CN112322039B - High-thermal-conductivity reinforced polyphenylene sulfide composite material and preparation method thereof - Google Patents

Abstract

The method of the invention discloses a reinforced polyphenylene sulfide composite material with high thermal conductivity and a preparation method thereof. The raw material composition of the reinforced polyphenylene sulfide composite material with high thermal conductivity includes: a polyphenylene sulfide base material 30 in weight percentage ～50%; surface carbonization reinforcement 5～30%; thermally conductive filler 20～60%; surface carbonization reinforcement is a reinforcement whose outer surface is covered with carbon layer. The preparation method comprises the following steps: blending monomer raw materials, reinforcements and optional two-dimensional sheet-like thermally conductive fillers, obtaining surface carbonization reinforcements after in-situ polymerization and carbonization; Using the surface carbonization reinforcement prepared above as a raw material, a reinforced polyphenylene sulfide composite material with high thermal conductivity is prepared after extrusion and granulation. The reinforced polyphenylene sulfide composite material with high thermal conductivity disclosed in the invention not only significantly improves the thermal conductivity of the polyphenylene sulfide composite material, but also ensures its excellent processing performance and mechanical performance.

Description

High-thermal-conductivity reinforced polyphenylene sulfide composite material and preparation method thereof

Technical Field

The invention relates to the technical field of heat-conducting polyphenylene sulfide, in particular to a high-heat-conducting reinforced polyphenylene sulfide composite material and a preparation method thereof.

Background

In recent years, with the improvement of the requirements of industrial development on corrosion resistance, mechanical property, processability and the like of heat conducting materials, the traditional metal heat conducting materials cannot meet the application requirements in some chemical fields. The metal section has the serious problems of serious corrosion, scaling, no acid and alkali resistance and the like in the long-term use process, the service life is shortened, the equipment safety is influenced, and the maintenance and replacement cost is increased; meanwhile, the weight of the device is heavier, and the development direction of light weight is not facilitated. The high polymer material has the characteristics of chemical corrosion resistance, excellent forming and processing performance, excellent electrical insulation performance, excellent mechanical property and the like, is smooth and non-stick to scale when being used as a section bar, has light weight, wear resistance and low price, has longer service life than a metal section bar, and is gradually applied to products. However, most polymer materials are poor thermal conductors, and therefore modification is required to improve the thermal conductivity of the materials.

Polyphenylene Sulfide (PPS) is thermoplastic resin with a phenylene sulfide group in a molecular main chain, is one of the resins with the highest stability in a thermoplastic polymer material, has excellent heat resistance, chemical corrosion resistance, radiation resistance, flame retardance, balanced physical and mechanical properties and better processing performance, is considered to be second to polytetrafluoroethylene, is widely applied to the fields of electronic and electrical products, chemical engineering, aerospace, automobile transportation and the like, and can be used for preparing heat-conducting plastic pipes. However, polyphenylene sulfide itself has poor thermal conductivity, so it is a key technology to improve the thermal conductivity of polyphenylene sulfide.

At present, in order to improve the heat conductivity of polyphenylene sulfide, a main method is to add various heat-conducting fillers into a base material and prepare a high-heat-conducting polyphenylene sulfide composite material through blending and extrusion. For example, chinese patent publication No. CN 109233279 a discloses a heat conductive and insulating polyphenylene sulfide composite material, which is prepared by adding a composite heat conductive additive to 80-90 parts by weight of polyphenylene sulfide, 2-5 parts by weight of silicon carbide, 1-3 parts by weight of carbolic acid, 0.5-1.5 parts by weight of boron nitride, and the like to improve the heat conductivity of the PPS composite material. As another example, chinese patent publication No. CN 111269551 a discloses a polyphenylene ether composition and its application in a battery protection case of a new energy vehicle, where the polyphenylene ether composition includes: 80-100 parts of polyphenyl ether resin, 30-50 parts of polyamide resin, 10-20 parts of polyphenylene sulfide resin, 30-50 parts of composite heat-conducting filler and 10-20 parts of dispersing agent; the composite heat-conducting filler consists of graphene nanoplatelets, silicon carbide and boron nitride. The polyphenyl ether composition is obtained by uniformly mixing the raw materials and then putting the mixture into a double-screw extruder for melt extrusion granulation. In the two technical schemes, because the addition amount of the heat-conducting filler is small, the heat-conducting fillers are isolated from each other, and an effective heat-conducting passage cannot be formed, the improvement degree of the heat-conducting performance is limited.

In order to further improve the heat conductivity, the most direct way is to increase the addition amount of the heat conductive filler, but it is known that the addition of a large amount of heat conductive filler not only causes too poor fluidity to cause processing difficulty, but also causes significant reduction in the mechanical properties of the composite material, and therefore, the improvement degree of the heat conductivity by simply increasing the addition amount of the heat conductive filler is still limited.

Disclosure of Invention

Aiming at the problems in the prior art, the invention discloses a high-thermal-conductivity reinforced polyphenylene sulfide composite material and a preparation method thereof, which can remarkably improve the thermal conductivity of the polyphenylene sulfide composite material and ensure the excellent processability and mechanical property of the polyphenylene sulfide composite material.

The specific technical scheme is as follows:

a high-thermal-conductivity reinforced polyphenylene sulfide composite material comprises the following raw materials in percentage by weight:

30-50% of polyphenylene sulfide base material;

5-30% of a surface carbonization reinforcement;

20-60% of heat-conducting filler;

the surface carbonization reinforcement body is a reinforcement body with the outer surface coated with a carbon layer.

The invention discloses a high-thermal-conductivity reinforced polyphenylene sulfide composite material, which takes polyphenylene sulfide as a base material, improves the thermal conductivity of the composite material by adding a thermal conductive filler, and improves the mechanical property of the composite material by adding a reinforcement. In order to further enhance the heat-conducting property of the material, the surface of the reinforcement is modified, the surface of the reinforcement is soaked in polymer monomer raw material liquid, and after in-situ polymerization and carbonization treatment, a carbonized layer is attached to the surface of the reinforcement. And finally, blending and extruding the surface carbonization reinforcement body and other raw materials to prepare the composite material. The contrast test shows that the surface carbonization reinforcement is adopted to replace the common reinforcement, so that the heat-conducting property of the composite material can be further improved while the reinforcement effect of the reinforcement is ensured.

Preferably, the melt flow rate of the polyphenylene sulfide base material is 800-1200 g/10 min. The polyphenylene sulfide at the melt flow rate is selected to be beneficial to reducing the granulation and molding difficulty of the composite material.

Preferably, the reinforcement is selected from alkali-free glass fibers and/or carbon fibers; more preferably, the length of the reinforcement body is 2-8 mm. If the length of the reinforcement body is too short, the mechanical property is not good; if the length is too long, the dispersibility is poor and the heat conductivity is poor. Still more preferably, the length of the reinforcement is 4 mm. Tests show that the composite material prepared by adopting the reinforcement body with the length has better heat-conducting property and mechanical property.

Preferably, the thermally conductive filler is selected from graphite and/or silicon carbide; further preferably graphite, and experiments show that the heat conduction effect of the system after the graphite is added is better than that of silicon carbide.

Preferably, the mesh number of the graphite is 200-800 meshes, and tests show that the graphite has overlarge particle size and poor mechanical property in the system; graphite particles with too small particle size tend to agglomerate, have low thermal conductivity and small bulk density, and are not uniformly mixed during extrusion. Still further preferably, the mesh number of the graphite is 500 meshes, and tests show that the composite material prepared by adopting the graphite with the mesh number has better heat-conducting property and mechanical property.

Preferably, the carbon layer further contains a two-dimensional sheet-like thermally conductive filler; the two-dimensional flaky heat-conducting filler is doped into a polymer monomer raw material liquid, and is doped into a carbonization layer on the surface of a reinforcing body after in-situ polymerization and carbonization treatment. Tests show that the heat-conducting property of the composite material can be further obviously improved by doping the two-dimensional flaky heat-conducting filler into the surface carbonization reinforcement. And a comparison test shows that if the same amount of two-dimensional flaky heat-conducting filler is directly added into the base material in a blending mode, the heat-conducting property of the finally prepared composite material is hardly influenced due to the extremely low addition amount.

Preferably, the precursor of the carbon layer is selected from Polyimide (PI) or Polyetherimide (PEI).

Preferably, the two-dimensional plate-like thermally conductive filler is selected from graphene and/or boron nitride.

Further preferably, the precursor of the carbon layer is selected from PI, and the two-dimensional plate-shaped heat conductive filler is selected from graphene. Experiments show that in the system, graphene is added into a raw material monomer of polyimide to generate in-situ polymerization, the graphene and the polyimide generate a synergistic effect, and a carbon layer obtained after carbonization can greatly improve the heat-conducting property of the composite material.

On the basis of the preferable raw materials, the high-thermal-conductivity reinforced polyphenylene sulfide composite material comprises the following raw materials in percentage by weight:

30-50% of polyphenylene sulfide base material;

10-20% of a surface carbonization reinforcement;

40-60% of heat-conducting filler.

Further preferably, the raw materials comprise:

30-50% of polyphenylene sulfide base material;

10-20% of a surface carbonization reinforcement;

40-50% of heat-conducting filler.

More preferably, the raw materials comprise:

40-50% of polyphenylene sulfide base material;

10-20% of a surface carbonization reinforcement;

40% of heat-conducting filler.

Still more preferably:

the reinforcement is selected from 4mm carbon fibers;

the heat-conducting filler is selected from graphite with the mesh number of 500 meshes;

the precursor of the carbon layer is selected from PI;

the two-dimensional flaky heat conducting filler is selected from graphene.

By adopting the further optimized raw material types and raw material compositions, the heat-conducting property and the mechanical property of the prepared PPS composite material are optimal.

Besides the raw materials, various functional additives can be added into the high-thermal-conductivity reinforced polyphenylene sulfide composite material according to the requirements of different application occasions. Such as coupling agents, compatibilizers, toughening agents, and the like.

The invention also discloses a preparation method of the high-thermal-conductivity reinforced polyphenylene sulfide composite material, which comprises the following steps:

(1) mixing the monomer raw material, the reinforcement and an optionally added two-dimensional flaky heat-conducting filler, and carrying out in-situ polymerization and carbonization to obtain a surface carbonization reinforcement;

(2) taking the polyphenylene sulfide base material, the heat-conducting filler and the surface carbonization reinforcement prepared in the step (1) as raw materials, and preparing the reinforced polyphenylene sulfide composite material with high heat conductivity after extrusion granulation.

In the step (1), firstly, a polymer monomer is used as a raw material, a polymer layer is coated on the surface of the reinforcement body in an in-situ polymerization mode, and the reinforcement body with the surface coated with the carbon layer is obtained after carbonization.

The in-situ polymerization method adopts the conventional technical means in the field, and selects polymer monomers suitable for the coated polymer layer according to different coated polymer layers. Because of the impregnation, solution polymerization, the specific polymerization temperature, the type of solvent used, and the subsequent carbonization temperature are all compatible with the type of polymer layer, and are generally selected in the art.

Taking polyimide as an example of the precursor of the carbon layer, the monomer raw material is selected from p-phenylenediamine and biphenyl tetracarboxylic dianhydride, N' -dimethylacetamide is used as a solvent, the polymerization temperature is normal temperature, and the carbonization temperature is 650-800 ℃.

Preferably, a two-dimensional flaky heat-conducting filler is added to prepare the reinforcement with the surface coated with the carbon layer doped with the two-dimensional flaky heat-conducting filler.

Further preferably, the mass ratio of the two-dimensional flaky heat-conducting filler to the reinforcing body is 0.1-0.5: 100, respectively; more preferably 0.27: 100.

In the step (2):

the polyphenylene sulfide base material and the heat-conducting filler are added into an extruder from a main feeding port;

adding the surface carbonization reinforcement into an extruder from a side feeding port;

the temperature of the extrusion granulation is 310-340 ℃.

Compared with the prior art, the invention has the following advantages:

the invention discloses a high-heat-conductivity reinforced polyphenylene sulfide composite material, which adopts a polyphenylene sulfide base material, a heat-conducting filler and a surface-modified reinforcement as raw materials, and a carbonized layer is attached to the surface of the reinforcement after polymer monomer raw material liquid is impregnated on the surface of the reinforcement and in-situ polymerization and carbonization treatment are carried out. The heat-conducting property of the polyphenylene sulfide composite material is further improved through the design. In the invention, two-dimensional flaky heat-conducting fillers are doped in a polymer monomer raw material liquid, a carbonized layer doped with the two-dimensional flaky heat-conducting fillers is attached to the surface of a reinforcement after in-situ polymerization and carbonization treatment, and the synergistic effect of the carbonized layer and the two-dimensional flaky heat-conducting fillers is utilized, so that the heat-conducting property of the polyphenylene sulfide composite material is further greatly improved, and the excellent processing property and mechanical property of the polyphenylene sulfide composite material are also ensured.

The polyphenylene sulfide composite material prepared by the invention has excellent heat conduction and mechanical properties, is a novel heat conduction material with large-scale industrial production prospect, and can be used in the fields of heat exchangers, radiators, heat dissipation shells, LED plastic packages, electronic devices, electronic equipment and large-scale equipment with high heat dissipation requirements.

Detailed Description

The present invention is further illustrated by the following specific examples, but the scope of the present invention is not limited to the following examples.

Example 1

Dissolving p-phenylenediamine (PDA, 8.9kg) in 300L N, N' -dimethylacetamide, and adding 2kg of graphene

Ultrasonic dispersion was carried out for 10 hours, then biphenyltetracarboxylic dianhydride (BPDA, 24.4kg) was added, and mechanical stirring was carried out for 4 hours under ice water cooling. 750kg of alkali-free glass fibers (length: 4mm) were added to the mixed viscous liquid, and the stirring was continued for 1 hour. Finally, the polyimide mucilage with the dispersed glass fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min under the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the surface carbonized glass fiber.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (500 meshes), and 20% of surface carbonized glass fiber obtained in the step (1), uniformly stirring the polyphenylene sulfide and the graphite, adding the mixture into a main feeding hopper of a double-screw extruder (18mm double-screw extruder), adding the surface carbonized glass fiber into a side feeding hopper, and setting the temperature of each section of the double-screw extruder from the hopper to a die head as follows: 285 ℃, 320 ℃, 340 ℃, 325 ℃, 315 ℃ and 325 ℃, the screw rotating speed of the main machine is 350rpm, the side feeding rotating speed is 250rpm, and the materials are blended, melted, extruded and cut into granules.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 2

Dissolving p-phenylenediamine (PDA, 8.9kg) in 300L N, N' -dimethylacetamide, and adding 2kg of graphene

Ultrasonic dispersion was carried out for 10 hours, then biphenyltetracarboxylic dianhydride (BPDA, 24.4kg) was added, and mechanical stirring was carried out for 4 hours under ice water cooling. 750kg of alkali-free glass fibers (length: 2mm) were added to the mixed viscous liquid, and the stirring was continued for 1 hour. Finally, the polyimide mucilage with the dispersed glass fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min under the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the surface carbonized glass fiber.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (500 mesh) and 20% of the surface carbonized glass fiber obtained in the step (1), and then, extrusion-granulating was carried out in the same manner as in example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 3

Dissolving p-phenylenediamine (PDA, 8.9kg) in 300L N, N' -dimethylacetamide, and adding 2kg of graphene

Ultrasonic dispersion was carried out for 10 hours, then biphenyltetracarboxylic dianhydride (BPDA, 24.4kg) was added, and mechanical stirring was carried out for 4 hours under ice water cooling. 750kg of alkali-free glass fibers (length: 8mm) were added to the mixed viscous liquid, and the stirring was continued for 1 hour. Finally, the polyimide mucilage with the dispersed glass fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min under the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the surface carbonized glass fiber.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (500 mesh) and 20% of the surface carbonized glass fiber obtained in the step (1), and then, extrusion-granulating was carried out in the same manner as in example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 4

Step (1), preparing the glass fiber with carbonized surface according to the method of the embodiment 1.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (200 mesh) and 20% of the surface carbonized glass fiber obtained in the step (1), and then, extrusion-granulating was carried out in the same manner as in example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 5

Step (1), preparing the glass fiber with carbonized surface according to the method of the embodiment 1.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (800 meshes) and 20% of the surface carbonized glass fiber obtained in the step (1), and then, extrusion-granulating was carried out in the same manner as in example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 6

Dissolving p-phenylenediamine (PDA, 8.9kg) in 300L N, N' -dimethylacetamide, and adding 2kg of graphene

Ultrasonic dispersion was carried out for 10 hours, then biphenyltetracarboxylic dianhydride (BPDA, 24.4kg) was added, and mechanical stirring was carried out for 4 hours under ice water cooling. 750kg of carbon fibers (length: 4mm) were added to the mixed viscous liquid, and stirring was continued for 1 hour. Finally, the polyimide mucilage with dispersed carbon fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min in the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the surface carbon fiber.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 50% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (500 mesh), and 10% of the surface-carbonized carbon fiber obtained in step (1), followed by extrusion and pelletization in the same manner as in example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 7

Step (1), preparing the glass fiber with carbonized surface according to the method of the embodiment 1.

And (2) drying the polyphenylene sulfide at 120 ℃ for 4 h.

Step (3), mixing the following components in percentage by mass: 30% of polyphenylene sulfide (NHU-PPS3490), 50% of silicon carbide and 20% of the surface carbonized glass fiber obtained in the step (1), and then extruding and granulating the mixture according to the same procedure as the example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 8

Dissolving p-phenylenediamine (PDA, 8.9kg) in 300L N, N' -dimethylacetamide, adding 2kg of boron nitride, ultrasonically dispersing for 10h, then adding biphenyl tetracarboxylic dianhydride (BPDA, 24.4kg), and mechanically stirring for 4h under the cooling of ice water. 750kg of alkali-free glass fibers (length: 4mm) were added to the mixed viscous liquid, and the stirring was continued for 1 hour. Finally, the polyimide mucilage with the dispersed glass fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min under the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the surface carbonized glass fiber.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (500 mesh) and 20% of the surface carbonized glass fiber obtained in the step (1), and then, extrusion-granulating was carried out in the same manner as in example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 9

In the step (1), p-phenylenediamine (PDA, 8.9kg) was dissolved in 300L N, N' -dimethylacetamide, and then biphenyltetracarboxylic dianhydride (BPDA, 24.4kg) was added, and mechanically stirred for 4 hours under ice water cooling. 750kg of alkali-free glass fiber is added into the mixed mucilage, and the stirring is continued for 1 hour. Finally, the polyimide mucilage with the dispersed glass fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min in the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the graphene-free carbonized glass fiber with the surface coated with the polyimide carbon layer.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide, 40% of graphite and 20% of the surface carbonized glass fiber without graphene obtained in the step (1), uniformly stirring the polyphenylene sulfide and the graphite, adding the polyphenylene sulfide and the graphite into a main feeding hopper of a double-screw extruder, adding the glass fiber into a side feeding hopper, and setting the temperature of each section of the double-screw extruder from the hopper to a die head as follows: 285 ℃, 320 ℃, 340 ℃, 325 ℃, 315 ℃ and 325 ℃, the screw rotating speed of the main machine is 350rpm, the side feeding rotating speed is 250rpm, and the materials are blended, melted, extruded and cut into granules.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 10

Dissolving bisphenol A diether dianhydride (BPADA, 5.2kg) in 100L N, N' -dimethylacetamide, and adding 0.4kg of graphene for ultrasonic dispersion for 10 h. P-phenylenediamine (PDA, 1.2kg) was dissolved in 20L N, N' -dimethylacetamide, and then added dropwise to the reaction solution, followed by mechanical stirring at 40 ℃ for 6 hours. Mixed viscose150kg of alkali-free glass fiber (length: 4mm) was added to the solution, and the stirring was continued for 1 hour. Finally, the polyetherimide mucilage with the dispersed glass fibers is placed in a tube furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min under the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the surface carbonized glass fiber.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide (NHU-PPS3490), 40% of graphite (500 mesh) and 20% of the surface carbonized glass fiber obtained in the step (1), and then, extrusion-granulating was carried out in the same manner as in example 1.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 11

In the step (1), p-phenylenediamine (PDA, 8.9kg) was dissolved in 300L N, N' -dimethylacetamide, and then biphenyltetracarboxylic dianhydride (BPDA, 24.4kg) was added, and mechanically stirred for 4 hours under ice water cooling. 750kg of alkali-free glass fiber is added into the mixed mucilage, and the stirring is continued for 1 hour. Finally, the polyimide mucilage with the dispersed glass fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min under the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the graphene-free surface carbonized glass fiber.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 40% of polyphenylene sulfide, 40% of graphite, 19.95% of the surface carbonized glass fiber without graphene obtained in the step (1) and 0.05% of graphene, uniformly stirring the polyphenylene sulfide, the graphite and the graphene, adding the mixture into a main feeding hopper of a double-screw extruder (18mm double-screw extruder), adding the glass fiber into a side feeding hopper, and setting the temperature of each section of the double-screw extruder from the hopper to a die head as follows: 285 ℃, 320 ℃, 340 ℃, 325 ℃, 315 ℃ and 325 ℃, the screw rotating speed of the main machine is 350rpm, the side feeding rotating speed is 250rpm, and the materials are blended, melted, extruded and cut into granules.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

Example 12

In the step (1), p-phenylenediamine (PDA, 8.9kg) was dissolved in 300L N, N' -dimethylacetamide, and then biphenyltetracarboxylic dianhydride (BPDA, 24.4kg) was added, and mechanically stirred for 4 hours under ice water cooling. 750kg of alkali-free glass fiber is added into the mixed mucilage, and the stirring is continued for 1 hour. Finally, the polyimide mucilage with the dispersed glass fibers is placed in a tubular furnace in N₂Heating to 400 ℃ at the heating rate of 5 ℃/min in the atmosphere, heating to 780 ℃ at the heating rate of 2 ℃/min, and preserving heat for 2h to obtain the graphene-free carbonized glass fiber with the surface coated with the polyimide carbon layer.

And (2) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (3), mixing the following components in percentage by mass: 20% of polyphenylene sulfide, 40% of graphite, 20% of surface carbonized glass fiber obtained in the step (1) and 20% of graphene, uniformly stirring the polyphenylene sulfide, the graphite and the graphene, adding the mixture into a main feeding hopper of a double-screw extruder (50mm double-screw extruder), adding the glass fiber into a side feeding hopper, and blending, melting, extruding and pelletizing the materials.

And (4) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

In this comparative example, since the content of the added heat conductive filler was as high as 60%, which caused processing difficulty, and extrusion could not be performed by conventional equipment (18mm twin-screw extruder), the 50mm twin-screw extruder was replaced.

Comparative example 1

And (1) drying the polyphenylene sulfide and the graphite for 4 hours at 120 ℃.

Step (2), mixing the following components in percentage by mass: 40% of polyphenylene sulfide, 40% of graphite and 20% of alkali-free glass fiber (length: 4mm) without surface treatment, uniformly stirring the polyphenylene sulfide and the graphite, then adding the polyphenylene sulfide and the graphite into a main feeding hopper of a double-screw extruder, adding the glass fiber into a side feeding hopper, and setting the temperature of each section of the double-screw extruder from the hopper to a die head as follows: 285 ℃, 320 ℃, 340 ℃, 325 ℃, 315 ℃ and 325 ℃, the screw rotating speed of the main machine is 350rpm, the side feeding rotating speed is 250rpm, and the materials are blended, melted, extruded and cut into granules.

And (3) preparing a sample, and performing performance test, wherein the test result is shown in the following table 2.

The formulation compositions of the above examples and comparative examples are shown in Table 1.

Testing of the various performance parameters in table 2:

determination of tensile properties of ISO527-1-2012 plastics;

determination of tensile properties of ISO527-2 plastics;

the bending property of the ISO178-2010 plastic is measured;

the impact performance of the ISO179-1-2000 plastic simply supported beam is measured;

determination of Izod (Izod) impact strength of ISO180-2000 plastics;

the heat-wire method, GB/T10297-.

TABLE 1

TABLE 2

Observing the data in the table 2, it is known that the heat conductivity of the PPS composite material can be improved by performing carbonization treatment on the surface of the reinforcement; a small amount of two-dimensional flaky filler is added into the carbonized layer, so that the heat-conducting property can be further remarkably improved; if the added two-dimensional platy filler is directly added into the raw materials in a blending mode, the improvement on the heat conduction performance is basically negligible; if the heat-conducting property equivalent to that of the technical scheme of the invention is required to be achieved, 60 percent of heat-conducting filler is required to be added on the basis of the prior art, but the processing is difficult, and the extrusion cannot be carried out by adopting conventional extrusion equipment; even if the extrusion equipment is replaced to realize smooth extrusion, the mechanical property of the prepared PPS composite material is remarkably reduced.

Comparing example 1 with examples 7, 8 and 10, it can be seen that the finally prepared PPS composite material has better thermal conductivity by using a system formed by compounding graphene as a two-dimensional sheet filler, polyimide PI as a carbonization precursor, and graphite as a thermal conductive filler.

Further comparing examples 1-3, it can be seen that when the length of the reinforcement is 4mm, the mechanical property and the heat conductivity of the prepared PPS composite material are better; comparing examples 1, 4-5, it can be seen that when the mesh number of the graphite is 500 meshes, the mechanical property and the heat conductivity of the prepared PPS composite material are better; comparing example 1 with example 6, it is known that when the reinforcement is selected from carbon fibers, mechanical properties comparable to those of example 1 can be obtained at an addition amount of 10%, but thermal conductivity is better.

Claims (8)

1. The reinforced polyphenylene sulfide composite material with high heat conductivity is characterized by comprising the following raw materials in percentage by weight:

30-50% of polyphenylene sulfide base material;

5-30% of a surface carbonization reinforcement;

20-60% of heat-conducting filler;

the surface carbonization reinforcement body is a reinforcement body with the outer surface coated with a carbon layer;

the precursor of the carbon layer is selected from polyimide;

the carbon layer also contains two-dimensional flaky heat-conducting fillers;

the preparation of the surface carbonization reinforcement body specifically comprises the following steps:

mixing a monomer raw material, a reinforcement and a two-dimensional flaky heat-conducting filler, and carrying out in-situ polymerization and carbonization to obtain a surface carbonization reinforcement;

the mass ratio of the two-dimensional flaky heat-conducting filler to the reinforcing body is 0.1-0.5: 100;

the length of the reinforcement body is 2-8 mm.

2. The reinforced polyphenylene sulfide composite material with high thermal conductivity as claimed in claim 1, wherein the melt flow rate of the polyphenylene sulfide base material is 800-1200 g/10 min.

3. The reinforced polyphenylene sulfide composite material with high thermal conductivity as claimed in claim 1, wherein:

the reinforcement is selected from alkali-free glass fiber and/or carbon fiber;

the thermally conductive filler is selected from graphite and/or silicon carbide.

4. The reinforced polyphenylene sulfide composite material with high thermal conductivity as claimed in claim 1, wherein the two-dimensional flaky thermal conductive filler is selected from graphene and/or boron nitride.

5. The reinforced polyphenylene sulfide composite material with high thermal conductivity as claimed in any one of claims 1 to 4, wherein the raw material composition comprises, by weight:

30-50% of polyphenylene sulfide base material;

10-20% of a surface carbonization reinforcement;

40-60% of heat-conducting filler.

6. The reinforced polyphenylene sulfide composite material with high thermal conductivity as claimed in claim 5, wherein:

the reinforcement is selected from carbon fibers;

the heat conducting filler is selected from graphite, and the mesh number is 200-800 meshes;

the two-dimensional flaky heat conducting filler is selected from graphene.

7. The preparation method of the reinforced polyphenylene sulfide composite material with high thermal conductivity as claimed in any one of claims 1 to 6, characterized by comprising the following steps:

(1) mixing a monomer raw material, a reinforcement and a two-dimensional flaky heat-conducting filler, and carrying out in-situ polymerization and carbonization to obtain a surface carbonization reinforcement;

(2) taking the polyphenylene sulfide base material, the heat-conducting filler and the surface carbonization reinforcement prepared in the step (1) as raw materials, and preparing the reinforced polyphenylene sulfide composite material with high heat conductivity after extrusion granulation.

8. The method for preparing the reinforced polyphenylene sulfide composite material with high thermal conductivity as claimed in claim 7, wherein in the step (2):

the polyphenylene sulfide base material and the heat-conducting filler are added into an extruder from a main feeding port;

adding the surface carbonization reinforcement into an extruder from a side feeding port;

the temperature of the extrusion granulation is 310-340 ℃.