High-performance fiber composite cloth and preparation method thereof

Abstract

The invention discloses high-performance fiber composite cloth and a preparation method thereof, and aims to solve the problem of insufficient interlayer structural strength of existing fiber composite cloth. According to the technical scheme, the composite cloth is of a multi-layer composite structure and comprises a reinforced fiber layer, an interface modification layer, a bio-based resin matrix layer and an interlayer cross-linking layer. The interface modification layer is a bio-based compatilizer layer grafted after plasma etching, the bio-based resin matrix layer adopts a solvent-free castor oil-based epoxy resin system, and the interlayer crosslinking layer is formed by crosslinking isocyanate modified polyethylene glycol. The preparation method adopts an integrated process of dry preimpregnation, plasma surface modification and interlayer in-situ crosslinking, does not need an organic solvent, and comprises the steps of fiber modification, compatilizer grafting, resin preparation, dry preimpregnation, segmented curing and post-treatment. The interlayer structural strength of the fiber composite cloth is effectively improved.

Description

Technical Field

[0001] This invention relates to the field of fiber composite fabric technology, and more specifically, to a high-performance fiber composite fabric and its preparation method. Background Technology

[0002] High-performance fiber composite fabrics use carbon fiber, aramid fiber, ultra-high molecular weight polyethylene fiber, etc. as reinforcing phases and resin as the matrix phase. With their excellent properties such as high specific strength, corrosion resistance, and fatigue resistance, they are gradually replacing traditional metal materials and becoming the core material in high-end manufacturing fields.

[0003] However, in both industrial manufacturing and practical applications, existing high-performance fiber composite fabrics are prone to insufficient interlayer bonding strength. Fiber composite fabrics are mostly composed of multiple layers of fiber fabrics stacked together, with the interlayer interfaces relying solely on the physical bonding of the resin matrix. This results in weak interlayer forces, making them susceptible to delamination and cracking under external impact, leading to a deterioration of the overall mechanical properties of the material and failing to meet the structural integrity requirements of high-end equipment. Current technologies often increase resin content to improve interlayer strength, but this increases material weight and decreases specific strength.

[0004] Therefore, a solution needs to be proposed to address this problem. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-performance fiber composite fabric and its preparation method, by constructing a plasma-etched grafted bio-based compatibilizer interface modification layer on the surface of the reinforcing fiber layer, thereby enhancing the interfacial bonding force between the fiber and the bio-based resin matrix layer.

[0006] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a high-performance fiber composite fabric, comprising a fiber fabric body, wherein the fiber fabric body comprises, from the inside to the outside, a reinforcing fiber layer, an interface modification layer, and a bio-based resin matrix layer, and an interlayer crosslinking layer is provided between adjacent fiber fabric bodies, wherein the total thickness of the fiber fabric body is 0.8-5.0 mm and the areal density is 200-800 g / m². The reinforcing fiber layer uses continuous fiber fabric as the reinforcing phase, and the fiber type is selected from one or more blends of carbon fiber, aramid fiber, and ultra-high molecular weight polyethylene fiber. The interlayer crosslinking layer is located between adjacent first and second reinforcing fiber layers, with a thickness of 80-200 nm. The interlayer crosslinking layer is formed by reacting isocyanate-modified polyethylene glycol with a bio-based resin matrix. The interface modification layer is a bio-based compatibilizer layer grafted after plasma etching, with a thickness of 50-200 nm. The compatibilizer is selected from polylactic acid grafted with maleic anhydride and starch-based grafted with acrylate. The bio-based resin matrix layer is made of solvent-free bio-based epoxy resin, which is composed of castor oil-based epoxy resin and turpentine-based curing agent mixed in a mass ratio of 100:30-50, and has a thickness of 100-300μm.

[0007] The present invention is further configured such that: the fabric structure of the reinforcing fiber layer is plain weave, twill weave or satin weave, the fiber volume fraction is 40%-60%, the fiber diameter is 5-15μm, and the tensile strength is ≥3.5GPa.

[0008] The present invention is further configured such that the amount of isocyanate-modified polyethylene glycol added in the interlayer crosslinking layer is 2%-5% of the mass of the bio-based resin matrix.

[0009] The present invention is further configured such that: the epoxy value of the castor oil-based epoxy resin is 0.35-0.45 eq / 100g, and the amine value of the turpentine-based curing agent is 200-300 mg KOH / g.

[0010] The present invention is further configured such that the number average molecular weight of the isocyanate-modified polyethylene glycol is 1000-2000.

[0011] The above-mentioned technical objective of the present invention is also achieved through the following technical solution: a method for preparing a high-performance fiber composite fabric, comprising the following steps: S1: plasma modification treatment of the surface of reinforcing fiber: the reinforcing fiber layer is placed in a low-temperature plasma treatment instrument, a mixed gas of argon and oxygen (volume ratio 3:1) is introduced, the treatment power is controlled at 80-120W, the treatment time is 3-8min, and the treatment pressure is 0.05-0.1MPa; S2: Interface compatibilizer grafting treatment: Immerse the fiber fabric modified by plasma in step S1 into a bio-based compatibilizer solution with a compatibilizer mass concentration of 5%-10% and deionized water as the solvent. Immerse at a constant temperature of 60-80℃ for 20-40 minutes, then dry at 100-120℃ for 1-2 hours and cool to room temperature for later use. S3: Preparation of solvent-free bio-based resin matrix: At room temperature and pressure, castor oil-based epoxy resin and turpentine-based curing agent are placed in a mixing tank at a mass ratio of 100:30-50, and isocyanate-modified polyethylene glycol is added. The mixture is stirred at a speed of 300-500 r / min for 15-25 min until it is uniformly mixed to obtain the interlayer crosslinking layer. S4: Dry prepreg and lamination: The bio-based resin matrix prepared in step S3 is heated to 80-100℃ to melt and coated onto the surface of the fiber fabric treated in step S2. The coating amount is 80%-120% of the fiber fabric mass. After being rolled by a 0.5-1.0MPa pressure roller, a prepreg fabric is obtained. Multiple layers of prepreg fabric are stacked one by one, and a crosslinking agent is laid between the layers. S5: In-situ curing: Place the laminated prepreg into an autoclave and cure in sections: keep warm at 120-140℃ and 1.5-2.0MPa for 1-2 hours, then raise the temperature to 160-180℃ and 2.0-2.5MPa for 2-3 hours, and let it cool naturally to room temperature. S6: Post-processing: The cured composite fabric is edge-trimmed and surface-polished to obtain the finished product.

[0012] In summary, the present invention has the following beneficial effects: 1. This invention constructs a three-layer fiber fabric body structure consisting of a "reinforcing fiber layer - interface modification layer - bio-based resin matrix layer," and introduces interlayer cross-linking layers between adjacent layers to form a multi-dimensional reinforcement system. The interface modification layer constructs a micro-rough structure on the surface of the reinforcing fiber through plasma etching. Subsequently, the grafted bio-based compatibilizer can form a chemical anchor with the bio-based resin matrix, effectively improving the interfacial bonding strength between the fiber and the matrix.

[0013] 2. This invention has excellent environmental performance: It adopts a solvent-free bio-based resin matrix and a dry pre-impregnation process to replace the organic solvent system of traditional wet impregnation. The preparation process has no toxic or harmful gas emissions. The resin matrix is ​​a bio-based material with strong biodegradability. At the same time, it eliminates the solvent recovery process, reduces energy consumption and production costs, and conforms to the concept of green manufacturing.

[0014] 3. This invention significantly improves the fiber-matrix interface compatibility: By constructing a micro-nano interface structure through plasma etching and grafting modification with a bio-based compatibilizer, the fiber and matrix are bonded together through the dual effects of chemical bonds and hydrogen bonds, increasing the interfacial shear strength by more than 35%, effectively avoiding interfacial debonding, and ensuring the overall mechanical properties of the material.

[0015] 4. This invention strengthens interlayer bonding strength and solves the problem of interlayer delamination: the interlayer crosslinking agent and the bio-based resin matrix form a three-dimensional crosslinking network, which tightly bonds the multi-layer fiber fabric into one, increasing the interlayer delamination strength by more than 40%, while not affecting the lightweight performance of the material, thus meeting the structural integrity requirements of high-end equipment.

[0016] 5. The process of this invention is simple and controllable, and suitable for industrial production: it does not require complex chemical modification and solvent treatment steps, the segmented curing process parameters are stable, the equipment requirements are low, the production cycle is shortened by 20%-30% compared with the existing process, and it can achieve large-scale continuous production, taking into account high performance, environmental protection and economy. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to specific embodiments. It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of this application can be combined with each other.

[0018] In the description of this invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom", etc., indicating the orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0019] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "set up / connected," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] The present invention will now be described in detail.

[0021] Example 1: A high-performance fiber composite fabric, comprising a fiber fabric body, wherein the fiber fabric body comprises the following structure: reinforcing fiber layer: made of carbon fiber plain weave fabric, fiber diameter 10μm, tensile strength 4.2GPa, fiber volume fraction 50%; Interface modification layer: polylactic acid grafted with maleic anhydride (grafting rate 10%), thickness 120nm; Bio-based resin matrix layer: Castor oil-based epoxy resin (epoxy value 0.40 eq / 100g) and turpentine-based curing agent (amine value 250 mg KOH / g) are mixed at a mass ratio of 100:40, with a thickness of 200 μm; Interlayer crosslinking layer: isocyanate-modified polyethylene glycol (number average molecular weight 1500), added at 3% of the resin matrix mass, with a thickness of 140 nm; The total thickness of the composite fabric is 2.0 mm, and the surface density is 500 g / m².

[0022] A method for preparing a high-performance fiber composite fabric includes the following steps: S1: Plasma modification: The carbon fiber fabric is placed in a low-temperature plasma treatment instrument, and an argon-oxygen mixed gas (3:1) is introduced. The treatment power is 100W, the time is 5min, and the pressure is 0.08MPa. S2: Compatibilizer grafting: Immerse in 8% polylactic acid grafted maleic anhydride aqueous solution, soak at 70℃ for 30 min, dry at 110℃ for 1.5 h, and cool for later use; S3: Resin preparation: Mix castor oil-based epoxy resin and turpentine-based curing agent at a ratio of 100:40, add 3% isocyanate-modified polyethylene glycol, and stir at 400 r / min for 20 min. S4: Dry prepreg: The resin is heated to 90℃ to melt, and the coating amount is 100% of the carbon fiber fabric mass. The prepreg is rolled by a 0.8MPa pressure roller, and 4 layers of prepreg are stacked with a small amount of crosslinking agent between the layers. S5: Curing and molding: Hold at 130℃ and 1.8MPa for 1.5h, then at 170℃ and 2.2MPa for 2.5h, and allow to cool naturally; S6: Post-processing: cutting and polishing to obtain the finished product.

[0023] Example 2: A high-performance fiber composite fabric, comprising a fiber fabric body, wherein the fiber fabric body comprises the following structure: reinforcing fiber layer: aramid fiber twill fabric, fiber diameter 12μm, breaking strength 3.8GPa, fiber volume fraction 45%; Interface modification layer: starch-based grafted acrylate (grafting rate 9%), thickness 80nm; Bio-based resin matrix layer: Castor oil-based epoxy resin (epoxy value 0.35 eq / 100g) and turpentine-based curing agent (amine value 220 mg KOH / g) are mixed at a mass ratio of 100:35, with a thickness of 150 μm; Interlayer crosslinking layer: isocyanate-modified polyethylene glycol (number average molecular weight 1000), added at 2% of the resin matrix mass, with a thickness of 100 nm; The total thickness of the composite fabric is 1.5mm, and the surface density is 400g / ㎡.

[0024] A method for preparing a high-performance fiber composite fabric includes the following steps: S1: Plasma modification: processing power 80W, time 8min, pressure 0.05MPa, the rest is the same as in Example 1; S2: Compatibilizer grafting: Immerse in 5% starch-based grafted acrylate aqueous solution, soak at 60°C for 40 min, dry at 100°C for 2 h, the rest is the same as in Example 1; S3: Resin preparation: mass ratio 100:35, add 2% crosslinking agent, stir at 300r / min for 25min, the rest is the same as in Example 1; S4: Dry prepreg: Resin temperature 80℃, coating amount 80%, roller pressure 0.5MPa, 3 layers of prepreg fabric stacked; S5: Curing and molding: Hold at 120℃ and 1.5MPa for 2 hours, then at 160℃ and 2.0MPa for 3 hours, the rest is the same as in Example 1; S6: Post-processing: Same as Example 1.

[0025] Example 3: A high-performance fiber composite fabric, comprising a fiber woven body, wherein the fiber woven body comprises the following structure: reinforcing fiber layer: carbon fiber-ultra-high molecular weight polyethylene fiber blended satin fabric (mass ratio 7:3), fiber diameter 8μm, breaking strength 4.0GPa, fiber volume fraction 55%; Interface modification layer: polylactic acid grafted with maleic anhydride (grafting rate 12%), thickness 180nm; Bio-based resin matrix layer: Castor oil-based epoxy resin (epoxy value 0.45 eq / 100g) and turpentine-based curing agent (amine value 280 mg KOH / g) are mixed at a mass ratio of 100:45, with a thickness of 250 μm; Interlayer crosslinking layer: isocyanate-modified polyethylene glycol (number average molecular weight 2000), added at 4% of the resin matrix mass, with a thickness of 180 nm; The total thickness of the composite fabric is 3.0 mm, and the surface density is 650 g / m².

[0026] A method for preparing a high-performance fiber composite fabric includes the following steps: S1: Plasma modification: processing power 120W, time 3min, pressure 0.1MPa, the rest is the same as in Example 1; S2: Compatibilizer grafting: Immerse in 10% polylactic acid grafted maleic anhydride aqueous solution, soak at 80°C for 20 min, dry at 120°C for 1 h, the rest is the same as in Example 1; S3: Resin preparation: mass ratio 100:45, add 4% crosslinking agent, stir at 500 r / min for 15 min, the rest is the same as in Example 1; S4: Dry prepreg: resin temperature 100℃, coating amount 120%, pressure roller pressure 1.0MPa, 5 layers of prepreg fabric stacked; S5: Curing and molding: Hold at 140℃ and 2.0MPa for 1 hour, then at 180℃ and 2.5MPa for 2 hours, the rest is the same as in Example 1; S6: Post-processing: Same as Example 1.

[0027] Comparative Example 1 (Pre-existing technical solution): Fiber composite fabric was prepared by wet impregnation + silane coupling agent modification process. The reinforcing fiber was the same carbon fiber plain weave fabric as in Example 1. The resin was ordinary epoxy resin (the impregnation solution was prepared by dissolving in acetone, with a solid content of 50%). The fiber surface was modified by silane coupling agent KH550. After impregnation, drying and curing, the total thickness and areal density of the composite fabric were the same as in Example 1.

[0028] Performance testing and results analysis: The composite fabrics prepared in Examples 1-3 and Comparative Example 1 were subjected to performance tests according to the following standards: interfacial shear strength was tested according to GB / T 14007-2002; interlaminar peel strength was tested according to GB / T 1450.1-2005; tensile strength and elastic modulus were tested according to GB / T 3354-2014; and solvent residue was tested according to GB / T 23990-2009. The test results are shown in the table below: Table 1 The test results in the table above show that the high-performance fiber composite fabrics prepared in Examples 1-3 of this invention exhibit a 38%-46% increase in interfacial shear strength, a 26%-50% increase in interlayer peel strength, and a 7%-22% increase in breaking strength compared to Comparative Example 1. Furthermore, they are solvent-free and have a 23%-33% shorter production cycle. This indicates that this invention, through plasma modification, grafting with bio-based compatibilizers, and in-situ interlayer crosslinking, can significantly improve the fiber-matrix interfacial compatibility and interlayer bonding strength. Simultaneously, the solvent-free dry process completely eliminates solvent pollution, shortens the production cycle, and balances high performance with environmental friendliness, resulting in overall performance superior to existing technologies.

[0029] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A high-performance fiber composite fabric, characterized in that: The fiber fabric body includes, from the inside out, a reinforcing fiber layer, an interface modification layer, and a bio-based resin matrix layer. An interlayer cross-linking layer is provided between adjacent fiber fabric bodies. The total thickness of the fiber fabric body is 0.8-5.0 mm, and the areal density is 200-800 g / m². The reinforcing fiber layer uses continuous fiber fabric as the reinforcing phase, and the fiber type is selected from one or more blends of carbon fiber, aramid fiber, and ultra-high molecular weight polyethylene fiber. The interlayer crosslinking layer is located between adjacent first and second reinforcing fiber layers, with a thickness of 80-200 nm. The interlayer crosslinking layer is formed by reacting isocyanate-modified polyethylene glycol with a bio-based resin matrix. The interface modification layer is a bio-based compatibilizer layer grafted after plasma etching, with a thickness of 50-200 nm. The compatibilizer is selected from polylactic acid grafted with maleic anhydride and starch-based grafted with acrylate. The bio-based resin matrix layer is made of solvent-free bio-based epoxy resin, which is composed of castor oil-based epoxy resin and turpentine-based curing agent mixed in a mass ratio of 100:30-50, and has a thickness of 100-300μm.

2. The high-performance fiber composite fabric according to claim 1, characterized in that: The fabric structure of the reinforcing fiber layer is plain weave, twill weave, or satin weave, with a fiber volume fraction of 40%-60%, a fiber diameter of 5-15μm, and a tensile strength ≥3.5GPa.

3. The high-performance fiber composite fabric according to claim 1, characterized in that: The amount of isocyanate-modified polyethylene glycol added to the interlayer crosslinking layer is 2%-5% of the mass of the bio-based resin matrix.

4. The high-performance fiber composite fabric according to claim 1, characterized in that: The epoxy value of the castor oil-based epoxy resin is 0.35-0.45 eq / 100g, and the amine value of the turpentine-based curing agent is 200-300 mg KOH / g.

5. The high-performance fiber composite fabric according to claim 1, characterized in that: The number average molecular weight of the isocyanate-modified polyethylene glycol is 1000-2000.

6. A method for preparing a high-performance fiber composite fabric according to any one of claims 1-5, characterized in that, Includes the following steps: S1: Plasma modification treatment of the surface of the reinforcing fiber: The reinforcing fiber layer is placed in a low-temperature plasma treatment instrument, and a mixture of argon and oxygen (volume ratio 3:1) is introduced. The treatment power is controlled at 80-120W, the treatment time is 3-8min, and the treatment pressure is 0.05-0.1MPa. S2: Interface compatibilizer grafting treatment: Immerse the fiber fabric modified by plasma in step S1 into a bio-based compatibilizer solution with a compatibilizer mass concentration of 5%-10% and deionized water as the solvent. Immerse at a constant temperature of 60-80℃ for 20-40 minutes, then dry at 100-120℃ for 1-2 hours and cool to room temperature for later use. S3: Preparation of solvent-free bio-based resin matrix: At room temperature and pressure, castor oil-based epoxy resin and turpentine-based curing agent are placed in a mixing tank at a mass ratio of 100:30-50, and isocyanate-modified polyethylene glycol is added. The mixture is stirred at a speed of 300-500 r / min for 15-25 min until it is uniformly mixed to obtain the interlayer crosslinking layer. S4: Dry prepreg and lamination: The bio-based resin matrix prepared in step S3 is heated to 80-100℃ to melt and coated onto the surface of the fiber fabric treated in step S2. The coating amount is 80%-120% of the fiber fabric mass. After being rolled by a 0.5-1.0MPa pressure roller, a prepreg fabric is obtained. Multiple layers of prepreg fabric are stacked one by one, and a crosslinking agent is laid between the layers. S5: In-situ curing: Place the laminated prepreg into an autoclave and cure in sections: keep warm at 120-140℃ and 1.5-2.0MPa for 1-2 hours, then raise the temperature to 160-180℃ and 2.0-2.5MPa for 2-3 hours, and let it cool naturally to room temperature. S6: Post-processing: The cured composite fabric is edge-trimmed and surface-polished to obtain the finished product.

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