阅读说明：本技术 一种氮化硼氧化石墨烯聚酰亚胺复合材料的制备方法 (Preparation method of boron nitride graphene oxide polyimide composite material ) 是由 周雨薇 于 2021-09-02 设计创作，主要内容包括：本发明涉及一种氮化硼氧化石墨烯聚酰亚胺复合材料的制备方法。该复合材料的制备方法为先通过化学氧化法制备氧化石墨烯,同时通过水热法将微米氮化硼制备成氮化硼纳米片,利用氮化硼和氧化石墨烯之间的π-π相互作用制备了导热绝缘复合填料,向复合填料的N,N-二甲基乙酰胺中加入二元胺的四羧酸二酸酐单体,原位制备聚酰胺酸,最后将添加有氮化硼氧化石墨烯复合填料的聚酰胺酸溶液烘干溶剂后高温脱水亚胺化得到氮化硼氧化石墨烯聚酰亚胺复合材料。本发明通过同时调控氮化硼与氧化石墨烯的比例调控填料粒子的微观结构,从而调控复合材料的导热性能,本发明所制备得到的复合材料热导率大于0.6W/mK,电阻率大于1×10～(11)Ωm。(The invention relates to a preparation method of a boron nitride graphene oxide polyimide composite material. The preparation method of the composite material comprises the steps of firstly preparing graphene oxide by a chemical oxidation method, simultaneously preparing boron nitride nanosheets from micron boron nitride by a hydrothermal method, preparing the heat-conducting and insulating composite filler by utilizing pi-pi interaction between the boron nitride and the graphene oxide, adding tetracarboxylic dianhydride monomer of diamine into N, N-dimethylacetamide of the composite filler, preparing polyamic acid in situ, and finally drying a solvent of polyamic acid solution added with the boron nitride-graphene oxide composite filler, and then dehydrating and imidizing at high temperature to obtain the boron nitride-graphene oxide polyimide composite material. The microstructure of the filler particles is regulated and controlled by simultaneously regulating and controlling the proportion of the boron nitride and the graphene oxide, so that the composite material is regulated and controlledThe thermal conductivity of the material, the thermal conductivity of the composite material prepared by the invention is more than 0.6W/mK, and the resistivity is more than 1 x 10 11 Ωm。)

1. A preparation method of a boron nitride graphene oxide polyimide composite material is characterized by comprising the following steps: the preparation method comprises the following steps:

(1) adding flake graphite, concentrated sulfuric acid and concentrated phosphoric acid into a flask, mechanically stirring at 100-400 r/min, adding potassium permanganate into the system while stirring, continuously stirring for 10-40 min after the addition is finished, then placing the system into a water bath at 40-80 ℃, stirring at the speed of 200-1000 r/min for reaction for 8-16 h, and pouring a mixed solution obtained after the reaction into a reaction kettle, wherein the volume ratio of the mixed solution to the concentrated sulfuric acid is 1: 1, stirring for 3-10 min at a stirring speed of 30-200 r/min, adding 30% of hydrogen peroxide into the system while stirring until the mixed solution turns golden yellow, standing the mixed solution for 8-30 h, pouring out the supernatant, washing the turbid solution below with deionized water again, centrifuging until the pH value is 5.5-7.0, and finally obtaining graphene oxide by a freeze drying method; wherein the dosage ratio of the flake graphite, the potassium permanganate, the concentrated sulfuric acid and the concentrated phosphoric acid is 1 g: 5-10 g: 100-200 mL: 10-20 mL;

(2) dispersing commercially available micron boron nitride in 2-10 mol/L sodium hydroxide solution to prepare 2-10 g/L dispersion, placing the dispersion in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W for 2-10 h, transferring the dispersion to a hydrothermal kettle, reacting at 130-180 ℃ for 4-12 h, naturally cooling to room temperature after the reaction is finished, washing the product to be neutral with deionized water, and placing the product in a vacuum oven at 60 ℃ for drying for 2-10 h to obtain boron nitride nanosheets;

(3) mixing graphene oxide and boron nitride nanosheets according to a mass ratio of 1: 3-10, adding the mixture into N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2-10 hours in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W at room temperature to obtain the boron nitride graphene oxide filler, wherein the concentration of the graphene oxide is 0.1-0.5 wt%;

(4) under the protection of nitrogen atmosphere, adding a diamine monomer into the system in the step (3), then adding tetracarboxylic dianhydride in 0.5-1 h, stirring and reacting for 8-16 h at room temperature to obtain a mixed solution of boron nitride graphene oxide polyamic acid, wherein the diamine is more than one of p-phenylenediamine, 4,4 '-diaminodiphenyl ether, 4, 4' -diaminophenylsulfone and 4,4 '-diaminodiphenylmethane, the tetracarboxylic dianhydride is more than one of pyromellitic dianhydride, 4, 4' -biphenyltetracarboxylic anhydride and 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride, and the molar ratio of the diamine to the tetracarboxylic dianhydride is 1: 1, the concentration of diamine is 0.1-0.5 mol/L;

(5) and (4) casting the mixed solution obtained in the step (4) on a glass plate, drying in an oven at 120-180 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 280-330 ℃ for 1-3 h, naturally cooling to room temperature, and stripping the sample from the glass plate to obtain the composite film.

Technical Field

The invention relates to a preparation method of a boron nitride graphene oxide polyimide composite material, and belongs to the field of heat-conducting composite materials.

Background

Polyimide (PI) refers to a high-performance engineering plastic containing imide ring (-CO-N-CO-) in the main chain. Polyimide can be widely applied to the fields of aerospace, microelectronics, lithium ion battery separation membranes and the like, mainly because the high temperature resistance of polyimide can reach more than 400 ℃, and the polyimide has extremely long service life in the temperature range of-200 ℃ to 300 ℃, and due to the advantages, the polyimide is called as one of polymer materials with optimal comprehensive performance in engineering plastics. In addition, the polyimide is simple in synthesis method and excellent in performance, can be produced in batches in actual production, keeps the optimal performance, and is considered as engineering plastic with the optimal application prospect in the 21 st century.

In order to make the polyimide be better applied in the field of heat-conducting insulating materials, the key point for solving the problem is to add high-performance filler into a polyimide matrix, the method combines the high heat-conducting property and the thermal stability of the filler, keeps the excellent heat resistance, dielectric property and flexibility of the polyimide, and the obtained polyimide/filler composite material has excellent comprehensive performance. Boron nitride is a typical two-dimensional ceramic material because of its similar interlayer structure to graphene, also known as "white graphite". Boron nitride has excellent insulating properties, high thermal conductivity, excellent mechanical properties, and corrosion resistance. Graphene is also a two-dimensional material with high thermal conductivity, and graphene oxide, as a derivative of graphene, is connected with a large number of oxygen-containing groups on the sheet layer while a honeycomb two-dimensional planar structure is kept, so that the graphene oxide has better chemical activity and solubility. According to the invention, the heat conduction and insulation properties of the polyimide-based composite material are improved by introducing high-heat-conduction particle hexagonal boron nitride and graphene oxide. Due to the similar interlayer structure of the boron nitride and the graphene oxide, pi-pi interaction exists between the two layers, the combination is easier, and the interface thermal resistance is lower.

Disclosure of Invention

The invention aims to solve the problems that the existing polyimide has poor heat-conducting property and the electric conductivity of the polyimide is increased after the conductive filler or graphene and other fillers are added, and provides a preparation method of a boron nitride-graphene oxide polyimide composite material. The preparation method specifically comprises the steps of firstly preparing graphene oxide by a chemical oxidation method, simultaneously preparing boron nitride nanosheets from micron boron nitride by a hydrothermal method, preparing a heat-conducting and insulating composite filler by utilizing pi-pi interaction between the boron nitride and the graphene oxide, adding a tetracarboxylic acid dianhydride monomer of diamine into N, N-dimethylacetamide of the composite filler, preparing polyamic acid in situ, and finally drying a solvent in a polyamic acid solution added with the boron nitride-graphene oxide composite filler, and then dehydrating and imidizing at high temperature to obtain the boron nitride-graphene oxide polyimide composite material.

The preparation method of the boron nitride graphene oxide polyimide composite material is characterized by comprising the following steps of: the preparation method comprises the following steps:

(1) adding flake graphite, concentrated sulfuric acid and concentrated phosphoric acid into a flask, mechanically stirring at 100-400 r/min, adding potassium permanganate into the system while stirring, continuously stirring for 10-40 min after the addition is finished, then placing the system into a water bath at 40-80 ℃, stirring at the speed of 200-1000 r/min for reaction for 8-16 h, and pouring a mixed solution obtained after the reaction into a reaction kettle, wherein the volume ratio of the mixed solution to the concentrated sulfuric acid is 1: 1, stirring for 3-10 min at a stirring speed of 30-200 r/min, adding 30% of hydrogen peroxide into the system while stirring until the mixed solution turns golden yellow, standing the mixed solution for 8-30 h, pouring out the supernatant, washing the turbid solution below with deionized water again, centrifuging until the pH value is 5.5-7.0, and finally obtaining graphene oxide by a freeze drying method; wherein the dosage ratio of the flake graphite, the potassium permanganate, the concentrated sulfuric acid and the concentrated phosphoric acid is 1 g: 5-10 g: 100-200 mL: 10-20 mL;

(2) dispersing commercially available micron boron nitride in 2-10 mol/L sodium hydroxide solution to prepare 2-10 g/L dispersion, placing the dispersion in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W for 2-10 h, transferring the dispersion to a hydrothermal kettle, reacting at 130-180 ℃ for 4-12 h, naturally cooling to room temperature after the reaction is finished, washing the product to be neutral with deionized water, and placing the product in a vacuum oven at 60 ℃ for drying for 2-10 h to obtain boron nitride nanosheets;

(3) mixing graphene oxide and boron nitride nanosheets according to a mass ratio of 1: 3-10, adding the mixture into N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2-10 hours in an ultrasonic bath with oscillation frequency of 26kHz and output power of 100-500W at room temperature to obtain the boron nitride graphene oxide filler, wherein the concentration of the graphene oxide is 0.1-0.5 wt%;

(4) under the protection of nitrogen atmosphere, adding a diamine monomer into the system in the step (3), then adding tetracarboxylic dianhydride in 0.5-1 h, stirring and reacting for 8-16 h at room temperature to obtain a mixed solution of boron nitride graphene oxide polyamic acid, wherein the diamine is more than one of p-phenylenediamine, 4,4 '-diaminodiphenyl ether, 4, 4' -diaminophenylsulfone and 4,4 '-diaminodiphenylmethane, the tetracarboxylic dianhydride is more than one of pyromellitic dianhydride, 4, 4' -biphenyltetracarboxylic anhydride and 3,3 ', 4, 4' -benzophenonetetracarboxylic dianhydride, and the molar ratio of the diamine to the tetracarboxylic dianhydride is 1: 1, the concentration of diamine is 0.1-0.5 mol/L;

(5) and (4) casting the mixed solution obtained in the step (4) on a glass plate, drying in an oven at 120-180 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 280-330 ℃ for 1-3 h, naturally cooling to room temperature, and stripping the sample from the glass plate to obtain the composite film.

The invention has the beneficial effects that: according to the invention, boron nitride and graphene oxide are added simultaneously, so that boron nitride is coated on graphene oxide, a heat conduction path is constructed, an insulating layer is formed, the increase of the electrical conductivity of the system is prevented, the boron nitride-graphene oxide composite filler is formed, the composite filler is added into polyimide by an in-situ dispersion method to prepare the composite material, and the finally obtained composite material has adjustable heat conductivity and electrical resistivity by regulating the proportion of the fillers. The thermal conductivity of the composite material prepared by the invention is more than 0.6W/mK, and the resistivity is more than 1 x 10¹¹Ωm。

Drawings

FIG. 1 is a schematic diagram of preparation of boron nitride graphene oxide composite filler

Detailed Description

The following examples of the preparation process of the present invention are presented, but the following examples are illustrative of the present invention and do not constitute any limitation to the claims of the present invention.

Example 1

(1) Adding 1.5g of flake graphite, 180mL of concentrated sulfuric acid and 20mL of concentrated phosphoric acid into a 500mL three-neck flask, mechanically stirring at 120r/min, adding 9g of potassium permanganate into the system while stirring, continuously stirring for 30min after the addition is finished, then placing the system into a water bath at 50 ℃ to stir and react for 12h at the speed of 600r/min, and pouring a mixed solution obtained after the reaction into a reaction kettle, wherein the volume ratio of the mixed solution to the concentrated sulfuric acid is 1: 1, stirring for 5min at a stirring speed of 60r/min, adding 30% of hydrogen peroxide into the system while stirring until the mixed solution turns golden yellow, standing the mixed solution for 20h, then pouring out the supernatant, washing the turbid solution below with deionized water again, centrifuging until the pH value is 6, and finally obtaining graphene oxide by a freeze-drying method;

(2) dispersing commercially available micron boron nitride in 5mol/L sodium hydroxide solution to prepare 4g/L dispersion, placing the dispersion in an ultrasonic bath with oscillation frequency of 26kHz and output power of 500W for 2h, transferring the dispersion to a hydrothermal kettle, reacting for 6h at 150 ℃, naturally cooling to room temperature after the reaction is finished, washing the product to be neutral by deionized water, and placing the product in a vacuum oven at 60 ℃ for drying for 8h to obtain boron nitride nanosheets;

(3) adding 0.1g of graphene oxide and 0.5g of boron nitride into 100g of N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2h at room temperature in an ultrasonic bath with oscillation frequency of 26kHz and output power of 500W to obtain boron nitride graphene oxide filler;

(4) under the protection of nitrogen atmosphere, adding 2.1g of 4, 4' -diaminodiphenyl ether into the system in the step (4), then adding 2.3g of pyromellitic anhydride within 0.5h, and stirring and reacting for 12h at room temperature to obtain a mixed solution of boron nitride graphene oxide polyamic acid;

(5) casting the mixed solution obtained in the step (5) on a glass plate, drying in an oven at 150 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 300 ℃ for 2h, naturally cooling to room temperature, stripping a sample from the glass plate to obtain the composite material, wherein the thermal conductivity of the composite material reaches 0.6W/mK, and the resistance is 2.0 multiplied by 10¹¹Ωm。

Example 2

(1) In accordance with example 1, step (1);

(2) in accordance with example 1, step (2); (ii) a

(3) Adding 0.1g of graphene oxide and 5g of boron nitride into 100g of N, N-dimethylacetamide, and carrying out ultrasonic treatment for 2h in an ultrasonic bath with oscillation frequency of 26kHz and output power of 500W at room temperature to obtain boron nitride graphene oxide filler;

(4) in accordance with step (4) of example 1;

(5) in accordance with example 1, step (5); the thermal conductivity of the composite material reaches 0.7W/mK, and the resistance is 2.5 multiplied by 10¹¹Ωm。

Example 3

(1) In accordance with example 1, step (1);

(2) in accordance with example 1, step (2);

(3) in accordance with example 1, step (3);

(4) under the protection of nitrogen atmosphere, 4.2g of 4, 4' -diaminodiphenyl ether is added into the system in the step (4), 4.6g of pyromellitic anhydride is added within 0.5h, and the mixture is stirred and reacted for 12h at room temperature to obtain a mixed solution of boron nitride graphene oxide polyamic acid;

(5) consistent with the step (5) of the example 1, the thermal conductivity of the composite material reaches 0.6W/mK, and the electric resistance is 1.8 multiplied by 10¹¹Ωm。

Example 4

(1) In accordance with example 1, step (1);

(2) in accordance with example 1, step (2);

(3) in accordance with example 1, step (3);

(4) under the protection of nitrogen atmosphere, adding 2.6g of 4, 4' -diamino phenylsulfone into the system in the step (4), then adding 2.3g of pyromellitic dianhydride within 0.5h, and stirring and reacting at room temperature for 12h to obtain a mixed solution of boron nitride graphene oxide polyamic acid;

(5) consistent with the step (5) of the example 1, the thermal conductivity of the composite material reaches 0.6W/mK, and the electric resistance is 2.0 multiplied by 10¹¹Ωm。

Example 5

(1) In accordance with example 1, step (1);

(2) in accordance with example 1, step (2);

(3) in accordance with example 1, step (3);

(4) in accordance with step (4) of example 1;

(5) casting the mixed solution obtained in the step (4) on a glass plate, drying in an oven at 160 ℃ until the solvent is completely volatilized, then placing in a muffle furnace, preserving the heat at 280 ℃ for 3h, naturally cooling to room temperature, stripping a sample from the glass plate to obtain the composite material, wherein the thermal conductivity of the composite material reaches 0.6W/mK, and the resistance is 2.0 multiplied by 10¹¹Ωm。