A carbon fiber reinforced thermoplastic composite based on co-attachment of a suspension and functional filler and a method for producing the same
Patent Information
- Application Number
- CN202611037114.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-13
- Publication Date
- 2026-10-30
AI Technical Summary
[0004]针对现有悬浮液共混法制备碳纤维增强热塑性复合材料过程中存在的界面结合弱、分散稳定性差、纤维长度单一、功能性不足等问题，本发明提供一种基于悬浮液与功能填料共附着的碳纤维增强热塑性复合材料及其制备方法，其核心在于：在悬浮液体系中同时引入经硅烷偶联剂与水性聚氨酯两步改性的碳纤维、热塑性树脂纤维及功能性填料，采用聚乙二醇与卡波姆复配的悬浮液体系以优化纤维分散与填料附着，并通过不同长度碳纤维的混杂设计及后续热处理，协同提升复合材料的力学性能与功能特性
[0023]1. 通过"悬浮液+"策略，在悬浮液共混阶段同步实现碳纤维表面多尺度改性、填料预分散与三相均匀混合，工艺路径短，集成度高。
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Figure CN123003918A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of carbon fiber composite materials, specifically relating to a method for preparing carbon fiber reinforced thermoplastic resin-based composite materials with high performance and multifunctional properties by using a "suspension+" strategy to introduce functional fillers during the suspension blending process. Background Technology
[0002] Suspension blending has been used to prepare carbon fiber / thermoplastic resin fiber hybrid felts, which can achieve uniform dispersion of reinforcing fibers and matrix fibers. However, the existing technology has the following shortcomings: (1) The interfacial bonding strength between carbon fiber and resin matrix is limited, and the modification effect of traditional single silane coupling agent still has room for improvement; (2) The means of controlling the dispersion stability of fibers in suspension is limited, and it is difficult to achieve both high fiber concentration and uniform dispersion; (3) The fiber length is limited, and it is difficult to achieve both high mechanical strength and good toughness at the same time; (4) The composite material has limited functionality and cannot meet the needs of aerospace, electronic devices and other fields for multifunctional integration of materials.
[0003] Therefore, there is an urgent need for an integrated preparation method that can simultaneously achieve interface enhancement, structural optimization, and functional integration during the suspension blending stage. Summary of the Invention
[0004] To address the problems of weak interfacial bonding, poor dispersion stability, single fiber length, and insufficient functionality in the existing suspension blending method for preparing carbon fiber reinforced thermoplastic composites, this invention provides a carbon fiber reinforced thermoplastic composite based on the co-attachment of suspension and functional fillers, and its preparation method. The core of this invention lies in simultaneously introducing carbon fibers, thermoplastic resin fibers, and functional fillers modified by silane coupling agent and waterborne polyurethane in two steps into the suspension system. A suspension system composed of polyethylene glycol and carbomer is used to optimize fiber dispersion and filler attachment. Furthermore, through the hybrid design of carbon fibers of different lengths and subsequent heat treatment, the mechanical properties and functional characteristics of the composite material are synergistically improved.
[0005] The present invention provides a carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional fillers, and a method for preparing the same, comprising the following steps:
[0006] Step (a) Carbon fiber pretreatment: The carbon fiber is sequentially subjected to desizing treatment, silane coupling agent modification and waterborne polyurethane modification to obtain multi-scale modified carbon fiber; wherein, the silane coupling agent used for silane coupling agent modification is selected from one or more of KH550, KH560 and KH570, the treatment concentration is 0.5~3wt% and the treatment time is 30~60min; the solid content of the waterborne polyurethane emulsion used for waterborne polyurethane modification is 2~8wt% and the impregnation time is 10~30min;
[0007] Step (b) Preparation of the multifunctional suspension: Using a mixed solvent of ethanol and water as the medium, polyethylene glycol and carbomer are added and stirred until completely dissolved to obtain a basic suspension with suitable viscosity and dispersion stability; the volume ratio of ethanol to water in the mixed solvent is 95:5; the amount of polyethylene glycol added is 0.1%~0.5% of the solvent mass, and the amount of carbomer added is 0.05%~0.3% of the solvent mass;
[0008] Step (c) Functional filler pre-dispersion: The functional filler is added to the basic suspension obtained in step (b), and pre-mixed at 5000~15000 rpm for 5~15 min with high shear, and then ultrasonically treated for 10~30 min to uniformly disperse the functional filler, thus obtaining a filler pre-dispersion suspension; the amount of the functional filler added is 0.1%~10% of the total fiber mass; the functional filler is one or more of carbon nanotubes, magnesium hydroxide, boron nitride, nano iron tetroxide, and nano zinc oxide, to impart one or more of the following properties to the composite material: electrical conductivity, thermal conductivity, flame retardancy, magnetism, antibacterial properties, antistatic properties, wave absorption, energy absorption, or phase change energy storage properties;
[0009] Step (d) Multi-component suspension blending: The modified carbon fiber, thermoplastic resin fiber and filler pre-dispersion suspension obtained in step (a) are injected into a suspension blending tank. While stirring, an ultrasonic-assisted device is started to perform three-phase mixing. The mixing time is 20~60 min to obtain a mixed slurry. The carbon fiber contains at least two hybrid systems with different length specifications.
[0010] Step (e) Filtration and felting: The mixed slurry obtained in step (d) is filtered through a filter screen to remove the liquid phase and obtain a wet mixed fiber felt;
[0011] Step (f) Drying: Dry the mixed fiber felt obtained in step (e) at 60~80℃ for 30~120 min to remove residual solvent;
[0012] Step (g) Hot pressing: Place the dried felt material in a hot pressing mold, preheat it to 20-80°C above the melting point of the thermoplastic resin fiber at 1-5 MPa, then press it at 5-20 MPa for 10-20 min, and after cooling, obtain carbon fiber reinforced thermoplastic composite material.
[0013] Heat treatment after step (h): Place the hot-pressed composite material in an oven and keep it at a temperature 10~50℃ below the melting point of the thermoplastic resin for 1~8 h, then slowly cool it to room temperature to obtain the final product.
[0014] Preferably, the desizing process in step (a) includes: immersing the carbon fiber in a desizing agent with a volume ratio of acetone to ethanol of 1:1 for 30-60 min, while stirring and simultaneously performing ultrasonic treatment; then washing with 0.1-0.5 mol / L sodium hydroxide solution and rinsing with water until neutral; and finally drying at 100-120℃ for 30-60 min to obtain pretreated carbon fiber with a clean surface.
[0015] Preferably, the hybrid system of carbon fibers in step (d) includes three specifications: substrate length, shorter length, and longer length; wherein the substrate length is 45~55 mm, the shorter length is 5~10 mm, and the longer length is 65~95 mm; the mass of the shorter length carbon fibers accounts for 5%~20% of the total mass of carbon fibers, the mass of the longer length carbon fibers accounts for 5%~15% of the total mass of carbon fibers, and the remainder is the substrate length carbon fibers.
[0016] Preferably, the thermoplastic resin fiber in step (d) is one or more of nylon fiber, polyetheretherketone fiber, polypropylene fiber, polylactic acid fiber, ultra-high molecular weight polyethylene fiber, and polyethylene terephthalate fiber; the fiber length is 5~100 mm and the fineness is 0.1~1.5 dtex.
[0017] Preferably, in step (d), modified carbon fiber, functional filler and thermoplastic resin fiber are added in proportions of 15% to 50% by mass of modified carbon fiber, 0.1% to 10% by mass of functional filler and 50% to 85% by mass of thermoplastic resin.
[0018] Preferably, the heating temperature of the hot pressing mold in step (g) is 110~400℃.
[0019] Preferably, the liquid suspension obtained by filtration in step (e) is recycled back to step (c) or step (d) after being supplemented with functional filler and / or dispersant thickener.
[0020] The present invention also provides a carbon fiber reinforced thermoplastic composite material prepared according to the above method, wherein the carbon fiber has a mixed length distribution and the functional filler is uniformly distributed at the interface between the carbon fiber and the thermoplastic resin and inside the resin matrix.
[0021] The carbon fiber reinforced thermoplastic composite material is used in aerospace, rail transportation, electronics, electromagnetic shielding, or energy storage packaging.
[0022] The beneficial effects of this invention are:
[0023] 1. By adopting the "suspension+" strategy, multi-scale surface modification of carbon fibers, pre-dispersion of fillers and uniform mixing of three phases are achieved simultaneously in the suspension blending stage. The process path is short and the integration is high.
[0024] 2. A two-step method using silane coupling agent / waterborne polyurethane was adopted to modify carbon fibers at multiple scales, which significantly improved the interfacial bonding strength between carbon fibers and thermoplastic resin matrix.
[0025] 3. The suspension system using a combination of polyethylene glycol and carbomer can simultaneously control the suspension viscosity and fiber dispersion stability, achieving both high fiber concentration and uniform dispersion.
[0026] 4. By using a hybrid design of carbon fibers of three specifications—base material length, shorter length, and longer length—the high mechanical strength and good toughness of the composite material are synergistically improved.
[0027] 5. By simultaneously introducing functional fillers during the suspension blending stage, composite materials are endowed with multiple functional properties such as electrical conductivity, thermal conductivity, flame retardancy, magnetism, and antibacterial properties, meeting the needs of multiple fields such as aerospace, rail transportation, electronic packaging, electromagnetic shielding, and energy storage devices for multifunctional material integration.
[0028] 6. The filtered liquid suspension can be recycled after adding functional fillers and / or dispersants and thickeners, reducing production costs and conforming to the concept of green manufacturing. Attached Figure Description
[0029] Figure 1 This is a schematic diagram of the process flow for a method of preparing carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional filler according to the present invention.
[0030] Wherein: 1-Unsizing carbon fiber, 2-Sizing agent, 3-First hot air oven, 4-Resin fiber, 5-Sizing desized carbon fiber, 6-Mechanical stirring device, 7-First ultrasonic device, 8-Basic suspension, 9-Functional filler, 10-Stirring rod, 11-Second ultrasonic device, 12-Filter screen, 13-Mold, 14-Filtrate collection box, 15-Second hot air oven, 16-Hot pressing device. Detailed Implementation
[0031] The present invention will be further described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Unless otherwise specified, the reagents and materials used in the following embodiments are all commercially available products.
[0032] Example 1
[0033] This embodiment uses 75 wt% polyetheretherketone (PEEK) fiber as the matrix, 5 wt% multi-walled carbon nanotubes (MWCNTs) as the functional filler, and the remaining 20 wt% carbon fiber. The specific implementation method includes the following steps:
[0034] Step (a) Immerse the carbon fibers in an acetone / ethanol (1:1) mixture for 40 min with mechanical stirring, then wash twice with 0.2 mol / L sodium hydroxide solution, wash with deionized water until neutral, and finally dry in an oven at 110℃ for 45 min to obtain pretreated carbon fibers; prepare a 2wt% KH550 ethanol / water (95:5) solution, immerse the desized carbon fibers in it, let it stand at room temperature for 45 min, remove it and dry it at 80℃; prepare a 5wt% solids content waterborne polyurethane emulsion, immerse the silane coupling agent modified carbon fibers in it for 20 min, remove it and dry it at 90℃ to obtain modified carbon fibers. Cut the modified carbon fibers according to the following mixing ratio: 70wt% for 50 mm length, 15wt% for 8 mm length, and 15wt% for 80 mm length, mix them evenly and set aside.
[0035] In step (b), using ethanol / deionized water at a volume ratio of 95:5 as the solvent, add 0.3% polyethylene glycol and 0.15% carbomer by mass of the solvent, and mechanically stir for 30 min until completely dissolved to obtain the basic suspension.
[0036] Step (c) 5 wt% of multi-walled carbon nanotubes are added to the basic suspension. First, they are premixed at 10,000 rpm for 10 min under high shear, and then ultrasonically treated at 40 kHz and 200 W / L for 20 min to obtain a pre-dispersed suspension in which the filler is uniformly dispersed.
[0037] Step (d) First, add the above pre-dispersed suspension to the suspension mixing tank in sequence, then add PEEK fiber and pretreated carbon fiber, control the total fiber concentration to 3 vol%, turn on the ultrasonic device while stirring, mix for 40 min, so that the carbon fiber, PEEK fiber and multi-walled carbon nanotubes are uniformly mixed and the multi-walled carbon nanotubes are uniformly attached to the fiber surface.
[0038] Step (e) involves filtering the mixed slurry through a filter screen to obtain a wet felt with a single layer thickness of approximately 10 mm.
[0039] Step (f) Place the wet felt in an 80°C hot air oven and dry for 60 min until constant weight.
[0040] Step (g) Place the dried felt material in the mold, preheat it to 380°C at 3 MPa pressure, keep it at that temperature for 5 min to allow the resin to melt completely, then pressurize it to 8 MPa, continue hot pressing for 10 min, keep it under pressure, cool it with water to room temperature, and open the mold to obtain a composite material with a thickness of about 1 mm.
[0041] After step (h), the hot-pressed composite material is placed in a hot air oven and kept at 180°C for 3 h, and then slowly cooled to room temperature at a rate of 0.5°C / min.
[0042] Example 2
[0043] In this embodiment, 65 wt% polypropylene (PP) fiber is used as the matrix, 10 wt% boron nitride (BN) nanosheets are used as functional fillers, and the remaining 25 wt% is carbon fiber.
[0044] Step (a) Carbon fiber modification is the same as step (a) in Example 1, and the mixing ratio is the same as in Example 1.
[0045] Step (b) The preparation of the basic suspension is the same as step (b) in Example 1.
[0046] Step (c) 10 wt% boron nitride nanosheets are added to the basic suspension, premixed at 10000 rpm for 10 min with high shear, and then sonicated at 40 kHz and 200 W / L for 20 min to obtain a pre-dispersed suspension in which the filler is uniformly dispersed.
[0047] Step (d) First, add the above pre-dispersed suspension to the suspension mixing tank in sequence, then add PP fiber and pretreated carbon fiber, control the total fiber concentration to 2 vol%, and turn on the ultrasonic device while stirring, and mix for 40 min.
[0048] Step (e) involves filtering the mixed slurry through a filter screen to obtain a wet felt with a single layer thickness of approximately 10 mm.
[0049] Step (f) Place the wet felt in an 80°C hot air oven and dry for 60 min until constant weight.
[0050] Step (g) Place the dried felt material in the mold, preheat it to 200°C at 2 MPa pressure, keep it at that temperature for 5 min to allow the resin to melt completely, then pressurize it to 5 MPa, continue hot pressing for 10 min, keep it under pressure, cool it with water to room temperature, and open the mold to obtain a composite material with a thickness of about 1 mm.
[0051] After step (h), the hot-pressed composite material is placed in a hot air oven and kept at 150°C for 3 h, and then slowly cooled to room temperature at a rate of 0.5°C / min.
[0052] Example 3
[0053] In this embodiment, 55wt% nylon 6 (PA6) fiber is used as the matrix, 15wt% magnesium hydroxide (Mg(OH)2) is used as the functional filler, and the remaining 30wt% is carbon fiber.
[0054] Step (a) Carbon fiber modification is the same as step (a) in Example 1, and the mixing ratio is the same as in Example 1.
[0055] Step (b) The preparation of the basic suspension is the same as step (b) in Example 1.
[0056] Step (c) Add 15 wt% magnesium hydroxide to the base suspension, premix at 10000 rpm for 10 min with high shear, and then sonicate at 40 kHz and 200 W / L for 20 min to obtain a pre-dispersed suspension in which the filler is uniformly dispersed.
[0057] Step (d) First, add the above pre-dispersed suspension to the suspension mixing tank in sequence, then add PA6 fiber and pretreated carbon fiber, control the total fiber concentration to 1 vol%, and turn on the ultrasonic device while stirring, and mix for 40 min.
[0058] Step (e) involves filtering the mixed slurry through a filter screen to obtain a wet felt with a single layer thickness of approximately 10 mm.
[0059] Step (f) Place the wet felt in an 80°C hot air oven and dry for 60 min until constant weight.
[0060] Step (g) Place the dried felt material in the mold, preheat it to 250°C at a pressure of 4 MPa, keep it at that temperature for 5 min to allow the resin to melt completely, then pressurize it to 5 MPa and continue hot pressing for 10 min. Hold the pressure and cool it to room temperature before opening the mold to obtain a composite material with a thickness of about 1 mm.
[0061] After step (h), the hot-pressed composite material is placed in a hot air oven and kept at 200°C for 3 h, and then slowly cooled to room temperature at a rate of 0.5°C / min.
[0062] The performance tests for Examples 1-3 are shown in Table 1.
[0063] Table 1
[0064] Example 1 Example 2 Example 3 resin matrix PEEK PP PA6 carbon fiber content 20wt% 25wt% 30wt% Functional packing 5% of multi-carbon nanotubes 10% boron nitride 15% magnesium hydroxide Tensile strength 455MPa 150MPa 230MPa Bending strength 467MPa 235MPa 383MPa Features <![CDATA[Volume resistivity 8×10 3 Ω]]> Thermal conductivity 1.85 W / (m·K) LOI 32%, UL94 V-1
[0065] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional filler, characterized in that, Includes the following steps: Step (a) Carbon fiber pretreatment: The carbon fiber is sequentially subjected to desizing treatment, silane coupling agent modification and waterborne polyurethane modification to obtain multi-scale modified carbon fiber; wherein, the silane coupling agent used for silane coupling agent modification is selected from one or more of KH550, KH560 and KH570, the treatment concentration is 0.5~3wt% and the treatment time is 30~60min; the solid content of the waterborne polyurethane emulsion used for waterborne polyurethane modification is 2~8wt% and the impregnation time is 10~30min; Step (b) Preparation of the multifunctional suspension: Using a mixed solvent of ethanol and water as the medium, polyethylene glycol and carbomer are added and stirred until completely dissolved to obtain a basic suspension with suitable viscosity and dispersion stability; the volume ratio of ethanol to water in the mixed solvent is 95:5; the amount of polyethylene glycol added is 0.1%~0.5% of the solvent mass, and the amount of carbomer added is 0.05%~0.3% of the solvent mass; Step (c) Functional filler pre-dispersion: The functional filler is added to the basic suspension obtained in step (b), and pre-mixed at 5000~15000 rpm for 5~15 min with high shear, and then ultrasonically treated for 10~30 min to uniformly disperse the functional filler, thus obtaining a filler pre-dispersion suspension; the amount of the functional filler added is 0.1%~10% of the total fiber mass; the functional filler is one or more of carbon nanotubes, magnesium hydroxide, boron nitride, nano iron tetroxide, and nano zinc oxide, to impart one or more of the following properties to the composite material: electrical conductivity, thermal conductivity, flame retardancy, magnetism, antibacterial properties, antistatic properties, wave absorption, energy absorption, or phase change energy storage properties; Step (d) Multi-component suspension blending: The modified carbon fiber, thermoplastic resin fiber and filler pre-dispersion suspension obtained in step (a) are injected into a suspension blending tank. While stirring, an ultrasonic-assisted device is started to perform three-phase mixing. The mixing time is 20~60 min to obtain a mixed slurry. The carbon fiber contains at least two hybrid systems with different length specifications. Step (e) Filtration and felting: The mixed slurry obtained in step (d) is filtered through a filter screen to remove the liquid phase and obtain a wet mixed fiber felt; Step (f) Drying: Dry the mixed fiber felt obtained in step (e) at 60~80℃ for 30~120 min to remove residual solvent; Step (g) Hot pressing: Place the dried felt material in a hot pressing mold, preheat it to 20-80°C above the melting point of the thermoplastic resin fiber at 1-5 MPa, then press it at 5-20 MPa for 10-20 min, and after cooling, obtain carbon fiber reinforced thermoplastic composite material. Heat treatment after step (h): Place the hot-pressed composite material in an oven and keep it at a temperature 10~50℃ below the melting point of the thermoplastic resin for 1~8 h, then slowly cool it to room temperature to obtain the final product.
2. The preparation method according to claim 1, characterized in that, The desizing process described in step (a) includes: immersing the carbon fiber in a desizing agent with a volume ratio of acetone to ethanol of 1:1 for 30 to 60 minutes, while stirring and simultaneously performing ultrasonic treatment; then washing with 0.1 to 0.5 mol / L sodium hydroxide solution and water washing until neutral; and finally drying at 100 to 120°C for 30 to 60 minutes to obtain pretreated carbon fiber with a clean surface.
3. The method for preparing carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional filler according to claim 1, characterized in that, The hybrid carbon fiber system described in step (d) includes three specifications: base material length, shorter length, and longer length; wherein the base material length is 45~55 mm, the shorter length is 5~10 mm, and the longer length is 65~95 mm; the mass of the shorter length carbon fiber accounts for 5%~20% of the total mass of carbon fiber, the mass of the longer length carbon fiber accounts for 5%~15% of the total mass of carbon fiber, and the remainder is the base material length carbon fiber.
4. The method for preparing carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional filler according to claim 1, characterized in that, The thermoplastic resin fiber mentioned in step (d) is one or more of nylon fiber, polyetheretherketone fiber, polypropylene fiber, polylactic acid fiber, ultra-high molecular weight polyethylene fiber, and polyethylene terephthalate fiber; the fiber length is 5~100 mm and the fineness is 0.1~1.5 dtex.
5. The method for preparing carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional filler according to claim 1, characterized in that, In step (d), modified carbon fiber, functional filler and thermoplastic resin fiber are added in proportions of 15% to 50% by mass of modified carbon fiber, 0.1% to 10% by mass of functional filler and 50% to 85% by mass of thermoplastic resin.
6. The method for preparing carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional filler according to claim 1, characterized in that, The heating temperature of the hot pressing mold in step (g) is 110~400℃.
7. The method for preparing carbon fiber reinforced thermoplastic composite material based on the co-attachment of suspension and functional filler according to claim 1, characterized in that, The liquid suspension obtained from filtration in step (e) is recycled to step (c) or step (d) after being supplemented with functional fillers and / or dispersants and thickeners.
8. A carbon fiber reinforced thermoplastic composite material prepared by the method according to any one of claims 1 to 7, characterized in that, The carbon fiber has a mixed length distribution, and the functional filler is uniformly distributed at the interface between the carbon fiber and the thermoplastic resin and inside the resin matrix.
9. The application of the carbon fiber reinforced thermoplastic composite material according to claim 8 in the fields of aerospace, rail transportation, electronics, electromagnetic shielding or energy storage packaging.