CN117089217A - A kind of preparation method of thermally conductive engineering plastics - Google Patents

Abstract

The invention discloses a heat conduction engineering plastic and a preparation method thereof. The process flow of the heat conduction engineering plastic prepared by the invention is as follows: carboxylation treatment, pretreatment, sintering, ionization, drying, ball milling, hydrogel preparation, aerogel preparation and finished product. When the heat-conducting engineering plastic prepared by the method is heated, air in the modified graphene aerogel is heated and expanded, and the mixed material of copper powder and magnesia powder is extruded, so that the powder is in great contact and series connection, a heat-conducting chain is formed, and the heat conductivity of the engineering plastic is realized; lithium ions in the modified graphene powder on the modified graphene aerogel are heated and dispersed between plastic matrixes, so that the plastic among the heat conducting particles is reduced, the binding property between the filler and the matrixes is increased, the thermal resistance of the machine body is reduced, and the thermal conductivity of the heat conducting engineering plastic is improved.

Description

A kind of preparation method of thermally conductive engineering plastics

Technical field

The invention relates to the technical field of new materials, specifically a preparation method of thermally conductive engineering plastics.

Background technique

There are two ways to improve the thermal conductivity of materials: one is intrinsic thermal conductive plastic, which refers to the material obtained by changing the molecular structure of the material through mechanical processing; due to its complete cleanliness, its thermal conductivity mechanism is mainly It conducts heat through phonons or electrons; the second type is filled thermally conductive plastics, which are composite materials made by using polymer resin as the matrix and adding thermally conductive fillers to the matrix resin; intrinsic thermally conductive composite materials have high The degree of crystallization orientation makes the material more difficult to process. However, the processing technology of filled thermally conductive composite materials is simple and low-cost, and has a wide range of applications. With the development of filled thermally conductive composite materials, people are paying more and more attention to it.

There is a lot of room for improvement in thermal conductivity of thermally conductive engineering plastics currently on the market, and the heat resistance of thermally conductive plastics itself needs to be improved. When the thermally conductive engineering plastic prepared by the present invention is heated, the air in the modified graphene aerogel expands due to heat, and the mixture of copper powder and magnesium oxide powder is squeezed, causing a large number of powders to contact and connect in series to form Thermal conductive chain realizes the thermal conductivity of engineering plastics; the lithium ions in the modified graphene powder on the modified graphene aerogel are heated and dispersed between the plastic matrix, reducing the plastic between the thermally conductive particles and increasing the gap between the filler and the matrix The combination can reduce the thermal resistance of the body itself and improve the thermal conductivity of thermally conductive engineering plastics.

Contents of the invention

The purpose of the present invention is to provide a thermally conductive engineering plastic and a preparation method thereof to solve the problems existing in the prior art.

In order to solve the above technical problems, the present invention provides the following technical solution: a method for preparing thermally conductive engineering plastics, which is characterized in that the process flow for preparing thermally conductive engineering plastics is:

Carboxylation treatment, pretreatment, sintering, ionization, drying, ball milling, hydrogel preparation, aerogel preparation, and finished product.

Further, a method for preparing thermally conductive engineering plastics is characterized by including the following specific steps:

(1) Add graphene microflakes and chloroacetic acid to 37% sodium hydroxide solution, and ultrasonic at a frequency of 40KHz for 2 to 3 hours to prepare carboxylated graphene microflakes;

(2) Soak the carboxylated graphene microsheets in the alkali solution for 1 to 2 hours. While soaking, increase the temperature to 80 to 90°C. After 1 hour of heat preservation, the carboxylated graphene microsheets after alkali leaching are hot-pressed and sintered. The sintering time is 3h, and the pretreated graphene microsheets are obtained;

(3) Add a lithium ion solution with a concentration of 2 mol/L to a 30% polyvinylpyrrolidone ethanol solution; add the pretreated graphene microsheets to a 30% polyvinylpyrrolidone ethanol solution containing lithium ions. The solution is electrified for ionization, the ionization time is 0.5~1h, and the voltage is 220V;

(4) Dry the ionized pretreated graphene microflakes with hot air for 30 to 40 minutes at a temperature of 40 to 50°C to obtain modified graphene microflakes;

(5) Use a rod-type ball mill to crush the modified graphene microflakes, and the ball milling time is 30~40 minutes to obtain modified graphene powder;

(6) Disperse the modified graphene powder in deionized water, add ethylenediamine, and react at 90 to 100°C for 5 to 6 hours to prepare a hydrogel;

(7) Freeze-dry the hydrogel in a freeze-dryer for 40 to 48 hours, and then microwave the freeze-dried product to prepare modified graphene aerogel;

(8) The modified graphene aerogel is dispersed inside the plastic matrix, and a mixture of copper powder and magnesium oxide powder is added to prepare a thermally conductive engineering plastic.

Further, in the above step (1), the mass ratio of graphene microsheets, 37% sodium hydroxide solution and chloroacetic acid is 1:3:0.6~1:3:0.7.

Further, in the above step (2), the alkali solution is 40% sodium hydroxide solution, the heating rate is 5°C/min, during hot press sintering, the sintering pressure is 30~35MPa, and the sintering temperature is 1000~1100°C.

Further, in the above step (3), the mass ratio of the lithium ion solution and the polyvinylpyrrolidone ethanol solution with a mass fraction of 30% is 0.2:1.3~0.4:1.3.

Further, in the above step (6), the mass ratio of modified graphene powder, deionized water and ethylenediamine is 1:9:1.3~1:10:1.5.

Further, in the above step (7), the temperature during freeze-drying is -78~-90°C; during microwave processing, the power is 800W and the processing time is 3~5 minutes.

Further, in the above step (8), the mass ratio of graphene aerogel and plastic matrix is 2:31~5:78; the mass ratio of copper powder and magnesium oxide powder is 2:3~2:4; plastic The mass ratio of the matrix to the mixture of copper powder and magnesium oxide powder is 37:7~37:10, and the plastic matrix is liquid epoxy resin.

Further, the thermally conductive engineering plastic prepared by the preparation method of thermally conductive engineering plastics includes the following parts by weight of raw materials: 100 to 130 parts of plastic matrix, 15 to 20 parts of modified graphene aerogel, and 25 to 30 parts of copper. The powder is mixed with magnesium oxide powder, and the plastic matrix is liquid epoxy resin.

Compared with the prior art, the beneficial effects achieved by the present invention are:

In the present invention, carboxylated graphene microchips are obtained by subjecting graphene microchips to carboxylation treatment. The carboxylated graphene microchips are first alkali-leached, heated while alkali-leaching, and then the carboxylated graphene microchips after alkali-leaching are The microchips are hot-pressed and sintered at high temperature to prepare pretreated graphene microchips; the pretreated graphene microchips are soaked in a polyvinylpyrrolidone ethanol solution containing lithium ions with a mass fraction of 30%, and then immersed in a polyvinylpyrrolidone ethanol solution with a mass fraction of 30%. % polyvinylpyrrolidone ethanol solution is electrified and ionized, and then dried for a period of time to obtain modified graphene microsheets; the carboxylation treatment of the graphene microsheets makes the surface of the graphene microsheets contain a large number of oxygen-containing functional groups, which increases While the graphene microflakes are dispersible in the alkali leaching solution, the surface activity of the graphene microflakes is increased; the alkali leaching increases the activity of the surface of the carboxylated graphene microflakes and contains a large number of free highly active hydroxyl radicals. ions, heating increases the activity of hydroxyl ions in alkaline solution and reduces the action time of alkali solution on carboxylated graphene microflakes; during hot-pressing sintering, a large number of hydroxyl ions affect the carboxylated graphene after alkali leaching. The microchips are eroded, taking away the hydrogen ions on the carboxylated graphene microchips under high temperature and high pressure, making the carboxylated graphene microchips dense in structure and reducing the bonding degree between the carboxylated graphene microchips; during ionization, Lithium ions are intercalated between the pre-treated graphene sheets and in the micropores under the action of electric current, making the pre-treated graphene micro-sheets have a positive charge and increasing the dispersion performance in the plastic matrix.

Modified graphene powder is obtained by ball milling the modified graphene microflakes. The modified graphene powder is dispersed in deionized water and washed, and then reacted with ethylenediamine to prepare a hydrogel. The hydrogel is freeze-dried. Perform microwave operation to prepare modified graphene aerogel; disperse the modified graphene aerogel inside the plastic matrix, add a mixture of copper powder and magnesium oxide powder to prepare a thermally conductive engineering plastic; disperse it in deionized The stability of modified graphene powder in water gradually decreases. As the stability weakens and the interaction between modified graphene powders increases, the modified graphene powder begins to slowly cross-link to form a hydrogel; it is removed by freeze-drying. By removing the solvent in the hydrogel, microwave operation not only removes other heteroatoms, but also enhances the interaction between the modified graphene powder and improves the stability of the modified graphene aerogel; modified graphene aerogel Dispersed inside the plastic matrix, when the matrix is heated, the air in the modified graphene aerogel expands due to heat, squeezing the mixture of copper powder and magnesium oxide powder, causing a large amount of contact between the powders and connecting them in series to form a thermal conductivity chain to achieve thermal conductivity of engineering plastics; the lithium ions in the modified graphene powder on the modified graphene aerogel are heated and dispersed between the plastic matrix, reducing the plastic between the thermally conductive particles and increasing the distance between the filler and the matrix. Combinability, thereby reducing the thermal resistance of the body itself and improving the thermal conductivity of thermally conductive engineering plastics.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

In order to explain the method provided by the present invention in detail through the following examples, the test methods for various indicators of the thermally conductive engineering plastics produced in the following examples are as follows:

Thermal conductivity: Use the transient plane heat source method ISO22007-2 to conduct thermal conductivity tests on the thermal conductive engineering plastics obtained in Example 1, Example 2 and Comparative Example 1 and Comparative Example 2. The higher the thermal conductivity, the greater the thermal conductivity of the material. Details See Table 1.

Example 1

A thermally conductive engineering plastic mainly includes: 100 parts of liquid resin, 15 parts of modified graphene aerogel, and 25 parts of copper powder and magnesium oxide powder mixture.

A preparation method of thermally conductive engineering plastics. The preparation method of thermally conductive engineering plastics mainly includes the following preparation steps:

(1) Add graphene microflakes and chloroacetic acid to 37% sodium hydroxide solution, and ultrasonic for 2 hours at a frequency of 40KHz. The mass ratio of graphene microflakes, 37% sodium hydroxide solution and chloroacetic acid is 1:3:0.6. Preparation of carboxylated graphene microsheets;

(2) Soak the carboxylated graphene microsheets in 40% sodium hydroxide solution for 1 hour. While soaking, increase the temperature to 80°C at a heating rate of 5°C/min. After 1 hour of heat preservation, the carboxylated graphene after alkali leaching will be treated. The graphene microsheets are hot-pressed and sintered at a sintering pressure of 30MPa, a sintering temperature of 1000°C, and a sintering time of 3 hours to obtain pretreated graphene microsheets;

(3) Add a lithium ion solution with a concentration of 2 mol/L to a 30% polyvinylpyrrolidone ethanol solution; add the pretreated graphene microsheets to a 30% polyvinylpyrrolidone ethanol solution containing lithium ions. The solution is ionized by electricity. The mass ratio of the lithium ion solution and the polyvinylpyrrolidone ethanol solution with a mass fraction of 30% is 0.2:1.3, the ionization time is 0.5h, and the voltage is 220V;

(4) Dry the ionized pretreated graphene microflakes with hot air for 30 minutes at a temperature of 40°C to obtain modified graphene microflakes;

(5) Use a rod-type ball mill to crush the modified graphene microflakes, and the ball milling time is 30 minutes to obtain modified graphene powder;

(6) Disperse the modified graphene powder in deionized water, add ethylenediamine, the mass ratio of modified graphene powder, deionized water and ethylenediamine is 1:9:1.3, react at 90°C for 5 hours. Prepare hydrogel;

(7) Freeze-dry the hydrogel in a freeze-drying machine for 40 hours. The temperature during freeze-drying is -78°C. Then the freeze-dried product is subjected to microwave processing with a power of 800W and a processing time of 3 minutes to obtain modified graphene. aerogel;

(8) Disperse the modified graphene aerogel inside the liquid resin. The mass ratio of the graphene aerogel to the liquid resin is 2:31. Add the mixture of copper powder and magnesium oxide powder and disperse it evenly to obtain a thermal conductor. Engineering plastics; the mass ratio of copper powder to magnesium oxide powder is 2:3; the mass ratio of liquid resin to copper powder and magnesium oxide powder mixture is 37:7.

Example 2

A thermally conductive engineering plastic mainly includes: 130 parts of liquid resin, 20 parts of modified graphene aerogel, and 30 parts of copper powder and magnesium oxide powder mixture.

A preparation method of thermally conductive engineering plastics. The preparation method of thermally conductive engineering plastics mainly includes the following preparation steps:

(1) Add graphene microflakes and chloroacetic acid to 37% sodium hydroxide solution, and ultrasonic for 3 hours at a frequency of 40KHz. The mass ratio of graphene microflakes, 37% sodium hydroxide solution and chloroacetic acid is 1:3:0.7. Preparation of carboxylated graphene microsheets;

(2) Soak the carboxylated graphene microsheets in 40% sodium hydroxide solution for 2 hours. While soaking, increase the temperature to 90°C at a heating rate of 5°C/min. After 1 hour of heat preservation, the carboxylated graphene after alkali leaching will be treated. The graphene microsheets are hot-pressed and sintered at a sintering pressure of 35MPa, a sintering temperature of 1100°C, and a sintering time of 3 hours to obtain pretreated graphene microsheets;

(3) Add a lithium ion solution with a concentration of 2 mol/L to a 30% polyvinylpyrrolidone ethanol solution; add the pretreated graphene microsheets to a 30% polyvinylpyrrolidone ethanol solution containing lithium ions. The solution is ionized by electricity. The mass ratio of the lithium ion solution and the polyvinylpyrrolidone ethanol solution with a mass fraction of 30% is 0.4:1.3. The ionization time is 1 hour and the voltage is 220V;

(4) Dry the ionized pretreated graphene microsheets with hot air for 40 minutes at a temperature of 50°C to obtain modified graphene microsheets;

(5) Use a rod-type ball mill to crush the modified graphene microflakes, and the ball milling time is 40 minutes to obtain modified graphene powder;

(6) Disperse the modified graphene powder in deionized water, add ethylenediamine, the mass ratio of modified graphene powder, deionized water and ethylenediamine is 1:10:1.5, react at 100°C for 6 hours, Prepare hydrogel;

(7) Freeze-dry the hydrogel in a freeze-drying machine for 48 hours. The temperature during freeze-drying is -90°C. Then the freeze-dried product is subjected to microwave processing with a power of 800W and a processing time of 5 minutes to obtain modified graphene. aerogel;

(8) Disperse the modified graphene aerogel inside the liquid resin. The mass ratio of the graphene aerogel to the liquid resin is 5:78. Add the mixture of copper powder and magnesium oxide powder and disperse it evenly to obtain a thermal conductivity. Engineering plastics; the mass ratio of copper powder to magnesium oxide powder is 2:4; the mass ratio of liquid resin to copper powder and magnesium oxide powder mixture is 37:10.

Comparative example 1

A thermally conductive engineering plastic mainly includes: 100 parts of liquid resin, 15 parts of modified graphene aerogel, and 25 parts of copper powder and magnesium oxide powder mixture.

A preparation method of thermally conductive engineering plastics. The preparation method of thermally conductive engineering plastics mainly includes the following preparation steps:

(1) Add graphene microflakes and chloroacetic acid to 37% sodium hydroxide solution, and ultrasonic for 2 hours at a frequency of 40KHz. The mass ratio of graphene microflakes, 37% sodium hydroxide solution and chloroacetic acid is 1:3:0.6. Preparation of carboxylated graphene microsheets;

(2) Soak the carboxylated graphene microsheets in 40% sodium hydroxide solution for 1 hour. While soaking, increase the temperature to 80°C at a heating rate of 5°C/min. After 1 hour of heat preservation, the carboxylated graphene after alkali leaching will be treated. The graphene microsheets are hot-pressed and sintered at a sintering pressure of 30MPa, a sintering temperature of 1000°C, and a sintering time of 3 hours to obtain pretreated graphene microsheets;

(3) Add a lithium ion solution with a concentration of 2 mol/L to a 30% polyvinylpyrrolidone ethanol solution; add the pretreated graphene microsheets to a 30% polyvinylpyrrolidone ethanol solution containing lithium ions. The solution is ionized by electricity. The mass ratio of the lithium ion solution and the polyvinylpyrrolidone ethanol solution with a mass fraction of 30% is 0.2:1.3, the ionization time is 0.5h, and the voltage is 220V;

(4) Use a rod-type ball mill to crush the ionized pre-treated graphene microflakes, and grind for 30 minutes to obtain modified graphene powder;

(5) Disperse the modified graphene powder in deionized water, add ethylenediamine, the mass ratio of modified graphene powder, deionized water and ethylenediamine is 1:9:1.3, react at 90°C for 5 hours. Prepare hydrogel;

(6) Freeze-dry the hydrogel in a freeze-drying machine for 40 hours. The temperature during freeze-drying is -78°C. Then the freeze-dried product is subjected to microwave processing with a power of 800W and a processing time of 3 minutes to obtain modified graphene. aerogel;

(7) Disperse the modified graphene aerogel inside the liquid resin. The mass ratio of the graphene aerogel to the liquid resin is 2:31. Add the mixture of copper powder and magnesium oxide powder and disperse it evenly to obtain a thermal conductivity. Engineering plastics; the mass ratio of copper powder to magnesium oxide powder is 2:3; the mass ratio of liquid resin to copper powder and magnesium oxide powder mixture is 37:7.

Comparative example 2

A thermally conductive engineering plastic mainly includes: 100 parts of liquid resin, 15 parts of modified graphene powder, 25 parts of copper powder and magnesium oxide powder mixture in parts by weight.

A preparation method of thermally conductive engineering plastics. The preparation method of thermally conductive engineering plastics mainly includes the following preparation steps:

(1) Add graphene microflakes and chloroacetic acid to 37% sodium hydroxide solution, and ultrasonic for 2 hours at a frequency of 40KHz. The mass ratio of graphene microflakes, 37% sodium hydroxide solution and chloroacetic acid is 1:3:0.6. Preparation of carboxylated graphene microsheets;

(2) Soak the carboxylated graphene microsheets in 40% sodium hydroxide solution for 1 hour. While soaking, increase the temperature to 80°C at a heating rate of 5°C/min. After 1 hour of heat preservation, the carboxylated graphene after alkali leaching will be treated. The graphene microsheets are hot-pressed and sintered at a sintering pressure of 30MPa, a sintering temperature of 1000°C, and a sintering time of 3 hours to obtain pretreated graphene microsheets;

(3) Add a lithium ion solution with a concentration of 2 mol/L to a 30% polyvinylpyrrolidone ethanol solution; add the pretreated graphene microsheets to a 30% polyvinylpyrrolidone ethanol solution containing lithium ions. The solution is ionized by electricity. The mass ratio of the lithium ion solution and the polyvinylpyrrolidone ethanol solution with a mass fraction of 30% is 0.2:1.3, the ionization time is 0.5h, and the voltage is 220V;

(4) Dry the ionized pretreated graphene microflakes with hot air for 30 minutes at a temperature of 40°C to obtain modified graphene microflakes;

(5) Use a rod-type ball mill to crush the modified graphene microflakes, and the ball milling time is 30 minutes to obtain modified graphene powder;

(6) Disperse the modified graphene powder inside the liquid resin. The mass ratio of the graphene powder to the liquid resin is 2:31. Add the mixture of copper powder and magnesium oxide powder and disperse it evenly to prepare a thermally conductive engineering plastic; copper The mass ratio of powder to magnesium oxide powder is 2:3; the mass ratio of liquid resin to copper powder and magnesium oxide powder mixture is 37:7.

Effect example

Table 1 below shows the analysis results of thermal conductivity properties of thermally conductive engineering plastics obtained using the components of Example 1, Example 2 and Comparative Examples 1 and 2 of the present invention.

Table 1

Example 1 Example 2 Comparative example 1 Comparative example 2 Thermal conductivity W/(m·K) 758 741 493 421

Thermal conductivity is one of the most important thermal and moisture physical parameters of building materials. As can be seen from the table above, compared to the thermally conductive engineering plastics of Example 2, Comparative Example 1 and Comparative Example 2, the thermally conductive engineering plastics of Example 1 exhibit better thermal conductivity, indicating that the modified graphene aerogel Dispersed inside the plastic matrix, when the matrix is heated, the air in the modified graphene aerogel expands due to heat, squeezing the mixture of copper powder and magnesium oxide powder, causing a large amount of contact between the powders and connecting them in series to form Thermal conductive chain realizes the thermal conductivity of engineering plastics; the lithium ions in the modified graphene powder on the modified graphene aerogel are heated and dispersed between the plastic matrix, reducing the plastic between the thermally conductive particles and increasing the gap between the filler and the matrix The combination can reduce the thermal resistance of the body itself and improve the thermal conductivity of thermally conductive engineering plastics.

It is obvious to those skilled in the art that the present invention is not limited to the details of the above-described exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, the embodiments should be regarded as illustrative and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is therefore intended that all claims falling within the claims All changes within the meaning and scope of equivalent elements are included in the present invention. Any reference signs in a claim shall not be construed as limiting the claim in question.

Claims (1)

1. A method for preparing thermally conductive engineering plastics, which is characterized in that: it mainly includes the following preparation steps: (1) Add graphene microflakes and chloroacetic acid to 37% sodium hydroxide solution, and ultrasonic for 2 hours at a frequency of 40KHz. The mass ratio of graphene microflakes, 37% sodium hydroxide solution and chloroacetic acid is 1:3:0.6. Preparation of carboxylated graphene microsheets; (2) Soak the carboxylated graphene microsheets in 40% sodium hydroxide solution for 1 hour. While soaking, increase the temperature to 80°C at a heating rate of 5°C/min. After 1 hour of heat preservation, the carboxylated graphene after alkali leaching will be treated. The graphene microsheets are hot-pressed and sintered at a sintering pressure of 30MPa, a sintering temperature of 1000°C, and a sintering time of 3 hours to obtain pretreated graphene microsheets; (3) Add a lithium ion solution with a concentration of 2 mol/L to a 30% polyvinylpyrrolidone ethanol solution; add the pretreated graphene microsheets to a 30% polyvinylpyrrolidone ethanol solution containing lithium ions. The solution is ionized by electricity. The mass ratio of the lithium ion solution and the polyvinylpyrrolidone ethanol solution with a mass fraction of 30% is 0.2:1.3, the ionization time is 0.5h, and the voltage is 220V; (4) Dry the ionized pretreated graphene microflakes with hot air for 30 minutes at a temperature of 40°C to obtain modified graphene microflakes; (5) Use a rod-type ball mill to crush the modified graphene microflakes, and the ball milling time is 30 minutes to obtain modified graphene powder; (6) Disperse the modified graphene powder in deionized water, add ethylenediamine, the mass ratio of modified graphene powder, deionized water and ethylenediamine is 1:9:1.3, react at 90°C for 5 hours. Prepare hydrogel; (7) Freeze-dry the hydrogel in a freeze-drying machine for 40 hours. The temperature during freeze-drying is -78°C. Then the freeze-dried product is subjected to microwave processing with a power of 800W and a processing time of 3 minutes to obtain modified graphene. aerogel; (8) Disperse the modified graphene aerogel inside the liquid resin. The mass ratio of the graphene aerogel to the liquid resin is 2:31. Add the mixture of copper powder and magnesium oxide powder and disperse it evenly to obtain a thermal conductor. Engineering plastics; the mass ratio of copper powder to magnesium oxide powder is 2:3; the mass ratio of liquid resin to copper powder and magnesium oxide powder mixture is 37:7.