A full-process recycling method of fiber reinforced composites

Abstract

The application belongs to the technical field of recycling of fiber reinforced composites, and particularly relates to a full-process recycling method of fiber reinforced composites. 2+ The modified fiber is prepared by constructing a dynamic coordination cross-linking interface layer formed by Co 2+ The fiber reinforced composite is placed in a coordination competition agent, the coordination competition agent is used for competitively dissociating the cobalt-oxygen and cobalt-nitrogen coordination bonds of the interface layer under a heating condition, the interface combination is destroyed, and then ultrasonic treatment is additionally used, so that the fiber and the resin matrix are efficiently and non-destructively separated. The process method is simple, convenient to operate and green, and has important practical significance and industrial application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fiber-reinforced composite material recycling technology, specifically relating to a full-process recycling method for fiber-reinforced composite materials. Background Technology

[0002] Fiber-reinforced polymer composites (FRPs) are among the most widely used high-performance structural materials. They possess high specific strength, high specific modulus, excellent fatigue and corrosion resistance, good processability, low coefficient of thermal expansion, and excellent durability. As a key material for lightweighting, FRPs significantly outperform traditional metallic materials in specific strength and specific modulus, thus finding wide application in critical fields such as wind turbine blades, aerospace, transportation, and sporting goods.

[0003] However, as a thermosetting composite material, FRPs have a stable three-dimensional cross-linked network structure, which makes it difficult for FRPs to degrade and be reprocessed after the end of their service life. They also exhibit obvious chemical inertness and interfacial bonding stability, making it difficult for the fibers and resin matrix in FRPs to separate efficiently, thus posing a serious challenge to their recycling and resource utilization.

[0004] Currently, the main methods for recycling FRPs include pyrolysis, mechanical recycling, and chemical recycling. Pyrolysis involves high-temperature pyrolysis or fluidized bed treatment to decompose the resin and recover the fibers. However, high temperatures can lead to fiber oxidation and a 20%–30% decrease in strength. Chemical recycling utilizes supercritical fluids, acidic or alkaline reagents to degrade the resin matrix. While it can retain relatively high fiber strength, it involves high equipment costs, demanding process conditions, and significant environmental impact. Physical-mechanical methods, although simple to operate, can only break down FRP materials into low-value fillers and cannot achieve fiber reuse.

[0005] Therefore, existing FRP recycling methods have failed to achieve high-value, non-destructive recycling of fibers. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention provides a complete recycling method for fiber-reinforced composite materials. This invention achieves efficient and non-destructive separation of fibers from the resin matrix by pre-constructing a dynamic coordination crosslinking interface layer on the fiber surface and then selectively dissociating this interface layer during the recycling stage using a coordination competition reaction. The recycling method of this invention can efficiently and non-destructively separate fibers from the resin matrix in fiber-reinforced composite materials under mild conditions, significantly improving the strength retention rate and surface integrity of the recycled fibers.

[0007] This invention introduces a dynamically coordinated crosslinking interface layer on the fiber surface, utilizing Co 2+ Modified fibers were prepared by coordinating ions with the phenolic hydroxyl and amino groups on the polydopamine molecular chain to form a dynamic coordination crosslinking interface layer on the fiber surface. This interface layer not only enhances the interfacial bonding strength of the fiber-reinforced composite material but also provides reaction sites for subsequent selective dissociation. Subsequently, the modified fibers were used as reinforcement and composited with a resin matrix to prepare fiber-reinforced composite materials. The dynamic coordination interface between the resin matrix and the modified fiber surface interacts to form a strong interfacial bond, ensuring that the fiber-reinforced composite material possesses excellent mechanical properties. After the fiber-reinforced composite material reaches the end of its service life, a coordination competitor was used as the dissociation medium to utilize the coordination competitor's reaction with Co... 2+ With stronger coordination ability, it competitively dissociates the cobalt-oxygen and cobalt-nitrogen coordination bonds in the dynamic coordination crosslinking interface layer, thereby efficiently and selectively destroying the interfacial bond and achieving efficient and non-destructive separation of the fiber and the resin matrix.

[0008] This invention provides a complete recycling method for fiber-reinforced composite materials, comprising the following steps:

[0009] The fibers were immersed in a dynamic crosslinking solution and left to stand to construct a crosslinking structure on the fiber surface using Co. 2+ Modified fibers are obtained by forming a dynamic coordination crosslinking interface layer with the phenolic hydroxyl and amino groups in polydopamine. The dynamic crosslinking solution is obtained by the self-polymerization reaction of dopamine hydrochloride, cobalt complex and solvent under pH=8-9 conditions. Fiber-reinforced composite materials are prepared using the modified fibers as reinforcement and the resin as matrix. The fiber-reinforced composite material is immersed in a coordination competitor to cause the dynamic coordination crosslinking interface layer to dissociate, and the fibers to separate from the resin, yielding recovered fibers. The coordination competitor is at least one of ethylenediaminetetraacetic acid, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0010] It should be noted that, in this invention, the fibers are pretreated before being immersed in the dynamic crosslinking liquid to remove surface processing aids, such as sizing agents or waxes, to avoid affecting the formation of the subsequent dynamic coordination crosslinking interface layer. Then, the pretreated fibers are immersed in a dynamic crosslinking liquid composed of polydopamine and a cobalt complex, and the crosslinking is carried out via Co... 2+ The coordination interaction between the phenolic hydroxyl and amino groups in polydopamine is used to construct a dynamically coordinated crosslinked interfacial layer in situ on the fiber surface, resulting in modified fibers. These modified fibers are then used as reinforcements to prepare fiber-reinforced composites with a resin matrix. This dynamically coordinated crosslinked interfacial layer provides the necessary interfacial bonding strength during the service life of the fiber-reinforced composite, while also exhibiting chemical reversibility. After the service life of the fiber-reinforced composite, the Co... 2+Using a coordination competitor with stronger coordination ability as a dissociation medium, the fiber-reinforced composite material is placed in the coordination competitor and treated under mild heating conditions; the interaction between the coordination competitor molecules and Co... 2+ It has a stronger coordination ability and can competitively dissociate cobalt-oxygen and cobalt-nitrogen coordination bonds in the dynamic coordination crosslinking interface layer, thereby destroying the dynamic coordination network and achieving fiber-resin interface separation without damaging the bulk structure of the fiber and resin.

[0011] Preferably, the ratio of dopamine hydrochloride to cobalt complex is 100 mg: 0.04 mmol.

[0012] Preferably, the treatment temperature for immersing the fiber-reinforced composite material in the coordination competitor is 60℃~90℃, and the treatment time is 24h~48h.

[0013] Preferably, the temperature at which the fiber is immersed in the dynamic crosslinking solution is 25°C to 35°C and the time is 8h to 16h.

[0014] Preferably, the cobalt complex is Co(NH2-DIP)2(BF4)2; and the solvent is ethanol.

[0015] Preferably, the fiber is at least one of carbon fiber, glass fiber and aramid fiber, and the fiber is in the form of fiber cloth or fabric.

[0016] Preferably, the preparation method of fiber-reinforced composite material is as follows: resin, curing agent and modified fiber are compounded and molding process is adopted to obtain fiber-reinforced composite material.

[0017] Preferably, the mass ratio of resin to curing agent is 100:30; the mass ratio of modified fiber to resin is 20:9 to 13.

[0018] Preferably, the resin is at least one selected from epoxy resin, unsaturated polyester resin, polyimide resin, thermosetting polyurethane resin, polypropylene, polyphenylene sulfide, polyvinyl chloride and polycarbonate; and the curing agent is curing agent H-256.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] 1. This invention obtains modified fibers by pre-constructing a dynamic coordination crosslinking interface layer on the fiber surface. The modified fibers are then used as reinforcement to prepare fiber-reinforced composite materials by compounding them with a resin matrix. During the recycling stage, a coordination competitor is used as a dissociation medium to selectively dissociate the interface layer through a coordination competition reaction, achieving efficient and non-destructive separation of the fibers and resin matrix in the fiber-reinforced composite material. Simultaneously, the introduction of the dynamic covalent interface layer enhances the interfacial bonding of the fiber-reinforced composite material.

[0021] 2. This invention adopts a dynamic coordination bond dissociation recycling process, which significantly improves the strength retention rate and surface integrity of the recycled fibers while achieving efficient separation of fibers and resins. The tensile strength retention rate of the recycled fibers is ≥70%, and the interlaminar shear strength retention rate is ≥65%, which can meet the mechanical requirements of regenerated fiber reinforced composite materials for reinforcing fibers. At the same time, it realizes the high-value recycling of fiber reinforced composite materials.

[0022] 3. The recycling process of this invention is mild and easy to operate. The coordinating agent is biodegradable and the solvent is recyclable. Compared with other recycling processes, it saves more energy and production costs. It also provides a reliable path for the closed-loop recycling and high-value utilization of fiber-reinforced composite materials, with significant economic and environmental benefits and broad prospects for industrial application. Attached Figure Description

[0023] Figure 1 The image shows the surface morphology of the glass fiber recovered in Comparative Example 4.

[0024] Figure 2 This is a surface morphology diagram of the glass fiber recovered in Example 1. Detailed Implementation

[0025] To enable those skilled in the art to better understand and implement the technical solutions of this invention, the invention will be further described below with reference to specific embodiments and accompanying drawings. Unless otherwise specified, all reagents used in this invention are commercially available, and all methods used are conventional techniques in the art.

[0026] The raw materials used in the following examples were purchased from the following sources:

[0027] Plain carbon fiber, Anqing Kawei Technology Co., Ltd.; Alkali-free glass fiber, Taishan Glass Fiber Co., Ltd.; Dopamine hydrochloride, purity > 98%, Shanghai Maclean Biochemical Technology Co., Ltd.; Acetone, Shanghai Maclean Biochemical Technology Co., Ltd.; Trifluoroacetic acid, from Shanghai Maclean Biochemical Technology Co., Ltd.; Tris-hydrochloric acid buffer, concentration 1M, pH=8.5, from Aladdin Reagent (Shanghai) Co., Ltd.; Bis[2,6-pyridinedicarboxaldehyde bis(p-aminobenzylamine)]cobalt(II) ditetrafluoroborate, abbreviated as bis(NH2-DIP)cobalt(II) ditetrafluoroborate, i.e. Co(NH2-DIP)2(BF4)2, 1.16mmol / g, from Saihan District Yuanyixin Experimental Instrument Consumables Business Department; Epoxy resin E-51 and curing agent H-256, from Shenzhen Langbowan Co., Ltd. The plain weave carbon fiber measures 400mm x 400mm and weighs 40g; the alkali-free glass fiber measures 400mm x 400mm and weighs 145g.

[0028] Example 1

[0029] A complete recycling method for fiber-reinforced composite materials includes the following steps:

[0030] Alkali-free glass fibers with a size of 400mm×400mm were soaked in acetone for 12 hours, ultrasonically cleaned twice, rinsed with deionized water, and dried at 60℃ for 2 hours to obtain pretreated glass fibers.

[0031] 0.8 g of dopamine hydrochloride was dissolved in 800 mL of 1 M Tris-hydrochloric acid buffer at pH 8.5 to obtain a polydopamine solution. 0.32 mmol of Co(NH₂-DIP)₂(BF₄)₂ was dissolved in 160 mL of anhydrous ethanol and ultrasonically dispersed for 10 min to form a red transparent solution. 1.6 mL of trifluoroacetic acid was added dropwise and stirred for 5 min to obtain a cobalt complex solution. The cobalt complex solution was then added dropwise to the polydopamine solution and stirred to obtain a dynamically crosslinked solution.

[0032] Pretreated glass fibers were immersed in a dynamic crosslinking solution and allowed to stand at 30°C for 8 hours to construct a dynamic coordination crosslinking interface layer on the surface of the pretreated glass fibers. The treated glass fibers were then removed, rinsed twice with anhydrous ethanol, and vacuum dried at 60°C for 2 hours to obtain modified glass fibers.

[0033] 400g of epoxy resin E-51 and 120g of curing agent H-256 were combined with eight pieces of modified glass fiber unidirectional layup to form an eight-layer composite. A vacuum-assisted resin infusion molding process was used, with vacuum degassing at -0.09MPa for 30 minutes to slowly and uniformly impregnate the modified glass fiber fabric with epoxy resin. After curing, a glass fiber reinforced composite material was obtained. The curing method was as follows: treatment at 60℃ for 2 hours, followed by treatment at 100℃ for 1 hour, and finally treatment at 120℃ for 2 hours.

[0034] The fiber-reinforced composite material was immersed in 500 mL of ethylenediaminetetraacetic acid and stirred in a constant temperature water bath at 60 °C for 24 h. Then, the treated sample was removed and subjected to ultrasonic-assisted peeling at an ultrasonic frequency of 35 kHz, an ultrasonic power of 400 W, and an ultrasonic temperature of 60 °C for 40 min to separate the glass fiber from the resin. The recovered glass fiber was rinsed twice with deionized water and vacuum dried at 60 °C for 2 h to complete the recovery process and obtain the recovered glass fiber.

[0035] Tensile testing of the fiber bundles was conducted according to ASTM D2343 standard. The results showed that the tensile strength of the virgin glass fiber bundles was 506.62 MPa, while the tensile strength of the recycled glass fiber bundles was 453.27 MPa. Compared with virgin glass fibers, the recycled glass fibers retained more than 89% of their tensile strength; and the resin residue on the surface of the recycled glass fibers was less than 5%.

[0036] Example 2

[0037] A complete recycling method for fiber-reinforced composite materials includes the following steps:

[0038] Plain-weave carbon fibers with dimensions of 400mm×400mm were soaked in acetone for 12 hours, ultrasonically cleaned twice, rinsed with deionized water, and dried at 60℃ for 2 hours to obtain pretreated carbon fibers.

[0039] 0.8 g of dopamine hydrochloride was dissolved in 800 mL of 1 M Tris-hydrochloric acid buffer at pH 8.5 to obtain a polydopamine solution. 0.32 mmol of Co(NH₂-DIP)₂(BF₄)₂ was dissolved in 160 mL of anhydrous ethanol and ultrasonically dispersed for 10 min to form a red transparent solution. 1.6 mL of trifluoroacetic acid was added dropwise and stirred for 5 min to obtain a cobalt complex solution. The cobalt complex solution was then added dropwise to the polydopamine solution and stirred to obtain a dynamically crosslinked solution.

[0040] The pretreated carbon fibers were immersed in a dynamic crosslinking solution and allowed to stand at 30°C for 16 hours to build a dynamic coordination crosslinking interface layer on the surface of the pretreated carbon fibers. The treated carbon fibers were then removed, rinsed twice with anhydrous ethanol, and vacuum dried at 60°C for 2 hours to obtain modified carbon fibers.

[0041] 400g of epoxy E-51 and 120g of curing agent H-256 were combined with eight modified carbon fiber unidirectional layups to form an eight-layer composite. A vacuum-assisted resin infusion molding process was used, with vacuum degassing at -0.09MPa for 30 minutes to slowly and uniformly impregnate the modified carbon fiber fabric with epoxy resin. After curing, a carbon fiber reinforced composite material was obtained. The curing method was as follows: treatment at 60℃ for 2 hours, followed by treatment at 100℃ for 1 hour, and finally treatment at 120℃ for 2 hours.

[0042] The fiber-reinforced composite material was immersed in 500 mL of N,N-dimethylacetamide, placed in a glass reactor, sealed, and treated at 60 °C for 48 h. Then, the treated sample was removed and subjected to ultrasonic-assisted exfoliation at 35 kHz, 400 W, and 60 °C for 1 h to separate the carbon fibers from the epoxy resin. The recovered carbon fibers were rinsed three times with deionized water and vacuum dried at 60 °C for 2 h to complete the recovery process, yielding the recovered carbon fibers.

[0043] The tensile properties of the fiber monofilaments were tested according to GB / T 31290-2022 standard. The results showed that the tensile strength of the virgin carbon fiber monofilaments was 3.5 GPa, while that of the recycled carbon fiber monofilaments was 2.73 GPa. Compared with virgin carbon fiber, the tensile strength retention rate of the recycled carbon fiber monofilaments was over 75%. Furthermore, the resin residue rate on the surface of the recycled carbon fiber was less than 5%.

[0044] Comparative Example 1

[0045] A method for preparing a fiber-reinforced composite material includes the following steps:

[0046] The difference from Example 1 is that glass fiber and epoxy resin are directly used as a composite.

[0047] Alkali-free glass fibers with a size of 400mm×400mm were soaked in acetone for 12 hours and ultrasonically cleaned twice to remove the sizing agent and wax on the surface. Then, they were rinsed with deionized water and dried at 60℃ for 2 hours to obtain pretreated glass fibers.

[0048] 400g of epoxy resin E-51 and 120g of curing agent H-256 were combined with eight pretreated glass fiber unidirectional layups to form an eight-layer composite. A vacuum-assisted resin infusion molding process was used, with vacuum degassing at -0.09MPa for 30 minutes to slowly and uniformly impregnate the glass fiber fabric with epoxy resin. After curing, a glass fiber reinforced composite material was obtained. The curing method was as follows: treatment at 60℃ for 2 hours, followed by treatment at 100℃ for 1 hour, and finally treatment at 120℃ for 2 hours.

[0049] Comparative Example 2

[0050] A method for preparing a fiber-reinforced composite material includes the following steps:

[0051] The difference from Example 2 is that carbon fiber and epoxy resin are directly used as a composite.

[0052] Plain-weave carbon fibers with a size of 400mm×400mm were soaked in acetone for 12 hours and ultrasonically cleaned twice to remove the sizing agent and wax on the surface; then, they were rinsed with deionized water and dried at 60℃ for 2 hours to obtain pretreated glass fibers.

[0053] 400g of epoxy resin E-51 and 120g of curing agent H-256 were combined with eight pretreated glass fiber unidirectional layups to form an eight-layer composite. A vacuum-assisted resin infusion molding process was used, with vacuum degassing at -0.09MPa for 30 minutes to slowly and uniformly impregnate the glass fiber fabric with epoxy resin. After curing, a carbon fiber reinforced composite material was obtained. The curing method was as follows: treatment at 60℃ for 2 hours, followed by treatment at 100℃ for 1 hour, and finally treatment at 120℃ for 2 hours.

[0054] Comparative Example 3

[0055] A method for preparing a fiber-reinforced composite material includes the following steps:

[0056] The difference from Example 2 is that the pretreated carbon fibers are immersed in a polydopamine solution to obtain polydopamine-modified carbon fibers.

[0057] Eight plain-weave carbon fibers, each measuring 400mm × 400mm, were soaked in acetone for 12 hours and ultrasonically cleaned twice to remove surface wax. Then, they were rinsed with deionized water and dried at 60℃ for 2 hours to obtain pretreated carbon fibers.

[0058] 1 g of dopamine hydrochloride was dissolved in 1000 mL of Tris-hydrochloric acid buffer solution with a pH of 8.5 and a concentration of 1 M. The solution was then magnetically stirred at 28 °C for 24 h to obtain a polydopamine solution.

[0059] The pretreated carbon fibers were immersed in a polydopamine solution and allowed to stand at 30°C for 8 hours. The treated carbon fibers were then removed, rinsed twice with anhydrous ethanol, and vacuum dried at 60°C for 2 hours to obtain polydopamine-modified carbon fibers.

[0060] 400g of epoxy resin E-51, 120g of curing agent H-256, and eight polydopamine-modified carbon fiber unidirectional layups were combined into an eight-layer composite. A vacuum-assisted resin infusion molding process was employed, with vacuum degassing at -0.09MPa for 30 minutes to slowly and uniformly impregnate the modified carbon fiber fabric with epoxy resin. After curing, a carbon fiber reinforced composite material was obtained. The curing method was as follows: treatment at 60℃ for 2 hours, followed by treatment at 100℃ for 1 hour, and finally treatment at 120℃ for 2 hours.

[0061] Comparative Example 4

[0062] A pyrolysis recycling method for fiber-reinforced composite materials includes the following steps:

[0063] The glass fiber reinforced composite material prepared in Comparative Example 1 was heated to 500℃ for 1h in a nitrogen atmosphere at a gas flow rate of 100mL / min and a heating rate of 10℃ / min to obtain recycled glass fibers.

[0064] Test 1.

[0065] like Figure 1 and Figure 2 As shown, compared to the glass fibers obtained by directly pyrolyzing the glass fiber reinforced composite material in Comparative Example 4, the surface morphology of the glass fibers recovered in Example 1 showed that the fiber structure was intact and there was no obvious damage.

[0066] Test 2.

[0067] The strength and modulus of the fiber-reinforced composite materials of Example 1 and Comparative Example 1 under axial compressive load were tested respectively, and the test standard was ASTM D3410 / D3410M.

[0068] The fracture toughness of the fiber-reinforced composite materials of Example 1 and Comparative Example 1 was tested according to ASTM D5528 / D5528M.

[0069] Table 1 Comparison of mechanical properties of fiber-reinforced composite materials of Example 1 and Comparative Example 1

[0070]

[0071] As shown in Table 1, compared with Comparative Example 1, which directly combines glass fiber and epoxy resin, the fiber-reinforced composite material prepared by the dynamic crosslinking modifier has no significant negative impact on the mechanical properties of the glass fiber and epoxy resin prepared by the dynamic crosslinking modifier. In fact, some properties are even improved, with interlaminar fracture toughness increased by 11% and flexural strength increased by 8%.

[0072] Test 3.

[0073] The strength and modulus of the fiber-reinforced composite materials of Example 2, Comparative Example 2, and Comparative Example 3 under bending loads were tested to simulate the bending conditions of beam-like members; the testing standard was ASTM D7264 / D7264M. The interlaminar shear strength of the fiber-reinforced composite materials of Example 2, Comparative Example 2, and Comparative Example 3 was also tested; the testing standard was ASTM D2344 / D2344M.

[0074] Table 2 Comparison of flexural strength and interlaminar shear strength of fiber-reinforced composites in Example 2, Comparative Example 2, and Comparative Example 3

[0075]

[0076] As shown in Table 2, the fiber-reinforced composite material prepared by combining carbon fiber with epoxy resin after dynamic crosslinking liquid treatment has an interlaminar shear strength that is more than 270% higher than that of the unmodified sample and a flexural modulus that is 12% higher; compared with the polydopamine-modified sample, the interlaminar shear strength is 239% higher and the flexural strength is 5% higher.

[0077] It should be noted that when numerical ranges are involved in this invention, it should be understood that the two endpoints of each numerical range, as well as any value between the two endpoints, can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described in this invention to avoid redundancy. Although preferred embodiments of this invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments, and all such changes and modifications fall within the scope of this invention.

[0078] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. If these modifications and variations fall within the scope of equivalents of this invention, then this invention also intends to include these modifications and variations.

Claims

1. A method for the complete recycling process of fiber-reinforced composite materials, characterized in that, Includes the following steps: The fibers were immersed in a dynamic crosslinking solution and left to stand to construct a crosslinking structure on the fiber surface using Co. 2+ A modified fiber is obtained by forming a dynamic coordination crosslinking interface layer with the phenolic hydroxyl and amino groups in polydopamine. The dynamic crosslinking solution is obtained by subjecting dopamine hydrochloride, a cobalt complex, and a solvent to a dopamine self-polymerization reaction under pH conditions of 8–9; the cobalt complex is Co(NH2-DIP)2(BF4)2. Fiber-reinforced composite materials were prepared using modified fibers as reinforcements and resin as the matrix. The fiber-reinforced composite material is immersed in a coordination competitor to cause the dynamic coordination crosslinking interface layer to dissociate, the fiber to separate from the resin, and the recovered fiber is obtained; the coordination competitor is at least one of ethylenediaminetetraacetic acid, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

2. The full-process recycling method for fiber-reinforced composite materials according to claim 1, characterized in that, The ratio of dopamine hydrochloride to cobalt complex was 100 mg: 0.04 mmol.

3. The whole-process recycling method for fiber-reinforced composite materials according to claim 1 or 2, characterized in that, The treatment temperature for immersing fiber-reinforced composite materials in a coordination competitor is 60℃~90℃.

4. The full-process recycling method for fiber-reinforced composite materials according to claim 3, characterized in that, The solvent is ethanol.

5. The full-process recycling method for fiber-reinforced composite materials according to claim 4, characterized in that, The temperature at which the fiber is immersed in the dynamic cross-linking solution and allowed to stand is 25℃~35℃.

6. The full-process recycling method for fiber-reinforced composite materials according to claim 1, characterized in that, The fiber is at least one of carbon fiber, glass fiber and aramid fiber.

7. The full-process recycling method for fiber-reinforced composite materials according to claim 1, characterized in that, The preparation method of fiber-reinforced composite materials is as follows: resin, curing agent and modified fiber are compounded and molding process is adopted to obtain fiber-reinforced composite materials.

8. The full-process recycling method for fiber-reinforced composite materials according to claim 7, characterized in that, The mass ratio of modified fiber to resin is 20:9 to 13.

9. The full-process recycling method for fiber-reinforced composite materials according to claim 8, characterized in that, The curing agent is curing agent H-256.

Images