A low thermal conductivity polyetheretherketone composite material and its preparation method

Abstract

The present invention discloses a low-thermal-conductivity polyether ether ketone composite material and a preparation method thereof. In the present invention, a nucleating agent and a foaming agent solution are added to polyether ether ketone powder, and after being stirred and evenly mixed, the foamed polyether ether ketone powder is obtained through drying; the foaming agent solution can evenly disperse the foaming agent in the polyether ether ketone powder, and the nucleating agent increases the number of cell pores, which is beneficial to the formation of polyether ether ketone with smaller and more numerous cell pores; the polyether ether ketone foam material prepared by the present invention has a relatively high porosity, with the porosity reaching 20% - 80%; the average cell pore diameter is 50 - 300 μm, and it has a low thermal conductivity, with the thermal conductivity being less than 0.2 W / (m·K).

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a low-thermal-conductivity polyether ether ketone composite material and a preparation method thereof. Background Art

[0002] Polyether ether ketone is a linear aromatic high molecular compound. As a semi-crystalline special polymer material, due to the rigid benzene ring, flexible ether bond and carbonyl group that enhances intermolecular force on the molecular chain, it has a regular structure and has outstanding advantages such as high temperature resistance (the heat distortion temperature under load is as high as 316 °C), chemical reagent erosion resistance, radiation resistance, high strength, and high fracture toughness, and has been widely used in high-speed rail transit systems, weapon systems, aerospace, and some high-end civilian fields. However, when the polyether ether ketone material is applied to some heat insulation devices, its thermal conductivity is relatively high (0.46 W / (m·K)), which will cause the heat of the device to dissipate quickly and the heat insulation effect is not obvious. Therefore, it is urgent to study low-thermal-conductivity polyether ether ketone materials to expand their applications in the field of heat insulation materials.

[0003] Constructing foam materials is an ideal way to reduce the thermal conductivity of materials. Foam materials are composed of an external skeleton and an internal porous structure. The large number of closed-cell structures formed inside can effectively increase the interfacial thermal resistance and greatly reduce the thermal conductivity of the materials. As a special polymer material with excellent properties, the too-high melting point (higher than 340 °C) of polyether ether ketone limits its application in the preparation of foam materials. At present, there is little research on polyether ether ketone foam materials, and only a few successful examples, such as: Chinese patents CN108250669A and CN107177052A prepared polyether ether ketone foam materials using supercritical carbon dioxide as a foaming agent. This method uses complex equipment, is difficult to operate, has high technical requirements, and is difficult to industrialize. Chinese patent CN110527129A prepared sheet-like polyether ether ketone foam materials by heating and foaming a mixture of a high-temperature foaming agent and polyether ether ketone on a vulcanizer. Its pore size is about 420 μm. The foam materials prepared by this method have a large pore size and poor mechanical properties, and their application prospects are greatly limited. Therefore, it is very meaningful to study polyether ether ketone foam materials with simple research methods, low equipment requirements, and small pore sizes. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-thermal-conductivity polyether ether ketone composite material and a preparation method thereof. The present invention dissolves a foaming agent and mixes it with polyether ether ketone powder, then obtains a powder raw material through drying treatment, and finally prepares a low-thermal-conductivity polyether ether ketone foam material through compression molding and foaming.

[0005] The present invention realizes the above purpose through the following technical solutions:

[0006] A low-thermal-conductivity polyether ether ketone composite material and a preparation method thereof, comprising the following steps:

[0007] Step 1: Crush the polyetheretherketone material to obtain polyetheretherketone material powder.

[0008] Step 2: Dissolve the foaming agent in a solvent to obtain a solution containing the foaming agent.

[0009] Step 3: Add the nucleating agent and the solution containing the foaming agent obtained in Step 2 to the polyetheretherketone material powder obtained in Step 1, stir and mix evenly, and obtain foamed polyetheretherketone powder after drying.

[0010] Step 4: Put the powder obtained in Step 3 into a mold, press it into a specified shape by a molding press, then heat it to a preset temperature and apply a preset pressure. After the foaming agent generates gas, quickly relieve the pressure and obtain polyetheretherketone foam material after cooling.

[0011] A further solution is that in Step 1, the polyetheretherketone masterbatch is crushed by physical methods to obtain powder, including high-speed rotary crushing and jet mill crushing, and the average particle size of the obtained powder is less than 300 μm.

[0012] A further solution is that in Step 2, the solvent for dissolving the foaming agent is one or more of ethanol, propanol, dimethylformamide, ethyl acetate, petroleum ether, cyclohexane, and n-hexane.

[0013] A further solution is that in Step 3, the nucleating agent used is one or more of silicon dioxide, titanium dioxide, calcium carbonate, and carbon black, and its particle size is nanometer or micrometer level.

[0014] A further solution is that in Step 2, the foaming agent used is one or more of light stabilizer UV-2026, light stabilizer UV-622, trihydrazine-s-triazine, and light stabilizer UV-3346.

[0015] A further solution is that in Step 3, the content of polyetheretherketone in the foamed polyetheretherketone powder is 90-98% (Wt), the content of the nucleating agent is 1-5% (Wt), and the foaming agent is 1-5% (Wt).

[0016] A further solution is that in Step 4, the temperature of the mold heated by the molding press is 340-420 °C, the heating time is 5-120 min, the pressure applied to the mold is 2-60 MPa, the pressure after pressure relief is 0.5-5 MPa, and the cooling temperature is lower than 200 °C.

[0017] On the other hand, the present invention provides a low-thermal-conductivity polyetheretherketone composite material obtained by the preparation method of the above low-thermal-conductivity polyetheretherketone composite material.

[0018] On the other hand, the present invention provides an application of the low-thermal-conductivity polyetheretherketone composite material obtained by the above-mentioned preparation method of the low-thermal-conductivity polyetheretherketone composite material in the field of thermal insulation materials.

[0019] The beneficial effects of the present invention are as follows:

[0020] In the present invention, a nucleating agent and a foaming agent solution are added to polyetheretherketone powder, and after being stirred and evenly mixed, the foamed polyetheretherketone powder is obtained through drying; the foaming agent solution can evenly disperse the foaming agent in the polyetheretherketone powder, and the nucleating agent increases the number of cell pores, which is beneficial for polyetheretherketone to form cell pores with smaller pore diameters and larger quantities; the polyetheretherketone foam material prepared by the present invention has a relatively high porosity, and the porosity reaches 20%-80%; the average pore diameter of the cell pores is 50-300 μm, and it has a low thermal conductivity, with the thermal conductivity being less than 0.2 W / (m·K). The process of the present invention is simple, easy to operate, has mild processing conditions, and is easy to promote. Description of the Drawings

[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a 3D optical micrograph of the cross-section of the polyetheretherketone foam material prepared in Example 3 of the present invention. This polyetheretherketone foam material has a relatively uniform cell pore structure, and the average pore diameter is about 210 μm. Detailed Embodiments

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions of the present invention will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other implementation manners obtained by those of ordinary skill in the art without creative efforts fall within the scope protected by the present invention.

[0024] Example 1

[0025] The polyether ether ketone material was crushed using a high-speed rotary crusher to obtain powder with an average particle size of less than 150 μm; 3 g of a foaming agent (light stabilizer UV-2026) was dissolved in 10 g of ethanol to form a solution, and then this solution and 2 g of carbon black were added to 95 g of polyether ether ketone powder. After stirring evenly, it was dried at 80 °C for 1 h to obtain foaming powder, which was then loaded into a mold, a pressure of 10 MPa was applied, and then it was heated to 380 °C. After holding for 10 min, the pressure was released to 1 MPa. When it was cooled below 200 °C, the sample was taken off.

[0026] The average pore diameter of the sample foam cells is approximately 200 μm, and the thermal conductivity is 0.152 W / (m·K).

[0027] Example 2

[0028] The polyether ether ketone material was crushed using a jet mill to obtain powder with an average particle size of less than 100 μm; 4 g of a foaming agent (light stabilizer UV-2026) was dissolved in 10 g of ethyl acetate to form a solution, and then this solution and 2 g of carbon black were added to 94 g of polyether ether ketone powder. After stirring evenly, it was dried at 80 °C for 1 h to obtain foaming powder, which was then loaded into a mold, a pressure of 10 MPa was applied, and then it was heated to 380 °C. After holding for 10 min, the pressure was released to 1 MPa. When it was cooled below 200 °C, the sample was taken off.

[0029] The average pore diameter of the sample foam cells is approximately 150 μm, and the thermal conductivity is 0.147 W / (m·K).

[0030] Example 3

[0031] The polyether ether ketone material was crushed using a jet mill to obtain powder with an average particle size of less than 100 μm; 3 g of a foaming agent (light stabilizer UV-3346) was dissolved in 10 g of ethanol to form a solution, and then this solution and 2 g of carbon black were added to 95 g of polyether ether ketone powder. After stirring evenly, it was dried at 80 °C for 1 h to obtain foaming powder, which was then loaded into a mold, a pressure of 10 MPa was applied, and then it was heated to 380 °C. After holding for 10 min, the pressure was released to 1 MPa. When it was cooled below 200 °C, the sample was taken off.

[0032] The average pore diameter of the sample foam cells is approximately 210 μm, and the thermal conductivity is 0.163 W / (m·K).

[0033] Figure 1 This is a 3D optical micrograph of the cross-section of the polyether ether ketone foam material prepared in Example 3 of the present invention. The polyether ether ketone foam material has a relatively uniform cell structure, and the average pore diameter is approximately 210 μm.

[0034] Example 4

[0035] The polyetheretherketone material was pulverized using a jet mill to obtain a powder with an average particle size of less than 200 μm; 4 g of a blowing agent (light stabilizer UV-3346) was dissolved in 10 g of ethanol to form a solution, and then this solution and 3 g of nano-silica were added to 93 g of polyetheretherketone powder. After stirring evenly, it was dried at 80 °C for 1 h to obtain a foaming powder, which was then loaded into a mold, a pressure of 10 MPa was applied, and then it was heated to 380 °C, held for 20 min and then depressurized to 1 MPa. When it was cooled to below 200 °C, the sample was removed.

[0036] The average pore diameter of the sample foam cells is approximately 165 μm, and the thermal conductivity is 0.158 W / (m·K).

[0037] Example 5

[0038] The polyetheretherketone material was pulverized using a jet mill to obtain a powder with an average particle size of less than 200 μm; 3 g of a blowing agent (light stabilizer UV-622) was dissolved in 10 g of ethanol to form a solution, and then this solution and 3 g of carbon black were added to 94 g of polyetheretherketone powder. After stirring evenly, it was dried at 80 °C for 1 h to obtain a foaming powder, which was then loaded into a mold, a pressure of 10 MPa was applied, and then it was heated to 390 °C, held for 10 min and then depressurized to 1 MPa. When it was cooled to below 200 °C, the sample was removed.

[0039] The average pore diameter of the sample foam cells is approximately 180 μm, and the thermal conductivity is 0.173 W / (m·K).

[0040] Example 6

[0041] The polyetheretherketone material was pulverized using a jet mill to obtain a powder with an average particle size of less than 150 μm; 3 g of a blowing agent (light stabilizer UV-622) was dissolved in 10 g of ethanol to form a solution, and then this solution and 3 g of carbon black were added to 94 g of polyetheretherketone powder. After stirring evenly, it was dried at 80 °C for 1 h to obtain a foaming powder, which was then loaded into a mold, a pressure of 10 MPa was applied, and then it was heated to 370 °C, held for 30 min and then depressurized to 1 MPa. When it was cooled to below 200 °C, the sample was removed.

[0042] The average pore diameter of the sample foam cells is approximately 230 μm, and the thermal conductivity is 0.171 W / (m·K).

[0043] Example 7

[0044] The polyetheretherketone material is pulverized using a jet mill to obtain a powder with an average particle size of less than 200 μm. 3 g of a foaming agent (light stabilizer UV-622) is dissolved in 10 g of ethanol to form a solution, and then this solution and 3 g of carbon black are added to 94 g of the polyetheretherketone powder. After stirring evenly, it is dried at 80 °C for 1 h to obtain a foaming powder, which is then loaded into a mold, a pressure of 10 MPa is applied, and then it is heated to 390 °C, held for 10 min, and then the pressure is released to 1 MPa. When it is cooled below 200 °C, the sample is removed.

[0045] The average pore diameter of the sample cell is approximately 180 μm, and the thermal conductivity is 0.167 W / (m·K).

[0046] Example 8

[0047] The polyetheretherketone material is pulverized using a high-speed rotary crusher to obtain a powder with an average particle size of less than 150 μm. 3 g of a foaming agent (light stabilizer UV-3346) is dissolved in 10 g of ethanol to form a solution, and then this solution and 2 g of nano-titanium dioxide are added to 95 g of the polyetheretherketone powder. After stirring evenly, the foaming powder after drying at 80 °C for 1 h is placed in a mold, a pressure of 15 MPa is applied, and then it is heated to 380 °C, held for 10 min, and then the pressure is released to 1 MPa. When it is cooled below 200 °C, the sample is removed.

[0048] The average pore diameter of the sample cell is approximately 190 μm, and the thermal conductivity is 0.154 W / (m·K).

[0049] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims. Additionally, it should be noted that in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention does not separately describe various possible combination methods. Furthermore, any arbitrary combination can be made between different embodiments of the present invention, as long as it does not violate the idea of the present invention, it should also be regarded as the content disclosed by the present invention.

Claims

1. A preparation method of a low thermal conductivity polyether ether ketone composite material, characterized in that It includes the following steps: Step 1: Crush the polyetheretherketone material to obtain polyetheretherketone material powder; Step 2: Dissolve the foaming agent in the solvent to obtain a solution containing the foaming agent; the solvent for dissolving the foaming agent is one or more of ethanol, propanol, dimethylformamide, ethyl acetate, petroleum ether, cyclohexane, and n-hexane; the foaming agent used is one or more of light stabilizer UV-2026, light stabilizer UV-622, trihydrazine-s-triazine, and light stabilizer UV-3346; Step 3: Add the nucleating agent and the solution containing the foaming agent obtained in Step 2 to the polyetheretherketone material powder obtained in Step 1, stir and mix evenly, and obtain foamed polyetheretherketone powder after drying; Step 4: Put the powder obtained in Step 3 into a mold, press it into a specified shape on a molding press, then heat it to a preset temperature and apply a preset pressure. After the foaming agent generates gas, quickly relieve the pressure and obtain a polyetheretherketone foam material after cooling; In the said Step 3, the content of polyetheretherketone in the foamed polyetheretherketone powder is 90-98 wt%, the content of the nucleating agent is 1-5 wt%, and the foaming agent is 1-5 wt%.

2. The preparation method according to claim 1, characterized in that, In the said Step 1, the polyetheretherketone masterbatch is crushed by a physical method to obtain powder, including high-speed rotary crushing and jet mill crushing, and the average particle size of the obtained powder is less than 300 μm.

3. The preparation method according to claim 1, characterized in that, The nucleating agent used is one or more of silicon dioxide, titanium dioxide, calcium carbonate, and carbon black, and its particle size is nanometer or micrometer level.

4. The preparation method according to any one of claims 1 to 3, characterized in that, In the said Step 4, the temperature of the mold heated on the molding press is 340-420 °C, the heating time is 5-120 min, the pressure applied to the mold is 2-60 MPa, the pressure after pressure relief is 0.5-5 MPa, and the cooling temperature is lower than 200 °C.

5. A low-thermal-conductivity polyetheretherketone composite material obtained by the preparation method according to any one of claims 1-4.

6. Application of the low-thermal-conductivity polyetheretherketone composite material obtained by the preparation method according to any one of claims 1-4 in the field of thermal insulation materials.

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