to concentrated sulfuric acid is 1: 50-1: 500 g/mL.
Further, in the step A, the mass concentration of the concentrated sulfuric acid is 75-98%.
Further, in the step A, the ultrasonic treatment time is 10-20 hours, and the ultrasonic power is 150-300W.
According to some implementation aspects of the invention, a conductive agent is further added into the mixed slurry, and the conductive agent accounts for 0-5% of the total mass of the heat-generating film. In some preferable and specific implementation aspects, the conductive agent accounts for 0.5-3% of the total mass of the heat-generating film. More preferably, the conductive agent accounts for 1-2% of the total mass of the heating film.
In some specific embodiments, the conductive agent is one or more of carbon black, graphite, carbon fiber, and carbon nanotube. Preferably, the conductive agent is carbon nanotubes. Wherein, the graphite preferably adopts superfine graphite powder.
According to some implementation aspects of the invention, a dispersing agent is further added into the mixed slurry, and the dispersing agent accounts for 0-5% of the total mass of the heating film. In some preferable and specific implementation aspects, the conductive agent accounts for 0.5-3% of the total mass of the heat-generating film. More preferably, the dispersant accounts for 1-2% of the total mass of the heating film.
In some specific embodiments, the dispersant is one or more of PVP, PVA, KD1, BYK-2150.
According to yet another technical scheme, the heating film prepared by the preparation method of the heating film is applied to a heating element of an electrothermal conversion device.
Due to the application of the technical scheme, compared with the prior art, the invention has the following advantages:
the preparation method comprises the steps of adding a certain amount of graphene into a polyamic acid solution, mixing to prepare a mixed solution, carrying out tape casting to form a film, drying, stretching, and carrying out heat treatment to carry out imidization to obtain the film. In the preparation process, the graphene filler is horizontally oriented in the film through stress induction, a continuous heat conducting network is formed through lapping, and the crystallization and orientation of polyimide molecular chains are induced at the same time. The film has few holes and low thermal resistance, the graphene is uniformly dispersed in the film and is efficiently lapped, and the prepared heating film has good flexibility and excellent mechanical strength. The strength and the folding resistance of the film are improved, water and oxygen are effectively blocked, the service life of the heating film is prolonged, the heat resistance and the heat conductivity of the film are also enhanced, the heating film can be rapidly heated and is uniform in heat, the heat absorption of the heating film is less, and the heat radiation efficiency is high.
The heating film prepared by the preparation method of the invention is used as a planar heating material, has high thermal efficiency, high heating speed, rapid heat conduction, uniform heating and small temperature difference of each part, and can realize large-area uniform heating. The heating film is light, soft, high in strength, stretch-proof, capable of being folded repeatedly, adjustable in heating area and suitable for irregular surfaces. Meanwhile, the electrothermal film has long service life, can resist the high temperature of 400 ℃, can stably work for a long time at the temperature of 300 ℃, has low starting and working voltage of the electrothermal film, works below the safe voltage of a human body, and has high energy efficiency ratio.
The heating film prepared by the preparation method can be used for heating of household and public facilities or heating elements of electrothermal conversion devices in the industrial field.
The preparation method provided by the invention adopts a wet method to form a film integrally, has the advantages of simple process, strong condition controllability and few steps, and is suitable for large-scale continuous production.
Detailed Description
The invention relates to a highly-oriented and high-power graphene heating film and a preparation method thereof. Wherein the solvent used by the polyamic acid solution is an organic solvent; the graphene accounts for 11-20% of the total mass of the heating film. In the preparation process of the heating film, the polyamide chains are regularly oriented by tensile stress, and simultaneously, the graphene fillers in the film are induced to be horizontally and directionally arranged and are lapped to form a continuous electric and heat conducting network, and then, the electric and heat conducting network is fixed by imidization, curing and molding. The stretching process can effectively reduce the pores in the heating film, and the regularly oriented polyimide provides support and protection effects for the heating medium without an additional binder. The prepared heating film has the advantages of good flexibility, excellent mechanical strength, high thermal stability, high electrothermal efficiency, high heating speed, good heat transfer performance, high thermal radiation efficiency and the like, is favorable for realizing rapid heating and uniform heat of the heating film and large-area uniform heating, and can be used for heating elements of electrothermal conversion devices.
The technical solutions of the present invention are described in detail below with reference to specific examples so that those skilled in the art can better understand and implement the technical solutions of the present invention, but the present invention is not limited to the scope of the examples.
Example 1
The heating film provided by the embodiment is prepared by the following method:
12g of 4, 4' -diaminodiphenyl ether was added to 100g of N, N-dimethylformamide solvent, and stirring and dissolution were continued. 13.36g of pyromellitic dianhydride was added to the above solution three times, and stirring was continued at room temperature for 4 hours to obtain a polyamic acid solution. 4.7g of graphene powder with the diameter of 16-20 mu m, 0.6g of multi-walled carbon nano-tube and 0.4g of PVP are dispersed in a 50g N N-dimethylformamide solvent, and then the solution is mixed and stirred continuously for 3 hours for fully mixing. And (3) casting the solution into a 0.5mm film, drying at 60 ℃ for 2h, unidirectionally stretching the semi-dry film to 2.25 times by using a differential roller, heating to 150 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 200 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 300 ℃ at the speed of 5 ℃/min, preserving heat for 1h, and imidizing to obtain the graphene-polyimide composite film, namely the heating film. Silver electrode strips are arranged at two ends of the heating film and are connected with a working power supply.
In this example, graphene powder was prepared by the method of example 1 in the embodiment of chinese patent CN 106554010A.
Example 2
The heating film provided by the embodiment is prepared by the following method:
12g of 4, 4' -diaminodiphenyl ether was added to 100g of N, N-dimethylformamide solvent, and stirring and dissolution were continued. 13.36g of pyromellitic dianhydride was added to the above solution three times, and stirring was continued at room temperature for 4 hours to obtain a polyamic acid solution. Dispersing 4.7g of graphene powder with the diameter of 16-20 mu m in a 50g N N-dimethylformamide solvent, mixing the graphene powder with the solution, and continuously stirring for 3 hours for fully mixing. And (3) casting the solution into a 0.5mm film, drying at 60 ℃ for 2h, unidirectionally stretching the semi-dry film to 2.25 times by using a differential roller, heating to 150 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 200 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 300 ℃ at the speed of 5 ℃/min, preserving heat for 1h, and imidizing to obtain the graphene-polyimide composite film, namely the heating film.
In this example, graphene powder was prepared by the method of example 1 in the embodiment of chinese patent CN 106554010A.
Example 3
The heating film provided by the embodiment is prepared by the following method:
15g of diaminodiphenylmethane and 16.5g of 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride were dissolved in 50g of N-methylpyrrolidone solvent, respectively. And adding the 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride solution into the diaminodiphenylmethane solution for three times, and continuously stirring for 6 hours at room temperature to obtain the polyamic acid solution. After 5.8g of graphene powder, 0.5g of conductive carbon black and 0.5g of PVP were dispersed in 60g N-methyl pyrrolidone, the above solution was added and stirred for 3 hours to disperse them uniformly. And (3) casting the solution into a 0.5mm film, drying at 80 ℃ for 2h, unidirectionally stretching the semi-dry film to 2.25 times by using a differential roller, heating to 150 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 200 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 300 ℃ at the speed of 5 ℃/min, preserving heat for 1h, and imidizing to obtain the graphene-polyimide composite film, namely the heating film.
In this example, graphene powder was prepared by the method of example 1 in the embodiment of chinese patent CN 106554010A.
Comparative example 1 (without drawing)
The comparative example provides a heat-generating film different from example 1 in that: the heat generating film of this example was not subjected to a stretching process.
The heating film of the embodiment is prepared by the following method:
12g of 4, 4' -diaminodiphenyl ether was added to 100g of N, N-dimethylformamide solvent, and stirring and dissolution were continued. 13.36g of pyromellitic dianhydride was added to the above solution three times, and stirring was continued at room temperature for 4 hours to obtain a polyamic acid solution. 4.7g of graphene powder with the diameter of 16-20 mu m, 0.6g of multi-walled carbon nano-tube and 0.4g of PVP are dispersed in a 50g N N-dimethylformamide solvent, and then the solution is mixed and stirred continuously for 3 hours for fully mixing. And (3) casting the solution into a 0.5mm film, heating to 150 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 200 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 300 ℃ at the speed of 5 ℃/min, preserving heat for 1h, and imidizing to obtain the graphene-polyimide composite film, namely the heating film. Silver electrode strips are arranged at two ends of the heating film and are connected with a working power supply.
Comparative example 2 (calendering instead of drawing)
The comparative example provides a heat-generating film different from example 1 in that: the heat-generating film of this example was rolled instead of stretched.
The heating film of the embodiment is prepared by the following method:
12g of 4, 4' -diaminodiphenyl ether was added to 100g of N, N-dimethylformamide solvent, and stirring and dissolution were continued. 13.36g of pyromellitic dianhydride was added to the above solution three times, and stirring was continued at room temperature for 4 hours to obtain a polyamic acid solution. 4.7g of graphene powder with the diameter of 16-20 mu m, 0.6g of multi-walled carbon nano-tube and 0.4g of PVP are dispersed in a 50g N N-dimethylformamide solvent, and then the solution is mixed and stirred continuously for 3 hours for fully mixing. And (2) casting the solution into a 0.5mm film, drying at 60 ℃ for 2h, rolling to the thickness of 0.2mm by a double-shaft double-roller machine, heating to 150 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 200 ℃ at the speed of 5 ℃/min, preserving heat for 1h, heating to 300 ℃ at the speed of 5 ℃/min, and carrying out imidization for 1h to obtain the graphene-polyimide composite film, namely the heating film. Silver electrode strips are arranged at two ends of the heating film and are connected with a working power supply.
Comparative example 3 (graphene is commercially available)
The comparative example provides a heat-generating film different from example 1 in that: the graphene is commercially available graphene which is purchased from Hezhou Hexi element material science and technology limited company and has the trade name of SE 1231.
The performance of the heat-generating films of examples 1 to 3 and comparative examples 1 to 3 was measured, and the results are shown in table 1.
Performance test results of the heating films of examples 1 to 3 and comparative examples 1 to 3
The tensile strength of the heating film in the stretching direction is measured by a universal tester at room temperature, and the horizontal heat conductivity coefficient is measured by a heat conductivity meter at 30 ℃. The surface resistance is obtained by cutting the product into 20 × 20cm squares, connecting electrodes at two ends, placing the squares in a heat-preservation oven, keeping the temperature at 100 ℃ and 300 ℃ for 1h, and testing and calculating by using a universal meter. The power attenuation is obtained by calculating the final heating power and the initial heating power after the product is connected to 220V mains supply and works for 300 h. The temperature uniformity is that the product is connected to 220V commercial power at room temperature to work for 1h, 9 temperatures which are evenly distributed on the surface of the product are measured by an infrared thermometer after the temperature is stable, and the maximum difference value is taken.
As can be seen from table 1, the graphene-polyimide heating film prepared in example 1 after the carbon nanotube and the PVP additive are added and the stretching treatment has the best performance indexes; the internal conductive network structure of the embodiment 2 without the addition of the auxiliary agent has poor stability, is suitable for being used at medium and low temperature (<150 ℃), and has large resistance change after working at high temperature or for a long time; example 3, in which carbon black was used instead of carbon nanotubes, exhibited a slight decrease in performance.
Compared with the embodiment 1, the comparative example 1 which is added with the same auxiliary agent and is not subjected to stretching treatment or the comparative example 2 which is subjected to calendering replacement treatment has the advantages that due to the fact that the graphene is randomly distributed in the film, a good electric and heat conducting network is not formed, so that the internal resistance difference of each part of the product is large, the electric heating power is inconsistent, and obvious heating unevenness is caused; in contrast, in comparative example 3, which was prepared using commercially available graphene, the difference in the size of the graphene powder was large, resulting in a decrease in the product performance.
The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
Claims (10)
1. A preparation method of a high-orientation and high-power graphene heating film is characterized by comprising the following steps:
(1) mixing a polyamic acid solution with graphene to obtain a mixed slurry, wherein a solvent used in the polyamic acid solution is an organic solvent;
(2) carrying out tape casting film forming, drying for a certain time, biaxial stretching and heat treatment on the mixed slurry obtained in the step (1) to carry out imidization, thus obtaining the heating film; wherein the graphene accounts for 11-20% of the total mass of the heating film.
2. The preparation method of the highly-oriented and high-power graphene heating film according to claim 1, characterized by comprising the following steps: in the step (2), the drying is carried out so that the mass of the solvent in the dried membrane accounts for 0-80% of the total mass of the membrane.
3. The preparation method of the highly-oriented and high-power graphene heating film according to claim 1, characterized by comprising the following steps: in the step (2), the stretching is performed so that the stretched film longitudinally extends to 1.5-3 times of the film before stretching and transversely extends to 1.5-2 times of the film before stretching.
4. The preparation method of the highly-oriented and high-power graphene heating film according to claim 3, characterized by comprising the following steps: the stretching is carried out by adopting a stretching roller, and the temperature of the stretching roller is 30-80 ℃.
5. The preparation method of the highly-oriented and high-power graphene heating film according to claim 1, characterized by comprising the following steps: in the step (2), the heat treatment is carried out at the temperature of 150-300 ℃ for 2-6 h.
6. The preparation method of the highly-oriented and high-power graphene heating film according to claim 1, characterized by comprising the following steps: the graphene accounts for 11-15% of the total mass of the heating film, the particle size of the graphene is 200 nm-50 mu m, and the thickness of the graphene is 1-50 nm.
7. The preparation method of the highly-oriented and high-power graphene heating film according to claim 1, wherein the graphene is prepared by the following steps:
A. mixing graphite and concentrated sulfuric acid to obtain a mixed solution, carrying out ultrasonic treatment on the mixed solution to simultaneously carry out chemical intercalation and mechanical stripping, wherein the solution obtained after ultrasonic treatment comprises upper graphene and lower concentrated sulfuric acid solution, and the mass concentration of the concentrated sulfuric acid is 75-98%;
B. separating the obtained graphene and concentrated sulfuric acid solution;
C. and C, washing the graphene separated in the step B with water, and filtering and drying to obtain the graphene.
8. The preparation method of the highly-oriented and high-power graphene heating film according to claim 1, characterized by comprising the following steps: in the step (1), a conductive agent and/or a dispersing agent is further added into the mixed slurry, the conductive agent is one or more of carbon black, graphite, carbon fiber and carbon nano tube, and the conductive agent accounts for 0-5% of the total mass of the heating film; the dispersing agent is one or more of PVP, PVA, KD1 and BYK-2150, and accounts for 0-5% of the total mass of the heating film.
9. The preparation method of the highly-oriented and high-power graphene heating film according to claim 1, characterized by comprising the following steps: the preparation method further comprises the step of carrying out polycondensation reaction on diamine and dianhydride in the presence of a polar organic solvent under the protection of inert gas to obtain the polyamic acid solution, wherein the addition amount of the organic solvent enables the solid content of the polyamic acid solution to be 5-30%.
10. Use of the heating film prepared by the preparation method of the highly-oriented and high-power graphene heating film according to any one of claims 1 to 9 in a heating element of an electrothermal conversion device.
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| CN202110307438.4A CN113105657A (en) | 2021-03-23 | 2021-03-23 | High-orientation and high-power graphene heating film and preparation method and application thereof |
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| CN114106385A (en) * | 2021-11-12 | 2022-03-01 | 江苏天奈科技股份有限公司 | Flexible heating film and preparation method thereof |
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| CN110396193A (en) * | 2019-09-04 | 2019-11-01 | 江苏亚宝绝缘材料股份有限公司 | A kind of preparation method and product of in-situ polymerization graphene hybrid modification polyamic acid resin |
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| CN103738940A (en) * | 2013-11-12 | 2014-04-23 | 宁波墨西科技有限公司 | Graphene-modified heat conduction film |
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| CN114106385A (en) * | 2021-11-12 | 2022-03-01 | 江苏天奈科技股份有限公司 | Flexible heating film and preparation method thereof |
| CN114106385B (en) * | 2021-11-12 | 2023-07-28 | 江苏天奈科技股份有限公司 | Flexible heating film and preparation method thereof |
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