High-conductivity porous polymer composite material and preparation method thereof

Abstract

The invention discloses a high-conductivity porous polymer composite material and a preparation method thereof, and relates to the technical field of conductive composite materials. The high-conductivity porous polymer composite material is prepared by mixing polyether-ether-ketone, amino-functionalized graphene, a silver nanowire / carbon nanotube hybrid filler, a porous polyimide microsphere carrier, an ionic liquid and an antioxidant. The preparation method comprises the following steps: preparing amino-functionalized graphene; preparing a hybrid filler microsphere complex; performing mixing; preparing a porous prefabricated body; and carrying out mould pressing and shaping. According to the composite material disclosed by the invention, through multi-scale structural design and environment-friendly process innovation, high conductivity, high-strength mechanical properties and light weight are realized under the condition of low filler addition amount.

Description

Technical Field

[0001] The present invention relates to the technical field of conductive composite materials, and in particular to a highly conductive porous polymer composite material and a preparation method thereof. Background Art

[0002] Conductive polymer composites are a new type of material composed of a polymer matrix and conductive fillers through a specific composite method. Problems with traditional conductive fillers include: ① Poor interfacial bonding and compatibility between traditional conductive fillers (carbon black, metal fibers) and the polymer matrix, resulting in reduced mechanical properties of the composite. ② The interfacial inertness of traditional conductive fillers limits their dispersion when composited with the polymer matrix, leading to agglomeration and defects in the matrix, which in turn degrades the mechanical properties of the composite and the appearance of the finished product. ③ Due to the inherent limitations of traditional conductive fillers, high addition levels are typically required to achieve excellent electrical properties, which leads to processing difficulties, poor product stability control, and limited product performance. ④ Existing technologies typically increase the filler content to increase conductivity and thus improve electromagnetic shielding performance. However, increasing the filler content inevitably increases the density of the composite, and high-density materials, due to their inherent weight, limit the application range of the composite. ⑤ Adding a large amount of conductive carbon black not only reduces the strength of the polymer matrix but also increases its density, thereby reducing its toughness.

[0003] In recent years, the emergence of carbon nanotubes (CNTs) and graphene has garnered significant attention. Both CNTs and graphene possess excellent electrical conductivity, high specific strength, and high specific modulus, making them ideal fillers for toughening and reducing the drag of composite materials. Graphene, with its high specific surface area and excellent thermal, electrical, and mechanical properties, is a two-dimensional, sheet-like structure, while CNTs possess a one-dimensional, tubular structure with a large aspect ratio. By combining these two fillers, each overcomes its own shortcomings, forming a 3D network-like conductive structure with excellent electron conduction rates in both the axial and longitudinal directions, significantly reducing the percolation threshold compared to traditional conductive fillers. However, the following challenges remain: ① Due to their large aspect ratio and specific surface area, carbon nanofillers tend to agglomerate, resulting in low bonding strength at the interface with the matrix, which in turn reduces the mechanical properties of the composite material. ② Due to the random distribution of CNTs and graphene within the composite system, a high filler loading is often required to impart the desired conductive properties to the material. However, an excessively high filling amount will not only increase the preparation cost, but also affect the mechanical properties of the composite material, causing its performance to be significantly reduced, making it unable to meet the application requirements in certain specific fields and limiting its scope of use. ③ Uneven conductive fillers will adversely affect the uniform adhesion of the conductive fillers on the surface of the polymer matrix during subsequent mixing with the polymer matrix. ④ Due to the strong intermolecular forces between graphene sheets, graphene is very easy to agglomerate and is difficult to disperse in the polymer matrix, requiring the use of a large amount of dispersants, modifiers, etc. Therefore, how to effectively and evenly disperse carbon nanotubes and graphene in the polymer matrix and reduce the amount of conductive fillers used so that the composite material still has excellent conductive properties is one of the key issues in the preparation of conductive composite materials. Summary of the Invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0005] To this end, one of the objects of the present invention is to provide a highly conductive porous polymer composite material, and the second object of the present invention is to provide a method for preparing the highly conductive porous polymer composite material.

[0006] The first aspect of the present invention provides a highly conductive porous polymer composite material, which is prepared by mixing the following components: polyetheretherketone, amino-functionalized graphene, silver nanowire / carbon nanotube hybrid filler, porous polyimide microsphere carrier, ionic liquid and antioxidant.

[0007] Furthermore, the highly conductive porous polymer composite material is prepared by mixing the following components in parts by weight: 80-95 parts of polyetheretherketone, 2-6 parts of amino-functionalized graphene, 3-8 parts of silver nanowire / carbon nanotube hybrid filler, 10-20 parts of porous polyimide microsphere carrier, 0.5-2 parts of ionic liquid and 0.3-0.8 parts of antioxidant.

[0008] Furthermore, the highly conductive porous polymer composite material is prepared by mixing the following components in parts by weight: 90 parts of polyetheretherketone, 4 parts of amino-functionalized graphene, 5 parts of silver nanowire / carbon nanotube hybrid filler, 15 parts of porous polyimide microsphere carrier, 1.2 parts of ionic liquid and 0.5 parts of antioxidant.

[0009] Furthermore, the preparation method of the amino-functionalized graphene includes: dispersing graphene oxide in ammonia water with a pH of 8.5-9.5, adding 3-aminopropyltriethoxysilane, reacting at 75°C-85°C for 5h-7h, centrifuging, washing, and vacuum drying to obtain amino-functionalized graphene.

[0010] Furthermore, in the silver nanowire / carbon nanotube hybrid filler, the mass ratio of silver nanowire:carbon nanotube=1:(1.5-2.5); the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid; and the antioxidant is a phosphite antioxidant.

[0011] Furthermore, the phosphite antioxidant is antioxidant 168.

[0012] A second aspect of the present invention provides a method for preparing the above-mentioned highly conductive porous polymer composite material, comprising the following steps:

[0013] Preparation of amino-functionalized graphene: Graphene oxide was dispersed in ammonia water with a pH of 8.5-9.5, 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 75°C-85°C for 5-7 hours. The mixture was centrifuged, washed, and vacuum-dried to obtain amino-functionalized graphene.

[0014] Preparation of hybrid filler microsphere complex: Silver nanowires and carbon nanotubes are dispersed in an ionic liquid at a mass ratio of 1:(1.5-2.5), ultrasonicated for 2-3 hours, and then a porous polyimide microsphere carrier is added. The mixture is stirred and adsorbed at 50-70°C for 11-13 hours, centrifuged, and dried to obtain a hybrid filler microsphere complex.

[0015] Mixing: melt-blending the polyetheretherketone, amino-functionalized graphene, hybrid filler microsphere composite and antioxidant in an internal mixer to obtain a mixed melt;

[0016] Preparation of the porous preform: The mixed melt is quickly immersed in liquid nitrogen to freeze, and then transferred to a freeze dryer for freeze drying to form a porous preform;

[0017] Molding: The porous preform is placed in a mold, hot-pressed, cooled and demoulded to obtain a finished product of a highly conductive porous polymer composite material.

[0018] Furthermore, in the mixing step, melt blending is carried out in an internal mixer at a temperature of 320° C.-340° C. and a rotation speed of 40 rpm-60 rpm for 10 min-20 min.

[0019] Furthermore, in the preparation step of the porous preform, the specific operation of transferring it to the freeze dryer for freeze drying is: in the freeze dryer, first cool it down to -20°C at 8°C / min-12°C / min and keep it warm for 30min-40min, and then cool it down to -50°C at 3°C / min-7°C / min and keep it warm for 24h-26h.

[0020] Furthermore, in the molding step, the hot pressing adopts a two-step hot pressing method: first, preheating and pressing at a temperature of 220℃-230℃ and a pressure of 1.5MPa-2.5MPa for 5min-7min; then heating to 240℃-250℃, increasing the pressure to 7MPa-9MPa and finally hot pressing for 5min-7min.

[0021] Compared with the prior art, the present invention has at least the following beneficial effects:

[0022] The highly conductive porous polymer composite material provided by the present invention uses amino-functionalized graphene to enhance the interfacial bonding between the graphene and the polymer matrix. It employs a silver nanowire / carbon nanotube hybrid filler design to form a "wire-tube" interpenetrating network of silver nanowires and carbon nanotubes, synergistically enhancing conductivity. It uses porous polyimide microsphere carriers for directional loading, utilizing the microsphere carriers to directional adsorb the conductive silver nanowire / carbon nanotube hybrid filler, avoiding the uneven dispersion caused by traditional mechanical mixing. It utilizes ionic liquid green solvents, which are completely free of toxic solvents, increasing dispersion efficiency by 50% compared to traditional methods. It utilizes low-temperature molding technology to construct a porous framework, followed by a two-step hot pressing process to balance the porous structure and the integrity of the highly conductive network, overcoming the limitations of high-temperature processing on conductive fillers. The highly conductive porous polymer composite material of the present invention achieves high conductivity, high strength, and lightweight with low filler additions through multi-scale structural design and environmentally friendly process innovations. DETAILED DESCRIPTION

[0023] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0024] According to a first aspect of an embodiment of the present invention, a highly conductive porous polymer composite material is provided, which is prepared by mixing the following components: polyetheretherketone, amino-functionalized graphene, silver nanowire / carbon nanotube hybrid filler, porous polyimide microsphere carrier, ionic liquid and antioxidant.

[0025] It is understandable that the composition of the filler material in the composite conductive polymer material, the dispersion state of the filler particles and their interaction with the polymer matrix all determine the conductivity of the composite material. The present invention significantly improves the conductivity and mechanical properties by designing a three-dimensional synergistic conductive network, while reducing the agglomeration of the conductive filler. In the present invention, the polyetheretherketone macromolecular chain forms a spatial structure of a helix, the cations are coordinated and complexed with it, and the macromolecular segment motion promotes the transition diffusion through vacancies in its spiral channel, reducing the agglomeration of the conductive filler. In the present invention, optionally, the graphene is modified by an aminosilane coupling agent to form amino-functionalized graphene, which significantly improves its interfacial bonding force with the polymer matrix, thereby improving the mechanical properties of the composite material. In the present invention, a silver nanowire / carbon nanotube hybrid filler is formed by premixing one-dimensional silver nanowires (diameter 30nm-50nm, aspect ratio>1000) with multi-walled carbon nanotubes (diameter 10nm-20nm), thereby forming a "wire-tube" interpenetrating structure, which significantly reduces the percolation threshold of the composite material. In the present invention, the synergy is enhanced by using a porous carrier, and porous polyimide microspheres (pore size 50nm-200nm) are used as a directional loading carrier of the conductive filler, which effectively avoids agglomeration and forms multi-level pores, thereby enhancing the electromagnetic shielding effectiveness.

[0026] In some feasible embodiments, the highly conductive porous polymer composite material is prepared by mixing the following components in parts by weight: 80-95 parts of polyetheretherketone, 2-6 parts of amino-functionalized graphene, 3-8 parts of silver nanowire / carbon nanotube hybrid filler, 10-20 parts of porous polyimide microsphere carrier, 0.5-2 parts of ionic liquid, and 0.3-0.8 parts of antioxidant. Preferably, the highly conductive porous polymer composite material is prepared by mixing the following components in parts by weight: 90 parts of polyetheretherketone, 4 parts of amino-functionalized graphene, 5 parts of silver nanowire / carbon nanotube hybrid filler, 15 parts of porous polyimide microsphere carrier, 1.2 parts of ionic liquid, and 0.5 parts of antioxidant.

[0027] Specifically, the porous polymer composite material provided by the present invention forms a three-dimensional collaborative network structure. The porous structure enables the conductive filler to be evenly distributed in the composite system, requiring only a small amount of conductive filler filling, which not only reduces the preparation cost but also significantly reduces the weight of the material itself.

[0028] In some feasible embodiments, the preparation method of amino-functionalized graphene includes: dispersing graphene oxide in ammonia water with a pH of 8.5-9.5, adding 3-aminopropyltriethoxysilane, reacting at 75°C-85°C for 5h-7h, centrifuging, washing, and vacuum drying to obtain amino-functionalized graphene.

[0029] Specifically, the present invention grafts graphene onto its surface through an aminosilane coupling agent to form amino-functionalized graphene. On the one hand, the compatibility of the conductive filler with the matrix is ​​improved and agglomeration is reduced. On the other hand, the bonding strength between the graphene and the matrix interface is enhanced, thereby improving the mechanical properties of the composite material.

[0030] In some feasible embodiments, in the silver nanowire / carbon nanotube hybrid filler, the mass ratio of silver nanowire:carbon nanotube=1:(1.5-2.5).

[0031] Specifically, the silver nanowire / carbon nanotube hybrid filler is pre-mixed by mixing one-dimensional silver nanowires (diameter 30-50 nm, aspect ratio > 1000) and multi-walled carbon nanotubes (diameter 10-20 nm) in a mass ratio of 1:(1.5-2.5), preferably in a mass ratio of 1:2, to form a "wire-tube" interpenetrating structure, thereby reducing the permeation threshold.

[0032] In some feasible embodiments, the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid.

[0033] Specifically, the present invention uses ionic liquid to assist dispersion. Preferably, 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid is used as a dispersion medium to replace traditional organic solvents to achieve stable dispersion of carbon nanotubes.

[0034] In some feasible embodiments, the antioxidant is a phosphite antioxidant.

[0035] Specifically, the present invention can effectively improve the processing stability and heat stability of the product by adding a phosphite antioxidant. Preferably, the phosphite antioxidant is antioxidant 168.

[0036] A second aspect of the present invention provides a method for preparing a highly conductive porous polymer composite material, comprising the following steps:

[0037] Preparation of amino-functionalized graphene: Graphene oxide was dispersed in ammonia water with a pH of 8.5-9.5, 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 75°C-85°C for 5-7 hours. The mixture was centrifuged, washed, and vacuum-dried to obtain amino-functionalized graphene.

[0038] Preparation of hybrid filler microsphere complex: Silver nanowires and carbon nanotubes are dispersed in an ionic liquid at a mass ratio of 1:(1.5-2.5), ultrasonicated for 2-3 hours, and then a porous polyimide microsphere carrier is added. The mixture is stirred and adsorbed at 50-70°C for 11-13 hours, centrifuged, and dried to obtain a hybrid filler microsphere complex.

[0039] Mixing: melt-blending the polyetheretherketone, amino-functionalized graphene, hybrid filler microsphere composite and antioxidant in an internal mixer to obtain a mixed melt;

[0040] Preparation of the porous preform: The mixed melt is quickly immersed in liquid nitrogen to freeze, and then transferred to a freeze dryer for freeze drying to form a porous preform;

[0041] Molding: The porous preform is placed in a mold, hot-pressed, cooled and demoulded to obtain a finished product of a highly conductive porous polymer composite material.

[0042] The present invention adopts a two-step forming process of freezing and hot pressing: first, a porous skeleton is constructed by freeze drying, and then low-temperature molding is combined to shape it, thereby avoiding damage to the filler by high temperature while retaining the pore structure, with a porosity of ≥70%.

[0043] In some feasible embodiments, in the mixing step, melt blending is performed in an internal mixer at a temperature of 320° C. to 340° C. and a rotation speed of 40 rpm to 60 rpm for 10 min to 20 min.

[0044] Specifically, the matrix and the conductive filler are melt-blended in an internal mixer to achieve efficient dispersion.

[0045] In some feasible embodiments, in the preparation step of the porous preform, the specific operation of transferring to a freeze dryer for freeze drying is: in the freeze dryer, first cool down to -20°C at 8°C / min-12°C / min and keep warm for 30min-40min, and then cool down to -50°C at 3°C / min-7°C / min and keep warm for 24h-26h.

[0046] Specifically, the present invention adopts gradual freeze-drying. The mixed melt is first kept at -20°C for 30-40 minutes to form a large-sized ice crystal skeleton, and then kept at -50°C for 24-26 hours to form a refined pore wall structure. Through gradual freeze-drying, the pore distribution of the composite material is made more uniform, and the pore size deviation is less than 15%, thereby avoiding stress cracks caused by liquid nitrogen rapid cooling.

[0047] In some feasible embodiments, in the molding step, hot pressing adopts a two-step hot pressing method: first, preheat pressing at a temperature of 220℃-230℃ and a pressure of 1.5MPa-2.5MPa for 5min-7min; then the temperature is raised to 240℃-250℃, and the pressure is raised to 7MPa-9MPa for final hot pressing for 5min-7min.

[0048] Specifically, the present invention adopts a two-stage hot pressing process: a pre-pressing stage to soften the preform; and a final pressing stage to promote the diffusion of PEEK molecular chains to fill pore interfaces and enhance tensile strength.

[0049] Example 1 A highly conductive porous polymer composite material and its preparation method

[0050] 1. Composition and ratio of highly conductive porous polymer composite materials

[0051] The method comprises a mixture of 80 g of polyetheretherketone, 2 g of amino-functionalized graphene, 3 g of silver nanowire / carbon nanotube hybrid filler (the mass ratio of silver nanowire to carbon nanotube is 1:1.5), 10 g of porous polyimide microsphere carrier, 0.5 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and 0.3 g of antioxidant 168.

[0052] 2. Preparation method, comprising the following steps:

[0053] 1. Preparation of amino-functionalized graphene

[0054] 5 g of graphene oxide was dispersed in 10 mL of ammonia water with a pH of 9, 5 g of 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 75° C. for 5 h. The mixture was centrifuged, washed with distilled water, and dried in vacuum at 100° C. for 12 h to obtain amino-functionalized graphene.

[0055] 2. Preparation of hybrid filler microsphere composites

[0056] Silver nanowires (diameter 30 nm, aspect ratio > 1000) and multi-walled carbon nanotubes (diameter 10 nm) were dispersed in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and ultrasonically treated at 400 W for 2 h. A porous polyimide microsphere carrier (pore diameter 50 nm) was added, and the mixture was stirred and adsorbed at 50°C for 11 h. The mixture was centrifuged and dried at 100°C for 12 h to obtain a hybrid filler microsphere complex.

[0057] 3. Mixing

[0058] Polyetheretherketone, amino-functionalized graphene, hybrid filler microsphere composite and antioxidant were melt-blended in an internal mixer at a temperature of 320° C. and a rotation speed of 40 rpm for 10 minutes to obtain a mixed melt.

[0059] 4. Preparation of porous preform

[0060] The mixed melt was quickly immersed in liquid nitrogen for freezing, and then transferred to a freeze dryer, first cooled to -20°C at 8°C / min and kept warm for 30 minutes, and then cooled to -50°C at 3°C / min and kept warm for 24 hours for freeze drying to form a porous preform.

[0061] 5. Molding

[0062] The porous preform is placed in a mold and subjected to a two-step hot pressing method: pre-pressing, first pre-pressing at a temperature of 220°C and a pressure of 1.5 MPa for 5 minutes; then heating to 240°C and pressure to 7 MPa for final hot pressing for 5 minutes, cooling and demolding to obtain a high-conductive porous polymer composite product.

[0063] 3. Performance: See Table 1 for details.

[0064] Example 2 A highly conductive porous polymer composite material and its preparation method

[0065] 1. Composition and ratio of highly conductive porous polymer composite materials

[0066] The method comprises a mixture of 90 g of polyetheretherketone, 4 g of amino-functionalized graphene, 5 g of silver nanowire / carbon nanotube hybrid filler (the mass ratio of silver nanowire to carbon nanotube is 1:2), 15 g of porous polyimide microsphere carrier, 1.2 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and 0.5 g of antioxidant 168.

[0067] 2. Preparation method, comprising the following steps:

[0068] 1. Preparation of amino-functionalized graphene

[0069] 5 g of graphene oxide was dispersed in 10 mL of ammonia water with a pH of 9, 5 g of 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 80° C. for 6 h. The mixture was centrifuged, washed with distilled water, and dried in vacuum at 100° C. for 12 h to obtain amino-functionalized graphene.

[0070] 2. Preparation of hybrid filler microsphere composites

[0071] Silver nanowires (diameter 40 nm, aspect ratio > 1000) and multi-walled carbon nanotubes (diameter 15 nm) were dispersed in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid, ultrasonically treated at 400 W for 2.5 h, and porous polyimide microsphere carriers (pore diameter 150 nm) were added. The mixture was stirred and adsorbed at 60°C for 12 h, centrifuged, and dried at 100°C for 12 h to obtain a hybrid filler microsphere complex.

[0072] 3. Mixing

[0073] Polyetheretherketone, amino-functionalized graphene, hybrid filler microsphere composite and antioxidant were melt-blended in an internal mixer at a temperature of 330° C. and a rotation speed of 50 rpm for 15 minutes to obtain a mixed melt.

[0074] 4. Preparation of porous preform

[0075] The mixed melt was quickly immersed in liquid nitrogen for freezing, and then transferred to a freeze dryer, first cooled to -20°C at a rate of 10°C / min and kept warm for 35 minutes, and then cooled to -50°C at a rate of 5°C / min and kept warm for 25 hours for freeze drying to form a porous preform.

[0076] 5. Molding

[0077] The porous preform is placed in a mold and subjected to a two-step hot pressing method: pre-pressing, first pre-pressing at a temperature of 220°C and a pressure of 2.0 MPa for 6 minutes; then heating to 240°C and pressure to 8 MPa for final hot pressing for 6 minutes, cooling and demolding to obtain a finished product of a highly conductive porous polymer composite material.

[0078] 3. Performance: See Table 1 for details.

[0079] Example 3 A highly conductive porous polymer composite material and its preparation method

[0080] 1. Composition and ratio of highly conductive porous polymer composite materials

[0081] The method comprises a mixture of 95 g of polyetheretherketone, 6 g of amino-functionalized graphene, 8 g of silver nanowire / carbon nanotube hybrid filler (the mass ratio of silver nanowire to carbon nanotube is 1:2.5), 20 g of porous polyimide microsphere carrier, 2 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and 0.8 g of antioxidant 168.

[0082] 2. Preparation method, comprising the following steps:

[0083] 1. Preparation of amino-functionalized graphene

[0084] 5 g of graphene oxide was dispersed in 10 mL of ammonia water with a pH of 9, 5 g of 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 85° C. for 7 h. The mixture was centrifuged, washed with distilled water, and dried in a vacuum at 100° C. for 12 h to obtain amino-functionalized graphene.

[0085] 2. Preparation of hybrid filler microsphere composites

[0086] Silver nanowires (diameter 50 nm, aspect ratio > 1000) and multi-walled carbon nanotubes (diameter 20 nm) were dispersed in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and ultrasonically treated at 400 W for 3 h. A porous polyimide microsphere carrier (pore diameter 200 nm) was added, stirred and adsorbed at 70°C for 13 h, centrifuged, and dried at 100°C for 12 h to obtain a hybrid filler microsphere complex.

[0087] 3. Mixing

[0088] Polyetheretherketone, amino-functionalized graphene, hybrid filler microsphere composite and antioxidant were melt-blended in an internal mixer at a temperature of 340° C. and a rotation speed of 60 rpm for 20 minutes to obtain a mixed melt.

[0089] 4. Preparation of porous preform

[0090] The mixed melt was quickly immersed in liquid nitrogen for freezing, and then transferred to a freeze dryer, first cooled to -20°C at a rate of 12°C / min and kept warm for 40 minutes, and then cooled to -50°C at a rate of 7°C / min and kept warm for 26 hours for freeze drying to form a porous preform.

[0091] 5. Molding

[0092] The porous preform is placed in a mold and subjected to a two-step hot pressing method: pre-pressing, first at a temperature of 230°C and a pressure of 2.5 MPa for 7 minutes; then the temperature is raised to 250°C and the pressure is raised to 9 MPa for a final hot pressing for 7 minutes, and the mold is cooled and demolded to obtain a finished product of a highly conductive porous polymer composite material.

[0093] 3. Performance: See Table 1 for details.

[0094] Comparative Example 1 A conductive polymer composite material and its preparation method

[0095] 1. Composition and ratio of composite materials

[0096] The difference between Comparative Example 1 and Example 2 is that 4 g of amino-functionalized graphene is replaced by 15 g of graphene.

[0097] The method comprises mixing 90 g of polyetheretherketone, 15 g of graphene, 5 g of silver nanowire / carbon nanotube hybrid filler (the mass ratio of silver nanowire to carbon nanotube is 1:2), 15 g of porous polyimide microsphere carrier, 1.2 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and 0.5 g of antioxidant 168.

[0098] 2. Preparation method, comprising the following steps:

[0099] 1. Preparation of hybrid filler microsphere composites

[0100] Silver nanowires (diameter 40 nm, aspect ratio > 1000) and multi-walled carbon nanotubes (diameter 15 nm) were dispersed in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid, ultrasonically treated at 400 W for 2.5 h, and porous polyimide microsphere carriers (pore diameter 150 nm) were added. The mixture was stirred and adsorbed at 60°C for 12 h, centrifuged, and dried at 100°C for 12 h to obtain a hybrid filler microsphere complex.

[0101] 2. Mix

[0102] Polyetheretherketone, graphene, hybrid filler microsphere composite and antioxidant were melt-blended in an internal mixer at a temperature of 330° C. and a rotation speed of 50 rpm for 15 minutes to obtain a mixed melt.

[0103] 3. Preparation of porous preform

[0104] The mixed melt was quickly immersed in liquid nitrogen for freezing, and then transferred to a freeze dryer, first cooled to -20°C at a rate of 10°C / min and kept warm for 35 minutes, and then cooled to -50°C at a rate of 5°C / min and kept warm for 25 hours for freeze drying to form a porous preform.

[0105] 4. Molding

[0106] The porous preform was placed in a mold and subjected to a two-step hot pressing method: pre-pressing, first at a temperature of 220°C and a pressure of 2.0 MPa for 6 minutes; then the temperature was raised to 240°C and the pressure was raised to 8 MPa for a final hot pressing for 6 minutes, and the mold was cooled and demolded to obtain a finished conductive polymer composite material.

[0107] 3. Performance: See Table 1 for details.

[0108] Comparative Example 2 A conductive polymer composite material and its preparation method

[0109] 1. Composition and ratio of composite materials

[0110] The difference between Comparative Example 2 and Example 2 is that the porous polyimide microsphere carrier is not added in Comparative Example 2.

[0111] The method comprises mixing 90 g of polyetheretherketone, 4 g of amino-functionalized graphene, 5 g of silver nanowire / carbon nanotube hybrid filler (the mass ratio of silver nanowire to carbon nanotube is 1:2), 1.2 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and 0.5 g of antioxidant 168.

[0112] 2. Preparation method, comprising the following steps:

[0113] 1. Preparation of amino-functionalized graphene

[0114] 5 g of graphene oxide was dispersed in 10 mL of ammonia water with a pH of 9, 5 g of 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 80° C. for 6 h. The mixture was centrifuged, washed with distilled water, and dried in vacuum at 100° C. for 12 h to obtain amino-functionalized graphene.

[0115] 2. Preparation of hybrid filler composites

[0116] Silver nanowires (diameter 40 nm, aspect ratio > 1000) and multi-walled carbon nanotubes (diameter 15 nm) were dispersed in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid, ultrasonically treated at 400 W for 2.5 h, stirred and adsorbed at 60 ° C for 12 h, centrifuged, and dried at 100 ° C for 12 h to obtain a hybrid filler composite.

[0117] 3. Mixing

[0118] Polyetheretherketone, amino-functionalized graphene, hybrid filler composite and antioxidant were melt-blended in an internal mixer at a temperature of 330° C. and a rotation speed of 50 rpm for 15 minutes to obtain a mixed melt.

[0119] 4. Preparation of porous preform

[0120] The mixed melt was quickly immersed in liquid nitrogen for freezing, and then transferred to a freeze dryer, first cooled to -20°C at a rate of 10°C / min and kept warm for 35 minutes, and then cooled to -50°C at a rate of 5°C / min and kept warm for 25 hours for freeze drying to form a porous preform.

[0121] 5. Molding

[0122] The porous preform was placed in a mold and subjected to a two-step hot pressing method: pre-pressing, first at a temperature of 220°C and a pressure of 2.0 MPa for 6 minutes; then the temperature was raised to 240°C and the pressure was raised to 8 MPa for a final hot pressing for 6 minutes, and the mold was cooled and demolded to obtain a finished conductive polymer composite material.

[0123] 3. Performance: See Table 1 for details.

[0124] Comparative Example 3 A conductive polymer composite material and its preparation method

[0125] 1. Composition and ratio of composite materials

[0126] The difference between Comparative Example 3 and Example 2 is that no silver nanowires are added in Comparative Example 3.

[0127] The invention comprises a mixture of 90 g of polyetheretherketone, 4 g of amino-functionalized graphene, 5 g of carbon nanotubes, 15 g of porous polyimide microsphere carrier, 1.2 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and 0.5 g of antioxidant 168.

[0128] 2. Preparation method, comprising the following steps:

[0129] 1. Preparation of amino-functionalized graphene

[0130] 5 g of graphene oxide was dispersed in 10 mL of ammonia water with a pH of 9, 5 g of 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 80° C. for 6 h. The mixture was centrifuged, washed with distilled water, and dried in vacuum at 100° C. for 12 h to obtain amino-functionalized graphene.

[0131] 2. Preparation of filler microsphere composites

[0132] Multi-walled carbon nanotubes (15 nm in diameter) were dispersed in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid, ultrasonically treated at 400 W for 2.5 h, and porous polyimide microsphere carriers (pore size 150 nm) were added. The mixture was stirred and adsorbed at 60°C for 12 h, centrifuged, and dried at 100°C for 12 h to obtain a filler microsphere complex.

[0133] 3. Mixing

[0134] Polyetheretherketone, amino-functionalized graphene, filler microsphere composite and antioxidant were melt-blended in an internal mixer at a temperature of 330° C. and a rotation speed of 50 rpm for 15 minutes to obtain a mixed melt.

[0135] 4. Preparation of porous preform

[0136] The mixed melt was quickly immersed in liquid nitrogen for freezing, and then transferred to a freeze dryer, first cooled to -20°C at a rate of 10°C / min and kept warm for 35 minutes, and then cooled to -50°C at a rate of 5°C / min and kept warm for 25 hours for freeze drying to form a porous preform.

[0137] 5. Molding

[0138] The porous preform is placed in a mold and subjected to a two-step hot pressing method: pre-pressing, first pre-pressing at a temperature of 220°C and a pressure of 2.0 MPa for 6 minutes; then heating to 240°C and pressure to 8 MPa for final hot pressing for 6 minutes, cooling and demolding to obtain a finished product of a highly conductive porous polymer composite material.

[0139] 3. Performance: See Table 1 for details.

[0140] Comparative Example 4: A conductive polymer composite material and its preparation method

[0141] 1. Composition and ratio of composite materials

[0142] The difference between Comparative Example 4 and Example 2 is that no carbon nanotubes are added in Comparative Example 4.

[0143] The invention comprises 90 g of polyetheretherketone, 4 g of amino-functionalized graphene, 5 g of silver nanowires, 15 g of porous polyimide microsphere carrier, 1.2 g of 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and 0.5 g of antioxidant 168.

[0144] 2. Preparation method, comprising the following steps:

[0145] 1. Preparation of amino-functionalized graphene

[0146] 5 g of graphene oxide was dispersed in 10 mL of ammonia water with a pH of 9, 5 g of 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 80° C. for 6 h. The mixture was centrifuged, washed with distilled water, and dried in vacuum at 100° C. for 12 h to obtain amino-functionalized graphene.

[0147] 2. Preparation of filler microsphere composites

[0148] Silver nanowires (diameter 40 nm, aspect ratio > 1000) were dispersed in 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid and ultrasonically treated at 400 W for 2.5 h. A porous polyimide microsphere carrier (pore size 150 nm) was added, stirred and adsorbed at 60°C for 12 h, centrifuged, and dried at 100°C for 12 h to obtain a filler microsphere complex.

[0149] 3. Mixing

[0150] Polyetheretherketone, amino-functionalized graphene, filler microsphere composite and antioxidant were melt-blended in an internal mixer at a temperature of 330° C. and a rotation speed of 50 rpm for 15 minutes to obtain a mixed melt.

[0151] 4. Preparation of porous preform

[0152] The mixed melt was quickly immersed in liquid nitrogen for freezing, and then transferred to a freeze dryer, first cooled to -20°C at a rate of 10°C / min and kept warm for 35 minutes, and then cooled to -50°C at a rate of 5°C / min and kept warm for 25 hours for freeze drying to form a porous preform.

[0153] 5. Molding

[0154] The porous preform is placed in a mold and subjected to a two-step hot pressing method: pre-pressing, first pre-pressing at a temperature of 220°C and a pressure of 2.0 MPa for 6 minutes; then heating to 240°C and pressure to 8 MPa for final hot pressing for 6 minutes, cooling and demolding to obtain a finished product of a highly conductive porous polymer composite material.

[0155] 3. Performance: See Table 1 for details.

[0156] Comparative Example 5 A conductive polymer composite material and its preparation method

[0157] 1. Composition and ratio of composite materials

[0158] Same as Example 2.

[0159] 2. Preparation Method

[0160] The difference from Example 2 is that: Comparative Example 5 does not perform freeze-drying, but adopts one-time hot pressing molding.

[0161] 1. Preparation of amino-functionalized graphene: same as Example 2.

[0162] 2. Preparation of hybrid filler microsphere composite: same as Example 2.

[0163] 3. Mixing: Same as Example 2.

[0164] 4. Molding

[0165] After the mixed melt is cooled to room temperature, it is placed in a mold and hot-pressed at 240° C. and 8 MPa for 6 minutes. The mold is then cooled and demolded to obtain a finished polymer composite material.

[0166] 3. Performance: See Table 1 for details.

[0167] Table 1 Properties of polymer composite materials of Examples 1-3 and Comparative Examples 1-5

[0168]

[0169] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application. The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application. These improvements and variations should also be regarded as the scope of protection of the present application.

Claims

1. A highly conductive porous polymer composite material, characterized in that: The invention is prepared by mixing the following components: polyetheretherketone, amino-functionalized graphene, silver nanowire / carbon nanotube hybrid filler, porous polyimide microsphere carrier, ionic liquid and antioxidant.

2. The highly conductive porous polymer composite material according to claim 1, characterized in that: The highly conductive porous polymer composite material is prepared by mixing the following components in parts by weight: 80-95 parts of polyetheretherketone, 2-6 parts of amino-functionalized graphene, 3-8 parts of silver nanowire / carbon nanotube hybrid filler, 10-20 parts of porous polyimide microsphere carrier, 0.5-2 parts of ionic liquid and 0.3-0.8 parts of antioxidant.

3. The highly conductive porous polymer composite material according to claim 1, characterized in that: The highly conductive porous polymer composite material is prepared by mixing the following components in parts by weight: 90 parts of polyetheretherketone, 4 parts of amino-functionalized graphene, 5 parts of silver nanowire / carbon nanotube hybrid filler, 15 parts of porous polyimide microsphere carrier, 1.2 parts of ionic liquid and 0.5 parts of antioxidant.

4. A highly conductive porous polymer composite material according to any one of claims 1 to 3, characterized in that: The preparation method of the amino-functionalized graphene includes: dispersing graphene oxide in ammonia water with a pH of 8.5-9.5, adding 3-aminopropyltriethoxysilane, reacting at 75° C.-85° C. for 5 h-7 h, centrifuging, washing, and vacuum drying to obtain the amino-functionalized graphene.

5. The highly conductive porous polymer composite material according to any one of claims 1 to 3, characterized in that: In the silver nanowire / carbon nanotube hybrid filler, the mass ratio of silver nanowire:carbon nanotube=1:(1.5-2.5); the ionic liquid is 1-butyl-3-methylimidazolium tetrafluoroborate ionic liquid; and the antioxidant is a phosphite antioxidant.

6. The highly conductive porous polymer composite material according to claim 5, characterized in that: The phosphite antioxidant is antioxidant 168.

7. A method for preparing a highly conductive porous polymer composite material, characterized in that: The method for preparing the highly conductive porous polymer composite material according to any one of claims 1 to 6 comprises the following steps: Preparation of amino-functionalized graphene: Graphene oxide was dispersed in ammonia water with a pH of 8.5-9.5, 3-aminopropyltriethoxysilane was added, and the mixture was reacted at 75°C-85°C for 5-7 hours. The mixture was centrifuged, washed, and vacuum-dried to obtain amino-functionalized graphene. Preparation of hybrid filler microsphere complex: Silver nanowires and carbon nanotubes are dispersed in an ionic liquid at a mass ratio of 1:(1.5-2.5), ultrasonicated for 2-3 hours, and then a porous polyimide microsphere carrier is added. The mixture is stirred and adsorbed at 50-70°C for 11-13 hours, centrifuged, and dried to obtain a hybrid filler microsphere complex. Mixing: melt-blending the polyetheretherketone, amino-functionalized graphene, hybrid filler microsphere composite and antioxidant in an internal mixer to obtain a mixed melt; Preparation of the porous preform: The mixed melt is quickly immersed in liquid nitrogen to freeze, and then transferred to a freeze dryer for freeze drying to form a porous preform; Molding: The porous preform is placed in a mold, hot-pressed, cooled and demoulded to obtain a finished product of a highly conductive porous polymer composite material.

8. The method for preparing a highly conductive porous polymer composite material according to claim 7, wherein: In the mixing step, the mixture is melt-blended in an internal mixer at a temperature of 320° C. to 340° C. and a rotation speed of 40 rpm to 60 rpm for 10 min to 20 min.

9. The method for preparing a highly conductive porous polymer composite material according to claim 7, wherein: In the preparation step of the porous preform, the specific operation of transferring the preform to the freeze dryer for freeze drying is as follows: first, in the freeze dryer, cool it to -20°C at 8°C / min-12°C / min and keep it warm for 30min-40min, then cool it to -50°C at 3°C / min-7°C / min and keep it warm for 24h-26h.

10. The method for preparing a highly conductive porous polymer composite material according to claim 7, wherein: In the molding step, the hot pressing adopts a two-step hot pressing method: first, preheating and pressing at a temperature of 220°C-230°C and a pressure of 1.5MPa-2.5MPa for 5min-7min; then heating to 240°C-250°C and raising the pressure to 7MPa-9MPa for final hot pressing for 5min-7min.

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