CN113045813B - High-molecular composite material with high mechanical strength and high bidirectional thermal conductivity and preparation thereof - Google Patents
High-molecular composite material with high mechanical strength and high bidirectional thermal conductivity and preparation thereof Download PDFInfo
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- C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
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- C08K2003/382—Boron-containing compounds and nitrogen
- C08K2003/385—Binary compounds of nitrogen with boron
Abstract
The invention relates to a heat-conducting composite material with high mechanical property and high bidirectional thermal conductivity and a preparation method thereof, belonging to the field of high polymer materials. The invention provides a heat-conducting polymer composite material, which is prepared by the following method: firstly, preparing a crystal-type high polymer material and a heat-conducting filler into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction to prepare the heat-conducting high polymer composite material; wherein the addition amount of the heat-conducting filler is 0-40 wt% of the mass of the crystalline polymer material. The invention prepares the heat-conducting polymer composite material with high mechanical property and high bidirectional thermal conductivity, and the comprehensive properties of the obtained composite material, such as mechanical property, thermal conductivity and the like, are greatly improved compared with the common blending system.
Description
Technical Field
The invention relates to a heat-conducting composite material with high mechanical property and high heat conductivity and a preparation method thereof, belonging to the field of high polymer materials.
Background
With the rapid development of microelectronic devices, thermally conductive polymers have attracted considerable attention for their insulating properties, low cost and ease of processing. However, unlike metals and inorganic materials, intrinsic polymers retain a relatively low thermal conductivity (0.1W/mk). Thermally conductive fillers are typically incorporated into polymers to form composites having enhanced thermal conductivity. Unfortunately, polymer composites with high filler content do not exhibit the corresponding thermal conductivity of the filler due to random distribution or aggregation of the filler, further degrading mechanical properties. At the same time, the high weight content of filler also increases the manufacturing costs and the processing viscosity. Consequently, the severe conflict between thermal diffusion and mechanical properties is increasingly problematic, limiting its wide range of applications. It is important to explore potential routes that can improve thermal conductivity while sacrificing some mechanical properties. The crystal string structure has high mechanical strength, good heat transfer efficiency in the orientation direction and the vertical orientation direction, and the characteristic that highly oriented molecular chains have high heat conductivity only along the flow direction of a flow field is avoided.
It is well known that the thermal conductivity of polymer-based composites depends to a large extent on their crystal morphology, weight loading and orientation of the fillers, the microstructure controlling the macroscopic properties of the composite. The self-reinforced cross-crystal structure inhibits random scattering of phonons caused by entangled molecular chains and crystal interfaces, and the orientation of the crystallites and molecular chains of the structure provides a high-speed phonon path. Compared to the oriented structure of the pure stretching process, the thermal conductivity perpendicular to the orientation direction is often much lower than the orientation direction. Therefore, based on the stress-induced cross-grain structure, the molecular chain bundle in the orientation direction not only provides a phonon transfer channel, but also provides a path for heat conduction in the direction of the attached growth platelet kebab in the vertical orientation direction, and the cross-grain can transfer heat in two directions has not been reported. This becomes an effective way to prepare composite materials having high thermal conductivity and mechanical strength.
Disclosure of Invention
The invention aims to provide a heat-conducting polymer composite material with high mechanical property and high heat conductivity, and the comprehensive properties of the obtained composite material, such as mechanical property, heat-conducting property and the like, are greatly improved compared with those of a common blending system.
The technical scheme of the invention is as follows:
the first technical problem to be solved by the invention is to provide a heat-conducting polymer composite material, which is prepared by adopting the following method: firstly, preparing a crystalline polymer material and a heat-conducting filler into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along a kebab direction (namely, the direction perpendicular to the shish direction, namely, a shearing direction) to prepare the heat-conducting polymer composite material; wherein the addition amount of the heat-conducting filler is 0-40 wt% of the mass of the crystalline polymer material. When the filling amount is too large, the filler inhibits crystallization, and the generation of a crystal string structure is greatly reduced.
Preferably, the addition amount of the heat-conducting filler is 1-40 wt% of the mass of the crystalline polymer material; more preferably 1 to 25 wt%.
Further, the crystalline polymer material is one of high-density polyethylene, polypropylene, polyvinyl chloride or polylactic acid.
Further, the heat-conducting filler is selected from flaky heat-conducting fillers, and is preferably hexagonal boron nitride or graphene.
Preferably, the particle size of the heat conductive filler is 100nm to 10 um. When the particle size is larger than 10um, the oriented molecular chain is prevented from forming shish, and the content of the cross crystal of the material is further reduced.
Further, the method for preparing the crystal-type high polymer material and the heat-conducting filler into the material with the shish-kebab series crystal structure comprises the following steps: firstly, melting and uniformly mixing a crystalline polymer material and a heat-conducting filler, then applying a circumferential shear field by using a rotary shearing device to prepare an annular material with a shish-kebab series crystal structure, wherein the filler is selectively distributed on the outer layer of the annular material. A rotating shearing device is adopted to apply a circumferential flow field to form a string crystal structure, and the filler is dispersed and tends to be selectively distributed on the outer layer, namely the step is favorable for forming the string crystal structure with high mechanical property and bidirectional heat conduction, and simultaneously promotes the uniform dispersion and selective distribution of the filler.
Further, in the process of preparing the material with the shish-kebab series crystal structure by applying a circumferential shear field by using a rotary shearing device, the rotary shearing device comprises an extruder, an upper die, a lower die, a core rod and a cooling mechanism, wherein the rotating speed of a screw rod of the extruder is 8 Hz-12 Hz, the pressure maintaining pressure is 3-5 MPa, the temperature of the die is 140-180 ℃, the shearing time of the core rod with the rotating speed of the core rod of 4-12rpm is 2-8 min, and the cooling temperature of the upper die and the lower die is lower than 110 ℃.
Further, the crystalline polymer material and the heat-conducting filler are melted and uniformly mixed by adopting a double-screw extruder, and the temperature of the extruder is controlled to be 160-235 ℃.
Further, the method for preparing the heat-conducting polymer composite material by carrying out thermocompression treatment on the obtained material comprises the following steps: placing the prepared annular material in a high-temperature environment for axial compression treatment; wherein the high temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material. The compressive stress promotes the further densification of the strung crystal oriented along the annular direction, the distance between adjacent orientations shish is reduced, the interlocking degree of the kebab is improved, the mechanical property and the chain segment orientation degree are further improved, the flaky filler is oriented along the direction vertical to the force field under the compressive stress, the contact probability among the fillers is further provided for the outer layer of the pipe, and the construction of a heat conduction path is facilitated.
Further, in the compression treatment process, the material is subjected to thermal compression more than 0% until the final deformation of the material is less than or equal to 10%, and the pressing time is 20-40 min.
Furthermore, in the compression treatment process, the compression rate is more than 0 and less than or equal to 1 mm/min.
The second technical problem to be solved by the present invention is to provide a preparation method of the above heat conductive polymer composite material, wherein the preparation method comprises: firstly, preparing a crystal-type high polymer material and a heat-conducting filler into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction to prepare the heat-conducting high polymer composite material; wherein the addition amount of the heat-conducting filler is 0-40 wt% of the mass of the crystalline polymer material.
The third technical problem to be solved by the present invention is to provide a method for simultaneously improving the mechanical properties and the thermal conductivity of a crystalline polymer material, wherein the method comprises: firstly, preparing a crystalline polymer material into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction.
Further, the method comprises the following steps: adding flaky heat-conducting filler into a crystalline polymer material, wherein the addition amount of the heat-conducting filler is 1-40 wt% of the crystalline polymer.
Further, the method for simultaneously improving the mechanical property and the thermal conductivity of the crystalline polymer material comprises the following steps: firstly, melting and uniformly mixing a crystalline polymer material and a heat-conducting filler, and then applying a circumferential shear field by using a rotary shearing device to prepare an annular material with a shish-kebab series crystal structure; then placing the obtained annular material in a high-temperature environment for axial compression treatment; wherein the high temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material.
The fourth technical problem to be solved by the present invention is to provide a method for simultaneously improving the thermal conductivity of a crystalline polymer in the orientation direction and the thermal conductivity of the crystalline polymer in the vertical direction, wherein the method comprises: firstly, preparing a crystalline polymer material into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction.
Further, the method comprises the following steps: adding flaky heat-conducting filler into the crystalline polymer material, wherein the addition amount of the heat-conducting filler is 1-40 wt% of the crystalline polymer material.
Further, the method for simultaneously improving the orientation direction heat conductivity coefficient and the vertical direction heat conductivity coefficient of the crystalline polymer comprises the following steps: firstly, melting and uniformly mixing a crystalline polymer material and a heat-conducting filler, and then applying a circumferential shear field by using a rotary shearing device to prepare an annular material with a shish-kebab series crystal structure; then placing the obtained annular material in a high-temperature environment for axial compression treatment; wherein the high temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material.
The invention has the beneficial effects that:
in the prior art, the thermal conductivity is improved on the premise of greatly reducing the mechanical property of the polymer by filling the polymer with large volume parts of the thermal conductive filler, but the mechanical property and the thermal conductivity are simultaneously improved by firstly utilizing a mode of constructing the crystal string, and then the thermal conductivity and the mechanical property of the composite material are further improved by applying thermal compression post-treatment in the axial direction.
According to the invention, a heat-conducting filler such as BN is added into a crystalline high polymer material such as high-density polyethylene resin, and a circumferential rotating shear force field is firstly applied to form a unique shish-kebab series crystal structure and a structure with selective distribution of the filler, so that a composite material with heat conduction in both shish and kebab directions and high mechanical property is formed; because the special self-reinforcing shish-kebab structure can conduct heat in the orientation direction and the vertical orientation direction, the filling of the filler is favorable for further constructing a heat conduction path between the filler and the string crystal filler. The tensile strength of the composite material is as high as 46.0MPa, the tensile strength is improved by 182% compared with that of a traditional sample R0C10UT, and the thermal conductivity in the orientation direction and the vertical orientation direction are respectively improved by 26.4% and 15.4%. Furthermore, the high temperature of the axial hot compression molding is beneficial to improving the crystallinity of the crystal, meanwhile, the compression stress promotes the compactness between shish, the deepening of the interlocking degree between kebabs is promoted, and the mechanical property and the heat conductivity of the kebab are further improved; the tensile strength of the composite material R8C10PT after the thermal compression treatment is as high as 75.0MPa, the tensile strength is improved by 38.7 percent compared with that of a sample R8C10UT before the treatment, and the thermal conductivity in the orientation direction and the vertical orientation direction are respectively improved by 11.7 percent and 7.7 percent. And the tensile strength of the composite material R8C25PT after the thermal compression treatment is up to 48.0MPa, the tensile strength is improved by 28.3 percent compared with that of the sample R8C25UT before the treatment, and the thermal conductivity in the orientation direction and the vertical orientation direction are respectively improved by 7.0 percent and 21.4 percent.
Drawings
FIG. 1 shows the tensile strength results of the composites obtained in examples 1 to 8 of the present invention.
Fig. 2a and 2b thermal conductivity results for composites obtained according to examples 1-8 of the present invention.
FIG. 3 is a schematic view of the orientation direction of the composite material obtained In examples 1 to 8 of the present invention, In which In-plane represents the circumferential direction and Out-plane represents the axial direction; (002) represents the radial direction of BN, (100) represents the thickness direction of BN; in-plane indicates the shish direction at a core rod rotation speed of 8rpm, and Out-plane indicates the kebab direction at a core rod rotation speed of 8 rpm.
FIG. 4 shows the results of the degree of orientation of the composite materials obtained in examples 1 to 8 of the present invention; the diffraction intensity I (002)/I (100) is expressed as the degree of orientation of the filler.
FIG. 5 is a graph showing the results of the degrees of crystal orientation of the composite materials obtained in examples 1 to 8 of the present invention, wherein fa, fb and fc are respectively referred to as a-axis of crystallization, b-axis of crystallization and c-axis of crystallization; fc represents the final degree of orientation of the crystal.
FIG. 6 shows the crystallinity results of the composite materials obtained in examples 1 to 8 of the present invention; figure 6 shows that the crystallinity of the samples increases with both rotational shear and axial thermal compression.
FIG. 7 shows the tensile strength results of the composites obtained in examples 9 to 12 of the present invention.
FIG. 8 shows the thermal conductivity results of the composite materials obtained in examples 9 to 12 of the present invention.
Fig. 9 is a schematic diagram of the mechanism for enhancing the mechanical properties and thermal conductivity of the heat-conductive polymer composite material of the present invention.
Detailed Description
The invention firstly prepares materials such as high-density polyethylene and the like into materials with a crystal structure, the materials with the crystal structure have good thermal conductivity and mechanical property in the orientation direction and the direction vertical to the orientation direction, and under the process condition of annular shearing, the dispersibility of the filler is favorably improved, and the larger the shearing rate is, the filler tends to the outer layer enrichment of the product due to the action of centrifugal force. At the moment, the filler of the outer layer is easy to form good contact to construct a heat conduction channel, and the filler of the inner layer is easy to form a self-reinforced crystal string structure, so that the balance of heat conductivity and mechanical property is achieved.
The key point of the invention for preparing the composite material with high mechanical property and balanced thermal conductivity is that a two-step method is adopted to control the compactness of a polymer base shish-kebab structure and the orientation of a flaky filler so as to obtain the composite material with high mechanical property and thermal conductivity: firstly, melting and blending a high-density polyethylene matrix and a BN filler by a double screw, and granulating; secondly, the particles are used for a rotary shearing device to prepare a ring-shaped workpiece oriented along the circumferential direction; and thirdly, placing the annular workpiece in a high-temperature environment and carrying out axial compression treatment. The second step of circumferential shearing is beneficial to selective distribution of the filler on the outer layer of the workpiece and formation of a stable series crystal structure, the third step of circumferential shearing is beneficial to improvement of the shish-kebab crystal compactness and the interlocking degree between kebabs, and meanwhile, a heat conduction path of the oriented filler is constructed, so that the polymer matrix composite obtained in the two steps can further improve the mechanical property and the heat conductivity of the polymer matrix composite.
Embodiments of the present invention will be described in detail below with reference to examples, but it will be understood by those skilled in the art that the following examples are only illustrative of the present invention and should not be construed as limiting the scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.
Examples 1 to 8
A preparation method for preparing a heat-conducting composite material with a compact crystal and oriented filler structure by adopting rotary shearing and axial hot compression comprises the following specific steps:
composite material with series crystal structure, dispersion and selective distribution of filler
Melting and blending the h-BN filler and HDPE (the trademark is HDPE100s) by using double screws and granulating; the particles are then used in a rotary shearing device (namely a rotary pipe making device disclosed in patent application No. 2019110377859, which comprises an extruder, a motor, an upper die, a lower die, a core rod, a rotary conductive mechanism, a cooling mechanism and an electric box), the temperature of the upper die and the lower die is 150 ℃, the temperature of the extruder is 160-235 ℃, the motor drives the core rod to apply a circumferential shearing field with the rotating speed of 8rpm, and meanwhile, the polymer melt is cooled by starting an internal and external oil cooling mode, so that a string crystal structure and dispersed fillers are retained to the maximum degree to enable the particles to tend to be selectively distributed on an outer layer.
Preparation of composite system of crystal compact and oriented filler
Cutting a 10mm sample from the HDPE/h-BN pipe prepared in the step one along the cross section direction, horizontally placing the end face of the HDPE/h-BN pipe on a universal tensile testing machine, raising the temperature of an oven from room temperature to 125 ℃, stably preheating for 2min after the temperature is reached, then lowering the upper pressure at a constant speed and applying a compressive stress until the deformation amount is 5%, standing still, and keeping for 30 min; the direction of compression is in the direction of the out-plane in fig. 3, and the arrow of "stress" in fig. 7.
The specific thermal compression process may be:
for convenience of description, the example samples were marked according to the mandrel rotation speed of the rotary shearing apparatus, the content of h-BN, and whether or not post-treatment (thermo-compression treatment) was performed; for example, "RxCyUT" and "RxCyPT" denote untreated and post-treated samples, where Rx denotes the mandrel speed (R0 and R8 denote 0rpm and 8rpm, respectively) and Cy denotes the h-BN content (0 wt% and 10 wt%, respectively, for C0 and C10); for example, R0C10PT indicates that a sample having an h-BN content of 10 wt% was prepared by a mandrel rotation speed of 0rpm and subjected to a post-treatment process.
The preparation process of R0C0UT is as follows: extruding HDPE particles through an extruder screw at the rotating speed of 8Hz, filling the HDPE particles into a mold cavity at the temperature of 150 ℃, and controlling the pressure maintaining pressure to be 5 HZ; the rotation speed of the core rod is 0rpm, a cooling system is started, and the inner part and the outer part are cooled to the temperature of the mold lower than 110 ℃; then, the sample was cut into a 10mm sample in the axial direction.
TABLE 1 thermal conductivity and tensile Strength results for samples from examples 1-8
| In-plane/thermal conductivity | Out-plane/thermal conductivity | Tensile strength | ||
| Example 1 | R0C0UT | 0.39 | 0.39 | 20.4 |
| Example 2 | R0C10UT | 0.48 | 0.47 | 16.3 |
| Example 3 | R0C0PT | 0.42 | 0.41 | 22.4 |
| Example 4 | R0C10PT | 0.52 | 0.5 | 21.9 |
| Example 5 | R8C0UT | 0.53 | 0.45 | 84.9 |
| Example 6 | R8C10UT | 0.6 | 0.52 | 46.0 |
| Example 7 | R8C0PT | 0.54 | 0.46 | 95.7 |
| Example 8 | R8C10PT | 0.67 | 0.56 | 75 |
Examples 9 to 12
A preparation method for preparing a heat-conducting composite material with a compact crystal and oriented filler structure by adopting rotary shearing and axial hot compression comprises the following specific steps:
composite material with series crystal structure, dispersion and selective distribution of filler
Melting and blending the h-BN filler and HDPE (the trademark is HDPE 4731B) by using double screws and granulating; the particles are then used in a rotary shearing device (namely a rotary pipe making device disclosed in patent application No. 2019110377859, which comprises an extruder, a motor, an upper die, a lower die, a core rod, a rotary conductive mechanism, a cooling mechanism and an electric box), the temperature of the upper die and the lower die is 150 ℃, the temperature of the extruder is 160-235 ℃, the motor drives the core rod to apply a circumferential shearing field with the rotating speed of 8rpm, and meanwhile, the polymer melt is cooled by starting an internal and external oil cooling mode, so that a string crystal structure and dispersed fillers are retained to the maximum degree to enable the particles to tend to be selectively distributed on an outer layer.
Preparation of composite system of crystal compact and oriented filler
Cutting a 10mm sample from the HDPE/h-BN pipe prepared in the step one along the cross section direction, horizontally placing the end face of the HDPE/h-BN pipe on a universal tensile testing machine, raising the temperature of an oven from room temperature to 125 ℃, stably preheating for 2min after the temperature is reached, then lowering the upper pressure at a constant speed and applying a compressive stress until the deformation amount is 5%, standing still, and keeping for 30 min; the direction of compression is in the direction of the out-plane in fig. 3, and the arrow of "stress" in fig. 7.
The specific thermal compression process may be:
for convenience of description, the example samples were marked according to the mandrel rotation speed of the rotary shearing apparatus, the content of h-BN, and whether or not post-treatment (thermo-compression treatment) was performed; for example, "RxCyUT" and "RxCyPT" denote untreated and post-treated samples, where Rx denotes the mandrel speed (R0 and R8 denote 0rpm and 8rpm, respectively) and Cy denotes the h-BN content (0 wt% and 25wt%, respectively, for C0 and C25); for example, R0C25PT indicates that a sample having an h-BN content of 25wt% was prepared by a mandrel rotation speed of 0rpm and subjected to a post-treatment process.
The preparation process of R0C25UT is as follows: extruding and granulating HDPE particles and 25wt% BN double screw, extruding at 8Hz by an extruder screw, filling the obtained product into a mold cavity at 150 ℃, and controlling the pressure to be 5 HZ; the rotation speed of the core rod is 0rpm, a cooling system is started, and the inner part and the outer part are cooled to the temperature of the mold lower than 110 ℃; then, the sample was cut into a 10mm sample in the axial direction.
TABLE 2 thermal conductivity and tensile Strength results for samples from examples 9-12
| In-plane/thermal conductivity | Out-plane/thermal conductivity | Tensile strength | ||
| Example 9 | R0C25UT | 0.82 | 0.91 | 18.67 |
| Example 10 | R0C25PT | 0.88 | 1.07 | 21.26 |
| Example 11 | R8C25UT | 1.15 | 0.84 | 39.69 |
| Example 12 | R8C25PT | 1.23 | 1.02 | 47.97 |
Claims (16)
1. A heat-conducting polymer composite material is characterized by being prepared by the following method: firstly, preparing a crystal-type high polymer material and a heat-conducting filler into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction to prepare the heat-conducting high polymer composite material; wherein the addition amount of the heat-conducting filler is 0-40 wt% of the mass of the crystalline polymer material;
the method of the thermal compression treatment comprises the following steps: placing the obtained material in a high-temperature environment for axial compression treatment; wherein the high-temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material; in the compression treatment process, hot compression is carried out for 0-40 min until the final deformation of the material is less than or equal to 10%, and the pressing time is 20-40 min; the compression rate is more than 0 and less than or equal to 1 mm/min.
2. A heat-conducting polymer composite material according to claim 1, wherein the amount of the heat-conducting filler added is 1-40 wt% of the mass of the crystalline polymer material.
3. A heat-conducting polymer composite material according to claim 2, wherein the amount of the heat-conducting filler added is 1-25 wt% of the mass of the crystalline polymer material.
4. The heat-conducting polymer composite material according to claim 1, wherein the crystalline polymer material is one of high-density polyethylene, polypropylene, polyvinyl chloride, or polylactic acid.
5. The thermally conductive polymer composite according to claim 1, wherein the thermally conductive filler is selected from a sheet-like thermally conductive filler.
6. The thermally conductive polymer composite according to claim 5, wherein the thermally conductive filler is hexagonal boron nitride or graphene.
7. The heat-conducting polymer composite material according to claim 5 or 6, wherein the particle size of the heat-conducting filler is 100nm to 10 um.
8. The heat-conducting polymer composite material according to claim 1 or 2, wherein the crystalline polymer material and the heat-conducting filler are prepared into the material with the shish-kebab crystal structure by the following method: firstly, melting and uniformly mixing a crystalline polymer material and a heat-conducting filler, then applying a circumferential shear field by using a rotary shearing device to prepare an annular material with a shish-kebab series crystal structure, wherein the filler is selectively distributed on the outer layer of the annular material.
9. The heat-conducting polymer composite material according to claim 8, wherein in the process of preparing the material with shish-kebab series crystal structure by applying a circumferential shear field by using a rotary shearing device, the rotary shearing device comprises an extruder, an upper die, a lower die, a core rod and a cooling mechanism, wherein the rotation speed of a screw of the extruder is 8 Hz-12 Hz, the processing temperature is 160-235 ℃, the pressure maintaining pressure is 3-5 MPa, the temperature of the die is 140-180 ℃, the rotation speed of the core rod is 4-12rpm, the shearing time of the core rod is 2-8 min, a cooling system is started during shearing, and the upper die and the lower die are demolded at the cooling temperature of less than 110 ℃.
10. The preparation method of the heat-conducting polymer composite material as claimed in any one of claims 1 to 9, wherein the preparation method comprises the following steps: firstly, preparing a crystal-type high polymer material and a heat-conducting filler into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction to prepare the heat-conducting high polymer composite material; wherein the addition amount of the heat-conducting filler is 0-40 wt% of the mass of the crystalline polymer material.
11. A method for simultaneously improving the mechanical property and the heat conductivity of a crystalline polymer material is characterized by comprising the following steps: firstly, preparing a crystalline polymer material into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction; the thermal compression treatment method comprises the following steps: placing the obtained material in a high-temperature environment for axial compression treatment; wherein the high-temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material; in the compression treatment process, hot compression is carried out for 0-40 min until the final deformation of the material is less than or equal to 10%, and the pressing time is 20-40 min; the compression rate is more than 0 and less than or equal to 1 mm/min.
12. The method as claimed in claim 11, wherein a flake-shaped thermal conductive filler is added to the crystalline polymer material, and the amount of the thermal conductive filler added is 1-40 wt% of the crystalline polymer.
13. The method of claim 11, wherein the method for simultaneously improving the mechanical property and the thermal conductivity of the crystalline polymer material comprises: firstly, melting and uniformly mixing a crystalline polymer material and a heat-conducting filler, and then applying a circumferential shear field by using a rotary shearing device to prepare an annular material with a shish-kebab series crystal structure; then placing the obtained annular material in a high-temperature environment for axial compression treatment; wherein the high temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material.
14. A method for simultaneously improving the orientation direction heat conductivity and the vertical direction heat conductivity of a crystalline polymer is characterized by comprising the following steps: firstly, preparing a crystalline polymer material into a material with a shish-kebab series crystal structure, and then carrying out thermal compression treatment on the obtained material along the kebab direction; the thermal compression treatment method comprises the following steps: placing the obtained material in a high-temperature environment for axial compression treatment; wherein the high-temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material; in the compression treatment process, hot compression is carried out for 0-40 min until the final deformation of the material is less than or equal to 10%, and the pressing time is 20-40 min; the compression rate is more than 0 and less than or equal to 1 mm/min.
15. The method for simultaneously improving the orientation direction thermal conductivity and the vertical direction thermal conductivity of the crystalline polymer according to claim 14, wherein the method comprises: adding flaky heat-conducting filler into the crystalline polymer material, wherein the addition amount of the heat-conducting filler is 1-40 wt% of the crystalline polymer material.
16. The method of claim 14 or 15, wherein the method for simultaneously increasing the orientation direction thermal conductivity and the vertical direction thermal conductivity of the crystalline polymer comprises: firstly, melting and uniformly mixing a crystalline polymer material and a heat-conducting filler, and then applying a circumferential shear field by using a rotary shearing device to prepare an annular material with a shish-kebab series crystal structure; then placing the obtained annular material in a high-temperature environment for axial compression treatment; wherein the high temperature environment is 5-20 ℃ lower than the melting point of the crystalline polymer material.
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| CN101488373A (en) * | 2009-02-27 | 2009-07-22 | 邓华 | Conductive composite material, preparation and use thereof |
| CN101787178A (en) * | 2010-03-09 | 2010-07-28 | 王全胜 | Heat-conduction electric insulation composite material component and manufacturing method thereof |
| RU2643985C1 (en) * | 2017-01-16 | 2018-02-06 | Федеральное государственное бюджетное учреждение науки Институт химической физики им. Н.Н. Семенова Российской академии наук (ИХФ РАН) | Heat-conductive electrically insulating composite material |
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| US10385250B2 (en) * | 2016-06-14 | 2019-08-20 | Nano And Advanced Materials Institute Limited | Thermally conductive composites and method of preparing same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN101488373A (en) * | 2009-02-27 | 2009-07-22 | 邓华 | Conductive composite material, preparation and use thereof |
| CN101787178A (en) * | 2010-03-09 | 2010-07-28 | 王全胜 | Heat-conduction electric insulation composite material component and manufacturing method thereof |
| RU2643985C1 (en) * | 2017-01-16 | 2018-02-06 | Федеральное государственное бюджетное учреждение науки Институт химической физики им. Н.Н. Семенова Российской академии наук (ИХФ РАН) | Heat-conductive electrically insulating composite material |
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| Bin Chen et al.The effect of high-temperature annealing on thermal properties and morphology of polyethylene pipes prepared by rotational shear.《Polymer》.2020,第204卷(第2020期),第1-10页. * |
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