Thermoplastic composite structural plate based on continuous fiber reinforcement and preparation method thereof

Abstract

The invention belongs to the technical field of polymer composite materials and structural engineering materials, and particularly relates to a thermoplastic composite structural plate based on continuous fiber reinforcement and a preparation method of the thermoplastic composite structural plate. The composite structural plate is prepared from modified polyaryletherketone, 2, 4, 6-trihydroxymethyl phenol, continuous carbon fiber fabric, a compatible flexibilizer, an antioxidant, a heat stabilizer and a lubricating dispersant. Wherein the modified polyaryletherketone is prepared through aromatic ring bromination, alkynyl grafting and in-situ graphdiyne construction reaction, a short-distance graphdiyne pi-segment structure is formed in the hot press molding stage, and a stable pi-pi conjugated interface is generated on the surface of the carbon fiber. The method comprises the steps of resin modification, mixing granulation, fiber impregnation and hot press molding. Compared with a traditional system, the interlaminar shear strength, bending strength and thermal deformation temperature of the material are remarkably improved, and the material has excellent interface bonding force, thermal stability and fracture toughness and is suitable for the fields of aerospace, rail transit and high-performance structural components.

Description

Technical Field

[0001] This invention belongs to the technical field of polymer composite materials and structural engineering materials, specifically relating to a thermoplastic composite structural plate based on continuous fiber reinforcement and its preparation method. Background Technology

[0002] With the increasing demand for high-performance structural materials in aerospace, rail transportation, automotive lightweighting, and construction, continuous fiber reinforced thermoplastic composites have become an important alternative to traditional metals and thermosetting composites due to their advantages such as high specific strength, high specific modulus, recyclability, and reprocessability. However, existing continuous fiber reinforced thermoplastic composite structural panels still suffer from problems such as poor interfacial bonding, insufficient thermal stability, and molding stress concentration, which limit further improvements in their high strength and high toughness properties.

[0003] While traditional polyaryletherketone resins possess excellent heat resistance and mechanical properties, their relatively inert molecular structure makes it difficult to form a strong interfacial bond with carbon fibers. Existing modification methods mostly rely on silane or phenolic coupling systems, with interfacial interactions primarily consisting of physical adsorption or polar interactions, making them prone to interfacial slippage and delamination failure under thermal loads. Furthermore, the high melt viscosity and poor fiber wettability of thermoplastic resins also limit the stress transfer efficiency between composite layers.

[0004] Therefore, the development of a continuous fiber-reinforced thermoplastic composite structural panel with high interfacial energy matching, high thermal stability, and excellent interlayer bonding performance has become an urgent need. This invention introduces a controllable alkyne group structure onto the polyaryletherketone backbone and constructs short-range graphdiyne-like π segments in situ during the molding process, forming a strong π-π coupling interface with the carbon fiber surface. This significantly improves the mechanical properties and thermal stability of the composite material, achieving a high-strength, lightweight, and highly reliable structural design. Summary of the Invention

[0005] To overcome the problems of insufficient interfacial bonding, poor thermal stability, and low stress transfer efficiency in existing continuous fiber reinforced thermoplastic composite structural panels, the present invention aims to provide a continuous fiber reinforced thermoplastic composite structural panel and its preparation method. This invention introduces alkynyl reaction sites into the molecular structure of polyaryletherketone (PAK). Through aromatic ring bromination, alkynyl grafting, and in-situ graphyne-like construction reactions, short-range graphyne-like π-segment structures are formed around the molecular chains of PAK during the hot pressing stage. These structures undergo strong π-π interfacial coupling with the surface of continuous carbon fibers, thereby significantly enhancing the chemical bonding and load transfer between the resin matrix and the fibers. The composite structural panel obtained by this invention exhibits excellent interfacial bonding strength and thermal stability.

[0006] The objective of this invention can be achieved through the following technical solutions: A thermoplastic composite structural panel based on continuous fiber reinforcement, the composite structural panel comprising the following raw materials in parts by weight: 80-120 parts of modified polyaryletherketone; 5-15 parts of 2,4,6-trimethylolphenol; 40-70 parts of continuous carbon fiber fabric; 2-6 parts of compatibility toughening agent; 0.2-0.8 parts of antioxidant; 0.3-1 part of heat stabilizer; and 0.5-1.5 parts of lubricating dispersant; wherein the modified polyaryletherketone is a modified resin obtained by bromination of polyaryletherketone with aromatic rings, grafting with alkynyl groups, and in-situ graphyne-like construction reaction; and the 2,4,6-trimethylolphenol is a phenolic organic compound containing three hydroxymethyl substituents.

[0007] Optionally, the modified polyarylether ketone comprises the following raw materials in parts by weight: 80-120 parts of polyarylether ketone; 3-6 parts of N-bromosuccinimide; 8-15 parts of trimethylsilylacetylene; 0.05-0.1 parts of palladium-diphenylphosphine complex catalyst; 0.05-0.1 parts of cuprous iodide; 10-20 parts of triethylamine; and 150-200 parts of N,N-dimethylformamide.

[0008] Optionally, the preparation method of modified polyaryletherketone includes the following steps: (1) Dissolve polyarylether ketone in an organic solvent, add N-bromosuccinimide to carry out bromination reaction, and obtain brominated polyarylether ketone; (2) The brominated polyarylether ketone was mixed with trimethylsilylacetylene, palladium catalyst, cuprous iodide and organic amine base to carry out alkynyl grafting coupling reaction to obtain alkynyl grafting intermediate; (3) The alkynyl grafting intermediate is deprotected to obtain terminal alkynyl polyarylether ketone; (4) During the hot pressing stage, the terminal alkyne polyarylether ketone undergoes a parallel coupling reaction under a copper catalytic system to form a graphdiyne-like structure, thereby obtaining the modified polyarylether ketone.

[0009] Optionally, the reaction conditions for step (1) are to react at 80–95°C for 2–4 hours under an inert atmosphere.

[0010] Optionally, the reaction conditions for step (2) are to react at 55-65°C for 6-8 hours under an inert atmosphere.

[0011] Optionally, the deprotection treatment in step (3) is performed using ammonium fluoride or tetrabutylammonium fluoride solution, reacting at 25–35°C for 0.5–1 hour.

[0012] Optionally, the hot pressing conditions in step (4) are a temperature of 330-350°C, a pressure of 3-5 MPa, and a holding time of 12-18 minutes.

[0013] Optionally, the continuous carbon fiber fabric is made by mixing carbon fiber tow with epoxy sizing agent at a mass ratio of 100:1 to 2, followed by stretching and shaping. The compatibility toughening agent is made by mixing maleic anhydride-grafted polyphenylene ether with polyetherimide at a mass ratio of 1:1 to 2. The antioxidant is made by mixing antioxidant 1010 with antioxidant 168 at a mass ratio of 1:1. The heat stabilizer is made by mixing hindered amine light stabilizer 944 with benzotriazole UV absorber UV-328 at a mass ratio of 1:0.5 to 1. The lubricating dispersant is made by mixing polytetrafluoroethylene micro powder with calcium stearate at a mass ratio of 1:1 to 3.

[0014] Optionally, a method for preparing a thermoplastic composite structural panel based on continuous fiber reinforcement includes the following steps: S1, modified polyarylether ketone, 2,4,6-tris(hydroxymethyl)phenol, compatibility toughening agent, antioxidant, heat stabilizer and lubricating dispersant are mixed evenly in proportion to obtain a thermoplastic composite resin mixture; S2, The thermoplastic composite resin mixture is melt-extruded and granulated to obtain uniform resin particles; S3, uniform resin particles are uniformly impregnated into a continuous carbon fiber fabric under heating to form a prepreg; S4. The prepreg is laid in the lamination mold according to the designed number of layers and then pressed under hot pressing conditions to obtain a thermoplastic composite structural board based on continuous fiber reinforcement.

[0015] Optionally, the reaction conditions for step S1 are stirring at 60–80°C for 30–60 minutes; the reaction conditions for step S2 are melt extrusion at 200–220°C with a screw speed of 80–120 rpm; the reaction conditions for step S3 are impregnation at 250–280°C for 10–20 minutes to allow the resin particles to fully penetrate the carbon fiber fabric; and the reaction conditions for step S4 are hot pressing at 330–350°C, pressure of 3–5 MPa, and holding time of 12–18 minutes.

[0016] The beneficial effects of this invention are: This invention introduces alkynyl reaction sites on the polyaryletherketone molecular chain and generates short-range graphdiyne π-segment structures in situ during the molding process, thereby forming a dense and continuous π–π conjugated interface layer between the polyaryletherketone matrix and the carbon fiber surface. This not only achieves chemical coupling and stress co-transmission at the molecular level, but also increases the interlaminar shear strength of the composite structural plate by more than 30% and the heat distortion temperature by more than 20°C, significantly enhancing the structural stability and high-temperature service reliability of the material. Attached Figure Description

[0017] The invention will now be further described with reference to the accompanying drawings.

[0018] Figure 1A comparison of the infrared spectra of polyaryletherketone and modified polyaryletherketone; Figure 2 Comparison of interlaminar shear strength test results for samples with different mix proportions; Figure 3 A comparison chart of the test results of bending strength and bending modulus for samples with different mix proportions; Figure 4 A comparison chart of heat distortion temperature test results for samples with different proportions; Figure 5 A comparison chart showing the interlaminar fracture toughness test results of samples with different mix proportions. Detailed Implementation

[0019] The present invention will be further described below with reference to specific embodiments. However, the present invention is not limited to the following embodiments. Equivalent adjustments made without departing from the spirit and essence of the present invention should also be considered to fall within the protection scope of the present invention.

[0020] Example 1 The purpose of this embodiment is to verify the effect of improving the interfacial bonding strength and thermal stability of the composite structural plate under the condition that the components are taken at the upper limit ratio.

[0021] S1, 120 parts of polyarylether ketone were dissolved in 200 parts of N,N-dimethylformamide, heated to 90°C and stirred until homogeneous. 6 parts of N-bromosuccinimide were added under a nitrogen atmosphere, and the reaction was carried out for 3 hours to obtain brominated polyarylether ketone. After cooling the brominated product, 15 parts of trimethylsilylacetylene, 0.1 parts of palladium diphenylphosphine chloride catalyst, 0.1 parts of cuprous iodide and 20 parts of triethylamine were added, and the reaction was carried out at 55°C for 8 hours to obtain an alkynyl grafting intermediate. The deprotection reaction was carried out using tetrabutylammonium fluoride solution, and the reaction was carried out at 30°C for 1 hour to obtain terminal alkynyl polyarylether ketone. Subsequently, 0.03 parts of cuprous bromide and 0.05 parts of tetramethylethylenediamine were added during the hot pressing stage, and the mixture was hot-pressed at 330-350°C and 3-5 MPa for 12 minutes to generate a graphdiyne-like π-segment structure in situ, thus obtaining the modified polyarylether ketone. S2, 120 parts of modified polyaryletherketone, 15 parts of 2,4,6-tris(hydroxymethyl)phenol, 6 parts of compatibility toughening agent, 0.8 parts of antioxidant, 1 part of heat stabilizer and 1.5 parts of lubricating dispersant are mixed and melt-extruded into granules at 200-220°C with a screw speed of 120 rpm to obtain uniform resin particles; S3, resin particles are impregnated with 70 parts of continuous carbon fiber fabric at 270°C and kept for 15 minutes to form a prepreg. The prepreg is laid in a lamination mold in a [0 / 90]4 layering manner and hot-pressed at 350°C and 5 MPa for 18 minutes to obtain a high-strength continuous fiber reinforced thermoplastic composite structural board.

[0022] Example 2 The purpose of this embodiment is to verify the balanced performance of the composite structural plate in terms of interface bonding, molding flowability and mechanical properties under intermediate ratio formulation.

[0023] S1, 100 parts of polyaryletherketone were dissolved in 180 parts of N,N-dimethylformamide, and 4.5 parts of N-bromosuccinimide were added at 85°C. The reaction was carried out for 3 hours to obtain brominated polyaryletherketone. The obtained intermediate was then added to 12 parts of trimethylsilylacetylene, 0.08 parts of palladium diphenylphosphine chloride catalyst, 0.08 parts of cuprous iodide, and 15 parts of triethylamine. The reaction was carried out at 60°C for 7 hours to obtain an alkynyl grafted product. The protecting group was then removed with tetrabutylammonium fluoride solution, and the reaction was carried out at 30°C for 0.5 hours to obtain terminal alkynyl polyaryletherketone. 0.02 parts of cuprous bromide and 0.05 parts of tetramethylethylenediamine were added, and the mixture was hot-pressed at 340°C for 15 minutes to form a short-range graphdiyne-like π-segment structure in situ, thus obtaining modified polyaryletherketone. Figure 1 As can be seen from the data, the unmodified polyaryletherketone mainly exhibits a 1660 cm⁻¹ diameter. - C=O stretching vibration at ¹ and 1260cm - The C–O–C absorption peak at ¹ indicates that its main chain structure is dominated by aryl ether ketones; in addition to retaining the original characteristic peaks, the modified sample also exhibits a peak at 2230 cm⁻¹. - ¹ and 2120cm - A distinct new peak appears at position ¹, corresponding to the C≡C and conjugate –C≡C–C≡C– vibrations of the alkynyl group, respectively, proving that the alkynyl group was successfully grafted and formed a graphdiyne-like structure; simultaneously, at 870 cm⁻¹... - A C–H bending vibration peak appears at position ¹, 500 cm⁻¹ - The appearance of a weak Cu–C bond peak at position ¹ indicates the occurrence of a copper-catalyzed coupling reaction; the overall spectrum shows obvious new peaks with sharp peak shapes, indicating that the modification reaction is complete and the π-conjugated network has been successfully introduced into the polyaryletherketone molecule structure. S2, 100 parts of modified polyarylether ketone, 10 parts of 2,4,6-tris(hydroxymethyl)phenol, 4 parts of compatibility toughening agent, 0.5 parts of antioxidant, 0.6 parts of heat stabilizer and 1 part of lubricating dispersant are mixed and melt-extruded and granulated at 210°C with a screw speed of 100 rpm to obtain uniform resin particles; S3 involves impregnating 55 parts of continuous carbon fiber fabric with resin particles at 260°C for 15 minutes to form a prepreg. The prepreg is then laid in a lamination mold and hot-pressed at 340°C and 4 MPa for 15 minutes to obtain a thermoplastic composite structural board with a dense structure and excellent interfacial bonding.

[0024] Example 3 The purpose of this embodiment is to verify the changes in interfacial bonding and thermodynamic properties of the composite structural board under conditions of low resin ratio and low fiber content.

[0025] S1, 80 parts of polyaryletherketone were dissolved in 150 parts of N,N-dimethylformamide, and 3 parts of N-bromosuccinimide were added at 80°C and reacted for 2 hours to obtain brominated polyaryletherketone; then 8 parts of trimethylsilylacetylene, 0.05 parts of palladium diphenylphosphine chloride catalyst, 0.05 parts of cuprous iodide and 10 parts of triethylamine were added, and reacted at 55°C for 6 hours to obtain an alkynyl grafting intermediate; the intermediate was deprotected with ammonium fluoride solution and reacted at 25°C for 0.5 hours to obtain terminal alkynyl polyaryletherketone. Subsequently, in the presence of 0.02 parts of cuprous bromide and 0.05 parts of tetramethylethylenediamine, it was hot-pressed at 330°C for 12 minutes to form a small amount of graphdiyne-like π-segment structure, thus obtaining modified polyaryletherketone; S2, 80 parts of modified polyarylether ketone, 5 parts of 2,4,6-tris(hydroxymethyl)phenol, 2 parts of compatibility toughening agent, 0.2 parts of antioxidant, 0.3 parts of heat stabilizer and 0.5 parts of lubricating dispersant are mixed and melt-extruded and granulated at 200°C with a screw speed of 80 rpm to obtain resin particles; S3. Resin particles are impregnated with 40 parts of continuous carbon fiber fabric at 250°C for 10 minutes to form a prepreg. The prepreg is laid in a lamination mold and hot-pressed at 330°C, 3 MPa, and holding pressure for 12 minutes to obtain a thermoplastic composite structural board with a low filler ratio.

[0026] Comparative Example 1 The purpose of this comparative example is to verify the interfacial bonding and molding performance when polyaryletherketone is brominated without alkynyl grafting and in-situ parallel coupling.

[0027] S1, 100 parts of polyarylether ketone were dissolved in 180 parts of N,N-dimethylformamide, and 4.5 parts of N-bromosuccinimide were added at 85°C and reacted for 3 hours to obtain brominated polyarylether ketone; without subsequent alkyne grafting, deprotection and in-situ parallel coupling, the obtained brominated polyarylether ketone was used directly as a resin matrix. S2, mix 100 parts of brominated polyarylether ketone, 10 parts of 2,4,6-tris(hydroxymethyl)phenol, 4 parts of compatibility toughening agent, 0.5 parts of antioxidant, 0.6 parts of heat stabilizer and 1 part of lubricating dispersant, and melt extrude and granulate at 210°C with a screw speed of 100 rpm to obtain resin particles; S3, resin particles are impregnated with 55 parts of continuous carbon fiber fabric at 260°C for 15 minutes to form a prepreg. The prepreg is placed in a lamination mold and hot-pressed at 340°C and 4 MPa for 15 minutes to obtain a sample plate.

[0028] Comparative Example 2 The purpose of this comparative example is to verify the interface behavior when only alkyne grafting is performed without in-situ parallel coupling to construct a graphdiyne-like structure.

[0029] S1, 100 parts of polyarylether ketone were dissolved in 180 parts of N,N-dimethylformamide, and 4.5 parts of N-bromosuccinimide were added at 85°C and reacted for 3 hours to obtain brominated polyarylether ketone; 12 parts of trimethylsilylacetylene, 0.08 parts of palladium diphenylphosphine chloride catalyst, 0.08 parts of cuprous iodide and 15 parts of triethylamine were added, and reacted at 60°C for 7 hours to obtain an alkynyl grafting intermediate; the protecting group was removed by reacting with tetrabutylammonium fluoride solution at 30°C for 0.5 hours to obtain terminal alkynyl polyarylether ketone; no cuprous bromide and tetramethylethylenediamine were added, and no in-situ parallel coupling treatment was performed; S2, mix 100 parts of terminal alkyne polyarylether ketone, 10 parts of 2,4,6-tris(hydroxymethyl)phenol, 4 parts of compatibility toughening agent, 0.5 parts of antioxidant, 0.6 parts of heat stabilizer and 1 part of lubricating dispersant, and melt extrude and granulate at 210°C with a screw speed of 100 rpm to obtain resin particles; S3, resin particles are impregnated with 55 parts of continuous carbon fiber fabric at 260°C for 15 minutes to form a prepreg. The prepreg is placed in a lamination mold and hot-pressed at 340°C and 4 MPa for 15 minutes to obtain a sample plate.

[0030] Comparative Example 3 The purpose of this comparative example is to verify the effect of adding a copper catalytic system for parallel coupling treatment only during the hot pressing stage on the interface, without bromination and alkyne grafting.

[0031] S1, 100 parts of polyaryletherketone were used directly as the resin matrix without bromination, alkyne grafting, or deprotection; in the subsequent hot pressing stage, 0.02 parts of cuprous bromide and 0.05 parts of tetramethylethylenediamine were added as in-situ parallel coupling treatment conditions only. S2, mix 100 parts of polyaryletherketone, 10 parts of 2,4,6-tris(hydroxymethyl)phenol, 4 parts of compatibility toughening agent, 0.5 parts of antioxidant, 0.6 parts of heat stabilizer and 1 part of lubricating dispersant, melt extrude and granulate at 210°C with a screw speed of 100 rpm to obtain resin particles; S3, resin particles are impregnated with 55 parts of continuous carbon fiber fabric at 260°C for 15 minutes to form a prepreg. The prepreg is placed in a lamination mold and hot-pressed at 340°C and 4 MPa for 15 minutes. Cuprous bromide and tetramethylethylenediamine are added to obtain a sample plate.

[0032] Comparative Example 4 The purpose of this comparative example is to verify the changes in interfacial bonding and molding properties when other modifications are kept consistent with those in Example 2 without the addition of 2,4,6-tris(hydroxymethyl)phenol.

[0033] S1, 100 parts of polyaryletherketone were dissolved in 180 parts of N,N-dimethylformamide, and 4.5 parts of N-bromosuccinimide were added at 85°C and reacted for 3 hours to obtain brominated polyaryletherketone; 12 parts of trimethylsilylacetylene, 0.08 parts of palladium diphenylphosphine chloride catalyst, 0.08 parts of cuprous iodide and 15 parts of triethylamine were added, and reacted at 60°C for 7 hours to obtain an alkynyl grafting intermediate; the protecting group was removed by reacting with tetrabutylammonium fluoride solution at 30°C for 0.5 hours to obtain terminal alkynyl polyaryletherketone; 0.02 parts of cuprous bromide and 0.05 parts of tetramethylethylenediamine were added, and the mixture was hot-pressed at 340°C for 15 minutes to generate a short-range graphyne-like structure, thus obtaining modified polyaryletherketone; S2, mix 100 parts of modified polyaryletherketone, 4 parts of compatibility toughening agent, 0.5 parts of antioxidant, 0.6 parts of heat stabilizer and 1 part of lubricating dispersant, without adding 2,4,6-tris(hydroxymethyl)phenol, melt extrude and granulate at 210°C with a screw speed of 100 rpm to obtain resin particles; S3, resin particles are impregnated with 55 parts of continuous carbon fiber fabric at 260°C for 15 minutes to form a prepreg. The prepreg is placed in a lamination mold and hot-pressed at 340°C and 4 MPa for 15 minutes to obtain a sample plate.

[0034] Performance testing 1. Interlaminar shear strength test The interlaminar shear strength of composite structural panels was determined using the short beam three-point bending method. The specimen dimensions were 24 mm long, 6 mm wide, and 3 mm thick, with a support span five times the thickness. Before testing, the specimens were conditioned for 48 hours at 23±2℃ and 50±5% relative humidity. During testing, the interlaminar surfaces of the specimens were placed parallel to the load-bearing surfaces, and bending tests were performed on a universal testing machine at a loading rate of 1 mm / min until the specimens failed. The maximum load value was recorded. Five specimens were tested in each group, and the average value was used for comparative analysis.

[0035] 2. Bending strength and bending modulus testing The flexural strength and flexural modulus of the composite structural plate were determined using the three-point bending method. The specimen dimensions were 64 mm long, 12.7 mm wide, and 3.2 mm thick, with a support span 32 times the thickness. The loading rate was controlled to ensure a maximum strain of approximately 0.01 s⁻¹. - ¹. During testing, the stress-strain curves are recorded. The bending strength is determined through the point of maximum load, and the bending modulus is calculated during the linear phase of the curve. Five specimens are tested in each group, and the average value and standard deviation are taken as the results.

[0036] 3. Heat distortion temperature test The thermal stability of the composite structural plate was determined using a heat distortion temperature tester. The sample dimensions were 120 mm long, 13 mm wide, and 3.2 mm thick, with silicone oil as the heating medium. A constant stress of 1.8 MPa was applied during testing, and the temperature was increased at a rate of 2 °C / min. The deflection change of the sample was recorded using a displacement sensor, and the temperature at which the deflection reached the standard specified value was taken as the heat distortion temperature. Three samples were tested in each group, and the average value was used for comparison.

[0037] 4. Interlaminar fracture toughness test Interlaminar fracture toughness of composite structural plates was determined using the open-end interlaminar test method. The specimens were pre-cracked double cantilever beam structures with a crack length of approximately 50 mm, a width of 25 mm, and a thickness of approximately 4 mm. The loading rate was 5 mm / min, and load and displacement data were recorded in real time, while the crack propagation process was tracked. The initial and propagation values ​​of interlaminar fracture toughness were analyzed based on changes in energy release. Three specimens were tested in each group, and the average value was taken as the result. The interfacial bonding characteristics were also analyzed in conjunction with the fracture surface microstructure.

[0038] Table 1 Performance test results of different samples As can be seen from the data in Table 1, the mechanical and thermal properties of Examples 1-3 are significantly better than those of Comparative Examples 1-4, indicating that the synergistic design of modified polyarylether ketone and the small organic molecule 2,4,6-tris(hydroxymethyl)phenol plays a key role in enhancing interfacial bonding and improving overall structural stability. Among them, Example 2 shows the most outstanding performance in all aspects and has the best overall performance.

[0039] Regarding interlaminar shear strength, Figure 2 Example 2 achieved a strength of 88.7 MPa, which is about 35% higher than the 65.4 MPa of Comparative Example 1. This significant improvement indicates that by introducing alkynyl reaction sites into the polyaryletherketone backbone and constructing a graphdiyne-like π-segment structure in situ during the hot pressing stage, the π–π interaction between the matrix resin and the carbon fiber surface is effectively promoted, resulting in more uniform stress transmission and significantly improved interlayer bonding strength.

[0040] In terms of bending performance, Figure 3 The flexural strength of Example 2 was 205.4 MPa, and the flexural modulus was 7.2 GPa, both higher than those of other samples. Compared with the comparative example, the increase in flexural modulus indicates that the modified system has a more compact macroscopic structure, more ordered molecular chain packing, and significantly enhanced structural rigidity, thus enabling the composite material to maintain stable deformation and high load-bearing capacity under high loads.

[0041] In terms of thermal performance, Figure 4The heat distortion temperature of Example 2 reached 246°C, which is about 29°C higher than that of Comparative Example 1, showing a significant improvement in thermal stability. This is because the graphdiyne-like structure forms a highly thermally stable conjugated network in the resin phase, which restricts the thermal vibration between molecular chains, thereby improving the material's ability to withstand thermal loads.

[0042] Regarding interlaminar fracture toughness, Figure 5 The measured value of Example 2 was 578 J / m², which is about 38% higher than that of Comparative Example 1 (420 J / m²). This result indicates that the in-situ generated π-conjugate network not only improves the interfacial bonding strength but also enhances the energy dissipation capacity during crack propagation, transforming the interfacial fracture mode from brittle fracture to ductile fracture.

[0043] In summary, the synergistic modification by alkyne grafting and in-situ graphdiyne significantly improves the mechanical properties and thermal stability of the composite structural plate. Example 2, in particular, exhibits the best performance in terms of interfacial bonding, flexural strength, heat resistance, and fracture toughness, fully demonstrating the innovation and superiority of this structural design in continuous fiber-reinforced thermoplastic composites.

Claims

1. A thermoplastic composite structural panel based on continuous fiber reinforcement, characterized in that, The composite structural plate comprises the following raw materials in parts by weight: 80-120 parts of modified polyaryletherketone; 5-15 parts of 2,4,6-trimethylolphenol; 40-70 parts of continuous carbon fiber fabric; 2-6 parts of compatibility toughening agent; 0.2-0.8 parts of antioxidant; 0.3-1 part of heat stabilizer; and 0.5-1.5 parts of lubricating dispersant. The modified polyaryletherketone is a modified resin obtained by bromination of polyaryletherketone with aromatic rings, grafting with alkynyl groups, and in-situ graphylene-like construction. The 2,4,6-trimethylolphenol is a phenolic organic compound containing three hydroxymethyl substituents.

2. The thermoplastic composite structural panel based on continuous fiber reinforcement according to claim 1, characterized in that, The modified polyaryletherketone comprises the following raw materials in parts by weight: 80-120 parts of polyaryletherketone; 3-6 parts of N-bromosuccinimide; 8-15 parts of trimethylsilylacetylene; 0.05-0.1 parts of palladium-diphenylphosphine complex catalyst; 0.05-0.1 parts of cuprous iodide; 10-20 parts of triethylamine; and 150-200 parts of N,N-dimethylformamide.

3. A thermoplastic composite structural panel based on continuous fiber reinforcement according to any one of claims 1 or 2, characterized in that, The preparation method of the modified polyarylether ketone includes the following steps: (1) Dissolve polyarylether ketone in an organic solvent, add N-bromosuccinimide to carry out bromination reaction, and obtain brominated polyarylether ketone; (2) The brominated polyarylether ketone was mixed with trimethylsilylacetylene, palladium catalyst, cuprous iodide and organic amine base to carry out alkynyl grafting coupling reaction to obtain alkynyl grafting intermediate; (3) The alkynyl grafting intermediate is deprotected to obtain terminal alkynyl polyarylether ketone; (4) During the hot pressing stage, the terminal alkyne polyarylether ketone undergoes a parallel coupling reaction under a copper catalytic system to form a graphdiyne-like structure, thereby obtaining the modified polyarylether ketone.

4. The thermoplastic composite structural panel based on continuous fiber reinforcement according to claim 3, characterized in that, The reaction conditions for step (1) are: reaction at 80-95°C for 2-4 hours under an inert atmosphere.

5. A thermoplastic composite structural panel based on continuous fiber reinforcement according to claim 3, characterized in that, The reaction conditions for step (2) are: reaction at 55-65°C for 6-8 hours under an inert atmosphere.

6. The thermoplastic composite structural panel based on continuous fiber reinforcement according to claim 3, characterized in that, The deprotection treatment in step (3) uses ammonium fluoride or tetrabutylammonium fluoride solution and reacts at 25-35°C for 0.5-1 hour.

7. A thermoplastic composite structural panel based on continuous fiber reinforcement according to claim 3, characterized in that, The hot pressing conditions for step (4) are: temperature 330-350℃, pressure 3-5MPa, and holding time 12-18 minutes.

8. The thermoplastic composite structural panel based on continuous fiber reinforcement according to claim 1, characterized in that, The continuous carbon fiber fabric is made by mixing carbon fiber tow and epoxy sizing agent at a mass ratio of 100:1-2, followed by stretching and shaping. The compatibility toughening agent is made by mixing maleic anhydride-grafted polyphenylene ether and polyetherimide at a mass ratio of 1:1-2. The antioxidant is made by mixing antioxidant 1010 and antioxidant 168 at a mass ratio of 1:

1. The heat stabilizer is made by mixing hindered amine light stabilizer 944 and benzotriazole UV absorber UV-328 at a mass ratio of 1:0.5-1. The lubricating dispersant is made by mixing polytetrafluoroethylene micro powder and calcium stearate at a mass ratio of 1:1-3.

9. A method for preparing a thermoplastic composite structural panel based on continuous fiber reinforcement, wherein the thermoplastic composite structural panel based on continuous fiber reinforcement is as described in any one of claims 1 to 8, characterized in that, Includes the following steps: S1, modified polyarylether ketone, 2,4,6-tris(hydroxymethyl)phenol, compatibility toughening agent, antioxidant, heat stabilizer and lubricating dispersant are mixed evenly in proportion to obtain a thermoplastic composite resin mixture; S2, The thermoplastic composite resin mixture is melt-extruded and granulated to obtain uniform resin particles; S3, uniform resin particles are uniformly impregnated into a continuous carbon fiber fabric under heating to form a prepreg; S4. The prepreg is laid in the lamination mold according to the designed number of layers and then pressed under hot pressing conditions to obtain a thermoplastic composite structural board based on continuous fiber reinforcement.

10. The method for preparing a thermoplastic composite structural plate based on continuous fiber reinforcement according to claim 9, characterized in that, The reaction conditions for step S1 are stirring at 60-80°C for 30-60 minutes; the reaction conditions for step S2 are melt extrusion at 200-220°C with a screw speed of 80-120 rpm; the reaction conditions for step S3 are impregnation at 250-280°C for 10-20 minutes to allow the resin particles to fully penetrate the carbon fiber fabric; the reaction conditions for step S4 are hot pressing at 330-350°C, pressure of 3-5 MPa, and holding time of 12-18 minutes.

Images