Modified fiber fabric, method for manufacturing the same, carbon fiber reinforced polymer composite, and method for monitoring safety of interlayer structure of the same

Abstract

This invention relates to modified fiber fabrics and their preparation methods, carbon fiber reinforced polymer composites, and methods for monitoring the interlayer structural safety of these composites, belonging to the field of polymer composite technology. The preparation method of the modified fiber fabric of this invention includes the following steps: immersing the fiber fabric in a modifier, removing it, and drying it to obtain the modified fiber fabric; the modifier consists of particulate matter, an adhesive, and a solvent, the particulate matter being composed of one-dimensional nanoparticles and two-dimensional nanoparticles, the one-dimensional nanoparticles being carbon nanotubes or silver nanowires, and the two-dimensional nanoparticles being graphene or Mxene. The preparation method of the modified fiber fabric of this invention utilizes the action of the adhesive to attach conductive particulate matter to the fiber surface, constructing a conductive network on the fiber surface, improving the conductivity of the fiber fabric, and facilitating the sensitive change of the overall resistance of the composite material during deformation, thereby realizing damage localization and structural health monitoring of the composite material.

Description

Technical Field

[0001] This invention relates to modified fiber fabrics and their preparation methods, carbon fiber reinforced polymer composites and their interlayer structural safety monitoring methods, belonging to the field of polymer composite technology. Background Technology

[0002] Carbon fiber reinforced polymer (CFRP) composites are widely used in the aerospace field due to their excellent mechanical properties, such as high strength-to-weight ratio, high stiffness, and high chemical resistance. However, CFRP composites have complex structures, are anisotropic, and exhibit poor interlaminar properties, particularly poor resistance to interlaminar cracking. They are also prone to damage such as fiber breakage, debonding, transverse cracking, and delamination. Therefore, improving the interlaminar properties of CFRP composites and achieving real-time monitoring of their structural integrity are essential.

[0003] As a technology for precise monitoring of deformation and damage in composite materials, structural health monitoring (SHM) technology can provide early warnings of composite structure failure and offer real-time detection methods to ensure the safe use of composite materials, thus attracting increasing attention from researchers both domestically and internationally. Designing and developing monitoring technologies capable of online detection of the health status of composite structures has become an important research direction in the field of composite materials. However, existing methods for detecting the health status of composite structures, such as fiber optic sensors and the addition of conductive materials, still face challenges such as difficulty in locating damage, impacting composite material performance, and increasing the complexity of molding processes.

[0004] Based on the concept of fiber hybrid reinforcement, this study aims to improve the interlaminar properties of composite materials, especially interlaminar shear strength, by designing reinforcing fiber phases that integrate reinforcing structure and sensing function. Furthermore, by altering the electrical properties of the reinforcing fiber phase network structure, it is expected to achieve intelligent characteristics such as structural health monitoring and self-sensing in high-performance CFRP composite materials during service.

[0005] The literature (Yang GM, et al. Composites Science and Technology, 2021, 213, 108959) describes a novel woven mesh fabricated using CNTs and graphene nanosheets (CG mesh). The conductive path density and conductivity of the CG mesh are significantly lower than those of traditional buckypaper. When the CG mesh structure is embedded in the middle of the CFRP composite material, it significantly improves the interlaminar fracture toughness of the composite. For type II delamination, the resistivity change rate (ΔR / R0%) of the composite material can jump by approximately 12% when delamination occurs. The formula for calculating the resistivity change rate is: R0 is the initial resistance of the composite material, and R is the instantaneous resistance of the composite material during shearing. When delamination caused by short beam shearing occurs, ΔR / R0% can reach 33%. However, the ΔR / R0% of the composite material exhibits irregularity with the displacement response, and the ΔR / R0% value is relatively low, making it unsuitable for delamination monitoring. Summary of the Invention

[0006] The purpose of this invention is to provide a modified fiber fabric that can solve the problem that when conductive particles are used to directly prepare conductive self-diagnostic carbon fiber reinforced resin matrix composites, the composite material's resistance change rate and displacement response regularity are poor, making it impossible to detect crack damage.

[0007] The second objective of this invention is to provide a method for preparing modified fiber fabrics that can solve the problem that existing carbon fiber reinforced polymers have poor shear strength and cannot be used for interlaminar damage monitoring.

[0008] The third objective of this invention is to provide a carbon fiber reinforced polymer composite material that can solve the problem that existing carbon fiber reinforced polymers have poor shear strength and cannot be used for interlaminar damage monitoring.

[0009] The fourth objective of this invention is to provide a method for monitoring the interlaminar structural safety of carbon fiber reinforced polymer composites, which can solve the problem that existing carbon fiber reinforced polymers have poor shear strength and cannot be used for interlaminar damage monitoring.

[0010] To achieve the above objectives, the technical solution adopted by the modified fiber fabric of the present invention is as follows:

[0011] A modified fiber fabric includes a fiber fabric matrix and particulate matter loaded on the fiber fabric matrix. The particulate matter consists of one-dimensional nanoparticles and two-dimensional nanoparticles in a mass ratio of (0.01–50):(0.01–50). The one-dimensional nanoparticles are carbon nanotubes or silver nanowires, and the two-dimensional nanoparticles are graphene or titanium carbide (Mxene). The total mass fraction of particulate matter in the modified fiber fabric is 0.01–60%.

[0012] The modified fiber fabric of the present invention includes a fiber fabric matrix and conductive particles adhered thereto. The adhered conductive particles can increase the surface roughness of the fiber, which is beneficial to improving the mechanical bonding and friction between the fiber and the matrix resin, thereby enhancing the interfacial bonding force between the fiber and the resin. Furthermore, a sensitive conductive network can be constructed on the surface of the fiber fabric, which is beneficial to the sensitive change of the overall resistance of the composite material during deformation, thereby realizing the damage location and structural health monitoring of the composite material.

[0013] Preferably, the fiber fabric is a silk fiber nonwoven fabric, glass fiber fabric, Kevlar fiber fabric, basalt fiber fabric, or ultra-high molecular weight polyethylene fiber fabric.

[0014] Preferably, the total mass fraction of particulate matter in the modified fiber fabric is 5% to 50%.

[0015] Preferably, the total mass fraction of particulate matter in the modified fiber fabric is 10-15%.

[0016] In this invention, the total mass fraction of particulate matter in the modified fiber fabric is equal to (the total mass of the modified fiber fabric - the total mass of the unmodified fiber fabric) / the total mass of the unmodified fiber fabric × 100%.

[0017] The technical solution adopted in the preparation method of the modified fiber fabric of the present invention is as follows:

[0018] A method for preparing a modified fiber fabric includes the following steps: coating a modifier onto a fiber fabric and drying it to obtain the modified fiber fabric; the modifier is composed of particulate matter, an adhesive, and a solvent; the adhesive is urea or polyvinyl alcohol; in the modifier, the mass fraction of particulate matter is 0.01-60%, and the mass fraction of the adhesive is 0.1-20%.

[0019] The method for preparing modified fiber fabrics of the present invention utilizes an adhesive to attach conductive particles to the fiber surface, constructing a conductive network on the fiber surface and improving the conductivity of the fiber fabric. Urea has a dissolving effect on the sericin layer on the fiber fabric surface, slightly dissolving it and allowing the conductive particles in the modifier to adhere. Polyvinyl alcohol has an adhesive effect, adhering the conductive particles to the fiber surface, improving the adhesion of the conductive particles to the fiber fabric surface, which is beneficial for improving the mechanical bonding and friction between the conductive particles and the matrix resin, thereby enhancing the interfacial bonding force between the fiber and the resin. Furthermore, it can construct a sensitive conductive network on the fiber fabric surface, which is beneficial for the sensitive change of the overall resistance of the composite material during deformation, thus enabling damage localization and structural health monitoring of the composite material. The coating in this invention includes immersion, spraying, dip coating, and brushing.

[0020] Preferably, the fiber fabric is a silk fiber nonwoven fabric, and the adhesive is urea.

[0021] Preferably, the fiber fabric is glass fiber fabric, Kevlar fiber fabric, basalt fiber fabric or ultra-high molecular weight polyethylene fiber fabric, and the adhesive is polyvinyl alcohol.

[0022] Preferably, the polyvinyl alcohol has a weight-average molecular weight of 5,000 to 200,000; the solvent is water; and the temperature of the modifier is room temperature to 90°C.

[0023] The technical solution adopted in the carbon fiber reinforced polymer composite material of the present invention is as follows:

[0024] A carbon fiber reinforced polymer composite material is composed of carbon fiber fabric, polymer and modified fiber fabric as described above, wherein the mass ratio of the modified fiber fabric, carbon fiber fabric and polymer is (5-30):(40-70):(10-50); the polymer is epoxy resin, unsaturated polyester or polyurethane.

[0025] The carbon fiber reinforced polymer composite material of the present invention comprises carbon fiber fabric, polymer, and modified fiber fabric. The conductive particles on the rough surface of the modified fiber fabric can effectively improve the bonding force between it and the polymer, enhance the interfacial bonding force between the fiber and the polymer, and improve the interlaminar shear strength. Furthermore, when the modified fiber fabric is inserted into multiple layers of stacked carbon fibers, the interlaminar shear strength and fracture toughness of the composite material can be significantly enhanced.

[0026] In this invention, the carbon fiber reinforced polymer composite material is prepared by resin transfer molding process using modified fiber fabric, carbon fiber fabric and polymer.

[0027] The technical solution adopted in the monitoring method for the interlaminar structure safety of carbon fiber reinforced polymer composites of the present invention is as follows:

[0028] A method for monitoring the interlaminar structure safety of a carbon fiber reinforced polymer composite material includes the following steps: detecting the rate of change of resistance of the carbon fiber reinforced polymer composite material as described above during use; if the rate of change of resistance exceeds a threshold, the interlaminar structure is considered to be damaged, and an early warning signal is issued.

[0029] The method for monitoring the interlaminar structural safety of carbon fiber reinforced polymer composites of the present invention can evaluate micro-crack damage by detecting the rate of change of electrical resistance of carbon fiber reinforced polymer composites during use, thereby realizing damage localization and structural health monitoring of composite materials. Attached Figure Description

[0030] Figure 1 This is a scanning electron microscope image of the appearance morphology of the silk fiber nonwoven fabric in Example 1;

[0031] Figure 2 The image shows the appearance morphology of the modified silk fiber nonwoven fabric in Example 1 using a scanning electron microscope.

[0032] Figure 3 The image shows a scanning electron microscope (SEM) image of the appearance morphology of the glass fiber fabric in Example 2.

[0033] Figure 4 The image shows the morphology of the modified glass fiber fabric in Example 2 using a scanning electron microscope.

[0034] Figure 5 Images showing the appearance of carbon fiber reinforced polymer composite materials cut into test samples;

[0035] Figure 6 This is a schematic diagram of interlaminar shear performance testing using a microcomputer-controlled electronic universal testing machine.

[0036] Figure 7 This shows the load-displacement curves and stage division diagrams of carbon fiber reinforced resin matrix composites during interlaminar shear deformation. Detailed Implementation

[0037] The method for preparing the modified fiber fabric of this invention is a pioneering invention. This invention utilizes an adhesive to attach conductive particles to the fiber surface, constructing a conductive network on the fiber surface, thereby improving the conductivity of the fiber fabric. This facilitates the sensitive change of the overall resistance of the composite material during deformation, thus enabling damage localization and structural health monitoring of the composite material.

[0038] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0039] I. Specific embodiments of the modified fiber fabric and its preparation method of the present invention are as follows:

[0040] Example 1

[0041] The method for preparing the modified fiber fabric in this embodiment specifically includes the following steps:

[0042] (1) One-dimensional nanoparticles and two-dimensional nanoparticles were stirred evenly and then ultrasonically dispersed in an adhesive solution to obtain a modifier; the one-dimensional nanoparticles were carbon nanotubes (purity >99%, outer diameter 5-15 nm, length <50 μm, specific surface area 260-330 m²). 2 / g), the two-dimensional nanoparticles are graphene (purity >99%, thickness 0.5–4 nm, diameter 0.5–3 μm, number of layers 1–10, specific surface area 520–560 m²). 2 / g), the mass ratio of one-dimensional nanoparticles to two-dimensional nanoparticles is 3:2; the adhesive solution is composed of urea and water; in the modifier, the total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles is 20%, and the mass fraction of urea is 5%; ultrasonic dispersion is carried out at 90℃.

[0043] (2) The silk fiber nonwoven fabric was immersed in the modifier for 5 seconds, then removed and dried to obtain the modified silk fiber fabric; the total mass fraction of one-dimensional and two-dimensional nanoparticles in the modified silk fiber fabric was 10%; the specification of the silk fiber nonwoven fabric was 35 g / m 2 .

[0044] Example 2

[0045] The method for preparing the modified fiber fabric in this embodiment specifically includes the following steps:

[0046] (1) One-dimensional nanoparticles and two-dimensional nanoparticles were stirred evenly and then ultrasonically dispersed in an adhesive solution to obtain a modifier; the one-dimensional nanoparticles were carbon nanotubes (purity >99%, outer diameter 5-15 nm, length <50 μm, specific surface area 260-330 m²). 2 / g), the two-dimensional nanoparticles are titanium carbide (Ti3C2T) x Mxene (purity >99%, thickness 3-5 nm, sheet diameter 0.5-3 μm, number of layers 1-10), with a mass ratio of one-dimensional nanoparticles to two-dimensional nanoparticles of 1:1; the adhesive solution is composed of polyvinyl alcohol and water; in the modifier, the total mass fraction of one-dimensional and two-dimensional nanoparticles is 30%, the mass fraction of polyvinyl alcohol is 3%, and the weight average molecular weight of polyvinyl alcohol is 100,000; ultrasonic dispersion is carried out at 25℃.

[0047] (2) The glass fiber fabric was immersed in the modifier, removed after 7 days, and dried to obtain the modified glass fiber fabric; the total mass fraction of one-dimensional and two-dimensional nanoparticles in the modified glass fiber fabric was 15%; the specification of the glass fiber fabric was 400 g / m 2 .

[0048] Example 3

[0049] The method for preparing the modified fiber fabric in this embodiment specifically includes the following steps:

[0050] (1) One-dimensional nanoparticles and two-dimensional nanoparticles were stirred evenly and then ultrasonically dispersed in an adhesive solution to obtain a modifier; the one-dimensional nanoparticles were silver nanowires (purity >99%, diameter 15-40 nm, length 10-35 μm), and the two-dimensional nanoparticles were graphene (purity >99%, thickness 0.5-4 nm, diameter 0.5-3 μm, number of layers 1-10, specific surface area 520-560 m²). 2 / g), the mass ratio of one-dimensional nanoparticles to two-dimensional nanoparticles is 0.01:50; the adhesive solution is composed of polyvinyl alcohol and water; in the modifier, the total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles is 60%, the mass fraction of polyvinyl alcohol is 10%, and the weight average molecular weight of polyvinyl alcohol is 5000; ultrasonic dispersion is carried out at 60℃.

[0051] (2) The Kevlar fiber fabric was immersed in the modifier, removed after 1 day, and dried to obtain the modified Kevlar fiber fabric; the total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles in the modified Kevlar fiber fabric was 50%; the specification of the Kevlar fiber fabric was 240 g / m2 .

[0052] Example 4

[0053] The method for preparing the modified fiber fabric in this embodiment specifically includes the following steps:

[0054] (1) One-dimensional nanoparticles and two-dimensional nanoparticles were stirred evenly and then ultrasonically dispersed in an adhesive solution to obtain a modifier; the one-dimensional nanoparticles were silver nanowires (purity >99%, diameter 15-40 nm, length 10-35 μm), and the two-dimensional nanoparticles were titanium carbide (Ti3C2T). x Mxene (purity >99%, thickness 3-5 nm, sheet diameter 0.5-3 μm, number of layers 1-10), with a mass ratio of one-dimensional nanoparticles to two-dimensional nanoparticles of 5:3; the adhesive solution is composed of polyvinyl alcohol and water; in the modifier, the total mass fraction of one-dimensional and two-dimensional nanoparticles is 25%, the mass fraction of polyvinyl alcohol is 7%, and the weight average molecular weight of polyvinyl alcohol is 10000; ultrasonic dispersion is carried out at 45℃.

[0055] (2) The basalt fiber fabric was immersed in the modifier, removed after 4 days, and dried to obtain the modified basalt fiber fabric; the total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles in the modified basalt fiber fabric was 20%; the specification of the basalt fiber fabric was 270 g / m 2 .

[0056] Example 5

[0057] The method for preparing the modified fiber fabric in this embodiment specifically includes the following steps:

[0058] (1) One-dimensional nanoparticles and two-dimensional nanoparticles were stirred evenly and then ultrasonically dispersed in an adhesive solution to obtain a modifier; the one-dimensional nanoparticles were carbon nanotubes (purity >99%, outer diameter 5-15 nm, length <50 μm, specific surface area 260-330 m²). 2 / g), the two-dimensional nanoparticles are graphene (purity >99%, thickness 0.5–4 nm, diameter 0.5–3 μm, number of layers 1–10, specific surface area 520–560 m²). 2 / g), the mass ratio of one-dimensional nanoparticles to two-dimensional nanoparticles is 50:0.01; the adhesive solution is composed of polyvinyl alcohol and water; in the modifier, the total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles is 40%, the mass fraction of polyvinyl alcohol is 2%, and the weight average molecular weight of polyvinyl alcohol is 200,000; ultrasonic dispersion is carried out at 70℃.

[0059] (2) The ultra-high molecular weight polyethylene (UHMWPE) fiber fabric was immersed in the modifier for 2 days, then removed and dried to obtain the modified UHMWPE fiber fabric; the total mass fraction of one-dimensional and two-dimensional nanoparticles in the modified UHMWPE fiber fabric was 5%; the specification of the UHMWPE fiber fabric was 220 g / m². 2 .

[0060] Example 6

[0061] The method for preparing the modified fiber fabric in this embodiment specifically includes the following steps:

[0062] (1) One-dimensional nanoparticles and two-dimensional nanoparticles were stirred evenly and then ultrasonically dispersed in an adhesive solution to obtain a modifier; the one-dimensional nanoparticles were silver nanowires (the same silver nanowires as in Example 3), and the two-dimensional nanoparticles were graphene (the same graphene as in Example 1), with a mass ratio of one-dimensional nanoparticles to two-dimensional nanoparticles of 2:3; the adhesive solution was composed of polyvinyl alcohol and water; in the modifier, the total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles was 10%, the mass fraction of polyvinyl alcohol was 5%, and the weight average molecular weight of polyvinyl alcohol was 50,000; ultrasonic dispersion was carried out at 60°C.

[0063] (2) The modifier was sprayed on both sides of the Kevlar fiber fabric and placed in a dry environment for 3 days to obtain the modified Kevlar fiber fabric; the total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles in the modified Kevlar fiber fabric was 7%; the Kevlar fiber fabric was the same as the Kevlar fiber fabric in Example 3.

[0064] Example 7

[0065] The method for preparing the modified fiber fabric in this embodiment specifically includes the following steps:

[0066] (1) One-dimensional nanoparticles and two-dimensional nanoparticles were stirred evenly and then ultrasonically dispersed in an adhesive solution to obtain a modifier; the one-dimensional nanoparticles were carbon nanotubes (the same carbon nanotubes as in Example 1), and the two-dimensional nanoparticles were graphene (the same graphene as in Example 1), with a mass ratio of 6:5 between the one-dimensional and two-dimensional nanoparticles; the adhesive solution was composed of polyvinyl alcohol and water; in the modifier, the total mass fraction of one-dimensional and two-dimensional nanoparticles was 5%, the mass fraction of polyvinyl alcohol was 20%, and the weight-average molecular weight of polyvinyl alcohol was 200,000; ultrasonic dispersion was carried out at 70°C.

[0067] (2) The modifier was applied to both sides of the basalt fiber fabric and placed in a dry environment for 12 hours to obtain the modified basalt fiber fabric. The total mass fraction of one-dimensional nanoparticles and two-dimensional nanoparticles in the modified basalt fiber fabric was 3%. The ultra-high molecular weight polyethylene fiber fabric was the same as the ultra-high molecular weight polyethylene fiber fabric in Example 5.

[0068] II. Specific embodiments of the carbon fiber reinforced polymer composite material of the present invention are as follows:

[0069] Example 8

[0070] The carbon fiber reinforced polymer composite material of this embodiment is composed of modified silk fiber nonwoven fabric, carbon fiber fabric and epoxy resin, and its preparation method specifically includes the following steps:

[0071] (1) Six layers of carbon fiber fabric and one layer of modified silk fiber nonwoven fabric are laid in a mold in a top-to-bottom order. The modified silk fiber nonwoven fabric is the modified silk fiber fabric of Example 1 and is located at the bottom of the layup. The carbon fiber fabric has a specification of 250 g / m³. 2 .

[0072] (2) A vacuum-assisted resin transfer molding process was used to transfer epoxy resin liquid into a mold. After curing, carbon fiber reinforced polymer composite material was obtained. The epoxy resin liquid consisted of epoxy resin and a curing agent. The epoxy resin was grade YD-128, and the curing agent was grade D-230. The mass ratio of epoxy resin to curing agent was 3:1. In the mold, the mass ratio of modified silk fiber fabric, carbon fiber fabric, and epoxy resin liquid was 5:70:25. Curing involved heating the material in the mold to 80°C and holding it there for 4 hours, followed by heating it to 120°C and holding it there for 2 hours.

[0073] Example 9

[0074] The carbon fiber reinforced polymer composite material of this embodiment is composed of modified glass fiber fabric, carbon fiber fabric and epoxy resin, and its preparation method specifically includes the following steps:

[0075] (1) Six layers of carbon fiber fabric and one layer of modified glass fiber fabric are laid in a mold in a top-to-bottom order. The modified glass fiber fabric is the same as that in Example 2 and is located at the bottom of the layup. The carbon fiber fabric has a specification of 250 g / m³. 2 .

[0076] (2) A vacuum-assisted resin transfer molding process was used to transfer epoxy resin liquid into a mold. After curing, a carbon fiber reinforced polymer composite material was obtained. The epoxy resin liquid consisted of epoxy resin and a curing agent. The epoxy resin was grade YD-128, and the curing agent was grade D-230. The mass ratio of epoxy resin to curing agent was 3:1. In the mold, the mass ratio of modified glass fiber fabric, carbon fiber fabric, and epoxy resin liquid was 15:65:20. Curing involved heating the material in the mold to 80°C and holding it there for 4 hours, followed by heating it to 120°C and holding it there for 2 hours.

[0077] Example 10

[0078] The carbon fiber reinforced polymer composite material of this embodiment is composed of modified Kevlar fiber fabric, carbon fiber fabric and epoxy resin, and its preparation method specifically includes the following steps:

[0079] (1) Six layers of carbon fiber fabric and one layer of modified Kevlar fiber fabric are laid in a mold in a top-to-bottom order. The modified Kevlar fiber fabric is the modified Kevlar fiber fabric of Example 3 and is located at the bottom of the layup. The carbon fiber fabric has a specification of 250 g / m³. 2 .

[0080] (2) A vacuum-assisted resin transfer molding process was used to transfer epoxy resin liquid into a mold. After curing, a carbon fiber reinforced polymer composite material was obtained. The epoxy resin liquid consisted of epoxy resin and a curing agent. The epoxy resin was grade YD-128, and the curing agent was grade D-230. The mass ratio of epoxy resin to curing agent was 3:1. In the mold, the mass ratio of modified Kevlar fiber fabric, carbon fiber fabric, and epoxy resin liquid was 10:60:30. Curing involved heating the material in the mold to 80°C and holding it there for 4 hours, followed by heating it to 120°C and holding it there for 2 hours.

[0081] Example 11

[0082] The carbon fiber reinforced polymer composite material of this embodiment is composed of modified basalt fiber fabric, carbon fiber fabric and epoxy resin, and its preparation method specifically includes the following steps:

[0083] (1) Six layers of carbon fiber fabric and one layer of modified basalt fiber fabric are laid in a mold in a top-to-bottom order. The modified basalt fiber fabric is the same as that in Example 4 and is located at the bottom of the layup. The carbon fiber fabric has a specification of 250 g / m³. 2 .

[0084] (2) A vacuum-assisted resin transfer molding process was used to transfer epoxy resin liquid into a mold. After curing, carbon fiber reinforced polymer composite material was obtained. The epoxy resin liquid consisted of epoxy resin and a curing agent. The epoxy resin grade was YD-128, and the curing agent grade was D-230. The mass ratio of epoxy resin to curing agent was 3:1. In the mold, the mass ratio of modified basalt fiber fabric, carbon fiber fabric, and epoxy resin liquid was 20:50:30. Curing involved heating the material in the mold to 80°C and holding it there for 4 hours, followed by heating it to 120°C and holding it there for 2 hours.

[0085] Example 12

[0086] The carbon fiber reinforced polymer composite material of this embodiment is composed of modified ultra-high molecular weight polyethylene fiber fabric, carbon fiber fabric, and epoxy resin. Its preparation method specifically includes the following steps:

[0087] (1) Six layers of carbon fiber fabric and one layer of modified ultra-high molecular weight polyethylene (UHMWPE) fiber fabric are laid in a mold in a top-to-bottom order. The modified UHMWPE fiber fabric is the same as that in Example 5 and is located at the bottom of the layup. The carbon fiber fabric has a specification of 250 g / m³. 2 .

[0088] (2) A vacuum-assisted resin transfer molding process was used to transfer epoxy resin liquid into a mold. After curing, carbon fiber reinforced polymer composite material was obtained. The epoxy resin liquid consisted of epoxy resin and a curing agent. The epoxy resin was grade YD-128, and the curing agent was grade D-230. The mass ratio of epoxy resin to curing agent was 3:1. In the mold, the mass ratio of modified ultra-high molecular weight polyethylene fiber fabric, carbon fiber fabric, and epoxy resin liquid was 10:60:30. Curing involved heating the material in the mold to 80°C and holding it there for 4 hours, followed by heating it to 120°C and holding it there for 2 hours.

[0089] Example 13

[0090] The carbon fiber reinforced polymer composite material of this embodiment is composed of modified Kevlar fiber fabric, carbon fiber fabric and unsaturated polyester, and its preparation method specifically includes the following steps:

[0091] (1) Five layers of carbon fiber fabric and two layers of modified Kevlar fiber fabric are laid in a mold in a top-to-bottom order. The modified Kevlar fiber fabric is the modified Kevlar fiber fabric of Example 3 and is located at the bottom of the layup. The carbon fiber fabric has a specification of 250 g / m³. 2 .

[0092] (2) A vacuum-assisted resin transfer molding process was used to transfer unsaturated polyester liquid into a mold. After curing, carbon fiber reinforced polymer composite material was obtained. The unsaturated polyester liquid consisted of unsaturated polyester, styrene, and an initiator. The unsaturated polyester was grade M-191DC, and the initiator was benzoyl peroxide. The mass ratio of unsaturated polyester, styrene, and initiator was 1:0.25:0.01. In the mold, the mass ratio of modified Kevlar fiber fabric, carbon fiber fabric, and unsaturated polyester liquid was 20:60:20. Curing involved heating the material in the mold to 80°C and holding it for 4 hours, followed by heating it to 120°C and holding it for 2 hours.

[0093] Example 14

[0094] The carbon fiber reinforced polymer composite material of this embodiment is composed of modified basalt fiber fabric, carbon fiber fabric and polyurethane resin, and its preparation method specifically includes the following steps:

[0095] (1) Five layers of carbon fiber fabric and two layers of modified basalt fiber fabric were laid in a mold in a top-to-bottom order. The modified basalt fiber fabric was the same as that in Example 4 and was located at the bottom of the layup. The carbon fiber fabric had a specification of 250 g / m³. 2 .

[0096] (2) A vacuum-assisted resin transfer molding process was used to transfer polyurethane resin liquid into a mold. After curing, a carbon fiber reinforced polymer composite material was obtained. The polyurethane resin liquid consisted of polyurethane A and polyurethane B components. The grade of polyurethane A was 5104L-A, and the grade of polyurethane B was 5104L-B. The mass ratio of polyurethane A to polyurethane B was 1:1.25. In the mold, the mass ratio of modified basalt fiber fabric, carbon fiber fabric, and polyurethane resin liquid was 40:50:20. Curing was performed by first heating the material in the mold to 100℃ and holding it at that temperature for 2 hours, and then heating it to 120℃ and holding it at that temperature for 2 hours.

[0097] The carbon fiber reinforced polymer composites of Examples 8-14 do not distinguish between the top and bottom surfaces during use.

[0098] Comparative Example 1

[0099] The preparation method of the carbon fiber reinforced polymer composite material in this comparative example includes the following steps:

[0100] Six layers of carbon fiber fabric and one layer of silk fiber nonwoven fabric were laid in a mold from top to bottom, with the silk fiber nonwoven fabric at the bottom. The silk fiber nonwoven fabric, carbon fiber fabric, and epoxy resin liquid were then used to prepare a carbon fiber reinforced polymer composite material using a vacuum-assisted resin transfer molding process. The mass ratio of the silk fiber nonwoven fabric, carbon fiber fabric, and epoxy resin liquid was equal to the mass ratio of the modified silk fiber fabric, carbon fiber fabric, and epoxy resin liquid in Example 8. The carbon fiber fabric was the same as that in Example 8, the epoxy resin liquid was the same as that in Example 8, and the silk fiber nonwoven fabric was the same as that in Example 1.

[0101] Comparative Example 2

[0102] The preparation method of the carbon fiber reinforced polymer composite material in this comparative example includes the following steps:

[0103] Six layers of carbon fiber fabric and one layer of glass fiber fabric were laid in a mold from top to bottom, with the glass fiber fabric at the bottom. The glass fiber fabric, carbon fiber fabric, and epoxy resin liquid were then used to prepare a carbon fiber reinforced polymer composite material using a vacuum-assisted resin transfer molding process. The mass ratio of the glass fiber fabric, carbon fiber fabric, and epoxy resin liquid was equal to the mass ratio of the modified glass fiber fabric, carbon fiber fabric, and epoxy resin liquid in Example 9. The carbon fiber fabric was the same as that in Example 9, the epoxy resin liquid was the same as that in Example 9, and the glass fiber fabric was the same as that in Example 2.

[0104] Comparative Example 3

[0105] The preparation method of the carbon fiber reinforced polymer composite material in this comparative example includes the following steps:

[0106] Six layers of carbon fiber fabric were laid in a mold from top to bottom; carbon nanotubes and epoxy resin liquid were stirred evenly to obtain a mixture, which was then transferred to the mold using a vacuum-assisted resin transfer molding process and cured to obtain a carbon fiber reinforced polymer composite material; the mass ratio of carbon nanotubes, carbon fiber fabric and epoxy resin liquid was equal to the mass ratio of modified silk fiber fabric, carbon fiber fabric and epoxy resin liquid in Example 8, the carbon nanotubes were the same as those in Example 2, the carbon fiber fabric was the same as those in Example 8, and the epoxy resin liquid was the same as those in Example 8; the curing was the same as that in Example 8.

[0107] Comparative Example 4

[0108] The preparation method of the carbon fiber reinforced polymer composite material in this comparative example includes the following steps:

[0109] Six layers of carbon fiber fabric were laid in a mold from top to bottom. Graphene and epoxy resin liquid were stirred evenly to obtain a mixture. The mixture was transferred to the mold using a vacuum-assisted resin transfer molding process and cured to obtain a carbon fiber reinforced polymer composite material. The mass ratio of graphene, carbon fiber fabric, and epoxy resin liquid was equal to the mass ratio of modified silk fiber fabric, carbon fiber fabric, and epoxy resin liquid in Example 8. The graphene was the same as that in Example 1, the carbon fiber fabric was the same as that in Example 8, and the epoxy resin liquid was the same as that in Example 8. The curing process was the same as in Example 8.

[0110] III. Specific embodiments of the monitoring method for the interlaminar structure safety of the carbon fiber reinforced polymer composite material of the present invention are as follows:

[0111] The resistance change rate of any carbon fiber reinforced polymer composite material in Examples 8-14 is detected during use. If the resistance change rate exceeds the threshold, it is considered that the interlayer structure is damaged, and an early warning signal is issued.

[0112] Experimental Example 1

[0113] This experiment characterizes the morphology of the modified fiber fabrics prepared in Examples 1-5. The morphologies of the fiber fabrics before and after modification in Examples 1 and 2 are as follows: Figure 1-4 As shown. Figure 1 This is a scanning electron microscope image of the appearance morphology of the silk fiber nonwoven fabric in Example 1. Figure 2 This is a scanning electron microscope (SEM) image of the morphology of the modified silk fiber nonwoven fabric in Example 1. Figure 3 This is a scanning electron microscope image of the appearance morphology of the glass fiber fabric in Example 2. Figure 4 The image shows the appearance morphology of the modified glass fiber fabric in Example 2 using a scanning electron microscope.

[0114] Depend on Figure 1-2 It is known that unmodified silk fibers have a smooth surface, with a thick layer of sericin coating the fibers. After surface modification, some of the sericin on the surface of the silk fibers is slightly dissolved by urea, and carbon nanotubes and graphene are uniformly adhered by the sericin. This significantly improves the interaction between the silk fiber nonwoven fabric and the resin matrix, which is beneficial to improving the interlaminar properties of the composite material. In addition, the uniformly adhered carbon nanotubes and graphene construct a sensitive conductive network on the surface of the silk fibers, which is beneficial to the sensitive change of the overall resistance of the composite material during bending deformation, thereby realizing damage localization and structural health monitoring of the composite material.

[0115] Depend on Figure 3-4It is known that the unmodified glass fiber surface is very smooth, with a diameter of approximately 21 μm. After surface modification, a hybrid coating composed of carbon nanotubes, MXene, and polyvinyl alcohol is uniformly applied to the glass fiber surface, making the fiber surface rougher and exhibiting a lamellar structure and numerous burrs. This structure facilitates the mechanical bonding and friction between the glass fiber and the matrix resin, and enhances the interfacial adhesion between the fiber and the resin. Furthermore, the uniformly adhered hybrid coating also constructs a sensitive conductive network on the glass fiber surface, which is beneficial for the sensitive change of the overall resistance of the composite material during bending deformation, thereby enabling damage localization and structural health monitoring of the composite material.

[0116] Experiment Example 2

[0117] This experiment investigates the structural changes and safety of the carbon fiber reinforced polymer composites prepared in Examples 8-14 and Comparative Examples 1-4 under stress. The specific method is as follows: The carbon fiber reinforced polymer composites are cut into test samples, such as... Figure 5 As shown, the sample is 20mm long, 10mm wide, and 2mm thick. Copper wires are connected to both ends of the sample. The interlaminar shear properties are then tested using a computer-controlled electronic universal testing machine according to the method specified in standard JC / T773-2010. Simultaneously, a multimeter is connected to the copper wires at both ends of the sample. Figure 6 As shown, the resistance change of the test sample during interlaminar shear deformation is observed. The test results indicate that the load-displacement curve and the corresponding resistance change rate-displacement curve of the carbon fiber reinforced resin matrix composite material prepared by the method of this invention during interlaminar shear deformation can be clearly divided into three stages: Stage I (undamaged stage; the load-displacement curve changes linearly in this stage, and no cracks are generated in the sample), Stage II (crack propagation stage; the load-displacement curve shows a nonlinear inflection point after point A, indicating that the bending resistance of the composite material has reached its limit, and cracks begin to appear on the surface of the material; subsequently, the cracks continue to propagate into the sample), and Stage III (failure stage; after the load-displacement curve passes point B, the sample is damaged and begins to fracture). The load-displacement curve and stage division diagram of the carbon fiber reinforced resin matrix composite material prepared in Example 8 during interlaminar shear deformation are shown in Figure 8. Figure 7 As shown in the figure. The comparative examples only show two stages (stage I and stage III). The rate of change of resistivity and the interlaminar shear strength test results of the carbon fiber reinforced polymer composites prepared in Examples 8-14 and Comparative Examples 1-4 at different stages are shown in Table 1. In Table 1, the rate of change of resistivity = (resistivity change rate at the end of a stage - resistance change rate at the beginning of a stage) / resistance change rate at the beginning of a stage × 100%.

[0118] Table 1 shows the changes in electrical resistance and interlaminar shear strength of the samples during interlaminar shear deformation.

[0119]

[0120] As shown in Table 1, the load-displacement curves and the corresponding resistance change rate-displacement curves of the carbon fiber reinforced resin matrix composites prepared by the method of the present invention during the interlaminar shear deformation process can be clearly divided into three stages. The prepared carbon fiber reinforced resin matrix composites have high interlaminar shear strength (74.6-98.9 MPa), which are better than the interlaminar shear strength of the unmodified carbon fiber reinforced resin matrix composites (the interlaminar shear strengths of the composites of Comparative Example 1 and Comparative Example 2 are 61.3 MPa and 68.6 MPa, respectively).

[0121] The composite materials prepared in Examples 8-14 all exhibited three distinct stages (Stage I, Stage II, and Stage III) in their resistivity change rate during interlaminar shear deformation, while the comparative examples only showed two stages (Stage I and Stage III). In all three resistivity change rate stages, the resistivity change rate of the composite materials prepared in Examples 8-14 was superior to that of the comparative examples, indicating that introducing a modified fiber phase integrating structural reinforcement and sensing functions can improve the sensitivity of the polymer composite material to microcracks in the matrix. In Stage II, the resistivity change rates of the composite materials prepared in Examples 8-14 during interlaminar shear deformation were 8.23%, 10.95%, 4.71%, 6.27%, 7.86%, 7.98%, and 5.25%, respectively. This demonstrates that when polymer composite materials are subjected to external forces or environmental influences, monitoring the resistivity change rate in Stage II can help identify anomalies in the composite material, provide early warning signals, prevent structural failure, and ensure the safety and reliability of the material.

[0122] Furthermore, the interlaminar shear strength of the composite materials prepared in Examples 8-14 was superior to that of the comparative examples, with Example 9 exhibiting the best interlaminar shear strength. This is because excessively high (Examples 10 and 11) or excessively low (Examples 12 and 14) loading of nanoparticles onto the fiber fabric surface are both detrimental to improving the interlaminar shear strength of the composite materials. When too many nanoparticles are loaded onto the fiber fabric surface, the nanoparticles will aggregate on the surface, thus affecting the improvement of the interlaminar shear strength of the composite material. When only a small amount of nanoparticles are loaded onto the fiber fabric surface, the nanoparticles cannot form a continuous micro-nano structure on the surface, which also affects the improvement of the interlaminar shear strength of the composite material. Therefore, only when an appropriate amount of nanoparticles are loaded onto the fiber fabric surface, and these nanoparticles form a continuous micro-nano structure on the surface, can the interlaminar shear strength of the composite material be significantly improved.

Claims

1. A modified fiber fabric, characterized in that, The modified fiber fabric includes a fiber fabric matrix and particulate matter loaded on the fiber fabric matrix. The particulate matter consists of one-dimensional nanoparticles and two-dimensional nanoparticles in a mass ratio of (0.01–50):(0.01–50). The one-dimensional nanoparticles are carbon nanotubes or silver nanowires, and the two-dimensional nanoparticles are graphene or titanium carbide (Mxene). The total mass fraction of particulate matter in the modified fiber fabric is 0.01–60%.

2. The modified fiber fabric as described in claim 1, characterized in that, The fiber fabric is a nonwoven fabric of silk fiber, glass fiber fabric, Kevlar fiber fabric, basalt fiber fabric or ultra-high molecular weight polyethylene fiber fabric.

3. The modified fiber fabric as described in claim 1 or 2, characterized in that, The total mass fraction of particulate matter in the modified fiber fabric is 5% to 50%.

4. The modified fiber fabric as described in claim 3, characterized in that, The total mass fraction of particulate matter in the modified fiber fabric is 10-15%.

5. A method for preparing a modified fiber fabric as described in any one of claims 1-4, characterized in that, The process includes the following steps: coating a modifier onto a fiber fabric, drying it, and obtaining the modified fiber fabric; The modifier consists of particulate matter, an adhesive, and a solvent; the adhesive is urea or polyvinyl alcohol; in the modifier, the mass fraction of particulate matter is 0.01-60%, and the mass fraction of the adhesive is 0.1-20%.

6. The method for preparing the modified fiber fabric as described in claim 5, characterized in that, The fiber fabric is a non-woven fabric made of silk fibers, and the adhesive is urea.

7. The method for preparing the modified fiber fabric as described in claim 5, characterized in that, The fiber fabric is made of glass fiber, Kevlar fiber, basalt fiber, or ultra-high molecular weight polyethylene fiber, and the adhesive is polyvinyl alcohol.

8. The method for preparing the modified fiber fabric as described in claim 7, characterized in that, The polyvinyl alcohol has a weight-average molecular weight of 5,000 to 200,000; the solvent is water; and the temperature of the modifier is room temperature to 90°C.

9. A carbon fiber reinforced polymer composite material, characterized in that, It is composed of carbon fiber fabric, polymer and modified fiber fabric as described in any one of claims 1-4, wherein the mass ratio of the modified fiber fabric, carbon fiber fabric and polymer is (5-30):(40-70):(10-50); wherein the polymer is epoxy resin, unsaturated polyester or polyurethane.

10. A method for monitoring the interlaminar structural safety of carbon fiber reinforced polymer composites, characterized in that, Includes the following steps: The resistance change rate of the carbon fiber reinforced polymer composite material as described in claim 9 is detected during use. If the resistance change rate exceeds the threshold, it is considered that the interlayer structure is damaged, and an early warning signal is issued.

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