High-strength uvioresistant foamed polypropylene material and method for producing same

Abstract

This invention relates to the field of polymer materials technology, specifically disclosing a high-strength UV-resistant foamed polypropylene material and its preparation method. The invention involves covalently grafting amino-terminated polydimethylsiloxane (PDMS) onto polypropylene segments. The low surface tension of the PDMS reduces the nucleation barrier of the foam cells and improves the stability of the foam walls, resulting in a uniform and dense closed-cell structure. Then, octyl p-aminobenzoate is used to chemically graft nano-TiO2, improving the dispersion and interfacial compatibility of inorganic particles in the matrix. When the foamed material is subjected to stress, the foam structure disperses stress, the flexible PDMS segments dissipate energy, and the rigid TiO2 bears the load, achieving a three-level synergy of "foam stabilization, toughening, and strengthening," significantly improving the tensile strength of the foamed material. Simultaneously, nano-TiO2 and octyl p-aminobenzoate form broadband UV protection, and the Si-O-Si structure constructs a highly stable protective layer, synergistically endowing the material with excellent weather resistance and aging resistance.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, specifically to a high-strength UV-resistant foamed polypropylene material and its preparation method. Background Technology

[0002] Expanded polypropylene (EPP) is a high-performance, highly crystalline polymer / gas composite material. It uses polypropylene resin as a matrix, and through physical or chemical foaming processes, a dense, closed-cell honeycomb microstructure is formed within it. This unique structure not only allows EPP to inherit the inherent heat resistance, chemical corrosion resistance, and processability of polypropylene, but also endows it with extremely low apparent density, excellent shock absorption properties, extremely high deformation recovery rate, and outstanding thermal and sound insulation effects. Compared to traditional expanded polystyrene (EPS) or expanded polyurethane (EPU), expanded polypropylene does not contain toxic additives and can be recycled, making it a green and environmentally friendly foam material that highly aligns with sustainable development principles. With these comprehensive advantages, expanded polypropylene has been widely used in numerous fields such as lightweight automotive structural components, cold chain logistics packaging, cushioning protection for precision electronic products, drone cushioning bases, and high-end sports protective equipment, demonstrating its irreplaceable application value.

[0003] However, as applications expand to harsh conditions such as deep-sea environments, high-altitude cold regions, and long-term outdoor exposure, the shortcomings of existing foamed polypropylene materials in terms of mechanical properties and UV aging resistance are becoming increasingly apparent, severely limiting their application potential. On one hand, the continuity of the matrix is ​​disrupted by numerous cells during the foaming process, inevitably leading to a significant decrease in absolute load-bearing capacity, tensile strength, and rigidity. Simply increasing density to compensate for strength would negate its lightweight advantage, making it difficult to meet the modern industrial requirements for structural components that combine lightweight and high strength. On the other hand, the polypropylene molecular backbone contains a large number of chemically highly reactive tertiary carbon atoms, making it extremely sensitive to ultraviolet light. Under the combined effects of long-term outdoor UV radiation and oxygen, it is highly susceptible to autocatalytic photo-oxidative degradation, leading to chain breakage and degradation of the macromolecular chains. This results in severe surface yellowing, powdering and flaking, cell collapse, and a precipitous decline in mechanical properties. Although existing technologies often modify materials by adding inorganic reinforcing fillers and small-molecule UV absorbers through physical blending, the addition of large amounts of inorganic fillers can easily cause particle agglomeration, destroy the uniformity of the cell structure, and significantly increase the material's specific gravity. Meanwhile, small-molecule anti-aging additives are prone to degradation, volatilization, or migration and precipitation to the surface in the high-pressure, high-temperature fluid environment of high-temperature melt extrusion and supercritical foaming, making it difficult to form a lasting bond with the matrix. As a result, the long-term UV aging resistance of the material cannot be fundamentally guaranteed.

[0004] Therefore, developing a foamed polypropylene material that combines high mechanical strength with long-lasting UV aging resistance has become a critical technological bottleneck that urgently needs to be overcome in the field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a high-strength UV-resistant foamed polypropylene material and its preparation method.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a high-strength, UV-resistant foamed polypropylene material includes the following steps: S1. Polypropylene is added to xylene and heated and stirred to dissolve under a nitrogen atmosphere. Then glycidyl methacrylate and dicumyl peroxide are added to it and the reaction is maintained at a certain temperature. After the reaction is completed, the polypropylene is precipitated, washed, dried and pulverized to obtain pretreated polypropylene. S2. Add the pretreated polypropylene to xylene, heat and stir to dissolve under a nitrogen atmosphere, then add ammonia-terminated polydimethylsiloxane, heat and stir to react. After the reaction is complete, precipitate, wash, dry and pulverize to obtain modified polypropylene. S3. Disperse nano-titanium dioxide ultrasonically in an ethanol aqueous solution, then add silane coupling agent KH560, stir, filter, wash and dry to obtain epoxy-grafted titanium dioxide. S4. Epoxy-grafted titanium dioxide is dispersed in DMF solvent, and then octyl p-aminobenzoate and triethylamine are added to it. The mixture is heated to react. After the reaction is completed, the mixture is filtered, washed and dried to obtain modified titanium dioxide. S5. After uniformly mixing modified polypropylene, modified titanium dioxide, talc, flame retardant, antioxidant, and dispersant, the mixture is extruded through an extruder and granulated. Then, it is placed in a reaction vessel, heated to 120-160℃, CO2 gas is introduced, and the pressure is increased to 15-20MPa. The pressure is maintained for 8-15 minutes, and then the gas in the reaction vessel is quickly released. The mold is then opened to obtain high-strength UV-resistant foamed polypropylene material.

[0007] In the technical solution disclosed in this invention, in step S1, the amount of glycidyl methacrylate added is 4-8% of the mass of polypropylene, and the amount of dicumyl peroxide added is 10-20% of the mass of glycidyl methacrylate.

[0008] In the technical solution disclosed in this invention, in step S1, the temperature of the heat preservation reaction is 120-125℃, and the heat preservation reaction time is 2-3h.

[0009] In step S1, highly active epoxy groups are introduced into the molecular chain of polypropylene through chemical grafting. These epoxy groups act as "chemical anchors" for the subsequent introduction of functional flexible segments, fundamentally solving the problem of poor compatibility between polar additives and non-polar PP matrix and easy macroscopic phase separation in traditional physical blending.

[0010] In the technical solution disclosed in this invention, in step S2, the mass ratio of pretreated polypropylene and ammonia-terminated polydimethylsiloxane is 10:2.5-4.

[0011] In the technical solution disclosed in this invention, in step S2, the temperature of the heating and stirring reaction is 125-130℃, and the heating and stirring reaction time is 4-6h.

[0012] In step S2, the primary amino groups (-NH2) at both ends of the amino-terminated polydimethylsiloxane exhibit high nucleophilic activity. Under heating conditions, they can undergo an amino-epoxy ring-opening addition reaction with the epoxy groups on the pretreated polypropylene, anchoring the polysiloxane segments to the polypropylene molecular chain in the form of covalent bonds. This forms a polymer chain with a certain branched topology, significantly improving the melt elasticity and strain hardening ability of polypropylene. During CO2 foaming, it effectively avoids the rupture and merging of cells, constructing a fine, dense, and thick-walled high-quality closed-cell microstructure. When subjected to external tensile loads, the dense cell structure uniformly disperses stress, and the flexible PDMS soft segments dissipate impact energy to prevent brittle fracture, significantly improving the mechanical properties of the foamed material. In addition, organosilicon has certain UV stability and weather resistance, which can help improve the aging resistance of the material.

[0013] In the technical solution disclosed in this invention, in step S3, the mass ratio of nano-titanium dioxide and silane coupling agent KH560 is 10:1.0-1.5.

[0014] In step S3, the nano-titanium dioxide surface has a large number of hydroxyl groups, which can undergo hydrolysis-condensation reaction with the silane coupling agent KH560 to introduce epoxy groups on the surface of inorganic particles, which is beneficial to the subsequent reaction. At the same time, it can also reduce the surface energy of nano-TiO2, inhibit particle agglomeration, and make it uniformly dispersed in the polymer. The uniformly dispersed TiO2 can not only improve the UV resistance, but also act as a heterogeneous nucleating agent, making the pores more uniform and fine, and improving the tensile strength of the foamed material.

[0015] In the technical solution disclosed in this invention, in step S4, the mass ratio of epoxy-grafted titanium dioxide, octyl para-aminobenzoate and triethylamine is 10:2-4:0.05-0.1.

[0016] In the technical solution disclosed in this invention, in step S4, the temperature of the heating reaction is 70-85℃, and the heating reaction time is 6-12h.

[0017] In step S4, the amino and epoxy groups in the octyl p-aminobenzoate molecule undergo a ring-opening grafting reaction, chemically grafting organic UV absorber molecules onto the surface of nano-TiO2. Nano-TiO2 itself is an excellent inorganic UV shielding agent (reflecting / scattering UVA and UVB), while octyl p-aminobenzoate is a highly efficient organic UVB absorber. The synergistic effect of the two improves the aging resistance of the foamed material. At the same time, the long-chain alkyl groups grafted on the surface further improve the wettability and dispersibility of nano-TiO2 in polypropylene, reduce defects, and further improve the tensile strength of the foamed material.

[0018] In the technical solution disclosed in this invention, in step S5, the mass ratio of modified polypropylene, modified titanium dioxide, talc, flame retardant, antioxidant, and dispersant is 100:8-12:5-10:2-4:0.5-1:0.5-1.

[0019] In the technical solution disclosed in this invention, the flame retardant is selected from decabromodiphenyl ethane or ammonium polyphosphate.

[0020] In the technical solution disclosed in this invention, the antioxidant is selected from antioxidant 1010 or antioxidant 168.

[0021] In the technical solution disclosed in this invention, the dispersant is selected from POE8400 or POE8402.

[0022] The present invention also provides a high-strength UV-resistant foamed polypropylene material prepared by the above preparation method.

[0023] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention covalently anchors flexible ammonia-terminated polydimethylsiloxane onto polypropylene segments to form polymer chains with certain side chain structures. During CO2 foaming, the introduced polysiloxane segments have extremely low surface tension, which significantly reduces the nucleation barrier of the cells and improves the surface stability of the cell walls, effectively preventing cell rupture and merging, and constructing a uniform and dense closed-cell structure. At the same time, octyl p-aminobenzoate is used to chemically graft nano-TiO2, and the long-chain alkyl (octyl) on its surface greatly improves the compatibility and dispersibility of inorganic particles in polypropylene and forms physical entanglement with polypropylene segments. When subjected to external tensile loads, the dense cell structure uniformly disperses stress, the flexible PDMS soft segments dissipate impact energy to prevent brittle fracture, and the stress can be transferred to the rigid nano-TiO2 core through the organic phase interface, realizing the three-level synergy of "melt stabilization, flexible segment toughening, and rigid filler strengthening chain", solving the technical problem of low tensile strength of foamed polypropylene materials.

[0024] (2) Nano TiO2 itself is an excellent inorganic broadband ultraviolet shielding agent (reflecting / scattering UVA and UVB), which complements the surface-grafted octyl para-aminobenzoate (high-efficiency organic UVB absorber) to achieve high-efficiency absorption and dissipation of broadband ultraviolet rays; at the same time, it is combined with the Si-O-Si siloxane soft segments introduced on the side chain of polypropylene to form a siloxane protective barrier with high chemical bond energy, which blocks the erosion of the environment into the interior. The synergistic effect of multiple factors makes the foamed material have excellent weather resistance and aging resistance. Detailed Implementation

[0025] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0026] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0027] The polypropylene used in this embodiment of the invention is grade H1600, manufactured by Lotte Chemicals, South Korea; the CAS number of the ammonia-terminated polydimethylsiloxane is 97917-34-5; the particle size of the nano titanium dioxide is 30nm; and the particle size of the talc is 20-30μm.

[0028] Example 1 A method for preparing a high-strength, UV-resistant foamed polypropylene material includes the following steps: S1. Add 10 parts of polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 0.4 parts of glycidyl methacrylate and 0.04 parts of dicumyl peroxide, keep the reaction at 120°C for 3 hours, after the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain pretreated polypropylene after pulverization. S2. Add 10 parts of pretreated polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 2.5 parts of amino-terminated polydimethylsiloxane, heat and stir to react at 125°C for 6 hours. After the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain modified polypropylene after pulverization. S3. Disperse 10 parts of nano-titanium dioxide ultrasonically in 150 parts of ethanol aqueous solution (volume ratio of ethanol to water is 4:1), then add 1 part of silane coupling agent KH560, stir for 3 hours, filter, wash and dry to obtain epoxy-grafted titanium dioxide. S4. Disperse 10 parts of epoxy-grafted titanium dioxide in 150 parts of DMF solvent, then add 2 parts of octyl p-aminobenzoate and 0.05 parts of triethylamine, heat at 80°C for 10 h, and after the reaction is completed, filter, wash and dry to obtain modified titanium dioxide. S5. Mix 100 parts modified polypropylene, 10 parts modified titanium dioxide, 8 parts talc, 3 parts flame retardant decabromodiphenyl ethane, 0.8 parts antioxidant 1010, and 0.8 parts dispersant POE8400 evenly, then extrude the mixture through an extruder to form granules. The granules are then placed in a reaction vessel, heated to 150°C, and CO2 gas is introduced. The pressure is increased to 15 MPa and maintained for 15 minutes. The gas in the reaction vessel is then quickly released, and the mold is opened to obtain a high-strength UV-resistant foamed polypropylene material.

[0029] Example 2 A method for preparing a high-strength, UV-resistant foamed polypropylene material includes the following steps: S1. Add 10 parts of polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 0.8 parts of glycidyl methacrylate and 0.08 parts of dicumyl peroxide, keep the reaction at 120°C for 3 hours, after the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain pretreated polypropylene after pulverization. S2. Add 10 parts of pretreated polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 4 parts of amino-terminated polydimethylsiloxane, heat and stir to react at 125°C for 6 hours. After the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain modified polypropylene after pulverization. S3. Disperse 10 parts of nano-titanium dioxide ultrasonically in 150 parts of ethanol aqueous solution (volume ratio of ethanol to water is 4:1), then add 1.5 parts of silane coupling agent KH560, stir for 3 hours, filter, wash and dry to obtain epoxy-grafted titanium dioxide. S4. Disperse 10 parts of epoxy-grafted titanium dioxide in 150 parts of DMF solvent, then add 4 parts of octyl p-aminobenzoate and 0.1 parts of triethylamine, heat at 80°C for 10 h, and after the reaction is completed, filter, wash and dry to obtain modified titanium dioxide. S5. Mix 100 parts modified polypropylene, 8 parts modified titanium dioxide, 5 parts talc, 2 parts flame retardant decabromodiphenyl ethane, 0.5 parts antioxidant 1010, and 0.5 parts dispersant POE8400 evenly, then extrude the mixture through an extruder to form granules. The granules are then placed in a reaction vessel, heated to 150°C, CO2 gas is introduced, and the pressure is increased to 15 MPa. The pressure is maintained for 15 minutes, and then the gas in the reaction vessel is quickly released. The mold is then opened to obtain a high-strength UV-resistant foamed polypropylene material.

[0030] Example 3 A method for preparing a high-strength, UV-resistant foamed polypropylene material includes the following steps: S1. Add 10 parts of polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 0.5 parts of glycidyl methacrylate and 0.05 parts of dicumyl peroxide, keep the reaction at 120°C for 3 hours, after the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain pretreated polypropylene after pulverization. S2. Add 10 parts of pretreated polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 3 parts of amino-terminated polydimethylsiloxane, heat and stir to react at 125°C for 6 hours. After the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain modified polypropylene after pulverization. S3. Disperse 10 parts of nano-titanium dioxide ultrasonically in 150 parts of ethanol aqueous solution (volume ratio of ethanol to water is 4:1), then add 1.5 parts of silane coupling agent KH560, stir for 3 hours, filter, wash and dry to obtain epoxy-grafted titanium dioxide. S4. Disperse 10 parts of epoxy-grafted titanium dioxide in 150 parts of DMF solvent, then add 3 parts of octyl p-aminobenzoate and 0.06 parts of triethylamine, heat at 80°C for 10 h, and after the reaction is completed, filter, wash and dry to obtain modified titanium dioxide. S5. Mix 100 parts of modified polypropylene, 12 parts of modified titanium dioxide, 10 parts of talc, 4 parts of flame retardant decabromodiphenyl ethane, 1 part of antioxidant 1010, and 1 part of dispersant POE8400 evenly, then extrude the mixture through an extruder to form granules. The granules are then placed in a reaction vessel, heated to 150°C, and CO2 gas is introduced. The pressure is increased to 15 MPa and maintained for 15 minutes. The gas in the reaction vessel is then quickly released, and the mold is opened to obtain a high-strength UV-resistant foamed polypropylene material.

[0031] Comparative Example 1 A method for preparing a high-strength, UV-resistant foamed polypropylene material includes the following steps: S1. Disperse 10 parts of nano-titanium dioxide ultrasonically in 150 parts of ethanol aqueous solution (volume ratio of ethanol to water is 4:1), then add 1 part of silane coupling agent KH560, stir for 3 hours, filter, wash and dry to obtain epoxy-grafted titanium dioxide. S2. Disperse 10 parts of epoxy-grafted titanium dioxide in 150 parts of DMF solvent, then add 2 parts of octyl p-aminobenzoate and 0.05 parts of triethylamine, heat at 80°C for 10 h, and after the reaction is completed, filter, wash and dry to obtain modified titanium dioxide. S3. Mix 100 parts polypropylene, 10 parts modified titanium dioxide, 8 parts talc, 3 parts flame retardant decabromodiphenyl ethane, 0.8 parts antioxidant 1010, and 0.8 parts dispersant POE8400 evenly, then extrude the mixture through an extruder to form granules. The granules are then placed in a reaction vessel, heated to 150°C, and CO2 gas is introduced. The pressure is increased to 15 MPa and maintained for 15 minutes. The gas in the reaction vessel is then quickly released, and the mold is opened to obtain a high-strength UV-resistant foamed polypropylene material.

[0032] Compared to Example 1, no modification treatment was performed on the polypropylene in Comparative Example 1.

[0033] Comparative Example 2 A method for preparing a high-strength, UV-resistant foamed polypropylene material includes the following steps: S1. Add 10 parts of polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 0.4 parts of glycidyl methacrylate and 0.04 parts of dicumyl peroxide, keep the reaction at 120°C for 3 hours, after the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain pretreated polypropylene after pulverization. S2. Add 10 parts of pretreated polypropylene to 150 parts of xylene, heat and stir to dissolve under nitrogen atmosphere at 120°C, then add 2.5 parts of amino-terminated polydimethylsiloxane, heat and stir to react at 125°C for 6 hours. After the reaction is completed, precipitate and wash with acetone, then dry in a vacuum drying oven, and obtain modified polypropylene after pulverization. S3. Mix 100 parts modified polypropylene, 10 parts nano titanium dioxide, 8 parts talc, 3 parts flame retardant decabromodiphenyl ethane, 0.8 parts antioxidant 1010, and 0.8 parts dispersant POE8400 evenly, then extrude the mixture through an extruder to form granules. The granules are then placed in a reaction vessel, heated to 150°C, CO2 gas is introduced, and the pressure is increased to 15 MPa. The pressure is maintained for 15 minutes, and then the gas in the reaction vessel is quickly released. The mold is then opened to obtain a high-strength UV-resistant foamed polypropylene material.

[0034] Compared with Example 1, Comparative Example 2 did not involve any modification treatment of the nano-titanium dioxide.

[0035] Comparative Example 3 100 parts polypropylene, 10 parts nano titanium dioxide, 8 parts talc, 3 parts flame retardant decabromodiphenyl ethane, 0.8 parts antioxidant 1010, and 0.8 parts dispersant POE8400 were mixed evenly and then extruded through an extruder to form granules. The granules were then placed in a reaction vessel, heated to 150°C, and CO2 gas was introduced. The pressure was increased to 15 MPa and maintained for 15 minutes. The gas in the reaction vessel was then quickly released, and the mold was opened to obtain a high-strength UV-resistant foamed polypropylene material.

[0036] Compared with Example 1, Comparative Example 3 did not involve any modification treatment of polypropylene and nano-titanium dioxide.

[0037] The foamed polypropylene materials prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests, and the specific steps are as follows: Tensile strength test: The test was conducted in accordance with GB / T1040.2-2022 standard. The foamed polypropylene material was prepared into a standard dumbbell-shaped specimen with a thickness of 4 mm. The tensile strength was measured on a tensile testing machine with a loading speed of 5 mm / min. The test was conducted three times and the average value of the results was taken. Anti-aging performance test method: Xenon lamps are used to simulate the entire spectrum of sunlight. The samples are placed in a xenon lamp accelerated aging test chamber for 360 hours. The experimental conditions are: air atmosphere, temperature 65℃, lamp source distance 25cm from the sample, and radiation intensity 550W / m². 2 Test the tensile strength again and calculate the tensile strength retention rate; The test results are shown in Table 1.

[0038] Table 1 Performance test results for different groups

[0039] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A method for preparing a high-strength, UV-resistant foamed polypropylene material, characterized in that, Includes the following steps: S1. Polypropylene is added to xylene and heated and stirred to dissolve under a nitrogen atmosphere. Then glycidyl methacrylate and dicumyl peroxide are added to it and the reaction is maintained at a certain temperature. After the reaction is completed, the polypropylene is precipitated, washed, dried and pulverized to obtain pretreated polypropylene. S2. Add the pretreated polypropylene to xylene, heat and stir to dissolve under a nitrogen atmosphere, then add ammonia-terminated polydimethylsiloxane, heat and stir to react. After the reaction is complete, precipitate, wash, dry and pulverize to obtain modified polypropylene. S3. Disperse nano-titanium dioxide ultrasonically in an ethanol aqueous solution, then add silane coupling agent KH560, stir, filter, wash and dry to obtain epoxy-grafted titanium dioxide. S4. Epoxy-grafted titanium dioxide is dispersed in DMF solvent, and then octyl p-aminobenzoate and triethylamine are added to it. The mixture is heated to react. After the reaction is completed, the mixture is filtered, washed and dried to obtain modified titanium dioxide. S5. After uniformly mixing modified polypropylene, modified titanium dioxide, talc, flame retardant, antioxidant, and dispersant, the mixture is extruded through an extruder and granulated. Then, it is placed in a reaction vessel, heated to 120-160℃, CO2 gas is introduced, and the pressure is increased to 15-20MPa. The pressure is maintained for 8-15 minutes, and then the gas in the reaction vessel is quickly released. The mold is then opened to obtain high-strength UV-resistant foamed polypropylene material.

2. The preparation method according to claim 1, characterized in that, In step S1, the amount of glycidyl methacrylate added is 4-8% of the mass of polypropylene, and the amount of dicumyl peroxide added is 10-20% of the mass of glycidyl methacrylate.

3. The preparation method according to claim 1, characterized in that, In step S2, the mass ratio of pretreated polypropylene to ammonia-terminated polydimethylsiloxane is 10:2.5-4.

4. The preparation method according to claim 1, characterized in that, In step S2, the temperature for heating and stirring the reaction is 125-130℃, and the reaction time is 4-6 hours.

5. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of nano-titanium dioxide to silane coupling agent KH560 is 10:1.0-1.

5.

6. The preparation method according to claim 1, characterized in that, In step S4, the mass ratio of epoxy-grafted titanium dioxide, octyl para-aminobenzoate, and triethylamine is 10:2-4:0.05-0.

1.

7. The preparation method according to claim 1, characterized in that, In step S4, the temperature of the heating reaction is 70-85℃, and the heating reaction time is 6-12h.

8. The preparation method according to claim 1, characterized in that, In step S5, the mass ratio of modified polypropylene, modified titanium dioxide, talc, flame retardant, antioxidant, and dispersant is 100:8-12:5-10:2-4:0.5-1:0.5-1.

9. The preparation method according to claim 1, characterized in that, In step S5, the flame retardant is selected from decabromodiphenyl ethane or ammonium polyphosphate; the antioxidant is selected from antioxidant 1010 or antioxidant 168; and the dispersant is selected from POE8400 or POE8402.

10. The high-strength UV-resistant foamed polypropylene material prepared by the preparation method according to any one of claims 1-9.

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