Polymer grafted surface-pruned mesoporous silica nanocomposite particles, preparation method and application thereof

Abstract

The present application relates to the technical field of polymer material reinforcing and toughening, and particularly discloses a kind of polymer grafted surface protruding mesoporous silica nano composite particles and its preparation method and application.The specific characteristics of the nano composite particles are as follows: the inner core is a surface protruding silica nanoparticle with a central divergent mesoporous structure; the outer layer is a polymer grafted on the surface of the inorganic inner core; it uses surface protruding mesoporous silica nanoparticles, amino silane coupling agent, polymerization initiator and polymerization monomer as raw materials, and the inorganic inner core particle size and the outer layer polymer graft length can be controlled during the synthesis process. As a polymer filler, the nano composite particle with this structure has similar light transmission performance to pure polymer, and its mechanical performance is better than that of pure inorganic nanoparticles; compared with traditional nanoparticles grafted with polymers, it comprehensively improves the light transmission, rigidity and toughness. The nano composite particle can effectively toughen the high-transparency polymer matrix while maintaining its excellent light transmission.

Description

Technical Field

[0001] This invention relates to the field of polymer material reinforcement and toughening technology, and in particular to a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, its preparation method, and its application. Background Technology

[0002] Polymer materials used in windshields, displays, lenses, and other applications typically require high strength, high toughness, and high light transmittance simultaneously. Therefore, the relevant polymer matrix usually needs to be modified with toughening additives to improve its strength, toughness, and other mechanical properties while ensuring that the light transmittance meets the usage requirements, thus achieving the required standards.

[0003] To achieve a balance between strength and light transmittance in modified high-transmittance thermoplastic polymer matrices, small-molecule or high-molecular-weight additives are commonly used. Reactive toughening additives can construct chemical cross-linking networks, connecting the polymer matrix through covalent bonds. These networks restrict the relative slippage of molecular chains to improve rigidity and modulus, and dissipate energy through chain segment movement and uniform stress distribution at cross-linking points, thus achieving toughening. However, the formation of these networks transforms linear thermoplastics into three-dimensional thermosets, leading to decreased melt flowability and making secondary molding using traditional thermoplastic processing methods impossible. In contrast, non-reactive toughening additives can enhance toughness through intermolecular interactions; however, these interactions are relatively weak, limiting their improvement in mechanical properties. Therefore, designing non-reactive toughening additives to further improve the mechanical properties of polymer matrices remains crucial.

[0004] Inorganic nanoparticles are commonly used reinforcing agents in polymer matrices, acting as non-reactive toughening additives to effectively improve the rigidity, strength, and modulus of the polymer matrix. However, due to the weak interfacial bonding between inorganic nanoparticles and the polymer matrix, they are prone to debonding under external forces, limiting their effectiveness in improving the toughness of the polymer matrix. Furthermore, inorganic nanoparticles used in high-transmittance materials can aggregate in the polymer matrix, forming light-scattering centers and significantly reducing the light transmittance of these materials. Constructing composite structures using polymer-derived inorganic nanoparticles can effectively improve the dispersibility of the nanoparticles and, to some extent, improve their interfacial bonding strength, thus enhancing the strength and toughness of the material. However, the light transmittance problem of composite nanoparticles remains unresolved. Therefore, constructing nanoparticle composite structures that simultaneously achieve polymer matrix strengthening and toughening while maintaining high light transmittance remains a significant challenge. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, its preparation method, and its application. When this polymer-grafted surface-spiked mesoporous silica nanocomposite particle is introduced into a compatible polymer matrix as a non-reactive toughening additive, it solves three major problems: nanoparticle agglomeration, interfacial debinding, and light scattering. It can achieve both toughness and high light transmittance, providing a new path for the toughening of high-transmittance polymer materials.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a method for preparing polymer-grafted surface-spiked mesoporous silica nanocomposite particles, comprising the following steps: amino-functionalizing spiked-mesoporous silica nanospheres to obtain amino-functionalized spiked-mesoporous silica nanospheres; and grafting polymers onto the surface of the amino-functionalized spiked-mesoporous silica nanospheres to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles.

[0007] This invention involves grafting polymers onto the surface of mesoporous silica nanospheres with a spiked structure. The resulting nanocomposite particles, when used to reinforce and toughen high-transmittance polymer matrices, exhibit several advantages: the mesoporous silica, due to its porous structure, has less impact on light scattering compared to solid nanoparticles, allowing it to more closely match the refractive index of the high-transmittance polymer matrix and reducing light scattering; the spiked structure helps control the particle size within a smaller range, further reducing light scattering and maintaining the high transmittance of the polymer matrix; and the grafted polymer inhibits particle aggregation through steric hindrance, significantly improving its dispersibility within the polymer matrix. More importantly, the surface spiked structure can form interfacial topological entanglements with the grafted polymer and the high-transmittance polymer matrix. When the material is subjected to stress, the molecular chains, constrained by the topological entanglement, can slide in multiple directions and reversibly along the surface of the nanocomposite particles, thereby efficiently dissipating energy and achieving toughening. Simultaneously, the grafted polymers, interwoven within the polymer matrix network, enhance the interfacial interaction between the nanocomposite particles and the polymer matrix. This allows stress to be transferred from local interchain interactions to the entire three-dimensional network, promoting energy dissipation across multiple scales and further improving the material's strength and toughness. Therefore, these polymer-grafted, surface-spiked mesoporous silica nanocomposite particles can effectively strengthen and toughen a high-transmittance polymer matrix while maintaining its excellent light transmittance.

[0008] As a further improvement to the above-described scheme of the present invention, the method of amino-functionalization is as follows: Spiked-mesoporous silica nanospheres are dispersed in solvent A, an aminosilane coupling agent is added, and the reaction is carried out under heating in an oxygen-free and anhydrous environment. The nanospheres are then separated and washed to obtain amino-functionalized spiked-mesoporous silica nanospheres. In the amino-functionalization step, the reaction is carried out in an air-free and anhydrous environment to suppress the hydrolysis and side reactions of the aminosilane coupling agent.

[0009] As a further improvement of the above-mentioned scheme of the present invention, the spiked-mesoporous silica nanospheres have a particle size of 50~100nm, and their surface has spike structures with a height of 3~5nm. Their mesoporous channels have a centrally divergent structure and open surfaces with a pore size of 6~8nm. The mass ratio of the spiked-mesoporous silica nanospheres to the aminosilane coupling agent is 1:1~2. The solvent A is at least one of anhydrous toluene, anhydrous ethanol, anhydrous cyclohexane, anhydrous n-hexane, and acetone. The heating reaction temperature is 40~130℃ and the time is 12~48 h.

[0010] As a further improvement to the above-mentioned scheme of the present invention, the method of grafting polymer is as follows: dispersing the amino-functionalized spiked mesoporous silica nanospheres, monomer A, and catalyst A in solvent B, heating and reacting, separating, washing, and drying to obtain polymer-grafted surface spiked mesoporous silica nanocomposite particles.

[0011] As a further improvement to the above-described scheme of the present invention, the monomer A is ε-caprolactone and the polymer is polycaprolactone, or the monomer A is lactide and the polymer is polylactic acid; And / or, the mass ratio of the amino-functionalized spiked mesoporous silica nanospheres, monomer A, and catalyst A is 0.1~0.5:1~5:0.0025~0.0125; And / or, the catalyst A is stannous octoate; the temperature of the heating reaction is 100~130℃; and the solvent B is anhydrous toluene.

[0012] As a further improvement to the above-mentioned scheme of the present invention, the method of grafting polymer is as follows: the amino-functionalized spiked-mesoporous silica nanospheres and the acid-binding agent are dispersed in solvent C under an oxygen-free and anhydrous environment, an ATRP initiator is added for reaction, separation, washing, and drying are performed to obtain spiked-mesoporous silica nanospheres with ATRP initiator solidified on the surface; under an oxygen-free environment, the spiked-mesoporous silica nanospheres with ATRP initiator solidified on the surface, catalyst B, ligand, and monomer B are dispersed in solvent D and heated for reaction, separation, washing, and drying are performed to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles.

[0013] As a further improvement to the above-described scheme of the present invention, the monomer B is methyl methacrylate and the polymer is polymethyl methacrylate; or, the monomer B is styrene and the polymer is polystyrene; or, the monomer B is N-isopropylacrylamide and the polymer is poly(N-isopropylacrylamide). And / or, the mass ratio of the amino-functionalized spiked mesoporous silica nanospheres, acid-binding agent, and ATRP initiator is 0.25~1:1.45~5.8:0.85~3.4; the mass ratio of the spiked mesoporous silica nanospheres with ATRP initiator cured on the surface, catalyst B, ligand, and monomer B is 0.10~0.20:0.01~0.03:0.02~0.04:0.5~1; And / or, the acid-binding agent is triethylamine; the solvent C is anhydrous dichloromethane; the ATRP initiator is 2-bromoisobutyryl bromide, and the reaction is carried out at room temperature after the addition of the ATRP initiator; the catalyst B is cuprous bromide or cuprous chloride; the ligand is at least one of N,N,N',N'',N''-pentamethyldiethylenetriamine, 2,2-bipyridine, 1,1,4,7,10,10-hexamethyltriethylenetetramine, and tris(2-dimethylaminoethyl)amine; the solvent D is at least one of anhydrous toluene, anhydrous N,N-dimethylformamide, anhydrous tetrahydrofuran, and isopropanol; the heating reaction temperature is 25~120℃ and the time is 12~48h.

[0014] As a further improvement to the above-described solution of the present invention, the preparation method of the spiked-mesoporous silica nanospheres includes the following steps: S1. The template agent and catalyst C are added to deionized water as the aqueous phase, and the silicon source is added to solvent E as the oil phase. The aqueous phase and oil phase undergo a two-phase reaction under stirring. The product obtained from the reaction is separated and dried to obtain mesoporous silica nanospheres. S2. Disperse mesoporous silica nanospheres in solvent F, then add catalyst D and structure protectant. Afterwards, adjust the pH to 8-11 using a buffer solution before the reaction. The product obtained from the reaction is centrifuged, washed, and dried to obtain spiked-mesoporous silica nanospheres.

[0015] The present invention also provides a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which is prepared by the preparation method described above.

[0016] The present invention also provides the application of polymer-grafted surface-spiked mesoporous silica nanocomposite particles prepared by the preparation method described above as a non-reactive toughening additive in resins or elastomers compatible with the polymer.

[0017] As a further improvement to the above-mentioned solution of the present invention, the application method is as follows: the polymer grafted surface protruding mesoporous silica nanocomposite particles are physically blended with the resin or elastomer, wherein the physical blending is performed by extrusion, injection molding, mixing, compression molding or casting.

[0018] Compared with the prior art, the present invention has the following beneficial effects: This invention involves grafting polymers onto the surface of mesoporous silica nanospheres with a spiked structure. The resulting nanocomposite particles, when used to reinforce and toughen high-transmittance polymer matrices, exhibit several advantages: the mesoporous silica, due to its porous structure, has less impact on light scattering compared to solid nanoparticles, allowing it to more closely match the refractive index of the high-transmittance polymer matrix and reducing light scattering; the spiked structure helps control the particle size within a smaller range, further reducing light scattering and maintaining the high transmittance of the polymer matrix; and the grafted polymer inhibits particle aggregation through steric hindrance, significantly improving its dispersibility within the polymer matrix. More importantly, the surface spiked structure can form interfacial topological entanglements with the grafted polymer and the high-transmittance polymer matrix. When the material is subjected to stress, the molecular chains, constrained by the topological entanglement, can slide in multiple directions and reversibly along the surface of the nanocomposite particles, thereby efficiently dissipating energy and achieving toughening. Simultaneously, the grafted polymers, interwoven within the polymer matrix network, enhance the interfacial interaction between the nanocomposite particles and the polymer matrix. This allows stress to be transferred from local interchain interactions to the entire three-dimensional network, promoting energy dissipation across multiple scales and further improving the material's strength and toughness. Therefore, these polymer-grafted, surface-spiked mesoporous silica nanocomposite particles can effectively strengthen and toughen a high-transmittance polymer matrix while maintaining its excellent light transmittance.

[0019] Unlike existing technologies where toughening modification often results in a significant decrease in light transmittance, this invention, through the synergistic design of a spiked structure and grafted polymers, produces polymer-grafted surface-spiked mesoporous silica nanocomposite particles. This solves three major problems: nanoparticle aggregation, interfacial debinding, and light scattering, achieving a balance between strength, toughness, and high light transmittance. When used as a non-reactive toughening additive in PVB materials, it achieves a maximum tensile strength of 32.3 MPa, a maximum tensile strain at break of 521%, and a maximum light transmittance of 92.2%, far exceeding international standards (GB / T32020—2015: tensile strength ≥20.0 MPa, tensile strain at break ≥200%, light transmittance ≥85%). This provides a new path for the toughening of high-transmittance polymer materials and has broad application prospects in windshields, displays, lenses, and other fields. Attached Figure Description

[0020] Figure 1 The infrared spectrum of SMSNs-g-PCL1 obtained in Example 1; Figure 2 The particle size distribution diagram of SMSNs-g-PCL1 prepared in Example 1 is shown. Figure 3 The image shows the tensile test results for resin sample 1. Figure 4 The figure shows the tensile test results of resin sample 6; Figure 5 The figure shows the tensile test results of resin sample 7; Figure 6 The figure shows the tensile test results of resin sample 8; Figure 7 The figure shows the tensile test results of resin sample 9; Figure 8 The image shows the transmittance test results for resin sample 1. Figure 9 The graph shows the light transmittance test results of commercially available plasticized PVB resin. Figure 10 The image shows the transmittance test results for resin sample 10. Figure 11 The image shows the transmittance test results for resin sample 11. Figure 12 The image shows the transmittance test results for resin sample 17. Figure 13 The graph shows the transmittance test results of waterborne polyurethane resin. Figure 14 The image shows the transmittance test results for resin sample 22. Figure 15 The image shows the transmittance test results for resin sample 23. Detailed Implementation

[0021] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] Example 1 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, the preparation method of which includes the following steps: S1. Preparation of spiked-mesoporous silica nanospheres In this embodiment, the spiked-mesoporous silica nanospheres are prepared using existing methods. Refer to Example 1 of patent publication CN120865617B for the preparation steps of the spiked-mesoporous silica nanospheres, specifically: The template agent and catalyst C were added to deionized water and mixed to form the aqueous phase. The template agent was a combination of hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride. The HLB value of the mixture of hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride was 12, and the mass fraction of the template agent in the aqueous phase was 45%. The catalyst C was a mixture of 2-methylaminoethanol and triethanolamine. The pKa of the mixture was 8.5, and the mass fraction of the catalyst C in the aqueous phase was 2%.

[0024] The silicon source was added to solvent E as the oil phase. The silicon source was a combination of tetraethyl orthosilicate and tetramethyl orthosilicate in a mass ratio of 5:2. Solvent E was a mixture of toluene and cyclohexane in a volume ratio of 1:1. The mass fraction of the silicon source in the oil phase was 10%.

[0025] The oil phase and water phase were mixed at a mass ratio of 0.25:1 and then subjected to a two-phase reaction by magnetic stirring at 400 rpm. The reaction was carried out at 80°C for 3 days. After the reaction was completed, the product was separated and spray-dried to obtain mesoporous silica nanospheres with low cross-linking degree, smooth surface and open central divergent surface.

[0026] Solvent F and mesoporous silica nanospheres were added to a hydrothermal reactor at a mass ratio of 350:1. The mixture was stirred to disperse the mesoporous silica nanospheres in solvent F, which was a 1:1 volume mixture of tetrahydrofuran and deionized water. Then, 4-dimethylaminopyridine and hexadecyltrimethylammonium bromide were added to the hydrothermal reactor. The mass ratio of 4-dimethylaminopyridine to mesoporous silica nanospheres was 0.8:1, and the mass ratio of hexadecyltrimethylammonium bromide to mesoporous silica nanospheres was 0.5:1. The pH of the solution in the hydrothermal reactor was adjusted to 10.0 using a sodium carbonate-sodium bicarbonate buffer solution. The reactor was then reacted at 60°C for 3 days. After the reaction, the product was centrifuged, washed, and spray-dried to obtain spiked-mesoporous silica nanospheres with open mesoporous channels radiating from the center and rigid nanospikes uniformly distributed on the outer surface. These nanospheres were denoted as SMSNs and had an average particle size of 80 nm.

[0027] S2. Preparation of amino-functionalized spiked-mesoporous silica nanospheres The SMSNs obtained in step S1 were dispersed in anhydrous toluene and sonicated for 30 min. 3-Aminopropyltriethoxysilane was then added, and the mixture was refluxed at 110 °C for 24 h under nitrogen protection, with a mass ratio of SMSNs to 3-aminopropyltriethoxysilane of 1:2. After the reaction, the mixture was centrifuged and washed with dichloromethane to obtain amino-functionalized spiked mesoporous silica nanospheres, denoted as SMSNs-NH2.

[0028] S3. Preparation of polymer-grafted surface-spiked mesoporous silica nanocomposite particles The SMSNs-NH2 obtained in step S2 was dispersed in anhydrous toluene and added to a flask. The flask was then evacuated and backfilled with nitrogen three times. Under a nitrogen atmosphere, a toluene solution of ε-caprolactone and stannous octoate (concentration of 0.1 g / mL) was injected. The mixture was stirred in an oil bath at 110 °C for 24 h, with the mass ratio of SMSNs-NH2, ε-caprolactone, and stannous octoate being 0.2:2:0.005. After the reaction was complete, the mixture was cooled to room temperature and centrifuged. The resulting solid was washed three times sequentially with tetrahydrofuran and dichloromethane. Finally, the product was dried in a vacuum oven at 40 °C for 24 h to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles with an average particle size of 332 nm, denoted as SMSNs-g-PCL1.

[0029] Figure 1 The infrared spectrum of the SMSNs-g-PCL1 prepared in this embodiment shows that the characteristic absorption peak of polycaprolactone (PCL) (such as 1730 cm⁻¹) appears in the infrared spectrum. -1 carbonyl peak at 2900 cm⁻¹ -1 The presence of methylene peaks at the surface of the PCL, while retaining characteristic peaks of SMSNs, indicates that PCL has been successfully grafted onto the surface of SMSNs.

[0030] The particle size of the SMSNs-g-PCL1 prepared in this embodiment was tested, and the results were obtained. Figure 2 The particle size distribution diagram shown indicates that the average particle size of the DLS in the SMSNs-g-PCL1 of this embodiment is approximately 332 nm.

[0031] Example 2 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Embodiment 1 in that: in step S1 of this embodiment, the oil phase and the water phase are magnetically stirred at a speed of 500 rpm to carry out a two-phase reaction, and finally, spiked-mesoporous silica nanospheres with an average particle size of 50 nm are obtained; the polymer-grafted surface-spiked mesoporous silica nanocomposite particle obtained in this embodiment is denoted as SMSNs-g-PCL2.

[0032] Example 3 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Embodiment 1 in that: in step S1 of this embodiment, the oil phase and the water phase are magnetically stirred at a speed of 300 rpm to carry out a two-phase reaction, and finally, spiked-mesoporous silica nanospheres with an average particle size of 100 nm are obtained; the polymer-grafted surface-spiked mesoporous silica nanocomposite particle obtained in this embodiment is denoted as SMSNs-g-PCL3.

[0033] Example 4 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Example 1 in that: in step S3 of this embodiment, the reaction is carried out in an oil bath at 110°C for 12 h with stirring to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles with an average particle size of 249 nm, denoted as SMSNs-g-PCL4.

[0034] Example 5 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Example 1 in that: in step S3 of this embodiment, the reaction is carried out in an oil bath at 110°C for 48 h with stirring to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles with an average particle size of 535 nm, denoted as SMSNs-g-PCL5.

[0035] Example 6 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Embodiment 1 in that step S3 in this embodiment specifically involves: The SMSNs-NH2 obtained in step S2 was dispersed in anhydrous toluene and added to a flask. The flask was then evacuated and backfilled with nitrogen three times. Under a nitrogen atmosphere, a toluene solution of lactide and stannous octoate (concentration of stannous octoate toluene solution was 0.1 g / mL) was injected, and the mixture was stirred in an oil bath at 110 °C for 24 h. The mass ratio of SMSNs-NH2, lactide, and stannous octoate was 0.2:2.53:0.005. After the reaction was complete, the mixture was cooled to room temperature, centrifuged, and the resulting solid product was dissolved in dichloromethane and then added dropwise to methanol to precipitate. The precipitate was collected by centrifugation and washed three times with ethanol. Finally, it was dried in a vacuum oven at 40 °C for 24 h to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles with an average particle size of 327 nm, denoted as SMSNs-g-PLA.

[0036] Example 7 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Embodiment 1 in that step S3 in this embodiment specifically involves: The SMSNs-NH2 obtained in step S2 was dispersed in anhydrous dichloromethane, and triethylamine was added. Under an ice-water bath cooling (0°C) and nitrogen atmosphere, 2-bromoisobutyryl bromide (ATRP initiator) was slowly added dropwise. After the addition was complete, the reaction was carried out at room temperature for 24 h. The mass ratio of SMSNs-NH2, triethylamine, and 2-bromoisobutyryl bromide was 0.5:2.9:1.7. After the reaction was completed, the solid was collected by centrifugation, thoroughly washed with anhydrous dichloromethane, and vacuum dried to obtain spiked mesoporous silica nanospheres with ATRP initiator solidified on the surface, denoted as Br-SMSNs. The prepared Br-SMSNs, cuprous bromide, and N,N,N',N'',N''-pentamethyldiethylenetriamine were added to a single-necked flask and subjected to three freeze-vacuum-thaw cycles to ensure thorough deoxygenation. Under nitrogen protection, anhydrous toluene was injected, followed by methyl methacrylate. The mixture was stirred in an oil bath at 70°C for 24 h. The mass ratio of Br-SMSNs, cuprous bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, and methyl methacrylate was 0.15:0.021:0.0365:0.75. After the reaction, the solid product was separated by centrifugation and washed five times with tetrahydrofuran. Finally, it was vacuum dried at 40°C for 24 h to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles with an average particle size of 335 nm, denoted as SMSNs-g-PMMA.

[0037] Example 8 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Embodiment 1 in that step S3 in this embodiment specifically involves: The SMSNs-NH2 obtained in step S2 was dispersed in anhydrous dichloromethane, and triethylamine was added. Under an ice-water bath cooling (0°C) and nitrogen atmosphere, 2-bromoisobutyryl bromide (ATRP initiator) was slowly added dropwise. After the addition was complete, the reaction was carried out at room temperature for 24 h. The mass ratio of SMSNs-NH2, triethylamine, and 2-bromoisobutyryl bromide was 0.5:2.9:1.7. After the reaction was completed, the solid was collected by centrifugation, washed thoroughly with tetrahydrofuran, and dried under vacuum to obtain spiked mesoporous silica nanospheres with ATRP initiator solidified on the surface, denoted as Br-SMSNs. The prepared Br-SMSNs, cuprous bromide, and N,N,N',N'',N''-pentamethyldiethylenetriamine were added to a single-necked flask and subjected to three freeze-vacuum-thaw cycles to ensure thorough deoxygenation. Under nitrogen protection, anhydrous toluene was injected, followed by styrene, and the mixture was stirred in an oil bath at 110°C for 24 h. The mass ratio of Br-SMSNs, cuprous bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, and styrene was 0.15:0.021:0.0365:0.75. After the reaction, the solid product was separated by centrifugation and washed three times each with tetrahydrofuran and chloroform. Finally, the solid product was dried in a vacuum oven at 40°C for 24 h to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles with an average particle size of 329 nm, denoted as SMSNs-g-PS.

[0038] Example 9 This embodiment proposes a polymer-grafted surface-spiked mesoporous silica nanocomposite particle, which differs from Embodiment 1 in that step S3 in this embodiment specifically involves: The SMSNs-NH2 obtained in step S2 was dispersed in anhydrous dichloromethane, and triethylamine was added. Under an ice-water bath cooling (0°C) and nitrogen atmosphere, 2-bromoisobutyryl bromide (ATRP initiator) was slowly added dropwise. After the addition was complete, the reaction was carried out at room temperature for 24 h. The mass ratio of SMSNs-NH2, triethylamine, and 2-bromoisobutyryl bromide was 0.5:2.9:1.7. After the reaction was completed, the solid was collected by centrifugation, washed thoroughly with tetrahydrofuran, and dried under vacuum to obtain spiked mesoporous silica nanospheres with ATRP initiator solidified on the surface, denoted as Br-SMSNs. The prepared Br-SMSNs, cuprous bromide, and N,N,N',N'',N''-pentamethyldiethylenetriamine were added to a single-necked flask and subjected to three freeze-vacuum-thaw cycles to ensure thorough deoxygenation. Under nitrogen protection, isopropanol and water were injected, followed by N-isopropylacrylamide. The mixture was stirred at room temperature for 24 h. The mass ratio of Br-SMSNs, cuprous bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, and N-isopropylacrylamide was 0.15:0.021:0.0365:0.75. After the reaction, the solid product was separated by centrifugation and washed three times each with deionized water and ethanol at 0 °C. Finally, the solid product was freeze-dried for 24 h to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles with an average particle size of 330 nm, denoted as SMSNs-g-PNIPAM.

[0039] Comparative Example 1 This comparative example provides a spiked mesoporous silica nanosphere, denoted as SMSNs, which is prepared using the same method as step S1 in Example 1.

[0040] Comparative Example 2 This comparative example provides a mesoporous silica nanosphere, denoted as MSNs, which is prepared using the same method as step S1 of Comparative Example 1.

[0041] Comparative Example 3 S1. Preparation of mesoporous silica nanospheres The template agent and catalyst C were added to deionized water and mixed to form the aqueous phase. The template agent was a combination of hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride. The HLB value of the mixture of hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride was 12, and the mass fraction of the template agent in the aqueous phase was 45%. The catalyst C was a mixture of 2-methylaminoethanol and triethanolamine. The pKa of the mixture was 8.5, and the mass fraction of the catalyst C in the aqueous phase was 2%.

[0042] The silicon source was added to solvent E as the oil phase. The silicon source was a combination of tetraethyl orthosilicate and tetramethyl orthosilicate in a mass ratio of 5:2. Solvent E was a mixture of toluene and cyclohexane in a volume ratio of 1:1. The mass fraction of the silicon source in the oil phase was 10%.

[0043] The oil phase and the water phase were mixed at a mass ratio of 0.25:1 and then subjected to a two-phase reaction by magnetic stirring at 400 rpm. The reaction was carried out at 80°C for 3 days. After the reaction was completed, the product was separated and spray-dried to obtain mesoporous silica nanospheres with low cross-linking degree, smooth surface and open central divergent surface, denoted as MSNs.

[0044] S2. Preparation of amino-functionalized mesoporous silica nanospheres The MSNs obtained in step S1 were dispersed in anhydrous toluene and sonicated for 30 min. 3-Aminopropyltriethoxysilane was then added, and the mixture was refluxed at 110 °C for 24 h under nitrogen protection. The mass ratio of MSNs to 3-aminopropyltriethoxysilane was 1:2. After the reaction, the mixture was centrifuged and washed successively with toluene and ethanol to obtain amino-functionalized mesoporous silica nanospheres, denoted as MSNs-NH2.

[0045] S3. Preparation of polymer-grafted mesoporous silica nanoparticles The SMSNs-NH2 obtained in step S2 was dispersed in anhydrous toluene and added to a flask. The flask was then evacuated and backfilled with nitrogen three times. Under a nitrogen atmosphere, a toluene solution of caprolactone and stannous octoate (concentration of stannous octoate toluene solution was 0.1 g / mL) was injected. The mixture was stirred in an oil bath at 110 °C for 24 h. The mass ratio of MSNs-NH2, caprolactone, and stannous octoate was 0.2:2:0.005. After the reaction was complete, the mixture was cooled to room temperature and centrifuged. The resulting solid was washed three times with tetrahydrofuran and dichloromethane to thoroughly remove unreacted monomers and homopolymers. Finally, the product was dried in a vacuum oven at 40 °C for 24 h to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles, denoted as MSNs-g-PCL.

[0046] Comparative Example 4 The difference between this comparative example and Comparative Example 3 is as follows: Step S3 in this comparative example is as follows: The SMSNs-NH2 obtained in step S2 was dispersed in anhydrous toluene and added to a flask. The flask was then evacuated and backfilled with nitrogen three times. Under a nitrogen atmosphere, a toluene solution of lactide and stannous octoate (concentration of stannous octoate toluene solution was 0.1 g / mL) was injected. The mixture was stirred in an oil bath at 110 °C for 24 h. The mass ratio of MSNs-NH2, lactide, and stannous octoate was 0.2:2.53:0.005. After the reaction was complete, the mixture was cooled to room temperature. The reactants were centrifuged, and the resulting solid product was dissolved in dichloromethane and then added dropwise to methanol to precipitate. The precipitate was collected by centrifugation and washed three times with ethanol. Finally, the precipitate was dried in a vacuum oven at 40 °C for 24 h. The final product was designated MSNs-g-PLA.

[0047] Comparative Example 5 The difference between this comparative example and Comparative Example 3 is as follows: Step S3 in this comparative example is as follows: The MSNs-NH2 obtained in step S2 was dispersed in anhydrous dichloromethane, and triethylamine was added. Under an ice-water bath cooling (0°C) and nitrogen atmosphere, 2-bromoisobutyryl bromide (ATRP initiator) was slowly added dropwise. After the addition was complete, the reaction was carried out at room temperature for 24 h. The mass ratio of MSNs-NH2, triethylamine, and 2-bromoisobutyryl bromide was 0.5:2.9:1.7. After the reaction was completed, the solid was collected by centrifugation, thoroughly washed with anhydrous dichloromethane, and vacuum dried to obtain thorny-mesoporous silica nanospheres with ATRP initiator solidified on the surface, denoted as Br-MSNs. The prepared Br-MSNs, cuprous bromide, and N,N,N',N'',N''-pentamethyldiethylenetriamine were added to a single-necked flask and subjected to three freeze-vacuum-thaw cycles to ensure thorough deoxygenation. Under nitrogen protection, anhydrous toluene was injected, followed by methyl methacrylate. The mixture was stirred in an oil bath at 70°C for 24 h. The mass ratio of Br-MSNs, cuprous bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, and methyl methacrylate was 0.15:0.021:0.0365:0.75. After the reaction was completed, the solid product was separated by centrifugation and washed five times with tetrahydrofuran. Finally, it was dried under vacuum at 40°C for 24 h. The final product was denoted as MSNs-g-PMMA.

[0048] Comparative Example 6 The difference between this comparative example and Comparative Example 3 is as follows: Step S3 in this comparative example is as follows: The MSNs-NH2 obtained in step S2 was dispersed in anhydrous dichloromethane, and triethylamine was added. Under an ice-water bath cooling (0°C) and nitrogen atmosphere, 2-bromoisobutyryl bromide (ATRP initiator) was slowly added dropwise. After the addition was complete, the reaction was carried out at room temperature for 24 h. The mass ratio of MSNs-NH2, triethylamine, and 2-bromoisobutyryl bromide was 0.5:2.9:1.7. After the reaction was completed, the solid was collected by centrifugation, washed thoroughly with tetrahydrofuran, and dried under vacuum to obtain spiked mesoporous silica nanospheres with ATRP initiator solidified on the surface, denoted as Br-MSNs. The prepared Br-MSNs, cuprous bromide, and N,N,N',N'',N''-pentamethyldiethylenetriamine were added to a single-necked flask and subjected to three freeze-vacuum-thaw cycles to ensure thorough deoxygenation. Under nitrogen protection, anhydrous toluene was injected, followed by styrene, and the mixture was stirred in an oil bath at 110°C for 24 h. The mass ratio of Br-MSNs, cuprous bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, and styrene was 0.15:0.021:0.0365:0.75. After the reaction, the solid product was separated by centrifugation and washed three times each with tetrahydrofuran and chloroform to thoroughly remove cuprous bromide and unreacted monomers. Finally, the solid product was dried in a vacuum oven at 40°C for 24 h. The final product was denoted as MSNs-g-PS.

[0049] Comparative Example 7 The difference between this comparative example and Comparative Example 4 is that step S3 in this comparative example is as follows: The MSNs-NH2 obtained in step S2 was dispersed in anhydrous dichloromethane, and triethylamine was added. Under an ice-water bath cooling (0°C) and nitrogen atmosphere, 2-bromoisobutyryl bromide (ATRP initiator) was slowly added dropwise. After the addition was complete, the reaction was carried out at room temperature for 24 h. The mass ratio of MSNs-NH2, triethylamine, and 2-bromoisobutyryl bromide was 0.5:2.9:1.7. After the reaction was completed, the solid was collected by centrifugation, washed thoroughly with tetrahydrofuran, and dried under vacuum to obtain spiked mesoporous silica nanospheres with ATRP initiator solidified on the surface, denoted as Br-MSNs. The prepared Br-MSNs, cuprous bromide, and N,N,N',N'',N''-pentamethyldiethylenetriamine were added to a single-necked flask, and the mixture was subjected to three freeze-vacuum-thaw cycles to ensure thorough deoxygenation. Under nitrogen protection, anhydrous toluene was injected, followed by N-isopropylacrylamide, and the mixture was stirred at room temperature for 24 h. The mass ratio of Br-MSNs, cuprous bromide, N,N,N',N'',N''-pentamethyldiethylenetriamine, and N-isopropylacrylamide was 0.15:0.021:0.0365:0.75. After the reaction was completed, the solid product was separated by centrifugation and washed three times each with deionized water and ethanol at 0 °C. Finally, the solid product was freeze-dried for 24 h, and the final product was denoted as MSNs-g-PNIPAM.

[0050] Test case The nanocomposite particles obtained in Examples 1-9 and Comparative Examples 1-7 were added to commercially available plasticized PVB resin (PVB to plasticizer mass ratio of 80:20). The amount of nanocomposite particles added was 2% of the mass of commercially available plasticized PVB resin. After stirring at room temperature for 6 h, the mixture was dried at 80 °C for 24 h. The resulting products were recorded as resin sample 1, resin sample 2, ..., resin sample 16.

[0051] The nanocomposite particles obtained in Examples 1, 6-9, and Comparative Examples 1-2 were added to waterborne polyurethane resin (the amount of nanocomposite particles added was 2% of the mass of waterborne polyurethane resin). After being placed at room temperature for 24 h, they were dried at 80 °C for 24 h. The resulting products were recorded as resin sample 17, resin sample 18, resin sample 19, resin sample 20, resin sample 21, resin sample 22, and resin sample 23, respectively.

[0052] Silica (SiO2) was added to commercially available plasticized PVB resin (PVB to plasticizer mass ratio of 80:20) and waterborne polyurethane resin, respectively. The amount of silica added was 2% of the resin mass. The resulting products were resin sample 24 and resin sample 25.

[0053] The following tests were performed on resin samples 1-16, resin sample 24, and commercially available plasticized PVB resin: tensile test according to GB / T1040.3-2006; light transmittance test according to GB / T 2410-2008.

[0054] The following tests were performed on resin samples 17-23, resin sample 25, and waterborne polyurethane resin (PU): tensile test according to GB / T528-2009; light transmittance test according to GB / T 2410-2008.

[0055] The test results are shown in Tables 1 and 2. Figures 3-15 As shown. Among them, Figures 3-7 In the diagram, the stress on the vertical axis represents the tensile strength, and the strain on the horizontal axis represents the tensile strain at fracture.

[0056] Table 1 Test results of PVB-based resin samples

[0057] Table 2 Test results of PU-based resin samples

[0058] Based on the results in Tables 1 and 2 and the figures: The results from Examples 1-9 show that the polymer-grafted surface-spiked mesoporous silica nanocomposite particles prepared in the embodiments of the present invention can significantly improve the mechanical properties of polyvinyl butyral resin and waterborne polyurethane resin, indicating that the polymer-grafted surface-spiked mesoporous silica nanocomposite particles of the present invention can effectively strengthen and toughen the high-transmittance polymer matrix.

[0059] In the visible light range, PVB has a transmittance of 94.1%. When 2% of the composite nanoparticles prepared in Example 1 are added, the transmittance reaches 92.2%, a decrease of only 2.1%, meeting the requirements for high transmittance. However, adding 2% of SMSNs, MSNs, and SiO2 significantly reduces the transmittance to 83.2%, 79.1%, and 63.4%, respectively. These results demonstrate that adding the polymer-grafted surface-spiked mesoporous silica nanocomposite particles of this invention to PVB can maintain the high transmittance of PVB.

[0060] In the visible light range, the transmittance of PU is 96.3%. When 2% of the composite nanoparticles prepared in Example 1 are added, the transmittance reaches 93.9%, a decrease of only 2.4%, meeting the requirements for high transmittance. However, the addition of 2% of SMSNs, MSNs, and SiO2 significantly reduces the transmittance, decreasing to 83.0%, 82.2%, and 66.5%, respectively. These results demonstrate that adding the polymer-grafted surface-spiked mesoporous silica nanocomposite particles of this invention to PU can maintain the high transmittance of PVB.

[0061] The results from Examples 1-5 show that when the same polymer is grafted, the toughening effect and light transmittance of the same polymer matrix are different when the core particle size of the nanocomposite particles is different or the length of the grafted polymer is different. If the grafted polymer is too long, it will lead to phase separation. If it is too short, the entanglement with the polymer matrix is ​​weak and the interpenetration is reduced.

[0062] The results of Examples 1 and 7-9 show that when different polymers are grafted, even if the core particle size and the nanocomposite particle size are the same, the toughening effect and light transmittance of the same polymer matrix are different. For PVB resin matrix, grafting PCL is the best.

[0063] Compared to Comparative Example 2, Comparative Example 1, due to its surface spike structure, can further improve the strength and toughness of the high-transmittance polymer matrix. Compared to Comparative Examples 3-7, when grafting the same polymer, Examples 1 and 6-9, due to their spike structure, can further improve the strength and toughness of the high-transmittance polymer matrix.

[0064] Compared with Comparative Example 1, Examples 1 and 6-9 can further improve the strength and toughness of the high-transmittance polymer matrix by grafting polymers onto the surface of the spiked-mesoporous silica nanospheres.

[0065] The polymer-grafted, surface-spiked mesoporous silica nanocomposite particles provided by this invention have significant advantages in resolving the optical and mechanical contradictions between nanofillers and polymer matrices. The polymer layer in the SMSNs-g-PCL structure effectively suppresses nanoparticle aggregation through steric hindrance and entropy repulsion, maintaining a uniform dispersion in the PVB matrix. This spiked structure, combined with the polymer, also effectively avoids light scattering caused by the formation of large-sized (>100nm) aggregates, thus preventing a significant decrease in transmittance.

[0066] In the above test examples, the waterborne polyurethane resin was prepared using existing methods. For example, a terminal-NCO prepolymer was prepared by reacting polytetrahydrofuran (PTMG, Mn=2000) with isophorone diisocyanate (IPDI). Chain extenders (such as 1,4-butanediol and 2,2-dimethylolpropionic acid) were added to extend the chain and reduce viscosity. Triethylamine was used to neutralize the carboxyl groups, followed by high-speed shear emulsification and vacuum distillation to remove acetone, thus obtaining a waterborne polyurethane emulsion with a specified solids content (e.g., 30%). Depending on the design requirements, appropriate fillers were added to the waterborne polyurethane emulsion, and after curing, the corresponding waterborne polyurethane resin was obtained.

[0067] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0068] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A polymer-grafted, surface-spiked, mesoporous silica nanocomposite particle, characterized in that, It includes spiked mesoporous silica nanospheres and polymers grafted onto the surface of the spiked mesoporous silica nanospheres; the spiked mesoporous silica nanospheres have a particle size of 50~100nm, have a centrally divergent structure and open mesoporous channels on the surface, and have spikes with a height of 3~5nm on their surface; the polymer is polycaprolactone.

2. A method for preparing polymer-grafted surface-spiked mesoporous silica nanocomposite particles as described in claim 1, characterized in that, It includes the following steps: Amino-functionalized spiked-mesoporous silica nanospheres are obtained by amino-functionalizing them; polymers are then grafted onto the surface of the amino-functionalized spiked-mesoporous silica nanospheres to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles.

3. The method for preparing polymer-grafted surface-spiked mesoporous silica nanocomposite particles according to claim 2, characterized in that, The method of amino-functionalization is as follows: Splintered mesoporous silica nanospheres are dispersed in solvent A, an aminosilane coupling agent is added, and the mixture is heated and reacted in an oxygen-free and anhydrous environment. After separation and washing, amino-functionalized splintered mesoporous silica nanospheres are obtained.

4. The method for preparing polymer-grafted surface-spiked mesoporous silica nanocomposite particles according to claim 3, characterized in that, The spiked-mesoporous silica nanospheres have a particle size of 50-100 nm, and their surface has spikes with a height of 3-5 nm. Their mesoporous channels have a centrally divergent structure with open surfaces and a pore size of 6-8 nm. The mass ratio of the spiked-mesoporous silica nanospheres to the aminosilane coupling agent is 1:1-2. The solvent A is at least one of anhydrous toluene, anhydrous ethanol, anhydrous cyclohexane, anhydrous n-hexane, and acetone. The temperature of the heating reaction is 40-130 °C.

5. The method for preparing polymer-grafted surface-spiked mesoporous silica nanocomposite particles according to claim 2, characterized in that, The method for grafting polymers is as follows: the amino-functionalized spiked mesoporous silica nanospheres, monomer A, and catalyst A are dispersed in solvent B and heated to react, then separated, washed, and dried to obtain polymer-grafted surface-spiked mesoporous silica nanocomposite particles; the monomer A is ε-caprolactone.

6. The method for preparing polymer-grafted surface-spiked mesoporous silica nanocomposite particles according to claim 5, characterized in that, The mass ratio of the amino-functionalized spiked mesoporous silica nanospheres, monomer A, and catalyst A is 0.1~0.5:1~5:0.0025~0.0125; And / or, the catalyst A is stannous octoate; the heating reaction temperature is 100~130℃ and the time is 12~48h; the solvent B is anhydrous toluene.

7. The use of polymer-grafted surface-spiked mesoporous silica nanocomposite particles as described in claim 1 as a non-reactive toughening additive in resins or elastomers compatible with the polymer.

8. The application according to claim 7, characterized in that, The application method is as follows: the polymer-grafted surface-spiked mesoporous silica nanocomposite particles are physically blended with the resin or elastomer, wherein the physical blending is performed by extrusion, injection molding, mixing, compression molding or casting.

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