Heat-conducting filler grafted polyarylether-polyimide composite material and preparation method thereof
阅读说明：本技术 一种导热填料接枝聚芳醚-聚酰亚胺复合材料及其制备方法 (Heat-conducting filler grafted polyarylether-polyimide composite material and preparation method thereof ) 是由 王大明 丛冰 赵君禹 王春博 周宏伟 赵晓刚 陈春海 于 2020-07-20 设计创作，主要内容包括：本发明提供了一种导热填料接枝聚芳醚-聚酰亚胺复合材料及其制备方法,属于导热材料技术领域。本发明通过水热反应将导热填料进行羟基化,使得羟基化导热填料参与聚芳醚的聚合反应,在羟基化导热填料和聚合物基体间形成共价键,为声子传输提供媒介,能够降低导热填料与聚芳醚聚合物之间的界面热阻,提高复合材料的导热系数；同时本发明以聚酰亚胺织物作为力学支撑网络,增强材料的力学性能,进一步扩大了复合材料的应用领域。实施例的结果表面,本发明制备的导热填料接枝聚芳醚-聚酰亚胺复合材料的导热系数可达1.53W/mK,拉伸强度可达54MPa,拉伸模量可达2.6GPa,断裂伸长率可达8.1％。(The invention provides a heat-conducting filler grafted polyarylether-polyimide composite material and a preparation method thereof, belonging to the technical field of heat-conducting materials. According to the invention, the heat-conducting filler is hydroxylated through a hydrothermal reaction, so that the hydroxylated heat-conducting filler participates in the polymerization reaction of the polyarylether, a covalent bond is formed between the hydroxylated heat-conducting filler and a polymer matrix, a medium is provided for phonon transmission, the interface thermal resistance between the heat-conducting filler and the polyarylether polymer can be reduced, and the heat conductivity coefficient of the composite material is improved; meanwhile, the polyimide fabric is used as a mechanical support network, so that the mechanical property of the material is enhanced, and the application field of the composite material is further expanded. The results of the examples show that the thermal conductivity coefficient of the thermal conductive filler grafted polyarylether-polyimide composite material prepared by the invention can reach 1.53W/mK, the tensile strength can reach 54MPa, the tensile modulus can reach 2.6GPa, and the elongation at break can reach 8.1%.)
1. A preparation method of a heat-conducting filler grafted polyarylether-polyimide composite material comprises the following steps:
mixing the heat-conducting filler with an alkaline solution, and carrying out hydrothermal reaction to obtain a hydroxylated heat-conducting filler;
mixing the hydroxylated heat-conducting filler, a dihalo monomer, a diphenol monomer, a catalyst, a reaction solvent and a water-carrying agent, and sequentially carrying out water-carrying and copolymerization reactions to obtain a heat-conducting filler grafted polyarylether; the dihalo monomer contains an aromatic group;
dispersing the heat-conducting filler grafted polyarylether in a dispersing agent to obtain a dispersion liquid;
and coating the dispersion liquid on the surface of a polyimide fabric, performing phase transition in water, and performing hot pressing on the obtained compound to obtain the heat-conducting filler grafted polyarylether-polyimide composite material.
2. The production method according to claim 1, wherein the thermally conductive filler comprises aluminum nitride, aluminum oxide, or boron nitride;
the alkaline solution comprises a potassium hydroxide aqueous solution, a sodium methoxide methanol solution or a sodium ethoxide ethanol solution; the concentration of the alkaline solution is 1-6 mol/L;
the dosage ratio of the heat-conducting filler to the alkaline solution is 50g (80-100) mL.
3. The preparation method according to claim 1, wherein the hydrothermal reaction is carried out at a temperature of 150 to 200 ℃ for a holding time of 15 to 30 min.
4. The method of claim 1, wherein the dihalogen monomer comprises 4,4 '-difluorobenzophenone, 4' -dichlorodiphenyl sulfone, 4 '-difluorodiphenyl sulfone, 1, 3-bis (4-fluorobenzoyl) benzene, 1, 4-bis (4-fluorobenzoyl) benzene, 4' -bis (4-fluorobenzoyl) biphenyl, bis (4-chloro-2-phthalimidophenyl) ether, 1, 4-bis (4-chloro-2-phthalimido) benzene or 1, 3-bis (4-chloro-2-phthalimido) benzene;
the diphenol monomer comprises 2, 2-bis (4-hydroxyphenyl) propane, 4 '-dihydroxytriphenylmethane-2' -carboxylic acid, 3-bis (4-hydroxyphenyl) -3H-isobenzofuranone, phenol red, 2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcinol, 4 '-biphenol, 4' -dihydroxybenzophenone, 4 '-dihydroxydiphenyl sulfone, 4' -dihydroxydiphenyl sulfoxide, 4 '-dihydroxydiphenyl sulfide, or 4,4' -dihydroxydiphenyl ether;
the reaction solvent comprises dimethyl sulfoxide, N-methyl pyrrolidone or sulfolane;
the catalyst comprises sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or cesium fluoride;
the water-carrying agent comprises toluene or xylene.
5. The preparation method according to claim 1 or 4, wherein the molar ratio of the dihalogen monomer, the diphenol monomer and the catalyst is 1 (0.98-0.99): (2-2.2);
the mass ratio of the total mass of the dihalogen monomer, the diphenol monomer and the hydroxylated heat-conducting filler to the reaction solvent is (15-20): (80-85);
the mass ratio of the total mass of the dihalogen monomer and the diphenol monomer to the mass of the hydroxylated heat-conducting filler is (40-80): (20-60).
6. The preparation method according to claim 1, wherein the temperature of the copolymerization reaction is 180-200 ℃ and the time is 4-8 h.
7. The preparation method of claim 1, wherein the mass ratio of the heat-conducting filler grafted polyarylether to the dispersant is (10-20) to (80-90);
the dispersion is carried out under the ultrasonic condition, the power of the ultrasonic is 250-400W, and the time is 0.5-2 h;
the dispersant comprises N-methyl pyrrolidone, N-dimethyl acetamide, N-dimethyl formamide, tetrahydrofuran, dioxane, dichloromethane or trichloromethane.
8. The preparation method according to claim 1 or 7, wherein the mass ratio of the dispersion to the polyimide fabric is (9-11) 0.85; the density of the polyimide fabric is 200g/m2。
9. The method according to claim 1, wherein the hot pressing is performed at a pressure of 1.5 to 2.0MPa and a temperature of 250 to 450 ℃.
10. The heat-conducting filler grafted polyarylether-polyimide composite material prepared by the preparation method of any one of claims 1 to 9 comprises a polyimide fabric substrate and a heat-conducting polymer filled in the polyimide fabric substrate, wherein the heat-conducting polymer is the heat-conducting filler grafted polyarylether.
Technical Field
The invention relates to the technical field of heat conduction materials, in particular to a heat conduction filler grafted polyarylether-polyimide composite material and a preparation method thereof.
Background
The heat conduction material is widely applied to various fields of national defense industry and national economy, and becomes an indispensable functional material in modern industry and life. With the development of science and technology, the rapid development of microelectronic integration and assembly technology, the volume of electronic components and logic circuits is continuously reduced, and the working frequency is rapidly increased, which results in the accumulation of a large amount of heat, thereby affecting the normal use of the devices. Therefore, whether heat dissipation can be performed quickly in time becomes a key factor for determining the service life of the device, and research and development of materials with higher thermal conductivity are urgently needed. Among them, polymer-based thermally conductive composite materials have been widely studied because of their excellent processability and relatively low cost.
In general, to increase the thermal conductivity, highly thermally conductive fillers are generally added to the polymer matrix, and the resulting composite materials generally have a higher thermal conductivity than the pure polymer. Currently, the fillers that have been used can be broadly classified into metallic, inorganic non-metallic, carbon, and mixed fillers. Chinese invention patent (CN110862669A) discloses a preparation method of a graphene/polyphenyl ether alloy heat-conducting composite material, which comprises the steps of dissolving a certain amount of polyphenyl ether alloy in a mixed solution of toluene/NMP, adding a certain amount of graphene after the polyphenyl ether alloy is dissolved, carrying out ultrasonic dispersion to form a uniformly mixed solution, finally adding methanol into the mixed solution to precipitate the polyphenyl ether alloy, and carrying out suction filtration to obtain the graphene/polyphenyl ether alloy composite material. However, the graphene surface hardly contains active functional groups, so that the interaction between the filler and the polyphenylene ether is limited, and the improvement on the thermal conductivity is limited. Chinese invention patent (CN110862686A) discloses a method for preparing a heat-conducting filler, which comprises mixing a heat-conducting filler, a high molecular material and an auxiliary agent uniformly to form a mixture, and forming close packing of the heat-conducting filler in the mixture by the centrifugal force generated by a centrifugal device; and polymerizing or drying the mixture to obtain the high-molecular heat-conducting composite material. However, the existence of the auxiliary agent in the method increases the interface, so that the interface thermal resistance is increased, and the improvement of the thermal conductivity coefficient is not facilitated.
Therefore, the thermal conductivity of the existing polymer is low, and the addition of the thermal conductive filler, especially the nano filler with a small size, increases the interface between the polymer and the thermal conductive filler, which further increases the interface thermal resistance, and cannot obtain an ideal thermal conductive effect, and usually a large amount of thermal conductive filler (the loading is more than 20%) needs to be added to obtain an ideal thermal conductive property, but at the same time, the mechanical property of the composite material is sharply reduced, so that the application of the composite material is limited.
Disclosure of Invention
The invention aims to provide a heat-conducting filler grafted polyarylether-polyimide composite material and a preparation method thereof.
In order to achieve the above object, the present invention provides the following technical solutions:
the invention provides a preparation method of a heat-conducting filler grafted polyarylether-polyimide composite material, which comprises the following steps:
mixing the heat-conducting filler with an alkaline solution, and carrying out hydrothermal reaction to obtain a hydroxylated heat-conducting filler;
mixing the hydroxylated heat-conducting filler, a dihalo monomer, a diphenol monomer, a catalyst, a reaction solvent and a water-carrying agent, and sequentially carrying out water-carrying and copolymerization reactions to obtain a heat-conducting filler grafted polyarylether; the dihalo monomer contains an aromatic group;
dispersing the heat-conducting filler grafted polyarylether in a dispersing agent to obtain a dispersion liquid;
and coating the dispersion liquid on the surface of a polyimide fabric, performing phase transition in water, and performing hot pressing on the obtained compound to obtain the heat-conducting filler grafted polyarylether-polyimide composite material.
Preferably, the thermally conductive filler includes aluminum nitride, aluminum oxide, or boron nitride.
The alkaline solution comprises a potassium hydroxide aqueous solution, a sodium methoxide methanol solution or a sodium ethoxide ethanol solution; the concentration of the alkaline solution is 1-6 mol/L;
the dosage ratio of the heat-conducting filler to the alkaline solution is 50g (80-100) mL.
Preferably, the temperature of the hydrothermal reaction is 150-200 ℃, and the heat preservation time is 15-30 min.
Preferably, the dihalo monomer includes 4,4 '-difluorobenzophenone, 4' -dichlorodiphenyl sulfone, 4 '-difluorodiphenyl sulfone, 1, 3-bis (4-fluorobenzoyl) benzene, 1, 4-bis (4-fluorobenzoyl) benzene, 4' -bis (4-fluorobenzoyl) biphenyl, bis (4-chloro-2-phthalimidophenyl) ether, 1, 4-bis (4-chloro-2-phthalimido) benzene or 1, 3-bis (4-chloro-2-phthalimido) benzene;
the diphenol monomer comprises 2, 2-bis (4-hydroxyphenyl) propane, 4 '-dihydroxytriphenylmethane-2' -carboxylic acid, 3-bis (4-hydroxyphenyl) -3H-isobenzofuranone, phenol red, 2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcinol, 4 '-biphenol, 4' -dihydroxybenzophenone, 4 '-dihydroxydiphenyl sulfone, 4' -dihydroxydiphenyl sulfoxide, 4 '-dihydroxydiphenyl sulfide, or 4,4' -dihydroxydiphenyl ether;
the reaction solvent comprises dimethyl sulfoxide, N-methyl pyrrolidone or sulfolane;
the catalyst comprises sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or cesium fluoride;
the water-carrying agent comprises toluene or xylene.
Preferably, the molar ratio of the dihalogen monomer, the diphenol monomer and the catalyst is 1 (0.98-0.99): (2-2.2);
the mass ratio of the total mass of the dihalogen monomer, the diphenol monomer and the hydroxylated heat-conducting filler to the reaction solvent is (15-20): (80-85);
the mass ratio of the total mass of the dihalogen monomer and the diphenol monomer to the mass of the hydroxylated heat-conducting filler is (40-80): (20-60).
Preferably, the temperature of the copolymerization reaction is 180-200 ℃, and the time is 4-8 h.
Preferably, the mass ratio of the heat-conducting filler grafted polyarylether to the dispersing agent is (10-20) to (80-90);
the dispersion is carried out under the ultrasonic condition, the power of the ultrasonic is 250-400W, and the time is 0.5-2 h;
the dispersant comprises N-methyl pyrrolidone, N-dimethyl acetamide, N-dimethyl formamide, tetrahydrofuran, dioxane, dichloromethane or trichloromethane.
Preferably, the mass ratio of the dispersion liquid to the polyimide fabric is (9-11) 0.85; the density of the polyimide fabric is 200g/m2。
Preferably, the hot pressing pressure is 1.5-2.0 MPa, and the temperature is 250-450 ℃.
The invention provides a heat-conducting filler grafted polyarylether-polyimide composite material prepared by the preparation method in the technical scheme, which comprises a polyimide fabric substrate and a heat-conducting polymer filled in the polyimide fabric substrate, wherein the heat-conducting polymer is the heat-conducting filler grafted polyarylether.
The invention provides a preparation method of a heat-conducting filler grafted polyarylether-polyimide composite material, which comprises the following steps: mixing the heat-conducting filler with an alkaline solution, and carrying out hydrothermal reaction to obtain a hydroxylated heat-conducting filler; mixing the hydroxylated heat-conducting filler, a dihalo monomer, a diphenol monomer, a catalyst, a reaction solvent and a water-carrying agent, and sequentially carrying out water-carrying and copolymerization reactions to obtain a heat-conducting filler grafted polyarylether; the dihalo monomer contains an aromatic group; dispersing the heat-conducting filler grafted polyarylether in a dispersing agent to obtain a dispersion liquid; and coating the dispersion liquid on the surface of a polyimide fabric, performing phase transition in water, and performing hot pressing on the obtained compound to obtain the heat-conducting filler grafted polyarylether-polyimide composite material. According to the invention, the heat-conducting filler is hydroxylated through a hydrothermal reaction, so that the hydroxylated heat-conducting filler can participate in a polymerization reaction for preparing the polyarylether, a covalent bond (namely an ether bond formed by the reaction of hydroxyl on the hydroxylated heat-conducting filler and halogen atoms on a dihalogen monomer) is formed between the hydroxylated heat-conducting filler and the polyarylether matrix, the heat-conducting filler is grafted on the polyarylether through the acting force of the covalent bond, a medium is provided for phonon transmission, the interface thermal resistance between the heat-conducting filler and the polyarylether can be reduced, the interaction between the heat-conducting filler and the polyarylether matrix is enhanced, the heat conductivity coefficient of the composite material is improved, and the heat-conducting property of the composite material is enhanced; meanwhile, the polyimide fabric is used as a mechanical support network, so that the mechanical property of the material is enhanced, and the application field of the composite material is further expanded. The results of the examples show that the thermal conductivity coefficient of the thermal conductive filler grafted polyarylether-polyimide composite material prepared by the invention can reach 1.53W/mK, the tensile strength can reach 54MPa, the tensile modulus can reach 2.6GPa, and the elongation at break can reach 8.1%.
Detailed Description
The invention provides a preparation method of a heat-conducting filler grafted polyarylether-polyimide composite material, which comprises the following steps:
mixing the heat-conducting filler with an alkaline solution, and carrying out hydrothermal reaction to obtain a hydroxylated heat-conducting filler;
mixing the hydroxylated heat-conducting filler, a dihalo monomer, a diphenol monomer, a catalyst, a reaction solvent and a water-carrying agent, and sequentially carrying out water-carrying and copolymerization reactions to obtain a heat-conducting filler grafted polyarylether; the dihalo monomer contains an aromatic group;
dispersing the heat-conducting filler grafted polyarylether in a dispersing agent to obtain a dispersion liquid;
and coating the dispersion liquid on the surface of a polyimide fabric, performing phase transition in water, and performing hot pressing on the obtained compound to obtain the heat-conducting filler grafted polyarylether-polyimide composite material.
In the present invention, unless otherwise specified, all the starting materials required for the preparation are commercially available products well known to those skilled in the art.
According to the invention, the heat-conducting filler and the alkaline solution are mixed and subjected to hydrothermal reaction to obtain the hydroxylated heat-conducting filler. In the present invention, the thermally conductive filler preferably includes aluminum nitride, aluminum oxide, or boron nitride; the alkaline solution preferably comprises an aqueous potassium hydroxide solution, an aqueous sodium hydroxide solution, a sodium methoxide solution in methanol or a sodium ethoxide solution in ethanol; the concentration of the alkaline solution is preferably 1-6 mol/L, more preferably 2-5 mol/L, and further preferably 3-4 mol/L; the dosage ratio of the heat-conducting filler to the alkaline solution is preferably 50g (80-100) mL. In the invention, the particle size of the heat-conducting filler is preferably 1-2 μm.
The process of mixing the heat conductive filler and the alkaline solution is not particularly limited in the present invention, and the raw materials can be uniformly mixed according to a process well known in the art. In the invention, the hydrothermal reaction is preferably carried out in a stainless steel reaction kettle, and the stainless steel reaction kettle is preferably screwed to be airtight, and then the reaction kettle is placed in an oven to carry out the hydrothermal reaction. The stainless steel reaction vessel is not particularly limited in the present invention, and any apparatus known in the art may be used. In the invention, the temperature of the hydrothermal reaction is preferably 150-200 ℃, and more preferably 160-180 ℃; the heat preservation time is preferably 15-30 min, and more preferably 20-25 min. In the hydrothermal reaction process, hydroxyl in the alkaline solution and the surface of the heat-conducting filler are subjected to hydroxylation reaction, so that the surface of the heat-conducting filler is grafted with the hydroxyl, and the subsequent reaction of the hydroxylated heat-conducting filler and the polymer is facilitated. The invention adopts hydrothermal reaction to prepare the hydroxylated heat-conducting filler, can effectively shorten the reaction time and improve the hydroxylation rate of the heat-conducting filler.
After the hydrothermal reaction is finished, the stainless steel reaction kettle is preferably cooled to room temperature, the obtained reaction product is washed for multiple times until the filtrate is neutral, and the hydroxylated heat-conducting filler is obtained after drying. The washing and drying processes are not particularly limited in the present invention and may be performed according to processes well known in the art.
After obtaining the hydroxylated heat-conducting filler, mixing the hydroxylated heat-conducting filler, a dihalo monomer, a diphenol monomer, a catalyst, a reaction solvent and a water-carrying agent, and sequentially carrying out water-carrying and copolymerization reactions to obtain the heat-conducting filler grafted polyarylether; the dihalogen monomer contains an aromatic group. In the present invention, the dihalogen monomer preferably includes 4,4' -difluorobenzophenone, 4' -dichlorodiphenyl sulfone, 4' -difluorodiphenyl sulfone, 1, 3-bis (4-fluorobenzoyl) benzene, 1, 4-bis (4-fluorobenzoyl) benzene, 4' -bis (4-fluorobenzoyl) biphenyl, bis (4-chloro-2-phthalimidophenyl) ether, 1, 4-bis (4-chloro-2-phthalimido) benzene or 1, 3-bis (4-chloro-2-phthalimido) benzene, more preferably 4,4' -difluorobenzophenone, 4' -dichlorodiphenyl sulfone, 4' -difluorodiphenyl sulfone, 1, 3-bis (4-fluorobenzoyl) benzene, 1, 4-bis (4-fluorobenzoyl) benzene or 4,4' -bis (4-fluorobenzoyl) biphenyl; the diphenol monomer preferably comprises 2, 2-bis (4-hydroxyphenyl) propane, 4 '-dihydroxytriphenylmethane-2' -carboxylic acid, 3-bis (4-hydroxyphenyl) -3H-isobenzofuranone, phenol red, 2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcinol, 4 '-biphenyldiol, 4' -dihydroxybenzophenone, 4 '-dihydroxydiphenylsulfone, 4' -dihydroxydiphenylsulfoxide, 4 '-dihydroxydiphenylsulfide or 4,4' -dihydroxydiphenylether, more preferably 2, 2-bis (4-hydroxyphenyl) propane, 4 '-dihydroxytriphenylmethane-2' -carboxylic acid, 3-bis (4-hydroxyphenyl) -3H-isobenzofuranone, 2, 4 '-dihydroxytriphenylmethane-2' -carboxylic acid, 4 '-dihydroxydiphenylsulfone, 4' -dihydroxydiphenylsulfoxide, 4 '-dihydroxydiphenylsulfide or 4,4' -dihydroxydiphenylether, Phenol red, 2-bis (4-hydroxyphenyl) hexafluoropropane, hydroquinone, resorcinol or 4,4' -biphenol; the reaction solvent preferably comprises dimethyl sulfoxide, N-methyl pyrrolidone or sulfolane; the catalyst preferably comprises sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or cesium fluoride; the catalyst preferably adopts a corresponding anhydrous product; the water-carrying agent preferably comprises toluene or xylene.
In the invention, the molar ratio of the dihalogen monomer, the diphenol monomer and the catalyst is preferably 1 (0.98-0.99): (2-2.2), more preferably 1 (0.983-0.986): (2.1-2.15); the mass ratio of the total mass of the dihalogen monomer, the diphenol monomer and the hydroxylated heat-conducting filler to the reaction solvent is preferably (15-20): (80-85), more preferably (16-18): (82-84); the mass ratio of the total mass of the dihalogen monomer and the diphenol monomer to the mass of the hydroxylated heat-conducting filler is preferably (40-80): (20-60), more preferably (50-70): (30-50), more preferably (55-65): (40-55). The invention has no special limit on the dosage of the water-carrying agent, and the sufficient amount of the water-carrying agent is ensured.
The process of mixing the hydroxylated heat-conducting filler, the dihalo monomer, the diphenol monomer, the catalyst, the reaction solvent and the water-carrying agent is not particularly limited, and all the raw materials can be uniformly mixed according to the process known in the art.
After the mixing is finished, the process of sequentially carrying out the water-carrying and copolymerization reaction is preferably that the temperature is continuously raised from room temperature to the reflux temperature of the water-carrying agent until no water is carried out in the system (removing water in the reaction, providing an anhydrous environment and avoiding the occurrence of subsequent side reactions); then, the temperature is firstly increased to be more than or equal to the boiling point of the water-carrying agent, and the water-carrying agent is steamed out in a first heat preservation way; and then the temperature is raised to the copolymerization reaction temperature for the second time, and the copolymerization reaction is carried out by the second heat preservation. In the invention, the temperature for evaporating the water-carrying agent is preferably 160-180 ℃, and more preferably 165-175 ℃; the first heat preservation time is preferably 3-6 hours, and more preferably 4-5 hours. In the invention, the temperature of the copolymerization reaction is preferably 180-200 ℃, and more preferably 185-195 ℃; the second heat preservation time is preferably 4-8 hours, and more preferably 5-6 hours. In the present invention, the temperature increase rates of the temperature increase, the first temperature increase, and the second temperature increase are all preferably 10 ℃/min.
In the copolymerization reaction process, a dihalogen monomer and a diphenol monomer are copolymerized to generate polyarylether, and meanwhile, hydroxyl on the hydroxylated heat-conducting filler reacts with halogen atoms on the dihalogen monomer to form ether bonds (-OH < + > -X → -O- + HX, wherein X is a halogen atom), so that the hydroxylated heat-conducting filler is grafted on the polyarylether. In the present invention, the polyarylether preferably comprises polyaryletherketone, polyarylethersulfone or polyaryletherimide.
After the copolymerization reaction is completed, preferably, the obtained product system is naturally cooled to room temperature and then poured into deionized water, the obtained white filamentous polymer is soaked in the deionized water for 12-24 hours (monomers and some small molecular polymers which do not participate in the reaction are removed), then the obtained product is crushed by a crusher, the crushed product is boiled and washed by distilled water for 8-10 times, and the boiled and washed product is dried to obtain the heat-conducting filler grafted polyarylether. In the invention, the power of the crusher is preferably 1200-2500W; the process of the present invention is not particularly limited, and the crushing may be performed according to a process known in the art. In the invention, the drying is preferably carried out in an oven, the drying temperature is preferably 130-150 ℃, and the drying time is preferably 8-12 h. The particle size of the heat-conducting filler grafted polyarylether is not specially limited, and the heat-conducting filler grafted polyarylether is crushed into smaller particle size according to the process so as to be beneficial to subsequent dissolution.
After the heat-conducting filler grafted polyarylether is obtained, the heat-conducting filler grafted polyarylether is dispersed in a dispersing agent to obtain a dispersion liquid. In the present invention, the dispersant preferably includes N-methylpyrrolidone, N-dimethylacetamide, N-dimethylformamide, tetrahydrofuran, dioxane, dichloromethane, or chloroform. In the invention, the mass ratio of the heat-conducting filler grafted polyarylether to the dispersant is preferably (10-20): 80-90), more preferably (12-18): 82-88, and further preferably (15-16): 85-86.
In the invention, the dispersion is preferably carried out under ultrasonic conditions, the power of the ultrasonic is preferably 250-400W, more preferably 300-350W, and the time is preferably 0.5-2 h, more preferably 1.0-1.5 h; the dispersion is preferably carried out in an ultrasonic cleaning machine.
After the dispersion liquid is obtained, the dispersion liquid is coated on the surface of the polyimide fabric, phase transformation is carried out in water, and the obtained composite is subjected to hot pressing to obtain the heat-conducting filler grafted polyarylether-polyimide composite material. In the present invention, the mass ratio of the dispersion to the polyimide fabric is preferably (9 to 11):0.85, more preferably (9.5 to 10.5):0.85, and still more preferably 10: 0.85. In the present invention, the density of the polyimide fabric is preferably 200g/m2(ii) a The polyimide fabric is preferably available from Shandong Orthon costume, Inc.
In the present invention, the coating mode is preferably dispensing, the rate of dispensing is not particularly limited in the present invention, and the dispensing may be performed by using a process well known in the art, and in the embodiment of the present invention, the dispensing is specifically performed by using a rubber head dropper. The invention fills the dispersion liquid into the structure of the polyimide fabric uniformly by coating. After the coating is finished, the polyimide fabric is preferably immersed in deionized water for 24-48 hours for phase transformation, then the obtained fabric is dried in a common oven at 130 ℃ for 8-12 hours, and then dried in a vacuum oven at 180-220 ℃ for 3-5 hours to obtain the composite. The conventional oven and the vacuum oven are not particularly limited in the present invention, and the conventional oven and the vacuum oven may be selected from apparatuses well known in the art. In the phase transition process, a liquid phase system (the heat-conducting filler grafted polyarylether) of the dispersion liquid is converted into three-dimensional macromolecular network gel of a macromolecular continuous phase, and the three-dimensional macromolecular network gel is used as a heat-conducting network of the heat-conducting property of the composite material to provide a heat-conducting path.
After the compound is obtained, the compound is subjected to hot pressing, the pressure of the hot pressing is preferably 1.5-2.0 MPa, more preferably 1.6-1.8 MPa, the temperature is preferably 250-450 ℃, and more preferably 300-400 ℃. The equipment used for hot pressing is not particularly limited, and equipment well known in the art is selected for hot pressing. In the hot pressing process, the heat-conducting filler grafted polyarylether immersed in the polyimide fabric is fully compounded (physically compounded) with the polyimide under the action of pressure to obtain the composite material.
The invention provides a heat-conducting filler grafted polyarylether-polyimide composite material prepared by the preparation method in the technical scheme, which comprises a polyimide fabric substrate and a heat-conducting polymer filled in the polyimide fabric substrate, wherein the heat-conducting polymer is the heat-conducting filler grafted polyarylether.
According to the invention, hydroxyl groups are grafted on the surface of the heat-conducting filler by adopting a hydrothermal reaction to obtain a hydroxylated heat-conducting filler, then the hydroxylated heat-conducting filler is grafted on the polyarylether polymer, and ether bonds formed by the reaction of the hydroxyl groups on the hydroxylated heat-conducting filler and halogen atoms on a dihalo monomer can effectively promote the transmission speed of phonons, reduce interface scattering and reduce interface thermal resistance, so that the heat conductivity coefficient of the composite material is improved; meanwhile, the polyimide fabric is used as a mechanical reinforcing network, so that the composite material is endowed with good mechanical properties.
The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.