CN114605658A - Preparation method of polyimide-based modified graphene heat-conducting composite material - Google Patents

Preparation method of polyimide-based modified graphene heat-conducting composite material Download PDF

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CN114605658A
CN114605658A CN202210336657.XA CN202210336657A CN114605658A CN 114605658 A CN114605658 A CN 114605658A CN 202210336657 A CN202210336657 A CN 202210336657A CN 114605658 A CN114605658 A CN 114605658A
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gns
composite material
maleimide
polyimide
graphene
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伍斌
兰慧雅
夏茹
钱家盛
陈鹏
曹明
杨斌
苗继斌
葛倩倩
苏丽芬
郑争志
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Anhui University
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Anhui University
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Abstract

The invention discloses a preparation method of a polyimide-based modified graphene heat-conducting composite material, which comprises the following steps: firstly, obtaining Graphene Nanosheets (GNS) by an electrochemical graphite stripping method; then, carrying out Diels-Alder reaction on maleimide and GNS to obtain maleimide modified graphene heat-conducting filler (M @ GNS); and finally, preparing a maleimide @ graphene/polyimide composite material (marked as M @ GNS/PI) with polyimide as a matrix and M @ GNS as a filler by an in-situ polymerization method and a chemical imine method. The method can connect the carboxyl-terminated PAA (polyamide acid) with the functionalized graphene through a C-N-C bond, so that the compatibility of the graphene and a matrix is enhanced, and the heat-conducting property of the polyimide composite material is obviously improved under the filling of low-content filler.

Description

Preparation method of polyimide-based modified graphene heat-conducting composite material
Technical Field
The invention relates to the technical field of heat-conducting polymer composite materials, in particular to a polyimide-based modified graphene heat-conducting composite material.
Background
With the coming of the 5G era, modern electronic technology is rapidly developing towards miniaturization, high integration and multi-functionalization, and the reliability and the service life of high-tech equipment are greatly threatened by a serious heat dissipation problem. The polymer based polymer is widely applied to the fields of microelectronic packaging and the like due to the characteristics of light weight, easy processing, excellent mechanical property and electrical insulation property and the like. However, their use is limited due to their low thermal conductivity. The heat-conducting property of the composite material is improved by introducing the filler, regulating and controlling the interface thermal resistance and constructing a heat-conducting passage.
At present, heat-conducting fillers such as graphene, carbon nano tubes, boron nitride nanosheets, carbon fibers and the like become a main force for regulating and controlling the heat-conducting performance of the composite material due to inherent advantages of super heat conductivity and heat channel. And the modification of the heat-conducting filler is an effective means for regulating and controlling the interface thermal resistance between the filler and the matrix and between the filler. The modification of the heat-conducting filler is divided into covalent bond modification and non-covalent bond modification, and the covalent bond modification has the advantages of various methods, stable product properties and the like. Recently, the construction of a heat conduction path by constructing a covalent bond between a filler and a matrix has been studied. The surface structure of the modified filler improves the dispersibility of the filler and simultaneously promotes the effective transmission of phonons between the filler and the matrix, thereby improving the heat-conducting property of the composite material.
Disclosure of Invention
Based on the problems in the prior art, the invention provides a preparation method of a polyimide-based modified graphene heat-conducting composite material, aiming at improving the heat-conducting property of the composite material.
The invention adopts the following technical scheme for realizing the purpose:
a preparation method of a polyimide-based modified graphene heat-conducting composite material is characterized by comprising the following steps: firstly, obtaining a graphene nanosheet, namely GNS, by an electrochemical graphite stripping method; then performing Diels-Alder reaction on maleimide and GNS to obtain maleimide modified graphene heat-conducting filler, and marking as M @ GNS; and finally, preparing the maleimide @ graphene/polyimide composite material which takes polyimide as a matrix and M @ GNS as a filler, namely M @ GNS/PI, by an in-situ polymerization method and a chemical imine method. The method specifically comprises the following steps:
step 1, preparation of GNS
Taking a graphite foil as an anode, a platinum sheet as a cathode, 0.1-0.12 mol/L ammonium sulfate aqueous solution as electrolyte, carrying out electrochemical stripping on the graphite foil at a constant stripping voltage of 15-15.3V, and carrying out suction filtration, washing and drying to obtain GNS;
step 2, synthesis of M @ GNS
Dissolving 45-50 mg of maleimide in 40-50 mL of N, N-dimethylformamide, adding 10-15 mg of GNS into the solution, carrying out ultrasonic treatment for 50-60 min, heating in an oil bath at 115-120 ℃ for 14-16 h, and irradiating under ultraviolet rays for 10-15 min; cooling to room temperature, filtering the obtained suspension through a polytetrafluoroethylene disc membrane, and then carrying out vacuum filtration and washing by using 60-75 mL of ethanol to remove unreacted maleimide; finally, collecting the filter cake and drying in vacuum at room temperature to obtain M @ GNS;
step 3, synthesis of M @ GNS/PAA/PI
Adding 0.5940-0.5950 g of 4, 4-diaminodiphenylmethane (MDA) and 8.5-9.5 mL of N, N dimethylformamide into a three-necked flask in a nitrogen atmosphere, dissolving, adding M @ GNS, performing ultrasonic treatment for 50-60 min, stirring for 5-10 min in an ice water bath, then adding 0.9000-0.9010 g of 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride (BPDA) and a molecular sieve, and stirring for 15-20 min in the ice water bath to obtain an M @ GNS/PAA solution; then adding 0.15-0.2 mL of triethylamine and 0.08-0.1 mL of pyridine to obtain an M @ GNS/PAA/PI solution;
step 4, synthesis of M @ GNS/PI
Pouring the obtained M @ GNS/PAA/PI solution on a clean glass substrate, coating by using a scraper, and drying at the temperature of 60-70 ℃ for 1-1.5 h; and finally, performing gradient thermal imidization to obtain the M @ GNS/PI heat-conducting composite material.
Further, the procedure of the gradient thermal imidization in step 4 is as follows: first at 120 ℃ for 1h, then at 200 ℃ for 1h, and finally at 250 ℃ for 1 h.
Further, in the step 3, the addition amount of M @ GNS is 0-15 wt% of the total mass of the 4, 4-diaminodiphenylmethane and the 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride.
The invention also discloses the M @ GNS/PI composite material obtained by the preparation method.
The invention has the beneficial effects that:
1. according to the invention, a heat transfer path between the graphene and the polyimide is constructed in the composite material through a covalent bond, and the heat transfer performance between the graphene and the matrix is greatly enhanced due to the effect of the C-N-C bond formed between the functionalized maleimide and the polyimide. Meanwhile, the covalent bond formed between the maleimide and the graphene also effectively improves the dispersibility of the filler, and improves the overall heat-conducting property of the composite material.
2. The method can connect the carboxyl-terminated PAA (polyamide acid) with the functionalized graphene through a C-N-C bond, so that the compatibility of the graphene and a matrix is enhanced, and the heat-conducting property of the polyimide composite material is obviously improved under the filling of low-content filler.
Drawings
FIG. 1 is a reaction mechanism diagram of functionalized graphene and polyamic acid according to the present invention, wherein (a) is a reaction mechanism diagram of maleimide modified graphene and polyamic acid, and (b) is a process of partial imidization of polyamic acid into polyimide;
FIG. 2 is an SEM image of GNS and M @ GNS obtained in example 1 of the present invention, wherein (a) is GNS and (b) is M @ GNS;
FIG. 3 is a graph showing thermal conductivity of the composite material obtained in each example of the present invention and comparative example.
Detailed Description
The following examples are given for the detailed implementation and specific operation of the present invention, but the scope of the present invention is not limited to the following examples.
Example 1
This example prepares a 5 wt% M @ GNS/PI composite as follows
Step 1, preparation of GNS
Taking a graphite foil as an anode, a platinum sheet as a cathode, 0.1mol/L ammonium sulfate aqueous solution as electrolyte, carrying out electrochemical stripping on the graphite foil at a constant stripping voltage of 15V, and carrying out suction filtration, washing and drying to obtain the GNS.
Step 2, synthesis of M @ GNS
Dissolving 45mg maleimide in 40mL N, N dimethylformamide, adding 10mg GNS into the solution, performing ultrasonic treatment for 50min, heating in 120 deg.C oil bath for 16h, and irradiating with ultraviolet for 13 min; after cooling to room temperature, the resulting suspension was filtered through a teflon disc membrane (0.1 μm pore size, 50mm diameter) and then washed with 75mL of ethanol by vacuum filtration to remove any unreacted maleimide; finally, the filter cake was collected and dried under vacuum at room temperature to obtain M @ GNS.
Step 3, synthesis of M @ GNS/PAA/PI
Adding 0.5948g of 4, 4-diaminodiphenylmethane and 9mL of N, N-dimethylformamide into a three-neck flask in a nitrogen atmosphere, dissolving, adding M @ GNS according to the mass fraction of 5 wt% (accounting for 5 wt% of the total mass of the 4, 4-diaminodiphenylmethane and the 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride), carrying out ultrasonic treatment for 50min, stirring for 5min in an ice-water bath, then adding 0.9003g of 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride and a molecular sieve, and stirring for 15min in the ice-water bath to obtain an M @ GNS/PAA solution with certain viscosity; followed by the addition of 0.2mL of triethylamine and 0.1mL of pyridine to give a solution of M @ GNS/PAA/PI with a certain viscosity.
Step 4, synthesis of M @ GNS/PI
The obtained M @ GNS/PAA/PI solution is poured on a clean glass substrate, coated by a scraper and dried for 1.5 hours at the temperature of 60 ℃; and finally, performing gradient thermal imidization (firstly heating at 120 ℃ for 1h, then heating at 200 ℃ for 1h, and finally heating at 250 ℃ for 1h) to obtain the M @ GNS/PI heat-conducting composite film.
Example 2
This example prepares a 10 wt% M @ GNS/PI composite in the same manner as example 1, except that M @ GNS is added in a mass fraction of 10 wt% in step 3.
Example 3
This example prepared a 15 wt% M @ GNS/PI composite in the same manner as example 1, except that M @ GNS was added in a mass fraction of 15 wt% in step 3.
Comparative example 1
This comparative example prepared a 5 wt% GNS/PI composite as follows:
step 1, preparation of GNS
Taking a graphite foil as an anode, a platinum sheet as a cathode, 0.1mol/L ammonium sulfate aqueous solution as electrolyte, carrying out electrochemical stripping on the graphite foil at a constant stripping voltage of 15V, and carrying out suction filtration, washing and drying to obtain the GNS.
Step 2, preparation of GNS/PI composite material
Adding 0.5948g of 4, 4-diaminodiphenylmethane and 9mL of N, N-dimethylformamide into a three-neck flask in a nitrogen atmosphere, dissolving, adding GNS according to the mass fraction of 5 wt% (accounting for 5 wt% of the total mass of the 4, 4-diaminodiphenylmethane and the 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride), carrying out ultrasonic treatment for 100min, stirring for 5min in an ice water bath, then adding 0.9003g of 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride and a molecular sieve, and stirring for 15min in the ice water bath to obtain an M @ GNS/PAA solution with certain viscosity; 0.2mL of triethylamine and 0.1mL of pyridine were then added to give a GNS/PAA/PI solution with a certain viscosity.
Step 3, Synthesis of GNS/PI
The obtained GNS/PAA/PI solution is poured on a clean glass substrate, coated by a scraper and dried for 1.5h at the temperature of 60 ℃; and finally, performing gradient thermal imidization (firstly heating at 120 ℃ for 1h, then heating at 200 ℃ for 1h, and finally heating at 250 ℃ for 1h) to obtain the GNS/PI heat-conducting composite film.
Comparative example 2
This comparative example 10 wt% GNS/PI composite was prepared in the same manner as in comparative example 1 except that GNS was added in step 2 in a mass fraction of 10 wt% (10 wt% based on the total mass of 4, 4-diaminodiphenylmethane and 3,3 '-4, 4' -biphenyltetracarboxylic dianhydride).
Comparative example 3
This comparative example 15 wt% GNS/PI composite was prepared in the same manner as in comparative example 1 except that GNS was added in step 2 in a mass fraction of 15 wt% (15 wt% based on the total mass of 4, 4-diaminodiphenylmethane and 3,3 '-4, 4' -biphenyltetracarboxylic dianhydride).
FIG. 1 is a reaction mechanism diagram of maleimide modified graphene and polyamic acid, and it can be seen from the diagram that N-H group in maleimide, which is a functional substance of M @ GNS, can react with carboxyl terminated polyamic acid (PAA) by a chemical imine method, and the maleimide and carboxyl at the end of the polyamic acid (PAA) are bridged by C-N-C bond. Meanwhile, the internal part of the polyamide acid (PAA) is partially imidized to form PAA/PI.
Fig. 2 is SEM images before and after maleimide modified graphene shows that the GNS surface before modification is smooth, and organic small particles exist on the graphene surface after modification, which indicates that maleimide is successfully grafted on the graphene surface through covalent bond formation between maleimide and graphene.
Fig. 3 shows the results of the thermal conductivity tests of the examples and the comparative examples, and it can be seen from the graph that as the content of the filler is increased, the thermal conductivity of the composite material is increased, because the thermal conduction path is denser as the content of the filler is higher, and the thermal conductivity of the M @ GNS/PI composite material is higher than that of the GNS/PI composite material under the same filler, which indicates that the effect of the C-N-C bond formed between the functionalized maleimide and the polyimide greatly enhances the thermal conductivity of the graphene and the matrix. Meanwhile, the covalent bond formed between the maleimide and the graphene also effectively improves the dispersibility of the filler, and improves the overall heat-conducting property of the composite material.
The present invention is not limited to the above exemplary embodiments, and any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (5)

1. A preparation method of a polyimide-based modified graphene heat-conducting composite material is characterized by comprising the following steps: firstly, obtaining a graphene nanosheet, namely GNS, by an electrochemical graphite stripping method; then performing Diels-Alder reaction on maleimide and GNS to obtain maleimide modified graphene heat-conducting filler, and marking as M @ GNS; and finally, preparing a maleimide @ graphene/polyimide composite material which takes polyimide as a matrix and M @ GNS as a filler by an in-situ polymerization method and a chemical imine method, wherein the maleimide @ graphene/polyimide composite material is marked as M @ GNS/PI.
2. The method of claim 1, comprising the steps of:
step 1, preparation of GNS
Taking a graphite foil as an anode, a platinum sheet as a cathode, 0.1-0.12 mol/L ammonium sulfate aqueous solution as electrolyte, carrying out electrochemical stripping on the graphite foil at a constant stripping voltage of 15-15.3V, and carrying out suction filtration, washing and drying to obtain GNS;
step 2, synthesis of M @ GNS
Dissolving 45-50 mg of maleimide in 40-50 mLN, N-dimethylformamide, adding 10-15 mg of GNS into the solution, carrying out ultrasonic treatment for 50-60 min, heating in an oil bath at 115-120 ℃ for 14-16 h, and irradiating under ultraviolet rays for 10-15 min; cooling to room temperature, filtering the obtained suspension through a polytetrafluoroethylene disc membrane, and then carrying out vacuum filtration and washing by using 60-75 mL of ethanol to remove unreacted maleimide; finally, collecting the filter cake and drying in vacuum at room temperature to obtain M @ GNS;
step 3, synthesis of M @ GNS/PAA/PI
Adding 0.5940-0.5950 g of 4, 4-diaminodiphenylmethane and 8.5-9.5 mLN, N-dimethylformamide into a three-neck flask in a nitrogen atmosphere, dissolving, adding M @ GNS, performing ultrasound for 50-60 min, stirring for 5-10 min in an ice-water bath, then adding 0.9000-0.9010 g of 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride and a molecular sieve, and stirring for 15-20 min in the ice-water bath to obtain an M @ GNS/PAA solution; then adding 0.15-0.2 mL of triethylamine and 0.08-0.1 mL of pyridine to obtain an M @ GNS/PAA/PI solution;
step 4, synthesis of M @ GNS/PI
Pouring the obtained M @ GNS/PAA/PI solution on a clean glass substrate, coating by using a scraper, and drying at the temperature of 60-70 ℃ for 1-1.5 h; and finally, performing gradient thermal imidization to obtain the M @ GNS/PI heat-conducting composite material.
3. The method of claim 2, wherein: the procedure of the gradient thermal imidization in the step 4 is as follows: first at 120 ℃ for 1h, then at 200 ℃ for 1h, and finally at 250 ℃ for 1 h.
4. The method of claim 2, wherein: in the step 3, the addition amount of M @ GNS accounts for 0-15 wt% of the total mass of the 4, 4-diaminodiphenylmethane and the 3,3 '-4, 4' -biphenyl tetracarboxylic dianhydride.
5. An M @ GNS/PI composite material obtained by the preparation method of any one of claims 1-4.
CN202210336657.XA 2022-03-31 2022-03-31 Preparation method of polyimide-based modified graphene heat-conducting composite material Pending CN114605658A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105820569A (en) * 2016-04-21 2016-08-03 常州达奥新材料科技有限公司 Preparation method of graphene/polyimide composite material
CN107501941A (en) * 2017-08-26 2017-12-22 福建师范大学 A kind of functional graphene oxide and room temperature vulcanized silicone rubber nano composite material and preparation method thereof
CN113789110A (en) * 2021-08-24 2021-12-14 福州大学 Method for preparing low-conductivity graphene/polyurethane composite coating through Diels-Alder reaction

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105820569A (en) * 2016-04-21 2016-08-03 常州达奥新材料科技有限公司 Preparation method of graphene/polyimide composite material
CN107501941A (en) * 2017-08-26 2017-12-22 福建师范大学 A kind of functional graphene oxide and room temperature vulcanized silicone rubber nano composite material and preparation method thereof
CN113789110A (en) * 2021-08-24 2021-12-14 福州大学 Method for preparing low-conductivity graphene/polyurethane composite coating through Diels-Alder reaction

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
ALFONSO FERRETTI等: "One-step functionalization of mildly and strongly reduced graphene oxide with maleimide: an experimental and theoretical investigation of the Diels–Alder [4+2] cycloaddition reaction", 《PHYSICAL CHEMISTRY CHEMICAL PHYSICS》 *
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