CN108323170B - Preparation method of composite film for thermistor - Google Patents
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Abstract
The invention discloses a preparation method of a composite film for a thermistor, which comprises the steps of preparing a graphene solution, carrying out surface corrosion by utilizing nano silver ions, forming a composite structure by microporous glass, preparing a thermistor matrix, and finally compounding the matrix and polytetrafluoroethylene to prepare the composite film so as to obtain the composite film for the thermistor. The composite film prepared by the improved method has specific thermistor characteristics, the resistance of the composite film has two stages along with the temperature change, the resistance of the first stage is reduced along with the temperature rise but is reduced slowly, and the resistance of the second stage is reduced rapidly along with the temperature rise and shows an obvious two-stage process, so that the composite film can be better applied to a thermistor material and exerts the specific performance of the composite film.
Description
Technical Field
The invention belongs to the technical field of thermistor preparation, and particularly relates to a preparation method of a composite film for a thermistor.
Background
The thermistor is a resistor whose resistance changes with the change of temperature, and can be divided into two types according to the change relationship between itself and temperature.
The characteristic that the resistance increases along with the temperature rise becomes a positive temperature coefficient, and the thermistor with the characteristic is called as a PTC thermistor for short; heiman et al, Netherlands Philips, 1955, found BaTiO3After a trace amount of rare earth elements are added into the ceramic, the resistivity at room temperature is greatly reduced, and the resistivity can be increased by more than three orders of magnitude within a certain narrow temperature range.
The characteristic that the resistance decreases with an increase in temperature is called a negative temperature coefficient, and a thermistor of this characteristic is referred to as an NTC thermistor for short. The thermistor is usually manufactured by using metal oxides such as manganese, cobalt, nickel, copper and the like as main materials and adopting a ceramic process. These metal oxide materials all have semiconductor properties because they are completely similar in conduction to semiconductor materials such as germanium, silicon, etc. At low temperatures, these oxide materials have a low number of carriers (electrons and holes) and therefore have a high resistance; as the temperature increases, the number of carriers increases, so the resistance value decreases.
At present, the thermistor is mainly applied to the two types of thermistors, and the resistance of the same thermistor shows more uniform change trend along with the rise of temperature. In the practical application process, resistors with two characteristics or the same specific resistor is often required to generate significant application differences in different temperature ranges, but the conventional thermistor at present is difficult to meet the requirements.
Disclosure of Invention
The present invention aims to overcome the above disadvantages of the prior art by providing a method for preparing a composite film for a thermistor, wherein the obtained composite film has significant application differences in different temperature ranges.
The technical scheme of the invention is as follows:
a preparation method of a composite film for a thermistor comprises the following steps:
step 1, adding graphite into a solvent, stirring for 40-50 minutes at low temperature, and then performing ultrasonic intercalation on solvent molecules between graphite layers to obtain an expanded graphite solution;
step 2, heating the expanded graphite solution to 60-70 ℃ under the vacuum condition, and keeping the temperature for 30-40 minutes to obtain expanded graphite;
step 3, stripping the expanded graphite through a liquid phase to obtain a graphene solution;
step 4, adding a silver nitrate solution into the graphene solution, stirring and mixing, heating to 70-80 ℃ under the protection of nitrogen, and performing ultrasonic dispersion to obtain a nano-silver modified graphene solution;
step 5, adding microporous glass and polyethylene glycol 400 into the nano-silver modified graphene solution, stirring and mixing, and then ball-milling in a ball mill until the particle size is below 200 mu m to obtain a mixed solution;
step 6, drying the mixed solution to obtain a composite modified material;
step 7, mixing the composite modified material with acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fiber, transferring the mixture into a reaction kettle, heating to 60-70 ℃ under the protection of nitrogen, keeping the temperature for 20-30 minutes, heating to 120 ℃ at the heating rate of 1 ℃/minute under the stirring condition, keeping the temperature for 10-15 minutes, and naturally cooling to room temperature to obtain a reaction mixture;
and 8, mixing the reaction mixture with polytetrafluoroethylene, and rolling to form a film to obtain the composite film for the thermistor.
Further, in the preparation method of the composite film for the thermistor, the weight percentage concentration of graphite added into the solvent in the step 1 is 1-3%.
Further, in the preparation method of the composite film for the thermistor, in the step 1, the ultrasonic power is 200W, and the ultrasonic time is 40-60 minutes.
Further, in the preparation method of the composite film for the thermistor, the solvent in the step 1 is N-methylpyrrolidone.
Further, in the preparation method of the composite film for the thermistor, the vacuum degree under the vacuum condition in the step 2 is 0.02-0.05 MPa.
Further, in the preparation method of the composite film for the thermistor, the weight percentage of silver nitrate after the silver nitrate solution is added in the step 4 is 0.5-1%.
Further, in the preparation method of the composite film for the thermistor, the ultrasonic power of ultrasonic dispersion in the step 4 is 180W, and the ultrasonic time is 40-50 minutes.
Further, in the preparation method of the composite film for the thermistor, in the step 5, the adding mass of the microporous glass is 2-3 times of the adding mass of the graphite in the step 1, and the adding mass of the polyethylene glycol 400 is 0.1-0.2% of the volume of the nano-silver modified graphene solution.
Further, in the preparation method of the composite film for the thermistor, in the step 7, the mass ratio of the composite modified material to the acrylic acid, the butyl acrylate, the tetrabutyl titanate and the carbon fiber is 100:160:80:20: 0.3; the carbon fiber has a fiber length of 2 to 6 μm.
Further, in the preparation method of the composite film for the thermistor, the mass ratio of the reaction mixture to the polytetrafluoroethylene in the step 8 is 5: 3.
The invention provides a preparation method of a composite film for a thermistor, which comprises the steps of carrying out liquid phase stripping on an expanded graphite solution to obtain a graphene solution, simultaneously adding silver ions into the graphene solution for modification to modify a layer of silver ions among graphene molecules, uniformly modifying the surface of a graphene layer by heating and ultrasonically stabilizing the silver ions to form a composite structure of nano-silver coated graphene, then adding microporous glass to enable the nano-silver modified graphene to enter micropores of the microporous glass, adding polyethylene glycol 400 to well adjust the liquid tension on the surface of particles in the solution to enable the nano-silver modified graphene to better enter the micropores of the microporous glass to form a composite structure taking the microporous glass as a carrier, then carrying out composite reaction with acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fibers, and forming a composite structure taking the microporous glass as a main body by introducing trace carbon fibers, the carbon fiber is a thermistor material matrix of the bridge and provided with an interconnection structure. The composite film for the thermistor is prepared by compounding the substrate with polytetrafluoroethylene.
The resistance of the composite film for the thermistor, which is improved by the invention, can be divided into two stages along with the temperature change, wherein the first stage is that when the temperature is lower than a critical temperature, the resistance is reduced along with the temperature rise, but the reduction speed is slow, because the composite film is mainly conducted by trace carbon fibers before the critical temperature, the conductivity of a microporous glass composite structure is poor due to the shielding property, and meanwhile, because of the temperature resistance and the low thermal expansion property of the composite film, the change of the temperature rise on the structure in the composite film is not large, and the resistance is slowly reduced along with the temperature rise; when the temperature is higher than the critical temperature, the electron movement capacity between the graphene sheet layers is enhanced, the surface nano silver ions are excited, meanwhile, the conductivity of the microporous glass is enhanced due to the increase of the temperature, and a conductive path between the carbon fiber and the microporous glass composite structure is triggered after the temperature reaches the critical temperature, so that the performance of a lead of the composite film is enhanced instantly and greatly, the resistance is reduced rapidly, and the rapid change of the resistance is generated. By utilizing the above properties, the composite film can be used in a thermistor material, and a specific application difference is exerted in both side ranges of the critical temperature thereof.
The composite membrane for the thermistor provided by the invention utilizes the stability of polytetrafluoroethylene, improves the temperature resistance and aging resistance of the membrane, and simultaneously reduces the thermal expansion performance of the composite membrane by the thermistor material matrix formed by taking a microporous glass composite structure as a main body, so that the thermal expansion performance of the composite membrane is smaller, the volume expansion rate of the membrane is smaller under the condition of continuously increasing the temperature, and the performance of the thermistor of the composite membrane provided by the invention is more easily exerted; the internal structure of the film is changed in the process of temperature rise due to large thermal expansion performance, so that the bridge action between carbon fibers is damaged, and the resistance is obviously increased, so that the composite film with the specific thermal resistance performance cannot be obtained.
Drawings
FIG. 1 is a resistance-temperature curve of the composite film for a thermistor prepared by the method provided by the invention.
The specific implementation mode is as follows:
example 1
A preparation method of a composite film for a thermistor comprises the following steps:
step 1, adding 100g of graphite into 3.3kg of N-methylpyrrolidone, stirring for 40 minutes at low temperature, and then performing ultrasonic intercalation on solvent molecules between layers of the graphite to obtain an expanded graphite solution, wherein the ultrasonic power is 200W, and the ultrasonic time is 40 minutes;
step 2, heating the expanded graphite solution to 60 ℃ under the vacuum condition with the vacuum degree of 0.02MPa, and keeping the temperature for 30 minutes to obtain expanded graphite;
step 3, stripping the expanded graphite through a liquid phase to obtain a graphene solution;
step 4, adding a silver nitrate solution into the graphene solution, stirring and mixing, heating to 70 ℃ under the protection of nitrogen, and performing ultrasonic dispersion to obtain a nano-silver modified graphene solution, wherein the weight percentage of silver nitrate after the silver nitrate solution is added is 0.5%, the ultrasonic power of ultrasonic dispersion is 180W, and the ultrasonic time is 40 minutes;
step 5, adding 200g of microporous glass and 400 g of polyethylene glycol into the nano-silver modified graphene solution, adding the nano-silver modified graphene solution with the mass of 0.1% of the volume of the nano-silver modified graphene solution, stirring and mixing, and then ball-milling the mixture in a ball mill until the particle size is less than 200 microns to obtain a mixed solution;
step 6, drying the mixed solution to obtain a composite modified material;
step 7, mixing the composite modified material with acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fiber, transferring the mixture into a reaction kettle, heating to 60 ℃ under the protection of nitrogen, keeping the temperature for 20 minutes, heating to 120 ℃ at the heating rate of 1 ℃/minute under the stirring condition, keeping the temperature for 10 minutes, and naturally cooling to room temperature to obtain a reaction mixture, wherein the adding mass ratio of the composite modified material to the acrylic acid, the butyl acrylate, the tetrabutyl titanate and the carbon fiber is 100:160:80:20: 0.3; the fiber length of the carbon fiber is 2-6 μm;
and 8, mixing the reaction mixture with polytetrafluoroethylene, wherein the mass ratio of the reaction mixture to the polytetrafluoroethylene is 5:3, and rolling to form a film to obtain the composite film for the thermistor.
Example 2
A preparation method of a composite film for a thermistor comprises the following steps:
step 1, adding 100g of graphite into 5kg of N-methyl pyrrolidone, stirring for 43 minutes at low temperature, and then performing ultrasonic intercalation on solvent molecules between layers of the graphite to obtain an expanded graphite solution, wherein the ultrasonic power is 200W, and the ultrasonic time is 45 minutes;
step 2, heating the expanded graphite solution to 64 ℃ under the vacuum condition with the vacuum degree of 0.03MPa, and keeping the temperature for 32 minutes to obtain expanded graphite;
step 3, stripping the expanded graphite through a liquid phase to obtain a graphene solution;
step 4, adding a silver nitrate solution into the graphene solution, stirring and mixing, heating to 75 ℃ under the protection of nitrogen, and performing ultrasonic dispersion to obtain a nano-silver modified graphene solution, wherein the weight percentage of silver nitrate after the silver nitrate solution is added is 0.6%, the ultrasonic power of the ultrasonic dispersion is 180W, and the ultrasonic time is 45 minutes;
step 5, adding 220g of microporous glass and 400 g of polyethylene glycol into the nano-silver modified graphene solution, adding the solution with the mass of 0.1% of the volume of the nano-silver modified graphene solution, stirring and mixing, and then ball-milling the solution in a ball mill until the particle size is below 200 mu m to obtain a mixed solution;
step 6, drying the mixed solution to obtain a composite modified material;
step 7, mixing the composite modified material with acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fiber, transferring the mixture into a reaction kettle, heating to 65 ℃ under the protection of nitrogen, keeping the temperature for 23 minutes, heating to 120 ℃ at the heating rate of 1 ℃/minute under the stirring condition, keeping the temperature for 12 minutes, and naturally cooling to room temperature to obtain a reaction mixture, wherein the adding mass ratio of the composite modified material to the acrylic acid, the butyl acrylate, the tetrabutyl titanate and the carbon fiber is 100:160:80:20: 0.3; the fiber length of the carbon fiber is 2-6 μm;
and 8, mixing the reaction mixture with polytetrafluoroethylene, wherein the mass ratio of the reaction mixture to the polytetrafluoroethylene is 5:3, and rolling to form a film to obtain the composite film for the thermistor.
Example 3
A preparation method of a composite film for a thermistor comprises the following steps:
step 1, adding 100g of graphite into 7kg of N-methylpyrrolidone, stirring for 47 minutes at low temperature, and then performing ultrasonic intercalation on solvent molecules between layers of the graphite to obtain an expanded graphite solution, wherein the ultrasonic power is 200W, and the ultrasonic time is 50 minutes;
step 2, heating the expanded graphite solution to 66 ℃ under the vacuum condition with the vacuum degree of 0.04MPa, and keeping the temperature for 35 minutes to obtain expanded graphite;
step 3, stripping the expanded graphite through a liquid phase to obtain a graphene solution;
step 4, adding a silver nitrate solution into the graphene solution, stirring and mixing, heating to 78 ℃ under the protection of nitrogen, and performing ultrasonic dispersion to obtain a nano-silver modified graphene solution, wherein the weight percentage of silver nitrate after the silver nitrate solution is added is 0.8%, the ultrasonic power of the ultrasonic dispersion is 180W, and the ultrasonic time is 46 minutes;
step 5, adding 280g of microporous glass and 400 g of polyethylene glycol into the nano-silver modified graphene solution, adding the solution with the mass of 0.2% of the volume of the nano-silver modified graphene solution, stirring and mixing, and then ball-milling the mixture in a ball mill until the particle size is below 200 microns to obtain a mixed solution;
step 6, drying the mixed solution to obtain a composite modified material;
step 7, mixing the composite modified material with acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fiber, transferring the mixture into a reaction kettle, heating to 70 ℃ under the protection of nitrogen, keeping the temperature for 27 minutes, heating to 120 ℃ at the heating rate of 1 ℃/minute under the stirring condition, keeping the temperature for 13 minutes, and naturally cooling to room temperature to obtain a reaction mixture, wherein the adding mass ratio of the composite modified material to the acrylic acid, the butyl acrylate, the tetrabutyl titanate and the carbon fiber is 100:160:80:20: 0.3; the fiber length of the carbon fiber is 2-6 μm;
and 8, mixing the reaction mixture with polytetrafluoroethylene, wherein the mass ratio of the reaction mixture to the polytetrafluoroethylene is 5:3, and rolling to form a film to obtain the composite film for the thermistor.
Example 4
A preparation method of a composite film for a thermistor comprises the following steps:
step 1, adding 100g of graphite into 10kg of N-methyl pyrrolidone, stirring for 50 minutes at low temperature, and then performing ultrasonic intercalation on solvent molecules between layers of the graphite to obtain an expanded graphite solution, wherein the ultrasonic power is 200W, and the ultrasonic time is 60 minutes;
step 2, heating the expanded graphite solution to 70 ℃ under the vacuum condition with the vacuum degree of 0.05MPa, and keeping the temperature for 40 minutes to obtain expanded graphite;
step 3, stripping the expanded graphite through a liquid phase to obtain a graphene solution;
step 4, adding a silver nitrate solution into the graphene solution, stirring and mixing, heating to 80 ℃ under the protection of nitrogen, and performing ultrasonic dispersion to obtain a nano-silver modified graphene solution, wherein the weight percentage of silver nitrate after the silver nitrate solution is added is 1%, the ultrasonic power of the ultrasonic dispersion is 180W, and the ultrasonic time is 50 minutes;
step 5, adding 300g of microporous glass and 400 g of polyethylene glycol into the nano-silver modified graphene solution, adding the nano-silver modified graphene solution with the mass of 0.2% of the volume of the nano-silver modified graphene solution, stirring and mixing, and then ball-milling the mixture in a ball mill until the particle size is less than 200 mu m to obtain a mixed solution;
step 6, drying the mixed solution to obtain a composite modified material;
step 7, mixing the composite modified material with acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fiber, transferring the mixture into a reaction kettle, heating to 70 ℃ under the protection of nitrogen, keeping the temperature for 30 minutes, heating to 120 ℃ at the heating rate of 1 ℃/minute under the stirring condition, keeping the temperature for 15 minutes, and naturally cooling to room temperature to obtain a reaction mixture, wherein the adding mass ratio of the composite modified material to the acrylic acid, the butyl acrylate, the tetrabutyl titanate and the carbon fiber is 100:160:80:20: 0.3; the fiber length of the carbon fiber is 2-6 μm;
and 8, mixing the reaction mixture with polytetrafluoroethylene, wherein the mass ratio of the reaction mixture to the polytetrafluoroethylene is 5:3, and rolling to form a film to obtain the composite film for the thermistor.
The resistance of the composite film for the thermistor obtained by the method provided by the invention can be divided into two stages along with the temperature change, as shown in figure 1, the first stage is that when the temperature is lower than a critical temperature (about 115 ℃), the resistance is reduced along with the temperature rise, but the reduction speed is slower, because the composite film is mainly conducted by trace carbon fibers before the critical temperature, the conductivity of a microporous glass composite structure is poorer because of the shielding property, and the temperature rise is not great for the structure in the composite film because of the temperature resistance and the low thermal expansion property of the composite film, and the resistance is slowly reduced along with the temperature rise; when the temperature is higher than the critical temperature, the electron movement capacity between the graphene sheet layers is enhanced, the surface nano silver ions are excited, meanwhile, the conductivity of the microporous glass is enhanced due to the increase of the temperature, and a conductive path between the carbon fiber and the microporous glass composite structure is triggered after the temperature reaches the critical temperature, so that the performance of a lead of the composite film is enhanced instantly and greatly, the resistance is reduced rapidly, and the rapid change of the resistance is generated. It can be seen in fig. 1 that in the second phase, the resistivity drops off rapidly and eventually stabilizes.
Claims (7)
1. A preparation method of a composite film for a thermistor is characterized by comprising the following steps: step 1, adding graphite into a solvent, stirring for 40-50 minutes at low temperature, and then performing ultrasonic intercalation on solvent molecules between graphite layers to obtain an expanded graphite solution; step 2, heating the expanded graphite solution to 60-70 ℃ under the vacuum condition, and keeping the temperature for 30-40 minutes to obtain expanded graphite; step 3, stripping the expanded graphite through a liquid phase to obtain a graphene solution; step 4, adding a silver nitrate solution into the graphene solution, stirring and mixing, heating to 70-80 ℃ under the protection of nitrogen, and performing ultrasonic dispersion to obtain a nano-silver modified graphene solution; step 5, adding microporous glass and polyethylene glycol 400 into the nano-silver modified graphene solution, stirring and mixing, and then ball-milling in a ball mill until the particle size is below 200 mu m to obtain a mixed solution; step 6, drying the mixed solution to obtain a composite modified material; step 7, mixing the composite modified material with acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fiber, transferring the mixture into a reaction kettle, heating to 60-70 ℃ under the protection of nitrogen, keeping the temperature for 20-30 minutes, heating to 120 ℃ at the heating speed of 1 ℃/minute under the stirring condition, keeping the temperature for 10-15 minutes, and naturally cooling to room temperature to obtain a reaction mixture; step 8, mixing the reaction mixture with polytetrafluoroethylene, and rolling to form a film to obtain a composite film for the thermistor;
wherein the weight percentage concentration of graphite added into the solvent in the step 1 is 1-3%; the solvent in the step 1 is N-methyl pyrrolidone; and 4, adding silver nitrate solution in the step 4, wherein the weight percentage of the silver nitrate is 0.5-1%.
2. The method of claim 1, wherein the ultrasonic power is 200W and the ultrasonic time is 40-60 minutes in step 1.
3. The method of preparing a composite film for a thermistor according to claim 1, characterized in that the degree of vacuum of the vacuum condition in step 2 is 0.02 to 0.05 MPa.
4. The method of preparing a composite film for a thermistor according to claim 1, wherein the ultrasonic power of the ultrasonic dispersion in step 4 is 180W and the ultrasonic time is 40 to 50 minutes.
5. The method for preparing a composite film for a thermistor according to claim 1, wherein the mass of the microporous glass added in step 5 is 2-3 times of the mass of the graphite added in step 1, and the mass of the polyethylene glycol 400 added is 0.1-0.2% of the volume of the nano-silver modified graphene solution.
6. The method for preparing a composite film for a thermistor according to claim 1, characterized in that the mass ratio of the composite modified material to acrylic acid, butyl acrylate, tetrabutyl titanate and carbon fiber in step 7 is 100:160:80:20: 0.3; the carbon fiber has a fiber length of 2 to 6 μm.
7. The method of preparing a composite film for a thermistor according to claim 1, characterized in that the mass ratio of the reaction mixture to polytetrafluoroethylene in step 8 is 5: 3.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1772799A (en) * | 2005-10-27 | 2006-05-17 | 复旦大学 | Thermosensitive temperature sensing material and its prepn |
| CN101350415A (en) * | 2008-07-22 | 2009-01-21 | 山东东岳神舟新材料有限公司 | Microporous-film-reinforced fluorine-containing cross-linking doping ion-exchange membrane and preparation method thereof |
| CN102796333A (en) * | 2012-09-06 | 2012-11-28 | 哈尔滨工业大学 | Preparation method of polyvinylidene-fluoride-base temperature-sensitive resistance material with negative temperature coefficient effect |
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