Method for producing a fiber-reinforced composite material with high efficient electric heating capability

Abstract

This invention discloses a method for preparing a fiber-reinforced composite material with high-efficiency electrothermal capability, belonging to the field of functional composite materials technology. The method includes the following steps: removing the sizing from a fiber fabric using an organic solvent; sequentially placing the desized fiber fabric in a solution of mesoporous polydopamine nanoparticles, a metal-organic framework precursor, and a conductive filler to construct a mesoporous polydopamine nanoparticle layer, a metal-organic framework reinforcement layer, and a conductive heating layer, forming a multi-level synergistic structure of "fiber-reinforcement layer-functional layer"; and then hot-pressing the resulting functionalized fiber fabric with a prepreg to obtain the fiber-reinforced composite material. This invention utilizes the strong adhesion of mesoporous polydopamine nanoparticles and the large specific surface area of ​​the metal-organic framework as a nanoscaffold, providing support for the construction of a stable three-dimensional conductive network for the conductive filler, enhancing the interfacial bonding force of the composite material, and endowing the composite material with high-efficiency electrothermal capability.

Description

Technical Field

[0001] This invention relates to a method for preparing fiber-reinforced composite materials with high-efficiency electrothermal heating capability, belonging to the field of functional composite materials technology. Background Technology

[0002] With the rapid development of science and technology, the demand and requirements for heating technology in both industrial and civilian fields are gradually increasing. Electrothermal heating technology is currently a relatively safe heating technology with broad development and application prospects, such as high-altitude wing de-icing and pipeline insulation. The high density and susceptibility to oxidation of traditional metals limit their further development in the field of electrothermal heating technology. Functional composite materials, with their lightweight and high-strength structural characteristics, low density, ease of functionalization, and good stability, are expected to replace traditional metal materials in the field of electrothermal heating. Among these, fibers, as a key reinforcement in composite materials, directly determine the macroscopic properties of the composite material through their surface characteristics. Therefore, precisely designing and functionalizing the fiber surface to endow it with the required functions has become one of the core technical approaches to enhance the added value of composite materials and meet the application needs of cutting-edge fields. In recent years, basalt fiber, due to its excellent strength and corrosion resistance, as well as its lower price compared to carbon fiber, has been regarded as a highly promising new generation of reinforcing material.

[0003] There are three main feasible approaches to endow basalt fiber composites with electrothermal functionality. The first is to directly introduce a functional layer with electrothermal capabilities into the composite material, i.e., first prepare an electrothermal film and then embed it into the composite. While the composite obtained in this way possesses the desired function, the lack of a strong bond between the embedded film and the composite significantly affects the lifespan of the functional composite. Furthermore, the embedded film's strength is far less than that of the composite material itself, making it the weakest point in the overall composite, thus reducing the overall mechanical properties of the composite. The second approach involves adding conductive fillers, including carbon nanotubes, graphene, carbon black, and mixtures thereof, to the matrix of the composite. This method is the most difficult to use, primarily because the composite matrix has a certain viscosity, making it difficult to overcome the agglomeration problem of the conductive filler. In addition, the poor conductivity of the composite matrix and the obstruction of basalt fibers make it difficult for the conductive filler to construct a complete conductive network, thus hindering the achievement of electrothermal functionality. The third approach involves depositing conductive fillers on the fiber surface through physical or chemical means. This method is currently the most efficient and commonly used, easily achieving a robust multi-level synergistic structure of "fiber-reinforcing layer-functional layer."

[0004] However, the high chemical inertness and low number of active functional groups on the surface of basalt fibers severely limit their effective bonding with conductive fillers, resulting in weak interfacial adhesion, easy detachment of functional layers, and rapid performance degradation, posing a challenge to their integration of structure and function. To address this challenge, various surface modification strategies exist, including silane coupling agent modification and dopamine biomimetic modification. Among these, mesoporous polydopamine nanoparticles, due to their unique mesoporous structure and specific surface area, show great potential in improving fiber surface activity and loading carbon nanotubes. However, the function of a single mesoporous polydopamine modification strategy is mainly limited to physical anchoring and chemical bonding, which is insufficient for constructing ultra-stable, high-load interfacial structures. Furthermore, while metal-organic frameworks with ultra-high specific surface area and designable pores are highly functional, their direct growth on fiber surfaces often suffers from weak adhesion and poor uniformity. Amidst these difficulties and challenges, we propose a modification strategy involving the synergistic reinforcement of mesoporous polydopamine nanoparticles and metal-organic frameworks to deposit conductive fillers on the surface of basalt fibers, thereby preparing fiber-reinforced composite materials with high-efficiency electrothermal capabilities. Compared to other modification strategies, the synergistic reinforcement of mesoporous polydopamine nanoparticles and metal-organic frameworks offers advantages such as uniform deposition, large specific surface area, strong interfacial bonding, and high activity. Therefore, this invention employs a modification strategy involving the synergistic reinforcement of mesoporous polydopamine nanoparticles and metal-organic frameworks to deposit conductive fillers on the surface of basalt fibers, thereby preparing fiber-reinforced composite materials with high-efficiency electrothermal capabilities. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the prior art by proposing a method for preparing fiber-reinforced composite materials with high-efficiency electrothermal capabilities. Through a synergistic reinforcement and modification strategy of mesoporous polydopamine nanoparticles and metal-organic frameworks, the basalt fiber composite material achieves high-efficiency electrothermal capabilities while also improving its mechanical properties.

[0006] The technical solution provided by this invention to solve the above-mentioned technical problems is: a method for preparing fiber-reinforced composite materials with high-efficiency electrothermal heating capability, comprising the following steps:

[0007] S1. Tris(hydroxymethyl)aminomethane and deionized water were mixed and the pH of the solution was adjusted to 8.5. Then, mesoporous polydopamine nanoparticles were added and sonicated to obtain a mesoporous polydopamine dispersion.

[0008] S2. Zirconium tetrachloride, N,N-dimethylformamide, acetic acid and terephthalic acid were mixed and stirred, and then the volume was adjusted to obtain a metal-organic framework precursor solution.

[0009] S3. Sodium dodecylbenzenesulfonate, conductive filler, and deionized water are mixed and ultrasonicated to obtain a conductive filler dispersion.

[0010] S4. Place the desizing basalt fiber fabric in mesoporous polydopamine dispersion, metal-organic framework precursor solution and conductive filler dispersion in sequence, filter, dry and perform post-treatment.

[0011] S5. The basalt fiber fabric obtained in S4 is laid up together with the prepreg and hot-pressed to obtain the basalt fiber composite material.

[0012] A further technical solution is that the concentration of the mesoporous polydopamine dispersion in step S1 is 1-2 mg / mL, the ultrasonic dispersion power is 250 W for 2 hours, and the ultrasonic frequency is 3 kHz.

[0013] A further technical solution is that, in step S2, the mass ratio of zirconium tetrachloride to terephthalic acid is 2.1:1, the volume ratio of acetic acid to N,N-dimethylformamide is 1:21, and the concentration of zirconium tetrachloride is 2.6-3 g / L.

[0014] A further technical solution is that, in step S3, the mass ratio of conductive filler to sodium dodecylbenzenesulfonate is 1:3, the ultrasonic dispersion power is 250W for 30 minutes, and the ultrasonic frequency is 3kHz; the concentration of conductive filler is 0.5-1mg / mL.

[0015] A further technical solution is that, in step S4, the basalt fiber fabric is first immersed in a mesoporous polydopamine dispersion for 24 hours, dried, and then placed in a metal-organic framework precursor solution for 18 hours via hydrothermal reaction at 120°C. After drying, it is immersed in a conductive filler dispersion for 24 hours, washed with deionized water, and then post-treated.

[0016] A further technical solution is that the post-processing adopted in step S4 is constrained drying and hot pressing. The constrained drying is performed by clamping with a plate that does not react with the conductive filler and drying in an environment of 60°C for 1-2 hours. The hot pressing is performed at a temperature of 120°C, a pressure of 1 MPa, and a time of 30 minutes.

[0017] A further technical solution is that, in step S5, epoxy resin and polyetheramine are mixed and stirred at a mass ratio of 100:32, with a rotation speed of 500 rpm and a time of 30 min; the mixed resin is degassed for 30 min at a temperature of 40°C; and basalt fiber prepreg is obtained by hot melt impregnation.

[0018] Furthermore, the prepreg and basalt fiber fabric are laid in a sequence of prepreg-basalt fiber fabric-prepreg, for a total of 8 layers of prepreg and 8 layers of basalt fiber fabric; the hot pressing is carried out at 100℃ / 1h and 140℃ / 8h for curing, with a hot pressing pressure of 10MPa and a heating rate of 10℃·min. -1 .

[0019] The molding method involved in this patent is not limited to hot pressing.

[0020] The second technical problem to be solved by the present invention is to provide a fiber-reinforced composite material with high-efficiency electrothermal capability prepared by the above method.

[0021] The present invention has the following beneficial effects:

[0022] (1) This invention utilizes the abundant mesoporous structure and surface functional groups of mesoporous polydopamine nanoparticles to endow the fiber substrate with high surface activity, providing growth sites for in-situ grown metal-organic framework crystals. Together, they construct a robust three-dimensional "micro-nano framework" with a high specific surface area. This synergistic effect not only enables the conductive nanofiller to be effectively deposited on the surface of basalt fiber, but also effectively enhances the bonding force between the conductive nanofiller and the fiber, ensuring the stability of the basalt fiber composite material for long-term use.

[0023] (2) The basalt fiber composite material prepared by the present invention has high-efficiency electrothermal performance. The conductive nanofiller is effectively "wound" and "pinned" in this multi-level structure by the "micro-nano skeleton" provided by the mesoporous polydopamine nanoparticles and metal-organic framework, realizing a qualitative change from "surface-line combination" to "volume-line encapsulation". Due to the extremely high specific surface area of ​​the synergistic structure of mesoporous polydopamine-metal-organic framework, the conductive nanofiller can be uniformly and discretely distributed. Moreover, thanks to the stable interface and low contact resistance, the energy loss of the basalt fiber composite material in the electro-thermal conversion process is greatly reduced, and a higher steady-state temperature can be obtained under the same power input. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the preparation process of the present invention;

[0025] Figure 2 A is a scanning electron microscope image of basalt fibers modified with mesoporous polydopamine nanoparticles. Figure 2 B is a scanning electron microscope image of basalt fibers co-modified with mesoporous polydopamine nanoparticles and metal-organic frameworks.

[0026] Figure 3 This is a diagram showing the interfacial shear strength of basalt fiber composite materials.

[0027] Figure 4 The diagram shows the electrothermal properties of basalt fiber composite materials.

[0028] Figure 5 The diagram shows the cyclic stability of the basalt fiber composite material. Detailed Implementation

[0029] The present invention will be further described below with reference to the embodiments and accompanying drawings.

[0030] Example 1

[0031] like Figure 1 As shown, the method for preparing the fiber-reinforced composite material with high-efficiency electrothermal heating capability of the present invention is carried out through the following steps:

[0032] Step 1: Mix 0.121g of tris(hydroxymethyl)aminomethane, 1mL of hydrochloric acid and 99mL of deionized water in a beaker, adjust the pH of the solution to 8.5, then add 0.1g of mesoporous polydopamine nanoparticles and ultrasonically disperse them in an aqueous environment with an ultrasonic intensity of 250W and an ultrasonic frequency of 3kHz for 2h to obtain a mesoporous polydopamine dispersion.

[0033] Step 2: Mix 0.262 g of zirconium tetrachloride, 0.125 g of terephthalic acid, 4.5 mL of acetic acid and 95.5 mL of N,N-dimethylformamide in a beaker and stir for 1 h at 500 rpm and 30 °C to obtain a metal-organic framework precursor solution.

[0034] Step 3: Mix 0.25g of carbon nanotubes, 0.75g of sodium dodecylbenzenesulfonate and 500mL of deionized water in a beaker, and ultrasonically disperse in an aqueous environment with an ultrasonic intensity of 250W and an ultrasonic frequency of 3kHz for 30min to obtain a carbon nanotube suspension.

[0035] Step 4: Soak the desized basalt fiber fabric (8cm long, 6cm wide) in mesoporous polydopamine dispersion for 24h, wash the fabric surface with deionized water and dry it at 60℃ for 3h to obtain basalt fiber fabric modified with mesoporous polydopamine nanoparticles (one-time modification).

[0036] Step 5: The basalt fiber fabric after primary modification is placed in a metal-organic framework precursor solution and reacted at 120℃ for 18 hours by hydrothermal method. After washing the fabric surface with deionized water, it is dried at 60℃ for 3 hours to obtain mesoporous polydopamine-metal-organic framework modified basalt fiber fabric (secondary modification).

[0037] Step 6: Immerse the basalt fiber fabric obtained in Step 5 after secondary modification in a carbon nanotube suspension for 24 hours. After cleaning the fabric surface with deionized water, hold the basalt fiber fabric loaded with carbon nanotubes in a clean glass plate and dry it at 60°C for 2 hours. Then, perform hot pressing treatment according to the process parameters of 120°C, 1MPa and 30min to obtain the basalt fiber fabric with deposited carbon nanotubes.

[0038] Step 7: The basalt fiber fabric with deposited carbon nanotubes is laid in the order of prepreg-functionalized basalt fiber fabric-prepreg, with a total of 8 layers of prepreg and 8 layers of functionalized basalt fiber fabric. The basalt fiber composite material sample is then formed by hot pressing.

[0039] The hot pressing process involves curing at 100℃ / 1h and 140℃ / 8h, with a hot pressing pressure of 10MPa and a heating rate of 10℃·min. -1 ;

[0040] The microstructure of the basalt fibers modified with mesoporous polydopamine and mesoporous polydopamine-metal-organic frameworks in Example 1 was observed, and the results are as follows: Figure 2 A and Figure 2 As shown in B.

[0041] Figure 2 A and Figure 2 B revealed the successful grafting of mesoporous polydopamine nanoparticles and metal-organic frameworks onto the surface of basalt fibers via solution and hydrothermal modification. The surface of the basalt fibers after secondary modification was very rough. Figure 2 A reveals a scanning electron microscope image of the modified mesoporous polydopamine nanoparticles. Figure 2 B reveals a scanning electron microscope image after secondary modification with a metal-organic framework. With the successful modification of mesoporous polydopamine nanoparticles and metal-organic frameworks, the number of active groups on the surface of basalt fibers increases, resulting in higher surface activity, which is beneficial for the subsequent tight bonding of carbon nanotubes to the fiber surface.

[0042] The desizing basalt fibers prepared in steps 4 and 5 of Example 1, the basalt fibers modified with mesoporous polydopamine nanoparticles, and the basalt fibers co-modified with mesoporous polydopamine-metal-organic frameworks were respectively prepared with epoxy resin to form standard microdroplet debonding test samples. Microdroplet debonding tests were then conducted, and the results are as follows: Figure 3 As shown.

[0043] Figure 3 The study revealed that the interfacial bonding strength between basalt fibers and epoxy resin was significantly improved after primary and secondary modifications. (Primary modification involves modifying the fiber surface with mesoporous polydopamine nanoparticles, while secondary modification refers to further modifying it with a metal-organic framework based on the primary modification.) The surface of the basalt fibers after primary or secondary modification becomes rougher, increasing the mechanical interlocking and contact area between the fiber and the resin matrix. Stress transmission from the matrix to the fiber is smoother and more uniform, resulting in a stronger interfacial bond and thus a significant increase in interfacial shear strength.

[0044] The basalt fiber composite material prepared in Example 1 was subjected to an electrothermal test, and the results are as follows: Figure 4As shown.

[0045] Figure 4 The study revealed the surface temperature variation of the basalt fiber composite material. Under an applied voltage of 15V, the final temperature of the composite surface reached 110℃ in approximately 3 minutes, demonstrating high heating efficiency. Furthermore, the final temperature of the composite surface increased with increasing applied voltage, and the temperature remained uniform and stable during the heating process. This indicates that the conductive network constructed by carbon nanotubes in the basalt fiber composite material is highly complete.

[0046] The basalt fiber composite material prepared in Example 1 was subjected to cyclic stability testing, and the results are as follows: Figure 5 As shown.

[0047] Figure 5 The cyclic stability of the basalt fiber composite material was revealed. With increasing cycles of heating and cooling, the final temperature of the composite surface decreased slightly within the test range. At 500 cycles, the final temperature of the composite surface still reached 106.8℃, a decrease of only 3.4% compared to the original composite, demonstrating excellent cyclic stability. This indicates that the synergistic reinforcement of mesoporous polydopamine nanoparticles and metal-organic frameworks ensures stable and reliable bonding between carbon nanotubes and basalt fibers, as well as the conductive network constructed by the carbon nanotubes.

[0048] The foregoing content does not constitute any limitation on the rights of this invention. Although the invention has been disclosed through the specific embodiments described above, it is not intended to limit the invention. Any simple adjustments, equivalent substitutions, and modifications made by those skilled in the art to the above embodiments without exceeding the scope of the invention's technical solution shall still fall within the protection scope of the invention's technical solution.

Claims

1. A method for preparing fiber-reinforced composite materials with high-efficiency electrothermal heating capability, characterized in that, Includes the following steps: S1. Tris(hydroxymethyl)aminomethane and deionized water were mixed and the pH of the solution was adjusted to 8.

5. Then, mesoporous polydopamine nanoparticles were added and sonicated to obtain a mesoporous polydopamine dispersion. S2. Zirconium tetrachloride, N,N-dimethylformamide, acetic acid and terephthalic acid were mixed and stirred, and then the volume was adjusted to obtain a metal-organic framework precursor solution. S3. Sodium dodecylbenzenesulfonate, conductive filler, and deionized water are mixed and ultrasonicated to obtain a conductive filler dispersion. S4. Place the desizing basalt fiber fabric in mesoporous polydopamine dispersion, metal-organic framework precursor solution and conductive filler dispersion in sequence, filter, dry and perform post-treatment. S5. Epoxy resin and polyetheramine are mixed and stirred at a mass ratio of 100:32 at a speed of 500 rpm for 30 min. The mixed resin is degassed for 30 min at a temperature of 40℃. Basalt fiber prepreg is obtained by hot melt impregnation. The basalt fiber fabric obtained in S4 is laid up together with the prepreg and hot-pressed to obtain basalt fiber composite material. In step S2, the mass ratio of zirconium tetrachloride to terephthalic acid is 2.1:1, the volume ratio of acetic acid to N,N-dimethylformamide is 1:21, and the concentration of zirconium tetrachloride is 2.6-3 g / L.

2. The method for preparing the fiber-reinforced composite material with high-efficiency electrothermal heating capability according to claim 1, characterized in that, In step S1, the concentration of the mesoporous polydopamine dispersion is 1-2 mg / mL, the ultrasonic dispersion power is 250 W, the ultrasonic dispersion time is 2 h, and the ultrasonic frequency is 3 kHz.

3. The method for preparing the fiber-reinforced composite material with high-efficiency electrothermal capability according to claim 1, characterized in that, In step S3, the mass ratio of conductive filler to sodium dodecylbenzenesulfonate is 1:3, the ultrasonic dispersion power is 250W for 30 minutes, and the ultrasonic frequency is 3kHz; the concentration of conductive filler is 0.5-1mg / mL.

4. The method for preparing the fiber-reinforced composite material with high-efficiency electrothermal heating capability according to claim 1, characterized in that, In step S4, the basalt fiber fabric is first immersed in a mesoporous polydopamine dispersion for 24 hours, dried, and then placed in a metal-organic framework precursor solution for hydrothermal reaction at 120°C for 18 hours. After drying, it is immersed in a conductive filler dispersion for 24 hours, washed with deionized water, and then post-treated.

5. The method for preparing the fiber-reinforced composite material with high-efficiency electrothermal capability according to claim 1, characterized in that, The post-processing in step S4 is constrained drying and hot pressing. The constrained drying is performed by clamping the material with a plate that does not react with the conductive filler and drying it at 60°C for 1-2 hours. The hot pressing is performed at 120°C, at 1 MPa, and for 30 minutes.

6. The method for preparing the fiber-reinforced composite material with high-efficiency electrothermal heating capability according to claim 1, characterized in that, In step S5, the layers are laid in the order of prepreg-basalt fiber fabric-prepreg, for a total of 8 layers of prepreg and 8 layers of basalt fiber fabric; the hot pressing is carried out at 100℃ / 1h and 140℃ / 8h for curing, with a hot pressing pressure of 10MPa and a heating rate of 10℃·min. -1 .

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