A three-dimensional printing-based directional high-thermal-conductivity impact-resistant isotactic polypropylene composite material and a preparation method thereof
By combining compression molding and 3D printing technologies with silane coupling agent-modified thermally conductive fillers, adjusting the orientation degree, and performing thermal annealing, directional high thermal conductivity and impact-resistant isotactic polypropylene composite materials were prepared. This solved the problems of limited filler orientation degree and insufficient mechanical properties, achieving high directional thermal conductivity and excellent impact strength.
Patent Information
- Application Number
- CN202411697465.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-26
- Publication Date
- 2025-11-28
- Estimated Expiration
- 2044-11-26
AI Technical Summary
Existing high thermal conductivity composite materials suffer from limited filler orientation and insufficient mechanical properties, resulting in insufficient thermal conductivity and poor mechanical properties in a certain direction.
By using compression molding and 3D printing technologies, combined with silane coupling agent surface modification thermally conductive filler, adjusting the filler orientation, and improving mechanical properties through hot annealing, directional high thermal conductivity and impact-resistant isotactic polypropylene composite materials are prepared.
It achieves high directional thermal conductivity and excellent impact strength, solving the problems of limited filler orientation and insufficient mechanical properties in existing technologies, and improving the overall performance of the material.
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Figure CN119661933B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of heat-conducting materials, and relates to a directional high-thermal-conductivity impact-resistant composite material based on three-dimensional printing and a preparation method thereof. BACKGROUND
[0002] High-thermal-conductivity composites have been widely demanded in the industrial fields of energy, electronic packaging, electrical equipment, aerospace, etc. in recent years, and have attracted more and more attention from researchers in various fields. Polymer materials have many advantages such as easy processing, low cost, light weight, etc. and the research on thermal-conductivity composites based on polymer materials is increasing.
[0003] In addition, anisotropic high-thermal-conductivity fillers such as carbon fibers (CF), graphene and hexagonal boron nitride nanosheets have attracted widespread attention in the field of thermal-conductivity polymers due to their high thermal conductivity, low density, high strength, good toughness, corrosion resistance, easy processing and other advantages.
[0004] However, there are two problems in the current related research: on the one hand, Xu et al. pointed out in "A Roadmap Review of Thermally Conductive Polymer Composites: Critical Factors, Progress, and Prospects" that CF or graphene is randomly mixed and dispersed in the composite with the matrix. This method utilizes the high thermal conductivity of the filler itself to reduce the scattering of phonons inside the composite material, but the thermal-conductivity material manufactured by this method is usually isotropic. In comparison, anisotropic thermal-conductivity materials can achieve higher thermal conductivity in a certain direction with less filler, meeting greater application requirements. On the other hand, Wang et al. pointed out in "3D-printing of segregated carbon nanotube / polylactic acid composite with enhanced electromagnetic interference shielding and mechanical performance" that due to the different surface adhesion between different material layers, the composite material can obtain excellent thermal-conductivity performance by adding a high content of filler, but the mechanical properties will rapidly decay with the increase of the content of the thermal-conductivity filler, resulting in certain limitations in mechanical properties.
[0005] Based on the above technical problems, it is urgent to develop a technical route that can solve the problems of limited orientation of the filler of the directional high-thermal-conductivity composite material and insufficient mechanical properties of the material. SUMMARY
[0006] The present application aims at the problems of limited orientation degree of fillers of directional high-thermal-conductivity composites in the prior art, and insufficient mechanical properties, etc., and utilizes a molding method to prepare a three-dimensional printing isotactic polypropylene substrate so that the thermal-conductivity fillers increase the orientation degree by the effect of the surface tension of the wire in the printing process, the thermal-conductivity fillers modified by a silane coupling agent are used to sufficiently adjust the orientation of the fillers by the difference in coupling degree, a three-dimensional printing is used to prepare a directional high-thermal-conductivity impact-resistant composite material, and finally, the mechanical properties are improved by heat annealing without affecting the orientation of the fillers as much as possible. The method can make the prepared thermal-conductivity composite material have the advantages of high shape controllability, high directional thermal conductivity, high orientation degree of fillers, excellent impact strength, etc.
[0007] The technical scheme of the present application is as follows:
[0008] A directional high-thermal-conductivity impact-resistant isotactic polypropylene composite material based on three-dimensional printing, comprising a molded polymer substrate and a directional high-thermal-conductivity impact-resistant isotactic polypropylene composite material formed by three-dimensional printing and heat annealing treatment of the isotactic polypropylene composite material filled with the surface-modified thermal-conductivity fillers.
[0009] The high-thermal-conductivity fillers are at least one of carbon fibers, carbon nanotubes, graphene nanosheets, graphene fibers, and boron nitride nanosheets, and are preferably carbon fibers.
[0010] The polymer substrate is molded by "Ziegler-Natta" catalytic isotactic polypropylene or metallocene catalytic isotactic polypropylene, different types of polypropylene have different adhesion to the printing wire, so that the surface tension of the wire can be adjusted to increase the orientation degree of the thermal-conductivity fillers in the composite material. Preferably, it is "Ziegler-Natta" catalytic isotactic polypropylene.
[0011] The silane coupling agent is one of γ-aminopropyltrimethoxysilane (KH550), γ-methacryloyloxypropyltrimethoxysilane (KH-570), and Titanate Coupling Agent Lica 12 (Lica 12), and is further preferably KH550.
[0012] The mass ratio of the thermal-conductivity fillers to the isotactic polypropylene is 3:2.
[0013] The thickness of the polymer substrate is 1mm-5mm.
[0014] A preparation method of a directional high-thermal-conductivity impact-resistant composite material, comprising the following steps:
[0015] (1) Preparation of a polymer substrate with increased fiber orientation:
[0016] The isotactic polypropylene is put into a hot-pressing mold for molding, wherein the molding temperature is 200-250 DEG C, the molding pressure is 10-20 MPa, and the molding time is 10-15 min; the surface tension of the printing wire is controlled by controlling whether the isotactic polypropylene matches the adhesion force of the printed wire, so as to further control the orientation degree of the fiber.
[0017] (2) Surface modification of the thermally conductive filler:
[0018] The ethanol and water are mixed in a volume ratio of 9:1, and then a coupling agent is added to the mixed solution to obtain a modifier, wherein the mass ratio of the mixed solution to the silane coupling agent is 98.5:1.5-97:93; the thermally conductive filler is added to the modifier and ultrasonically treated for 1 hour and then left to stand for 12 hours, and after being taken out, is dried at 80 DEG C for 2 hours; in addition to the improved compatibility, different coupling agents are used to obtain different viscosities, so as to control the induced orientation degree of the fiber by the shear flow.
[0019] (3) Preparation of the oriented high-thermal-conductivity impact-resistant composite material:
[0020] The modified thermally conductive filler and the isotactic polypropylene are mixed in a mass ratio of 3:2, and then are added to a single-screw extruder to prepare a standard wire with a diameter of 1.75 mm; the extrusion temperature is higher than the melting temperature of the polymer matrix by 20-50 DEG C, and the extrusion speed is 25-50 r / min; according to a three-dimensional digital model of the desired oriented thermally conductive product, a uniaxially oriented ordered high-thermal-conductivity impact-resistant composite material part is prepared by a fused deposition technology; the printing speed is 50-80 mm / s, and the extruded wire is controlled to be stacked along the specified direction layer by layer.
[0021] (4) Heat annealing treatment:
[0022] The printed three-dimensional part is put into an oven at 85-95 DEG C for 12-24 h. The silane coupling agent is one of gamma-aminopropyltrimethoxysilane (KH550), gamma-methacryloyloxypropyltrimethoxysilane (KH-570), and Titanate Coupling Agent Lica 12 (Lica 12), and is further preferably KH550.
[0023] The heat annealing temperature is higher than the glass transition temperature of the polymer matrix by 10-15 DEG C.
[0024] Advantages of the present application:
[0025] ① The present application effectively improves the problem of limited orientation degree of the filler in the prior art oriented high-thermal-conductivity composite material, and obtains higher out-of-plane thermal conductivity.
[0026] 2. The application effectively improves the imbalance between mechanical properties and high out-of-plane thermal conductivity of the directional high thermal conductivity composite material in the prior art, and simultaneously enhances both in the composite material. BRIEF DESCRIPTION OF DRAWINGS
[0027] Figure 1 Schematic diagram of the polypropylene substrate described in the examples;
[0028] Figure 2 Schematic diagram of the final three-dimensional structure printed entity having a thermally conductive and high impact material described in the examples. DETAILED DESCRIPTION
[0029] The specific embodiments of the application are further described below in conjunction with the drawings and technical solutions.
[0030] Example 1
[0031] A directional high thermal conductivity impact-resistant composite material based on three-dimensional printing and a preparation method thereof, the preparation method comprising the following steps:
[0032] Preparation of the polypropylene substrate:
[0033] Isotactic polypropylene with a brand of T30S was placed into a hot-pressing mold with the same size as the substrate, and hot-pressed for 10 minutes at a mold pressing temperature of 200℃ and a mold pressing pressure of 10MPa, and cold-pressed for 5 minutes.
[0034] Preparation of the modifier solution:
[0035] Ethanol and water were mixed in a volume ratio of 9:1 to obtain a 500mL mixed solution, and then KH550 silane coupling agent was added to the mixed solution to obtain a modifier, wherein the specific gravity of the mixed solution to the silane coupling agent was 98.5:1.5, that is, 6.17g of KH550 was added to the mixed solution and mixed uniformly to obtain the modifier.
[0036] Preparation of the modified carbon fiber:
[0037] The carbon fiber was added to the modifier and ultrasonicated for 1 hour and left to stand for 12 hours, and after taking out, it was dried at 80℃ for 2 hours, and the process was repeated twice.
[0038] Preparation of the directional high thermal conductivity impact-resistant composite material:
[0039] The modified carbon fiber and the polypropylene were mixed uniformly in a ratio of 3:2, and then added to a single screw extruder to prepare a standard wire of 1.75mm. The extrusion temperature was 200℃, and the extrusion speed was 35r / min. According to the three-dimensional digital model of the required directional thermal conductivity product, a uniaxial directional ordered high thermal conductivity impact-resistant composite material part was prepared by a fused deposition technology. The printing speed was 50mm / s, and the extruded wire was controlled to stack and accumulate along the specified direction layer by layer.
[0040] Heat annealing treatment:
[0041] The printed three-dimensional product is placed in an 85℃ oven for 12 hours.
[0042] The out-of-plane thermal conductivity of the final product of Example 1 is 4.92 W / (m·K), the impact strength is 35.11 KJ / m 2 , and the tensile strength is 45.56 MPa.
[0043] Example 2
[0044] A three-dimensional printing-based directional high-thermal-conductivity impact-resistant composite material and a preparation method thereof, the preparation method comprising the following steps:
[0045] Preparation of a polypropylene substrate:
[0046] Isotactic polypropylene with a brand of T30S is placed in a hot-pressing mold with the same size as the substrate, and hot-pressed at a mold pressing temperature of 200℃ and a mold pressing pressure of 10 MPa for 10 minutes, and cold-pressed for 5 minutes.
[0047] Preparation of a modifier solution:
[0048] Ethanol and water are mixed in a volume ratio of 9:1 to obtain a 500 mL mixed solution, acetic acid is added until the pH value is 4.0, and then KH570 silane coupling agent is added to the mixed solution to obtain a modifier, wherein the proportion of the mixed solution to the silane coupling agent is 98.5:1.5, that is, 6.17 g of KH570 is added to the mixed solution and mixed uniformly to obtain the modifier.
[0049] Preparation of modified carbon fibers:
[0050] The carbon fibers are added to the modifier and ultrasonically treated for 1 hour and left to stand for 12 hours, and after being taken out, they are dried at 80℃ for 2 hours, and the process is repeated twice.
[0051] Preparation of a directional high-thermal-conductivity impact-resistant composite material:
[0052] The modified carbon fibers and the polypropylene are mixed uniformly in a ratio of 3:2, and then added to a single-screw extruder to prepare a standard wire of 1.75 mm. The extrusion temperature is 200℃, and the extrusion speed is 35 r / min. According to the three-dimensional digital model of the required directional thermal conductive product, a uniaxially oriented and ordered high-thermal-conductivity impact-resistant composite material product is prepared by a fused deposition technology. The printing speed is 50 mm / s, and the extruded wire is controlled to be stacked layer by layer along the specified direction.
[0053] Heat annealing treatment:
[0054] The printed three-dimensional product is placed in an 85℃ oven for 12 hours.
[0055] The out-of-plane thermal conductivity of the final product of Example 3 was 4.27 W / (m·K), the impact strength was 31.05 KJ / m 2 , and the tensile strength was 42.88 MPa.
[0056] Example 3
[0057] A three-dimensional printing-based directional high-thermal-conductivity impact-resistant composite material and a preparation method thereof, the preparation method comprising the following steps:
[0058] Preparation of a polypropylene substrate:
[0059] Isotactic polypropylene with a brand of T30S was placed into a hot-pressing mold with the same size as the substrate, and hot-pressing was performed at a mold pressing temperature of 200℃ and a mold pressing pressure of 10 MPa for 10 minutes, and cold pressing was performed for 5 minutes.
[0060] Preparation of a modifier solution:
[0061] 500 mL of a mixed solution was obtained by mixing ethanol and water at a volume ratio of 9:1, acetic acid was added until the pH value was 4.0, and then Lica12 titanate coupling agent was added to the mixed solution to obtain a modifier, wherein the specific gravity of the mixed solution to the silane coupling agent was 98.5:1.5, that is, 6.17 g of Lica12 was added to the mixed solution and mixed uniformly to obtain the modifier.
[0062] Preparation of modified carbon fibers:
[0063] The carbon fibers were added to the modifier and ultrasonically treated for 1 hour and left to stand for 12 hours, and after being taken out, they were dried at 80℃ for 2 hours, and the process was repeated twice.
[0064] Preparation of a directional high-thermal-conductivity impact-resistant composite material:
[0065] The modified carbon fibers and the polypropylene were mixed uniformly at a ratio of 3:2, and then were added to a single-screw extruder to prepare a standard wire with a diameter of 1.75 mm. The extrusion temperature was 200℃, and the extrusion speed was 35 r / min. According to the three-dimensional digital model of the required directional thermal conductive product, a uniaxially oriented and ordered high-thermal-conductivity impact-resistant composite material product was prepared by a fused deposition technology. The printing speed was 50 mm / s, and the extruded wire was controlled to be stacked layer by layer along the specified direction.
[0066] Thermal annealing treatment:
[0067] The printed three-dimensional product was placed in an oven at 85℃ for 12 hours.
[0068] The out-of-plane thermal conductivity of the final product of Example 4 was 4.11 W / (m·K), the impact strength was 29.75 KJ / m 2 , and the tensile strength was 40.24 MPa.
[0069] Comparative Example 1
[0070] Comparative Example 1 uses a substrate made of polyetherimide compared to Example 1. A three-dimensional printing based directional high thermal conductive impact-resistant composite material and a preparation method thereof, the preparation method comprising the following steps:
[0071] Preparation of polypropylene substrate:
[0072] Polyetherimide (PEI) with a grade of PEI-1000 was placed into a hot-pressing mold with the same size as the substrate, and hot-pressed at a mold pressing temperature of 360°C and a mold pressing pressure of 20 MPa for 10 minutes, and cold-pressed for 5 minutes.
[0073] Preparation of modifier solution:
[0074] Ethanol and water were mixed in a volume ratio of 9:1 to obtain a 500 mL mixed solution, and then KH550 silane coupling agent was added to the mixed solution to obtain a modifier, wherein the specific gravity of the mixed solution to the silane coupling agent was 98.5:1.5, that is, 6.17 g of KH550 was added to the mixed solution and mixed uniformly to obtain the modifier.
[0075] Preparation of modified carbon fiber:
[0076] The carbon fiber was added to the modifier and ultrasonically treated for 1 hour and left to stand for 12 hours, and after taking out, it was dried at 80°C for 2 hours, and the process was repeated twice.
[0077] Preparation of directional high thermal conductive impact-resistant composite material:
[0078] The modified carbon fiber and polypropylene were mixed uniformly in a ratio of 3:2, and then added to a single screw extruder to prepare a standard wire of 1.75 mm. The extrusion temperature was 200°C, and the extrusion speed was 35 r / min. According to the three-dimensional digital model of the required directional thermal conductive product, a uniaxially oriented and ordered high thermal conductive impact-resistant composite material part was prepared by a fused deposition technology. The printing speed was 50 mm / s, and the extruded wire was controlled to be stacked layer by layer along the specified direction.
[0079] Thermal annealing treatment:
[0080] The printed three-dimensional part was placed in an 85°C oven for 12 hours.
[0081] After detection, the out-of-plane thermal conductivity of the final product of Example 2 was 2.06 W / (m·K), the impact strength was 15.86 KJ / m 2 , and the tensile strength was 22.71 MPa. Compared with Example 1, the printing substrate of Comparative Example 1 was made of PEI by molding, and due to the serious mismatch of the adhesion between the extruded wire and the substrate, the surface tension experienced by the carbon fiber during printing was greatly reduced, thereby affecting the performance of the present embodiment.
[0082] Comparative Example 2
[0083] Comparative Example 2 uses a higher concentration of coupling agent than Example 1. A three-dimensional printing-based directional high-thermal-conductivity impact-resistant composite material and a preparation method thereof, the preparation method comprising the following steps:
[0084] Preparation of a polypropylene substrate:
[0085] Isotactic polypropylene with a brand of T30S was placed in a hot-pressing mold with the same size as the substrate, and hot-pressed at a mold temperature of 200°C and a mold pressure of 10 MPa for 10 minutes, and cold-pressed for 5 minutes.
[0086] Preparation of a modifier solution:
[0087] Ethanol and water were mixed in a volume ratio of 9:1 to obtain a 500 mL mixed solution, and then KH550 silane coupling agent was added to the mixed solution to obtain a modifier, wherein the proportion of the mixed solution to the silane coupling agent was 95:5, i.e., 21.34 g of KH550 was added to the mixed solution and mixed uniformly to obtain the modifier.
[0088] Preparation of modified carbon fibers:
[0089] The carbon fibers were added to the modifier and ultrasonically treated for 1 hour and left to stand for 12 hours, and then taken out and dried at 80°C for 2 hours, repeated twice.
[0090] Preparation of a directional high-thermal-conductivity impact-resistant composite material:
[0091] The modified carbon fibers and the polypropylene were mixed uniformly in a ratio of 3:2, and then added to a single-screw extruder to prepare a standard wire of 1.75 mm. The extrusion temperature was 200°C, and the extrusion speed was 35 r / min. According to the three-dimensional digital model of the required directional thermal-conductivity product, a uniaxially oriented and ordered high-thermal-conductivity impact-resistant composite material part was prepared by a fused deposition technology. The printing speed was 50 mm / s, and the extruded wire was controlled to be stacked and accumulated along the specified direction layer by layer.
[0092] Thermal annealing treatment:
[0093] The printed three-dimensional part was placed in an oven at 85°C for 12 hours.
[0094] It was detected that the out-of-plane thermal conductivity of the final product of Example 5 was 2.69 W / (m·K), and the impact strength was 22.13 KJ / m 2, the tensile strength is 30.84 MPa. Compared with Example 1, the melt strength of the composite material of Comparative Example 2 increases sharply due to the addition of excessive coupling agent, which reduces the external force (shear induction, tensile induction) on the carbon fibers at the nozzle, significantly reduces the uniaxial orientation order of the carbon fibers in the composite material, and finally makes the performance of the composite material decrease to different degrees.
Claims
1. A three-dimensional printing based, directionally high thermal conductive, impact resistant, isotactic polypropylene composite material, characterized in that, The oriented high thermal conductive impact isotactic polypropylene composite material is formed by three-dimensional printing and heat annealing treatment of the isotactic polypropylene composite material filled with surface-modified thermal conductive filler and molded by compression molding of a polymer substrate and the isotactic polypropylene composite material; The polymer substrate is molded by compression molding of "Ziegler-Natta" catalyzed isotactic polypropylene or metallocene catalyzed isotactic polypropylene; Surface modification of the thermal conductive filler: ethanol and water are mixed in a volume ratio of 9:1, and then a coupling agent is added to the mixed solution to obtain a modifier, wherein the mass ratio of the mixed solution to the coupling agent is 98.5:1.5; the thermal conductive filler is added to the modifier and ultrasonically treated for 1 hour and left to stand for 12 hours, and then dried at 80°C for 2 hours after being taken out; The mass ratio of the thermal conductive filler to the isotactic polypropylene in the isotactic polypropylene composite material filled with the surface-modified thermal conductive filler is 3:
2.
2. The oriented, high thermal conductive, impact resistant, isotactic polypropylene composite of claim 1, wherein, The thermal conductive filler is at least one of carbon fiber, carbon nanotube, graphene nanosheet, graphene fiber, and boron nitride nanosheet.
3. The oriented, high thermal conductive, impact resistant, isotactic polypropylene composite of claim 1, wherein, The thickness of the polymer substrate is 1 mm-5 mm.
4. A process for the preparation of a directionally high thermally conductive impact isotactic polypropylene composite material, characterized by, The steps are as follows: (1) Preparation of the isotactic polypropylene substrate: isotactic polypropylene is placed in a hot-pressing mold for compression molding, wherein the compression molding temperature is 200°C-250°C, the compression molding pressure is 10 MPa-20 MPa, and the compression molding time is 10 min-15 min; the surface tension of the printing wire is controlled by controlling whether the isotactic polypropylene is matched with the adhesion force of the printed wire; (2) Surface modification of the thermal conductive filler: ethanol and water are mixed in a volume ratio of 9:1, and then a coupling agent is added to the mixed solution to obtain a modifier, wherein the mass ratio of the mixed solution to the coupling agent is 98.5:1.5; the thermal conductive filler is added to the modifier and ultrasonically treated for 1 hour and left to stand for 12 hours, and then dried at 80°C for 2 hours after being taken out; (3) Preparation of the oriented high thermal conductive impact composite material: the modified thermal conductive filler and the isotactic polypropylene are mixed in a mass ratio of 3:2 and then added to a single-screw extruder to prepare a standard wire with a diameter of 1.75 mm; the extrusion temperature is higher than the melting temperature of the polymer substrate by 20°C-50°C, and the extrusion speed is 25 r / min-50 r / min; a uniaxially oriented ordered high thermal conductive impact composite material part is prepared by a fused deposition technology according to a three-dimensional digital model of a desired oriented thermal conductive product; the printing speed is 50 mm / s-80 mm / s, and the extruded wire is controlled to be stacked and accumulated along a specified direction layer by layer; (4) Heat annealing treatment: the printed three-dimensional part is placed in an oven at 85°C-95°C for 12 h-24 h.
5. The preparation method according to claim 4, characterized in that, The coupling agent is one of γ-aminopropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, and Titanate Coupling Agent Lica 12.