A glass flake reinforced composite based on interfacial covalent bonding and its preparation method and application

Abstract

This invention belongs to the interdisciplinary field of high-performance composite material manufacturing technology and interface engineering, specifically including a glass flake reinforced composite material based on interfacial covalent bonding, its preparation method, and its application. The preparation method includes the following steps: S1, immersing glass flakes in a silane coupling agent solution containing methacryloxypropylmethyldichlorosilane to obtain glass flakes with a high density of multiple covalent bonding sites on the surface; S2, adding the glass flakes obtained in step S1 to a polymer prepolymer solution, mixing evenly to obtain a precursor; S3, sequentially coating a substrate surface with a silane coupling agent solution and an initiator solution, then coating the precursor onto it, and then pressing another substrate sequentially coated with a silane coupling agent solution and an initiator solution onto the precursor, so that the precursor is uniformly spread between the two substrates, initiating an in-situ polymerization reaction to obtain a glass flake reinforced composite material.

Description

Technical Field

[0001] This invention belongs to the interdisciplinary field of high-performance composite material manufacturing technology and interface engineering, specifically including a glass flake reinforced composite material based on interface covalent bonding, its preparation method and application. Background Technology

[0002] Polymer-based composite materials are widely used in electronic packaging, aerospace, and automotive manufacturing due to their advantages such as light weight, high strength, and corrosion resistance. Among them, thermosetting materials such as epoxy resins and unsaturated polyesters have a variety of applications due to their excellent mechanical properties and dimensional stability. However, their high crosslinking density after curing, resulting in brittleness and poor crack propagation resistance, greatly limits their serviceability in applications requiring high toughness.

[0003] To improve the brittleness and strength of the aforementioned materials, existing technologies often employ the addition of toughening agents. Adding liquid rubber can significantly improve impact strength, but it typically lowers the glass transition temperature and flexural modulus, leading to a decrease in heat resistance and rigidity. While adding rigid inorganic particles can increase strength, it often results in brittleness. Among these, glass flakes, due to their unique lamellar structure, can extend crack propagation paths through the "labyrinth effect," making them an ideal toughening filler.

[0004] However, the existing technology of directly adding glass flakes has the following technical drawbacks: First, the interfacial bonding is weak, with a large difference in interfacial energy between the glass flakes and the polymer. This is because, on the one hand, untreated glass flakes may aggregate within the monomers, forming pores after polymerization; on the other hand, traditional methods can only form single-point or sparse double bond anchoring, resulting in low interfacial covalent bond density. Glass flake-polymer systems with weak interfacial bonding are prone to forming porosity defects at the interface after UV curing, leading to interfacial debonding of the composite material under stress. This not only fails to toughen the composite but also becomes a point of failure initiation.

[0005] Second, the lack of a stress-dissipating interface layer means that strength and toughness cannot be simultaneously achieved. The surface of unmodified or only monolayer-modified glass flakes is a "rigid" interface. When cracks propagate to the interface, stress concentration cannot be released, resulting in composite materials that are either low in strength or brittle. Current technology cannot construct a "flexible buffer layer" around the glass flakes that can both strongly anchor the material and dissipate energy during deformation.

[0006] Third, the dispersion stability of glass flakes in the monomer solution is poor before polymerization, which easily leads to uneven distribution after polymerization. Methods such as compacting glass flakes and filtering to inject monomers into the gaps between glass flakes are difficult to achieve adjustable toughness, resulting in low toughening efficiency and limiting its application in more high-performance scenarios.

[0007] Therefore, the key to realizing the enhancement potential lies in how to construct a rigid-flexible interface structure with "high-density covalent anchor points + flexible stress buffer layer" in situ on the surface of glass flakes from the perspective of interface molecular engineering. Summary of the Invention

[0008] In view of the problems existing in the prior art, the first objective of this invention is to provide a method for preparing glass flake reinforced composite materials based on interfacial covalent bonding. By constructing high-density multi-covalent bonding sites on the glass flakes, it is beneficial to form in-plane, dense covalent connections between the polymer matrix and the glass flakes, thereby constructing a flexible stress buffer layer and further improving the interfacial strength. At the same time, an initiator is pre-placed at the interface between the substrate and the flexible stress buffer layer formed by the glass flakes and polymer to initiate directional initiation and completely eliminate the problem of interfacial debonding.

[0009] The second objective of this invention is to provide a glass flake reinforced composite material based on interfacial covalent bonding prepared by the preparation method described above.

[0010] The third objective of this invention is to provide an application of the glass flake reinforced composite material described above in the manufacture of load-bearing structural components, wind turbine blades, automobile body parts, aerospace interior panels, and sports and leisure equipment.

[0011] To achieve the first objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses a method for preparing glass flake reinforced composite materials based on interfacial covalent bonding, comprising the following steps: S1. Glass flakes are immersed in a silane coupling agent solution containing methacryloxypropylmethyldichlorosilane to obtain glass flakes with high density of multiple covalent binding sites on the surface. S2. Add the glass flakes obtained in step S1 to the polymer prepolymer liquid and mix them evenly to obtain the precursor. S3. A silane coupling agent solution and an initiator solution are sequentially coated on the substrate surface, and then a precursor is coated on it. Another substrate, which is sequentially coated with a silane coupling agent solution and an initiator solution, is then pressed onto the precursor, so that the precursor is evenly spread between the two substrates, initiating an in-situ polymerization reaction to obtain a glass flake reinforced composite material.

[0012] It should be noted that the high-density multi-covalent binding sites in this invention are formed by the hydrolysis of methacryloyloxypropylmethyldichlorosilane under the action of a very small amount of water molecules, producing a main chain with -Si-O- as the repeating unit, while simultaneously removing HCl molecules. This results in a special arrangement of binding site groups where the double bonds on each silane molecule are arranged in a string or tree-like structure. Traditional coupling agents (such as KH570) are difficult to form molecular units with multiple double bonds existing simultaneously through the reaction, and therefore cannot form a high-density multi-site network.

[0013] This invention constructs a high-density, multi-site covalently bonded network on the surface of glass flakes, enabling the polymer matrix and glass flakes to form in-plane, dense covalent connections. This provides the conditions for subsequently constructing a flexible stress buffer layer between the two substrates, further enhancing the interfacial strength compared to the traditional "sparse single-point anchoring." Furthermore, the flexible stress buffer layer constructed from the polymer matrix and glass flakes has a certain thickness (approximately 10 nm), which can both anchor the polymer matrix and glass flakes through covalent bonds and dissipate a large amount of impact energy during impact through conformational changes (such as extension and rotation) of its own molecular chains, thus achieving both strength and toughness. In addition, the glass flakes with the high-density, multi-site covalently bonded network are generally loose and easily dispersed by stirring, thus uniformly distributing in the polymer prepolymer solution. This solves the problem of achieving consistent glass flake orientation. When the glass flake orientation is uniform, it can exert an effective "maze effect" within the substrate, significantly hindering and deflecting the crack propagation path under impact loads.

[0014] Furthermore, the concentration of methacryloxypropylmethyldichlorosilane in the silane coupling agent solution is 1-10 vol%. If the concentration is too low, the effect of high density and multiple covalent bonding sites cannot be effectively utilized, resulting in limited improvement in the impact resistance or bending resistance of the composite material. If the concentration is too high, it is uneconomical on the one hand, and on the other hand, too many sites will compete with each other, resulting in limited impact resistance or bending resistance.

[0015] Furthermore, the solvent of the silane coupling agent solution is selected from one or more of toluene, xylene, n-hexane, and cyclohexane.

[0016] The glass flakes and substrates used in this invention have been pre-treated with hydrophilicity to make the surfaces of the glass flakes and substrates uniformly rich in hydroxyl (-OH) active groups, providing anchoring sites for subsequent silane grafting reactions. Technicians can treat the substrate based on currently reported hydrophilicity treatment methods, such as oxygen plasma treatment or piranha solution treatment.

[0017] Furthermore, the initiator is selected from one or more of DEAP, Irgacure 1173, Irgacure 184, Irgacure 819, TPO, tert-butyl peroxide, and tert-butyl peroxyneodecanate.

[0018] Furthermore, the volume concentration of the initiator solution is 2-4 vol%.

[0019] Furthermore, the amount of the initiator solution coated on the substrate surface is 2-4 μL / cm. 2 .

[0020] Furthermore, the solvent of the initiator solution is selected from one or more volatile organic solvents such as ethanol, isopropanol, acetone, and ethyl acetate.

[0021] By pre-placing the initiator between the substrate and the precursor, it is beneficial to enable the initiator to achieve directional initiation at the interface, complete the covalent bonding at the interface between the substrate and the glass flake-polymer, and eliminate the problem of interface debonding.

[0022] The glass flakes used in this invention are commercially available products, such as MEG160FY-M01, MEG160FY-M02, MEG160FY-M03, MEG160FY-M04, and MEG160FY-M06, with a flake diameter ranging from 140-180 μm and a thickness ranging from 0.5-1.0 μm. The preferred flake diameter is 160 μm and the thickness is 0.7 μm. Glass flakes of this size have a high surface area, enabling the provision of more bonding interfaces within a given quality.

[0023] Furthermore, the polymer prepolymer liquid is prepared according to the following steps: The product is obtained by mixing monomers containing active groups, natural polymers with thermally reversible gel properties, toughening modifiers, and solvents in a certain proportion and heating to dissolve them. In the raw materials forming the polymer prepolymer liquid, monomers account for 50-90 wt%, natural polymers account for 1-10 wt%, toughening regulators account for 1-10 wt%, and the remainder is solvent.

[0024] Furthermore, the monomer is selected from one or more of acrylamide, N-hydroxyethylacrylamide, and N,N-dimethylacrylamide; The natural polymer is selected from one or more of gelatin, agarose, carrageenan, chitosan, and sodium alginate; The toughening modifier is selected from one or more of ethylene glycol, propylene glycol, glycerin, and polyethylene glycol; The solvent is water.

[0025] Furthermore, the mass ratio of the glass flakes with high-density multi-covalent bonding sites to the polymer prepolymer liquid is 0.075-0.125:1. This control allows for precise regulation of the mechanical properties of the composite material, such as rigidity and toughness.

[0026] Furthermore, the amount of the precursor coated on the substrate surface is 0.8-1.5 mL / cm². 2 .

[0027] Furthermore, the methods for initiating in-situ polymerization reactions include thermal initiation or ultraviolet light initiation; The thermal initiation conditions are as follows: the thermal initiation temperature is 80-100℃, and the in-situ polymerization reaction time is 150-300 min. The conditions for ultraviolet light initiation are: ultraviolet light irradiation wavelength of 250-400 nm and light intensity of 10-200 mW / cm². 2 The in-situ polymerization reaction takes 30-60 minutes.

[0028] Furthermore, the substrate is selected from a variety of materials such as glass, alumina, aluminum, titanium, granite, or marble.

[0029] To achieve the second objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses a glass flake reinforced composite material based on interfacial covalent bonding, prepared using the preparation method described above.

[0030] To achieve the third objective mentioned above, the technical solution adopted by the present invention includes: This invention discloses the application of glass flake reinforced composite material as described above in the preparation of load-bearing structural components, wind turbine blades, automobile body parts, aerospace interior panels, and sports and leisure equipment.

[0031] Beneficial effects of this invention: This invention introduces a specific silane coupling agent, methacryloxypropylmethyldichlorosilane, to treat glass flakes and a substrate. On one hand, this facilitates the construction of high-density multi-covalent bonding sites on the glass flake surface, enabling the polymer matrix and glass flakes to form in-plane, dense covalent bonds. In subsequent operations, a flexible stress buffer layer can be formed between the polymer matrix and the glass flakes in the middle of the substrate, improving both interfacial strength and the toughness of the composite material. On the other hand, high-density grafting sites are also formed on the substrate surface, ensuring the interfacial bonding strength between the substrate and the glass flake-polymer. Simultaneously, it facilitates the penetration of the initiator into the high-density grafting site region, enhancing the reinforcing effect of internal crosslinking.

[0032] The present invention pre-places an initiator at the interface, which facilitates the directional initiation of the initiator at the interface, completes the covalent bonding at the interface between the substrate and the glass flake-polymer, enhances the degree of polymerization reaction, and eliminates the problem of interface debonding.

[0033] The preparation process provided by this invention is simple, the curing speed is fast, the experimental conditions are easy to control, and no complex high-temperature and high-pressure equipment is required. It is easy to scale up production and has broad prospects for industrial application. The prepared glass flake reinforced composite material has excellent impact resistance and structural stability and can be used in aerospace, automobile manufacturing, building reinforcement and other fields. Attached Figure Description

[0034] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0035] Figure 1 The image shows a SEM image of the sample prepared in Example 1 after it was subjected to an impact.

[0036] Figure 2 The force-displacement curve of the sample prepared in Example 1 under quasi-static impact is shown.

[0037] Figure 3 The force-displacement curve of the sample prepared in Example 2 under quasi-static impact is shown.

[0038] Figure 4 The force-displacement curve of the sample prepared in Comparative Example 1 under quasi-static impact is shown.

[0039] Figure 5 The force-displacement curves of the samples prepared in Comparative Examples 2 and 3 under quasi-static impact are shown.

[0040] Figure 6 The force-displacement curves of the samples prepared in Comparative Examples 4 and 5 under quasi-static impact are shown.

[0041] Figure 7 The force-displacement curve of the sample prepared in Comparative Example 6 under quasi-static impact is shown. Detailed Implementation

[0042] To more clearly illustrate the present invention, the following description, in conjunction with preferred embodiments and accompanying drawings, further clarifies the invention. It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0043] Example 1: High-strength and high-toughness glass flake reinforced laminated glass A method for preparing high-strength, high-toughness glass flake reinforced laminated glass includes the following steps: a) Glass flakes (160 μm in diameter and 0.7 μm in thickness) were immersed in a piranha solution at 90 °C for 1 h and heated. The piranha solution was a mixture of H₂SO₄ and H₂O₂ at a volume ratio of 7:3. After washing, the flakes were rinsed with deionized water and filtered. This method not only removed the original modifying groups on the glass flakes but also enriched them with hydroxyl (-OH) active groups, providing anchoring sites for the subsequent silane grafting reaction.

[0044] b) Prepare a 1 vol% hexane solution containing methacryloxypropylmethyldichlorosilane. Immerse the glass flakes treated in step a) into the hexane solution and shake on a shaker for 1 hour. Then remove the supernatant, wash three times with anhydrous ethanol, and dry in a vacuum oven at 60°C for 2 hours to obtain glass flakes with a high density of multi-covalent binding sites on the surface. Prepare a 2 vol% ethyl acetate solution of DEAP for later use.

[0045] c) Treat the glass substrate (22 mm long, 22 mm wide, and 220 μm thick) with oxygen plasma for 5 minutes, then modify it with the hexane solution containing methacryloxypropylmethyldichlorosilane prepared in step b), and then uniformly coat its surface with the ethyl acetate solution containing DEAP prepared in step b) (coating amount: 2.1 μL / cm²) using a blade coating method. 2 ), air dry at room temperature, and then process another glass substrate using the same process as step c), and set aside.

[0046] d) Add 32g of N-hydroxyethylacrylamide monomer, 2g of agarose, 1.8g of ethylene glycol, and 4.2g of water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix the polymer, resulting in a clear and transparent solution. Add the modified glass flakes prepared in step b) at 10 wt% of the total mass of the polymer prepolymer solution and stir gently to initially disperse the flakes. Then allow the solution to stand for 20 minutes to remove bubbles, thus obtaining the precursor.

[0047] e) Coat the precursor onto any of the glass substrates used in step d) (coating amount: 1.2 mL / cm²). 2 Then, another glass substrate is pressed onto the precursor, so that the precursor is evenly spread between the two glass substrates to obtain a laminate. If the amount of the above-mentioned precursor coating is excessive, the excess precursor will be squeezed out during pressing. The excess precursor will be wiped off. To ensure the consistency of subsequent experimental tests, the pressing thickness is controlled so that the final glass flake reinforced laminated glass size is 22 × 22 × 1 mm.

[0048] f) Place the laminate obtained in step e) under an ultraviolet light source with a wavelength of 365 nm and an irradiance of 20 mW / cm². 2 Under the specified conditions, in-situ polymerization and curing were carried out for 30 min to obtain the final product. The resulting sample underwent a quasi-static puncture test. The sample was fixed on all four sides and loaded using a testing machine equipped with a hemispherical indenter (approximately 3 mm in radius). The puncture rate was 10 μm / s until the sample was penetrated, followed by SEM characterization. The synthesized high-strength, high-toughness glass flake-reinforced laminated glass exhibited dense internal interfacial bonding with no obvious pores. The polymer matrix uniformly encapsulated the glass flakes, and no large-area interfacial debonding was observed within the sample (see [reference]). Figure 1 (a) The fracture surface shows only interfacial cracking, and adhesions remain (see [reference]). Figure 1 (b) Performance tests show that the material prepared by this process can achieve a maximum puncture force of 97.3 N and a puncture energy consumption of 479.41 mJ, demonstrating excellent impact resistance (see [reference]). Figure 2 ).

[0049] Example 2: High-strength and high-toughness glass flake-reinforced flexural laminated glass beam A method for preparing high-strength, high-toughness glass flake reinforced laminated glass includes the following steps: a) Glass flakes (160 μm in diameter and 0.7 μm in thickness) were immersed in a piranha solution at 90 °C for 1 h and heated. The piranha solution was a mixture of H₂SO₄ and H₂O₂ at a volume ratio of 7:3. After washing, the flakes were rinsed with deionized water and filtered. This method not only removed the original modifying groups on the glass flakes but also enriched them with hydroxyl (-OH) active groups, providing anchoring sites for the subsequent silane grafting reaction.

[0050] b) Prepare a 1 vol% hexane solution containing methacryloxypropylmethyldichlorosilane. Immerse the glass flakes treated in step a) into the hexane solution and shake on a shaker for 1 hour. Then remove the supernatant, wash three times with anhydrous ethanol, and dry in a vacuum oven at 60°C for 2 hours to obtain glass flakes with a high density of multi-covalent binding sites on the surface. Prepare a 2 vol% ethyl acetate solution of DEAP for later use.

[0051] c) Treat the glass substrate (22 mm long, 2 mm wide, 220 μm thick) with oxygen plasma for 5 minutes, then modify it with the hexane solution containing methacryloxypropylmethyldichlorosilane prepared in step b), and then uniformly coat its surface with the ethyl acetate solution containing DEAP prepared in step b) (coating amount: 2.1 μL / cm²) using a blade coating method. 2 ), air dry at room temperature, and then process other glass substrates in the same way as step c), and set aside.

[0052] d) Add 32g of N-hydroxyethylacrylamide monomer, 2g of agarose, 1.8g of ethylene glycol, and 4.2g of water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix the polymer, resulting in a clear and transparent solution. Add the modified glass flakes prepared in step b) at 10 wt% of the total mass of the polymer prepolymer solution and stir gently to initially disperse the flakes. Then allow the solution to stand for 20 minutes to remove bubbles, thus obtaining the precursor.

[0053] e) Seal both sides of the glass substrate with a mold, place the first glass substrate in the middle, and coat the precursor onto any of the glass substrates on it (2 mL / cm²). 2 Then, another glass substrate is pressed onto the precursor and compacted. The glass is pressed together in this way according to the above steps and the precursor and initiator are applied. The resulting sample consists of 8 pieces of glass sandwiched with 7 layers of adhesive, ensuring that the final test sample is a 22×2×2mm cuboid.

[0054] f) Place the laminate obtained in step e) under an ultraviolet light source with a wavelength of 365 nm and an irradiance of 20 mW / cm². 2 Under the specified conditions, in-situ polymerization and curing for 30 min yielded the final product. The prepared sample underwent a three-point bending test with a span of 10 mm, compressed at a constant rate of 1 μm / s. The instrument recorded key data such as displacement, force, stress, and strain. Calculations showed that its modulus reached 14.7 GPa, and its flexural strength reached 166.7 MPa (see [reference]). Figure 3 ).

[0055] Comparative Example 1 a) Glass flakes (160 μm in diameter and 5 μm in thickness) were immersed in a piranha solution at 90 °C for 1 h and heated. The piranha solution was a mixture of H₂SO₄ and H₂O₂ at a volume ratio of 7:3. After washing, the flakes were rinsed with deionized water and filtered. This method not only removed the original modifying groups on the glass flakes but also enriched them with hydroxyl (-OH) active groups, providing anchoring sites for the subsequent silane grafting reaction.

[0056] b) Prepare a 1 vol% hexane solution containing methacryloxypropylmethyldichlorosilane. Immerse the glass flakes treated in step a) into the hexane solution and shake on a shaker for 1 hour. Then remove the supernatant, wash three times with anhydrous ethanol, and dry in a vacuum oven at 60°C for 2 hours to obtain glass flakes with a high density of multi-covalent binding sites on the surface. Prepare a 2 vol% ethyl acetate solution of DEAP for later use.

[0057] c) Treat the glass substrate (22 mm long, 22 mm wide, 220 μm thick) with oxygen plasma for 5 minutes, then modify it with the hexane solution containing methacryloxypropylmethyldichlorosilane prepared in step b), and then uniformly coat its surface with the ethyl acetate solution containing DEAP prepared in step b) (coating amount: 2.1 μL / cm²) using a blade coating method. 2 ), air dry at room temperature, and then process another glass substrate using the same process as step c), and set aside.

[0058] d) Add 32g of N-hydroxyethylacrylamide monomer, 2g of agarose, 1.8g of ethylene glycol, and 4.2g of water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix the polymer, resulting in a clear and transparent solution. Add the modified glass flakes prepared in step b) at 10 wt% of the total mass of the polymer prepolymer solution and stir gently to initially disperse the flakes. Then allow the solution to stand for 20 minutes to remove bubbles, thus obtaining the precursor.

[0059] e) Coat the precursor onto any of the glass substrates used in step d) (coating amount: 1.2 mL / cm²). 2 Then, another glass substrate is pressed onto the precursor, so that the precursor is evenly spread between the two glass substrates to obtain a laminate. If the amount of the above-mentioned precursor coating is excessive, the excess precursor will be squeezed out during pressing. In order to ensure the consistency of subsequent experimental tests, the pressing thickness is controlled so that the final glass flake reinforced laminate glass size is 22 × 22 × 1 mm.

[0060] f) Place the laminate obtained in step e) under an ultraviolet light source with a wavelength of 365 nm and an irradiance of 20 mW / cm². 2 Under these conditions, in-situ polymerization and curing for 30 min yielded the product. Testing showed that its puncture energy consumption was approximately 320 mJ, a decrease of nearly 50% compared to the energy consumption of the sample in Example 1 prepared from glass flakes with a diameter of 160 μm and a thickness of 0.7 μm (see [link to example 1]). Figure 4 ).

[0061] Comparative Example 2 a) Immerse glass flakes (160 μm in diameter and 0.7 μm in thickness) in a piranha solution at 90 °C and heat for 1 h. The piranha solution is a mixture of H2SO4 and H2O2 with a volume ratio of 7:3. After washing, rinse with deionized water and filter.

[0062] b) Prepare a 2 vol% ethyl acetate solution of DEAP (photoinitiator) for later use; c) Mix 2 ml of 3-(methacryloyloxy)propyltrimethoxysilane, 100 ml of anhydrous ethanol and 5 ml of deionized water evenly and sonicate for 20 min to obtain a silane coupling agent solution. Treat the glass substrate (22 mm long, 22 mm wide and 220 μm thick) with oxygen plasma for 5 min. Then immerse the glass substrate and the above glass flakes in the silane coupling agent solution for 48 h and then dry at 60 °C.

[0063] d) The glass substrates obtained in step c) are uniformly coated with the ethyl acetate solution containing DEAP prepared in step b) using a blade coating method (the coating amount is 2.1 μL / cm). 2 ), air dry at room temperature, and then process another glass substrate using the same process as steps c) and d), and set aside.

[0064] e) Add 32g N-hydroxyethylacrylamide, 2g agarose, 1.8g ethylene glycol and 4.2g water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix them until they are clear and transparent, thus obtaining a polymer prepolymer solution. Add glass flakes obtained in step c) equivalent to 10 wt% of the total mass of the polymer prepolymer solution and stir gently to initially disperse them. Then let it stand for 20 minutes to degas, thus obtaining the precursor.

[0065] f) Coat the precursor onto any of the glass substrates used in step d) (coating amount: 1.2 mL / cm²). 2 Then, another glass substrate is pressed onto the precursor, so that the precursor is evenly spread between the two glass substrates to obtain a laminate. If the amount of the above-mentioned precursor coating is excessive, the excess precursor will be squeezed out during pressing. In order to ensure the consistency of subsequent experimental tests, the pressing thickness is controlled so that the final glass flake reinforced laminate glass size is 22 × 22 × 1 mm.

[0066] g) Place the laminate obtained in step f) under an ultraviolet light source with a wavelength of 365 nm and an illumination intensity of 20 mW / cm². 2 Under these conditions, in-situ polymerization and curing were carried out for 30 minutes to obtain the final product. The puncture force of the sample in Comparative Example 2 was 77.5 N, and the puncture energy consumption was 363.25 mJ, which was significantly lower than that in Example 1 (see [link to example 1]). Figure 5 ).

[0067] Comparative Example 3 a) Immerse glass flakes (160 μm in diameter and 0.7 μm in thickness) in a piranha solution at 90 °C and heat for 1 h. The piranha solution is a mixture of H2SO4 and H2O2 with a volume ratio of 7:3. After washing, rinse with deionized water, filter, and dry.

[0068] b) Prepare a 2 vol% ethyl acetate solution of DEAP (photoinitiator) for later use; c) Apply a uniform coating of the glass substrate with the ethyl acetate solution containing DEAP prepared in step b) using a blade coating method (the coating amount is 2.1 μL / cm²). 2 ), air dry at room temperature, and then process another glass substrate using the same process as steps c) and d), and set aside.

[0069] e) Add 32g N-hydroxyethylacrylamide, 2g agarose, 1.8g ethylene glycol and 4.2g water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix them until they are clear and transparent, thus obtaining a polymer prepolymer solution. Add glass flakes obtained in step c) equivalent to 10 wt% of the total mass of the polymer prepolymer solution and stir gently to initially disperse them. Then let it stand for 20 minutes to degas, thus obtaining the precursor.

[0070] f) Coat the precursor onto any of the glass substrates used in step d) (coating amount: 1.2 mL / cm²). 2 Then, another glass substrate is pressed onto the precursor, so that the precursor is evenly spread between the two glass substrates to obtain a laminate. If the amount of the above-mentioned precursor coating is excessive, the excess precursor will be squeezed out during pressing. In order to ensure the consistency of subsequent experimental tests, the pressing thickness is controlled so that the final glass flake reinforced laminate glass size is 22 × 22 × 1 mm.

[0071] g) Place the laminate obtained in step f) under an ultraviolet light source with a wavelength of 365 nm and an illumination intensity of 20 mW / cm². 2 Under these conditions, in-situ polymerization and curing were carried out for 30 minutes to obtain the final product. The puncture force of the sample in Comparative Example 3 was 76.9 N, and the energy consumption was 319.79 mJ, which was significantly lower than that in Example 1 (see [link to example 1]). Figure 5 ).

[0072] Comparative Example 4 a) Glass flakes (160 μm in diameter and 0.7 μm in thickness) were immersed in a piranha solution at 90 °C for 1 h and heated. The piranha solution was a mixture of H₂SO₄ and H₂O₂ at a volume ratio of 7:3. After washing, the flakes were rinsed with deionized water and filtered. This method not only removed the original modifying groups on the glass flakes but also enriched them with hydroxyl (-OH) active groups, providing anchoring sites for the subsequent silane grafting reaction.

[0073] b) Prepare a 1 vol% hexane solution containing methacryloxypropylmethyldichlorosilane. Immerse the glass flakes treated in step a) into the hexane solution and shake on a shaker for 1 hour. Then remove the supernatant, wash three times with anhydrous ethanol, and dry in a vacuum oven at 60°C for 2 hours to obtain glass flakes with a high density of multi-covalent binding sites on the surface. Prepare a 2 vol% ethyl acetate solution of DEAP for later use.

[0074] c) Treat the glass substrate (22 mm long, 22 mm wide, 220 μm thick) with oxygen plasma for 5 minutes, then modify it with the hexane solution containing methacryloxypropylmethyldichlorosilane prepared in step b), and then uniformly coat its surface with the ethyl acetate solution containing DEAP prepared in step b) (coating amount: 2.1 μL / cm²) using a blade coating method. 2 ), air dry at room temperature, and then process another glass substrate using the same process as step c), and set aside.

[0075] d) Add 32g of N-hydroxyethylacrylamide monomer, 2g of agarose, 1.8g of ethylene glycol, and 4.2g of water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix the polymer, resulting in a clear and transparent solution. Add the modified glass flakes prepared in step b) at 20 wt% of the total mass of the polymer prepolymer solution and stir gently to initially disperse the flakes. Then allow the solution to stand for 20 minutes to remove bubbles, thus obtaining the precursor.

[0076] e) Coat the precursor onto any of the glass substrates used in step d) (coating amount: 1.2 mL / cm²). 2 Then, another glass substrate is pressed onto the precursor, so that the precursor is evenly spread between the two glass substrates to obtain a laminate. If the amount of the above-mentioned precursor coating is excessive, the excess precursor will be squeezed out during pressing. In order to ensure the consistency of subsequent experimental tests, the pressing thickness is controlled so that the final glass flake reinforced laminate glass size is 22 × 22 × 1 mm.

[0077] f) Place the laminate obtained in step e) under an ultraviolet light source with a wavelength of 365 nm and an irradiance of 20 mW / cm². 2 Under these conditions, in-situ polymerization and curing for 30 minutes yielded the final product. Testing showed that its puncture force was only 28 N, with an energy consumption of approximately 144 mJ. This indicates that introducing excessive glass flakes makes the system brittle and fragile, negatively impacting the impact resistance of the composite material (see [link to product description]). Figure 6 ).

[0078] Comparative Example 5 a) Glass flakes (160 μm in diameter and 0.7 μm in thickness) were immersed in a piranha solution at 90 °C for 1 h and heated. The piranha solution was a mixture of H₂SO₄ and H₂O₂ at a volume ratio of 7:3. After washing, the flakes were rinsed with deionized water and filtered. This method not only removed the original modifying groups on the glass flakes but also enriched them with hydroxyl (-OH) active groups, providing anchoring sites for the subsequent silane grafting reaction.

[0079] b) Prepare a 1 vol% hexane solution containing methacryloxypropylmethyldichlorosilane. Immerse the glass flakes treated in step a) into the hexane solution and shake on a shaker for 1 hour. Then remove the supernatant, wash three times with anhydrous ethanol, and dry in a vacuum oven at 60°C for 2 hours to obtain glass flakes with a high density of multi-covalent binding sites on the surface. Prepare a 2 vol% ethyl acetate solution of DEAP for later use.

[0080] c) Treat the glass substrate (22 mm long, 22 mm wide, 220 μm thick) with oxygen plasma for 5 minutes, then modify it with the hexane solution containing methacryloxypropylmethyldichlorosilane prepared in step b), and then uniformly coat its surface with the ethyl acetate solution containing DEAP prepared in step b) (coating amount: 2.1 μL / cm²) using a blade coating method. 2 ), air dry at room temperature, and then process another glass substrate using the same process as step c), and set aside.

[0081] d) Add 32g of N-hydroxyethylacrylamide monomer, 2g of agarose, 1.8g of ethylene glycol and 4.2g of water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix the polymer, resulting in a clear and transparent solution. Add the modified glass flakes prepared in step b) at 5wt% of the total mass of the polymer prepolymer solution and stir gently to initially disperse them. Then let it stand for 20 minutes to remove bubbles and obtain the precursor.

[0082] e) Coat the precursor onto any of the glass substrates used in step d) (coating amount: 1.2 mL / cm²). 2 Then, another glass substrate is pressed onto the precursor, so that the precursor is evenly spread between the two glass substrates to obtain a laminate. If the amount of the above-mentioned precursor coating is excessive, the excess precursor will be squeezed out during pressing. In order to ensure the consistency of subsequent experimental tests, the pressing thickness is controlled so that the final glass flake reinforced laminate glass size is 22 × 22 × 1 mm.

[0083] f) Place the laminate obtained in step e) under an ultraviolet light source with a wavelength of 365 nm and an irradiance of 20 mW / cm². 2Under these conditions, in-situ polymerization and curing for 30 minutes yields the final product. Testing showed its puncture resistance to be 78.4 N and its energy consumption to be approximately 363 mJ. This indicates that a small number of glass flakes has a limited impact on improving the overall impact resistance of the material (see [link to product description]). Figure 6 ).

[0084] Comparative Example 6 a) Glass flakes (160 μm in diameter and 0.7 μm in thickness) were immersed in a piranha solution at 90 °C for 1 h and heated. The piranha solution was a mixture of H₂SO₄ and H₂O₂ at a volume ratio of 7:3. After washing, the flakes were rinsed with deionized water and filtered. This method not only removed the original modifying groups on the glass flakes but also enriched them with hydroxyl (-OH) active groups, providing anchoring sites for the subsequent silane grafting reaction.

[0085] b) Prepare a 0.1 vol% hexane solution containing methacryloyloxypropylmethyldichlorosilane. Immerse the glass flakes treated in step a) into the hexane solution and shake on a shaker for 1 hour. Then remove the supernatant, wash three times with anhydrous ethanol, and dry in a vacuum oven at 60°C for 2 hours to obtain glass flakes with a high density of multi-covalent binding sites on the surface. Prepare a 2 vol% ethyl acetate solution of DEAP for later use.

[0086] c) Treat the glass substrate (22 mm long, 22 mm wide, 220 μm thick) with oxygen plasma for 5 minutes, then modify it with the hexane solution containing methacryloxypropylmethyldichlorosilane prepared in step b), and then uniformly coat its surface with the ethyl acetate solution containing DEAP prepared in step b) (coating amount: 2.1 μL / cm²) using a blade coating method. 2 ), air dry at room temperature, and then process another glass substrate using the same process as step c), and set aside.

[0087] d) Add 32g of N-hydroxyethylacrylamide monomer, 2g of agarose, 1.8g of ethylene glycol, and 4.2g of water to a flask and mechanically stir at 95 °C for 30 min to fully dissolve and mix the polymer, resulting in a clear and transparent solution. Add the modified glass flakes prepared in step b) at 10wt% of the total mass of the polymer prepolymer solution and gently stir to initially disperse the flakes. Then allow the solution to stand for 20 minutes to remove bubbles, thus obtaining the precursor.

[0088] e) Coat the precursor onto any of the glass substrates used in step d) (coating amount: 1.2 mL / cm²). 2Then, another glass substrate is pressed onto the precursor, so that the precursor is evenly spread between the two glass substrates to obtain a laminate. If the amount of the above-mentioned precursor coating is excessive, the excess precursor will be squeezed out during pressing. In order to ensure the consistency of subsequent experimental tests, the pressing thickness is controlled so that the final glass flake reinforced laminate glass size is 22 × 22 × 1 mm.

[0089] f) Place the laminate obtained in step e) under an ultraviolet light source with a wavelength of 365 nm and an irradiance of 20 mW / cm². 2 Under these conditions, in-situ polymerization and curing for 30 min yielded the product. Testing showed a maximum puncture force of 53.6 N and a puncture energy consumption of approximately 346 mJ, indicating that a low modification concentration is not conducive to creating more covalently bonded active sites, thus limiting the performance improvement (see [link to product description]). Figure 7 ).

[0090] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is impossible to exhaustively list all the implementation methods here. All obvious variations or modifications derived from the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A method for preparing glass flake reinforced composite materials based on interfacial covalent bonding, characterized in that, Includes the following steps: S1. Glass flakes are immersed in a silane coupling agent solution containing methacryloxypropylmethyldichlorosilane to obtain glass flakes with high density of multiple covalent binding sites on the surface. S2. Add the glass flakes obtained in step S1 to the polymer prepolymer liquid and mix them evenly to obtain the precursor. S3. A silane coupling agent solution and an initiator solution are sequentially coated on the substrate surface, and then a precursor is coated on it. Another substrate, which is sequentially coated with a silane coupling agent solution and an initiator solution, is then pressed onto the precursor, so that the precursor is evenly spread between the two substrates, initiating an in-situ polymerization reaction to obtain a glass flake reinforced composite material.

2. The preparation method according to claim 1, characterized in that, The concentration of methacryloxypropylmethyldichlorosilane in the silane coupling agent solution is 1-10 vol%. The solvent of the silane coupling agent solution is selected from one or more of toluene, xylene, n-hexane, and cyclohexane.

3. The preparation method according to claim 1, characterized in that, The glass flakes have a diameter of 140-180 μm and a thickness of 0.5-1.0 μm.

4. The preparation method according to claim 1, characterized in that, The initiator is selected from one or more of DEAP, Irgacure 1173, Irgacure 184, Irgacure 819, TPO, tert-butyl peroxide, and tert-butyl peroxide. The initiator solution has a volume concentration of 2-4 vol%. The initiator solution is coated at a concentration of 2-4 μL / cm² on the substrate surface. 2 .

5. The preparation method according to claim 1, characterized in that, The polymer prepolymer liquid was prepared according to the following steps: The product is obtained by mixing monomers containing active groups, natural polymers with thermally reversible gel properties, toughening modifiers, and solvents in a certain proportion and heating to dissolve them. In the raw materials forming the polymer prepolymer liquid, monomers account for 50-90 wt%, natural polymers account for 1-10 wt%, toughening regulators account for 1-10 wt%, and the remainder is solvent.

6. The preparation method according to claim 5, characterized in that, The monomer is selected from one or more of acrylamide, N-hydroxyethylacrylamide, and N,N-dimethylacrylamide; The natural polymer is selected from one or more of gelatin, agarose, carrageenan, chitosan, and sodium alginate; The toughening modifier is selected from one or more of ethylene glycol, propylene glycol, glycerin, and polyethylene glycol; The solvent is water.

7. The preparation method according to claim 5, characterized in that, The mass ratio of the glass flakes with high-density multi-covalent bonding sites to the polymer prepolymer liquid is 0.075-0.125:1; The amount of the precursor coated on the substrate surface is 0.8-1.5 mL / cm². 2 .

8. The preparation method according to claim 1, characterized in that, Initiation of in-situ polymerization reactions can be achieved through thermal initiation or ultraviolet light initiation; The thermal initiation conditions are as follows: the thermal initiation temperature is 80-100℃, and the in-situ polymerization reaction time is 150-300 min. The conditions for ultraviolet light initiation are: ultraviolet light irradiation wavelength of 250-400 nm and light intensity of 10-200 mW / cm². 2 The in-situ polymerization reaction takes 30-60 minutes.

9. A glass flake reinforced composite material based on interfacial covalent bonding, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the glass flake reinforced composite material as described in claim 9 in the preparation of load-bearing structural components, wind turbine blades, automobile body parts, aerospace interior panels, and sports and leisure equipment.

Images