Flexible self-cleaning anti-bird umbrella cover made of graphene modified silicone rubber and preparation method of flexible self-cleaning anti-bird umbrella cover

Abstract

The invention discloses a flexible self-cleaning anti-bird umbrella cover made of graphene modified silicone rubber and a preparation method of the flexible self-cleaning anti-bird umbrella cover, and belongs to the technical field of high polymer materials and production of the high polymer materials. The inorganic filler is stably dispersed in the methyl vinyl silicone rubber, and mechanical property reduction caused by large polarity difference is avoided; the graphene modified silicone rubber flexible self-cleaning anti-bird umbrella cover has a good flame-retardant effect, zinc oxide and titanium-based MOF serve as Lewis acid catalysts, reaction between phosphorus and polymer molecular chains can be accelerated, a carbon layer is promoted to be formed more quickly, the structure is more compact, the compact carbon layer can effectively isolate oxygen and heat, combustible gas is prevented from being released, and the anti-bird umbrella cover has a good anti-bird effect. Therefore, the condensed-phase flame-retardant effect of the phosphorus-based flame retardant is enhanced.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials and their production technology, specifically a graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella cover and its preparation method. Background Technology

[0002] To effectively suppress electromagnetic interference and pollution, the design and fabrication of high-efficiency electromagnetic shielding materials has become an urgent problem to solve. Currently, conductive shielding materials on the market are mainly metals, but their disadvantages include high weight, high price, and difficulty in processing and molding. With the development of the materials industry, conductive rubber materials for shielding electromagnetic radiation are constantly being developed and applied, gradually replacing pure metal shielding materials. Utilizing graphene fillers and studying its dispersion and conductivity mechanism in rubber can meet the needs of small and lightweight precision electronic devices and improve the overall performance of electromagnetic shielding rubber, thus achieving the development requirements of "thin, light, wide, and strong" electromagnetic shielding rubber. However, because graphene has virtually no functional groups on its surface, it is difficult to achieve uniform dispersion in a rubber matrix, and existing technologies require the addition of metal materials, resulting in a high density.

[0003] Silicone rubber possesses excellent high-temperature resistance, superior electrical insulation, weather resistance, ozone resistance, and breathability. It is non-toxic and odorless, making it widely used in aerospace, electronics, construction, and automotive industries. Graphene, a novel nanomaterial, exhibits excellent electrical, thermal, and mechanical properties, showing great potential as a functional additive for silicone rubber. However, graphene's tendency to agglomerate and its poor compatibility with silicone rubber hinder its uniform dispersion, preventing the full realization of its superior properties. Summary of the Invention

[0004] The purpose of this invention is to provide a flexible, self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber and its preparation method. By forming a titanium-based MOF on flame-retardant composite modified graphene through hydrothermal coordination and copolymerizing it with methyl vinyl silicone rubber, the inorganic filler is stably dispersed in the methyl vinyl silicone rubber, avoiding the decline in mechanical properties caused by large polarity differences.

[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing a graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella cover includes the following steps: Step 1: Zinc oxide nanoneedles are coated onto the surface of graphene as a carrier to obtain modified graphene, which is then condensed with 3-aminopropyltriethoxysilane to obtain composite modified graphene.

[0006] Step 2: Flame-retardant composite modified graphene is obtained by substituting the composite modified graphene with 4-aminobenzoic acid. Self-cleaning composite graphene is obtained by hydrothermal coordination of the flame-retardant composite modified graphene with methyl 4-amino-2-vinylbenzoate and titanium tetrachloride.

[0007] Step 3: By copolymerizing the double bonds on the surface of self-cleaning composite graphene with the double bonds on the surface of methyl vinyl silicone rubber, a graphene silicone rubber composite is obtained.

[0008] Step 4: Graphene-modified silicone rubber compound, stearic acid, hydroxyl silicone oil, diatomaceous earth and 2,5-dimethyl-2,5-di-tert-butylhexane are blended in an open mill and vulcanized. The metal umbrella frame is fixed in the positioning groove of the lower mold and molded to obtain a flexible self-cleaning bird-proof umbrella made of graphene-modified silicone rubber.

[0009] Furthermore, the ratio of graphene silicone rubber compound, stearic acid, hydroxyl silicone oil, diatomaceous earth and 2,5-dimethyl-2,5-di-tert-butylperoxide is 200-300g: 0.5-0.6g: 0.4-0.7g: 3-4g: 0.2-0.4g.

[0010] Furthermore, the specific preparation steps for modified graphene are as follows: Graphene, zinc acetate dihydrate powder, and anhydrous ethanol were added to a reaction vessel and stirred for 1-2 hours at 20-25℃ and 500-600 r / min. Then, hexamethylenetetramine and deionized water were added, and the mixture was heated to 80-90℃ and stirred for another 15-16 hours. The mixture was then filtered, and the filter cake was washed 2-4 times with deionized water and dried under vacuum at 60-70℃ for 1-2 hours to obtain modified graphene.

[0011] Furthermore, the ratio of graphene, zinc acetate dihydrate powder, anhydrous ethanol, hexamethylenetetramine and deionized water is 80-90g: 20-30g: 300-400mL: 12-14g: 120-140mL.

[0012] Furthermore, the specific preparation steps for composite modified graphene are as follows: Modified graphene, anhydrous ethanol, and deionized water were added to a reaction vessel and stirred for 10-12 minutes at 60-70℃ and 500-600 r / min. Then, 3-aminopropyltriethoxysilane was added, and the pH was adjusted to 3-4 with hydrochloric acid solution. The reaction was continued with stirring for 6-7 hours. The mixture was filtered, and the product was washed 2-3 times with deionized water and anhydrous ethanol. The product was then vacuum dried at 60-80℃ for 1-2 hours to obtain the composite modified graphene.

[0013] Furthermore, the ratio of modified graphene, anhydrous ethanol, deionized water, and 3-aminopropyltriethoxysilane is 70-80g: 80-100mL: 160-200mL: 20-22mL.

[0014] Furthermore, the specific preparation steps of flame-retardant composite modified graphene are as follows: Phosphorus oxychloride, composite modified graphene, 4-aminobenzoic acid, acetonitrile, and acetic acid were added to a reaction vessel and stirred for 6-9 hours at 20-25℃ and 500-600 r / min. After filtration, the product was washed 2-3 times with deionized water and anhydrous ethanol and dried under vacuum at 60-80℃ for 1-2 hours to obtain flame-retardant composite modified graphene.

[0015] Furthermore, the ratio of phosphorus oxychloride, composite modified graphene, 4-aminobenzoic acid, acetonitrile, and acetic acid is 20-24g: 20-22g: 34-36g: 800-900mL: 1.2-1.4L.

[0016] Furthermore, the specific preparation steps for self-cleaning composite graphene are as follows: Flame-retardant composite modified graphene and N,N-dimethylformamide were added to a polytetrafluoroethylene-lined reactor, sealed, and ultrasonically dispersed at 130-135℃ for 20-40 min. Then, methyl 4-amino-2-vinylbenzoate and titanium tetrachloride were added, and ultrasonically dispersed for 40-60 min. Stirring was continued for 24-26 h, and the mixture was naturally cooled to room temperature. After filtration, the filter cake was washed 2-3 times with N,N-dimethylformamide and methanol, respectively, and vacuum dried at 60-80℃ for 1-2 h to obtain self-cleaning composite graphene.

[0017] Furthermore, the ratio of flame-retardant composite modified graphene, N,N-dimethylformamide, methyl 4-amino-2-vinylbenzoate and titanium tetrachloride is 18-20g: 200-300mL: 25-30g: 30-40g.

[0018] Furthermore, the specific preparation steps of the graphene-silicone rubber composite are as follows: Self-cleaning composite graphene, methyl vinyl silicone rubber, and N,N-dimethylformamide were added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 400-500 r / min. The mixture was then heated to 70-80℃, and ammonium persulfate was added. Under a nitrogen atmosphere, the mixture was stirred and reacted for 6-7 hours. After filtration, the filter cake was washed 2-4 times with petroleum ether and deionized water, respectively, and then vacuum dried at 60-70℃ for 1-2 hours to obtain the graphene-silicone rubber composite.

[0019] Furthermore, the ratio of self-cleaning composite graphene, methyl vinyl silicone rubber, N,N-dimethylformamide and ammonium persulfate is 15-20g: 300-400g: 700-800mL: 2-4g.

[0020] The beneficial effects of this invention are: 1. The flexible self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber of the present invention forms a titanium-based MOF by hydrothermal coordination on flame-retardant composite modified graphene and copolymerizes it with methyl vinyl silicone rubber, thereby achieving stable dispersion of inorganic fillers in methyl vinyl silicone rubber and avoiding the decline in mechanical properties caused by large polarity differences.

[0021] 2. The flame-retardant composite modified graphene of the present invention uses phosphorus oxychloride as a medium to graft titanium-based MOF onto the surface of the composite modified graphene. The large specific surface area of ​​the composite modified graphene can accommodate the growth of more titanium-based MOF. The titanium-based MOF has excellent photocatalytic activity, which can endow the bird-proof umbrella cover with self-cleaning properties and prevent bacterial growth. In an alkaline environment, zinc oxide crystals preferentially grow along the graphene crystal plane to form a nano-needle structure. The growth of zinc oxide significantly increases the surface roughness of graphene, providing good attachment sites for phosphorus grafting, and the needle-like structure of zinc oxide can increase the antibacterial properties of the bird-proof umbrella cover.

[0022] 3. The self-cleaning composite graphene of the present invention is achieved by hydrothermally synthesizing a titanium-based MOF structure on the surface of flame-retardant composite modified graphene. The abundant active sites on the surface of the flame-retardant composite modified graphene can provide good adhesion sites for the subsequent growth of titanium-based MOF. Furthermore, during the growth of titanium-based MOF, phosphorus ions will dop the lattice of titanium-based MOF. Titanium-based MOF has photocatalytic activity, which can significantly increase the self-cleaning performance of bird-proof umbrellas. In addition, the presence of zinc oxide can significantly improve the pollution and bacterial growth of bird-proof umbrellas during daily use, and avoid ultraviolet aging caused by direct sunlight.

[0023] 4. The graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella cover of the present invention has good flame retardant properties. Zinc oxide and titanium-based MOF, as Lewis acid catalysts, can accelerate the reaction between phosphorus and polymer molecular chains, promote faster formation of carbon layer and more compact structure. The dense carbon layer can effectively isolate oxygen and heat and prevent the release of combustible gases, thereby enhancing the condensed phase flame retardant effect of phosphorus-based flame retardants. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1: A method for preparing a flexible, self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber, comprising the following steps: S1: Add 80g graphene, 20g zinc acetate dihydrate powder and 300mL anhydrous ethanol to a reaction vessel and stir for 1h at 20℃ and 500r / min. Then add 12g hexamethylenetetramine and 120mL deionized water, heat to 80℃, and continue stirring for 15h. Filter, wash the filter cake twice with deionized water, and vacuum dry at 60℃ for 1h to obtain modified graphene.

[0026] S2: Add 70g of modified graphene, 80mL of anhydrous ethanol and 160mL of deionized water to a reaction vessel, stir for 10min at 60℃ and 500r / min, then add 20mL of 3-aminopropyltriethoxysilane, adjust the pH to 3 with hydrochloric acid solution, continue stirring for 6h, filter, wash the product twice with deionized water and anhydrous ethanol, and vacuum dry at 60℃ for 1h to obtain composite modified graphene.

[0027] S3: Add 20g of phosphorus oxychloride, 20g of composite modified graphene, 34g of 4-aminobenzoic acid, 800mL of acetonitrile and 1.2L of acetic acid to a reaction vessel, stir for 6h at 20℃ and 500r / min, filter, wash the product twice with deionized water and anhydrous ethanol, and vacuum dry at 60℃ for 1h to obtain flame-retardant composite modified graphene.

[0028] S4: Add 18g of flame-retardant composite modified graphene and 200mL of N,N-dimethylformamide to a polytetrafluoroethylene-lined reactor, seal, and ultrasonically disperse at 130℃ for 20min. Then add 25g of methyl 4-amino-2-vinylbenzoate and 30g of titanium tetrachloride, ultrasonically disperse for 40min, continue stirring for 24h, cool naturally to room temperature, filter, wash the filter cake twice with N,N-dimethylformamide and methanol respectively, and vacuum dry at 60℃ for 1h to obtain self-cleaning composite graphene.

[0029] S5: Add 15g of self-cleaning composite graphene, 300g of methyl vinyl silicone rubber and 700mL of N,N-dimethylformamide to a reaction vessel, stir for 20min at 20℃ and 400r / min, heat to 70℃, add 2g of ammonium persulfate, and continue stirring for 6h under a nitrogen atmosphere. Filter, wash the filter cake twice with petroleum ether and deionized water respectively, and dry under vacuum at 60℃ for 1h to obtain the graphene silicone rubber composite.

[0030] S6: Place 200g of graphene silicone rubber compound, 0.5g of stearic acid, 0.4g of hydroxyl silicone oil and 3g of diatomaceous earth in a mixer and mix for 40min. Then add 0.2g of 2,5-dimethyl-2,5-di-tert-butylperoxide and mix on a two-roll mill. Vulcanize at 170℃ for 5min on a flat vulcanizing machine. Fix the metal umbrella frame in the positioning groove of the lower mold and mold it to obtain a flexible self-cleaning bird-proof umbrella made of graphene modified silicone rubber.

[0031] Example 2: A method for preparing a flexible, self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber, comprising the following steps: S1: Add 85g graphene, 25g zinc acetate dihydrate powder and 350mL anhydrous ethanol to a reaction vessel and stir for 1.5h at 22.5℃ and 550r / min. Then add 13g hexamethylenetetramine and 130mL deionized water, heat to 85℃, and continue stirring for 15.5h. Filter, wash the filter cake three times with deionized water, and vacuum dry at 65℃ for 1.5h to obtain modified graphene.

[0032] S2: Add 75g of modified graphene, 90mL of anhydrous ethanol and 180mL of deionized water to a reaction vessel, stir for 11min at 65℃ and 550r / min, then add 21mL of 3-aminopropyltriethoxysilane, adjust the pH to 3.5 with hydrochloric acid solution, continue stirring for 6.5h, filter, wash the product 2.5 times with deionized water and anhydrous ethanol, and vacuum dry at 70℃ for 1.5h to obtain composite modified graphene.

[0033] S3: Add 22g of phosphorus oxychloride, 21g of composite modified graphene, 35g of 4-aminobenzoic acid, 850mL of acetonitrile and 1.3L of acetic acid to a reaction vessel, stir for 7.5h at 22.5℃ and 550r / min, filter, wash the product 2.5 times with deionized water and anhydrous ethanol, and vacuum dry at 70℃ for 1.5h to obtain flame-retardant composite modified graphene.

[0034] S4: 19g of flame-retardant composite modified graphene and 250mL of N,N-dimethylformamide were added to a polytetrafluoroethylene-lined reactor, sealed, and ultrasonically dispersed at 132.5℃ for 30min. Then, 27.5g of methyl 4-amino-2-vinylbenzoate and 35g of titanium tetrachloride were added, ultrasonically dispersed for 50min, and stirred for 25h. The mixture was then naturally cooled to room temperature, filtered, and the filter cake was washed 2.5 times with N,N-dimethylformamide and methanol, respectively. The mixture was then vacuum dried at 70℃ for 1.5h to obtain self-cleaning composite graphene.

[0035] S5: Add 17.5g of self-cleaning composite graphene, 350g of methyl vinyl silicone rubber and 750mL of N,N-dimethylformamide to a reaction vessel, stir for 25min at 22.5℃ and 450r / min, heat to 75℃, add 3g of ammonium persulfate, and continue stirring and reacting for 6.5h under a nitrogen atmosphere. Filter, wash the filter cake three times with petroleum ether and deionized water respectively, and dry under vacuum at 65℃ for 1.5h to obtain the graphene silicone rubber composite.

[0036] S6: Place 250g of graphene silicone rubber compound, 0.55g of stearic acid, 0.55g of hydroxyl silicone oil and 3.5g of diatomaceous earth in a mixer and mix for 50min. Then add 0.3g of 2,5-dimethyl-2,5-di-tert-butylperoxide and mix on a two-roll mill. Vulcanize at 170℃ for 5.5min on a flat vulcanizing machine. Fix the metal umbrella frame in the positioning groove of the lower mold and mold it to obtain a flexible self-cleaning bird-proof umbrella made of graphene modified silicone rubber.

[0037] Example 3: A method for preparing a flexible, self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber, comprising the following steps: S1: Add 90g graphene, 30g zinc acetate dihydrate powder and 400mL anhydrous ethanol to a reaction vessel and stir for 2h at 25℃ and 600r / min. Then add 14g hexamethylenetetramine and 140mL deionized water, heat to 90℃, and continue stirring for 16h. Filter, wash the filter cake 4 times with deionized water, and vacuum dry at 70℃ for 2h to obtain modified graphene.

[0038] S2: Add 80g of modified graphene, 100mL of anhydrous ethanol and 200mL of deionized water to a reaction vessel, stir for 12min at 70℃ and 600r / min, then add 22mL of 3-aminopropyltriethoxysilane, adjust the pH to 4 with hydrochloric acid solution, continue stirring for 7h, filter, wash the product three times with deionized water and anhydrous ethanol, and vacuum dry at 80℃ for 2h to obtain composite modified graphene.

[0039] S3: Add 24g of phosphorus oxychloride, 22g of composite modified graphene, 36g of 4-aminobenzoic acid, 900mL of acetonitrile and 1.4L of acetic acid to a reaction vessel, stir for 9h at 25℃ and 600r / min, filter, wash the product three times with deionized water and anhydrous ethanol, and vacuum dry at 80℃ for 2h to obtain flame-retardant composite modified graphene.

[0040] S4: Add 20g of flame-retardant composite modified graphene and 300mL of N,N-dimethylformamide to a polytetrafluoroethylene-lined reactor, seal, and ultrasonically disperse at 135℃ for 40min. Then add 30g of methyl 4-amino-2-vinylbenzoate and 40g of titanium tetrachloride, ultrasonically disperse for 60min, continue stirring for 26h, cool naturally to room temperature, filter, wash the filter cake three times with N,N-dimethylformamide and methanol respectively, and vacuum dry at 80℃ for 2h to obtain self-cleaning composite graphene.

[0041] S5: Add 20g of self-cleaning composite graphene, 400g of methyl vinyl silicone rubber and 800mL of N,N-dimethylformamide to a reaction vessel, stir for 30min at 25℃ and 500r / min, heat to 80℃, add 4g of ammonium persulfate, and continue stirring for 7h under a nitrogen atmosphere. Filter, wash the filter cake 4 times with petroleum ether and deionized water respectively, and dry under vacuum at 70℃ for 2h to obtain the graphene silicone rubber composite.

[0042] S6: Place 300g of graphene silicone rubber compound, 0.6g of stearic acid, 0.7g of hydroxyl silicone oil and 4g of diatomaceous earth in a mixer and mix for 60min. Then add 0.4g of 2,5-dimethyl-2,5-di-tert-butylperoxide and mix on a two-roll mill. Vulcanize at 170℃ for 6min on a flat vulcanizing machine. Fix the metal umbrella frame in the positioning groove of the lower mold and mold it to obtain a flexible self-cleaning bird-proof umbrella made of graphene modified silicone rubber.

[0043] Comparative Example 1: Based on Example 3, the flame-retardant composite modified graphene in step S4 was replaced with the composite modified graphene in step S2.

[0044] Comparative Example 2: Based on Example 3, 4-aminobenzoic acid in step S3 was omitted.

[0045] Comparative Example 3: Based on Example 3, the self-cleaning composite graphene in step S5 was replaced with a mixture of flame-retardant composite modified graphene and commercially available titanium-based MOF.

[0046] The graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella covers obtained in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. The performance of the products was tested in accordance with GB / T533-2008 "Determination of density of vulcanized rubber or thermoplastic rubber" and GB / T528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber".

[0047] The limiting oxygen index was determined according to ASTM D2863 standard: the sample size was 125mm × 6.5mm × 3mm; the tensile strength was determined according to GB / T 528-2009 standard, with a tensile rate of 500mm / min; and the ultraviolet aging test was conducted according to GB / T 16422-2014 standard, using a xenon arc lamp as the light source and an irradiation intensity of 0.5W / m². 2 (340nm) After 5 days of UV aging of silicone rubber, the tensile strength before and after aging was measured, and the tensile strength retention rate was calculated. The results are shown in Table 1. Table 1. Performance Test Table of Flexible Self-Cleaning Bird-Proof Umbrella Covers Made of Graphene-Modified Silicone Rubber

[0048] As can be seen from Table 1, the tensile strength, elongation at break, density, and L01 value of the graphene-modified silicone rubber flexible self-cleaning bird-proof umbrellas obtained in Examples 1-3 are significantly better than those of the comparative examples before and after aging. This indicates that the graphene-modified silicone rubber flexible self-cleaning bird-proof umbrellas prepared in this invention have good mechanical properties, aging resistance, and flame retardancy.

[0049] In Comparative Example 1, flame-retardant composite modified graphene was replaced with composite modified graphene. Phosphorus oxychloride is a key source of phosphorus, which is the core component of the flame-retardant system. It forms a char layer to isolate oxygen and heat. Without phosphorus, zinc oxide and titanium-based MOF lose the core material for synergistic flame retardancy and cannot form a dense char layer, resulting in a significant reduction in flame retardant effect. 4-Aminobenzoic acid can increase the active sites on the surface of composite modified graphene, providing attachment points for the in-situ growth of titanium-based MOF. Without this modification, titanium-based MOF is difficult to grow stably, the photocatalytic active area is reduced, and the self-cleaning ability decreases. Composite modified graphene has not been modified with phosphorus and 4-aminobenzoic acid, resulting in poor compatibility with subsequent titanium-based MOF and silicone rubber, uneven dispersion, and a decrease in tensile strength and elongation at break.

[0050] In Comparative Example 2, 4-aminobenzoic acid was omitted in step S3, resulting in insufficient phosphorus grafting. The amino group of 4-aminobenzoic acid can react with phosphorus oxychloride to more stably anchor the phosphorus group on the surface of the composite modified graphene. Without this substance, the amount of phosphorus grafting is reduced, weakening the synergistic system of phosphorus, zinc oxide, and titanium-based MOF required for flame retardancy. The carbon layer formation rate and density decrease. The carboxyl group of 4-aminobenzoic acid can provide additional active sites for the in-situ growth of titanium-based MOF. Without it, titanium-based MOF is prone to agglomeration, reducing photocatalytic activity and self-cleaning performance. Insufficient phosphorus grafting and poor dispersion of titanium-based MOF lead to weakened interfacial bonding between inorganic fillers and silicone rubber matrix, resulting in decreased tensile strength and elongation at break.

[0051] Comparative Example 3 replaced the self-cleaning composite graphene with a mixture of flame-retardant composite modified graphene and commercially available titanium-based MOF. The titanium-based MOF was grown in situ on the surface of the flame-retardant composite graphene through hydrothermal coordination, forming a strong chemical bond with the graphene. It can be uniformly dispersed and expose the maximum photocatalytic area. In contrast, the commercially available titanium-based MOF and graphene are only physically mixed and are prone to agglomeration, resulting in a reduction in the photocatalytic active area and a significant decrease in self-cleaning function. The physically mixed titanium-based MOF has poor compatibility with graphene, forming stress concentration points in the silicone rubber matrix, which leads to a decrease in tensile strength and elongation at break, and an increase in material brittleness. The in-situ grown titanium-based MOF can form a three-dimensional synergistic network with zinc oxide and phosphorus elements, accelerating the formation of the carbon layer. However, the components in the physical mixture are unevenly dispersed and cannot form an effective synergy, resulting in a decrease in flame-retardant performance.

[0052] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a flexible, self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber, characterized in that, The process includes the following steps: Step 1: Zinc oxide nanoneedles are coated onto the surface of graphene as a carrier to obtain modified graphene, which is then condensed with 3-aminopropyltriethoxysilane to obtain composite modified graphene; Step 2: The composite modified graphene is substituted with 4-aminobenzoic acid to obtain flame-retardant composite modified graphene, and self-cleaning composite graphene is obtained through hydrothermal coordination of the flame-retardant composite modified graphene with methyl 4-amino-2-vinylbenzoate and titanium tetrachloride; Step 3: The double bonds on the surface of the self-cleaning composite graphene are copolymerized with the double bonds on the surface of methyl vinyl silicone rubber to obtain a graphene silicone rubber composite; Step 4: The graphene silicone rubber composite, stearic acid, hydroxyl silicone oil, diatomaceous earth, and 2,5-dimethyl-2,5-di-tert-butylperoxide are open-milled and blended, vulcanized, and the metal umbrella frame is fixed in the positioning groove of the lower mold and molded to obtain a flexible self-cleaning bird-proof umbrella made of graphene modified silicone rubber.

2. The method for preparing a graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella cover according to claim 1, characterized in that, The ratio of the graphene-silicone rubber compound, stearic acid, hydroxyl silicone oil, diatomaceous earth, and 2,5-dimethyl-2,5-di-tert-butylperoxide is 200-300g: 0.5-0.6g: 0.4-0.7g: 3-4g: 0.2-0.4g.

3. The method for preparing a flexible self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber according to claim 1, characterized in that, The specific preparation steps for the modified graphene are as follows: Graphene, zinc acetate dihydrate powder, and anhydrous ethanol were added to a reaction vessel and stirred for 1-2 hours at 20-25℃ and 500-600 r / min. Then, hexamethylenetetramine and deionized water were added, heated to 80-90℃, and stirred for 15-16 hours. The mixture was filtered, and the filter cake was washed 2-4 times with deionized water and dried under vacuum at 60-70℃ for 1-2 hours to obtain modified graphene. The ratio of graphene, zinc acetate dihydrate powder, anhydrous ethanol, hexamethylenetetramine and deionized water is 80-90g: 20-30g: 300-400mL: 12-14g: 120-140mL.

4. The method for preparing a flexible self-cleaning bird-proof umbrella cover of graphene-modified silicone rubber according to claim 1, characterized in that, The specific preparation steps of the composite modified graphene are as follows: Modified graphene, anhydrous ethanol, and deionized water were added to a reaction vessel and stirred for 10-12 minutes at 60-70℃ and 500-600 r / min. Then, 3-aminopropyltriethoxysilane was added, and the pH was adjusted to 3-4 with hydrochloric acid solution. The reaction was continued with stirring for 6-7 hours. The mixture was filtered, and the product was washed 2-3 times with deionized water and anhydrous ethanol. The product was then vacuum dried at 60-80℃ for 1-2 hours to obtain the composite modified graphene.

5. The method for preparing a graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella cover according to claim 4, characterized in that, The ratio of the modified graphene, anhydrous ethanol, deionized water and 3-aminopropyltriethoxysilane is 70-80g: 80-100mL: 160-200mL: 20-22mL.

6. The method for preparing a flexible self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber according to claim 1, characterized in that, The specific preparation steps of the flame-retardant composite modified graphene are as follows: Phosphorus oxychloride, composite modified graphene, 4-aminobenzoic acid, acetonitrile and acetic acid were added to a reaction vessel and stirred for 6-9 hours at 20-25℃ and 500-600 r / min. After filtration, the product was washed 2-3 times with deionized water and anhydrous ethanol and dried under vacuum at 60-80℃ for 1-2 hours to obtain flame-retardant composite modified graphene. The ratio of phosphorus oxychloride, composite modified graphene, 4-aminobenzoic acid, acetonitrile and acetic acid is 20-24g: 20-22g: 34-36g: 800-900mL: 1.2-1.4L.

7. The method for preparing a graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella cover according to claim 1, characterized in that, The specific preparation steps of the self-cleaning composite graphene are as follows: Flame-retardant composite modified graphene and N,N-dimethylformamide were added to a polytetrafluoroethylene-lined reactor, sealed, and ultrasonically dispersed at 130-135℃ for 20-40 min. Then, methyl 4-amino-2-vinylbenzoate and titanium tetrachloride were added, and ultrasonically dispersed for 40-60 min. The mixture was stirred for 24-26 h, naturally cooled to room temperature, filtered, and the filter cake was washed 2-3 times with N,N-dimethylformamide and methanol, respectively. The mixture was then vacuum dried at 60-80℃ for 1-2 h to obtain self-cleaning composite graphene. The ratio of the flame-retardant composite modified graphene, N,N-dimethylformamide, methyl 4-amino-2-vinylbenzoate and titanium tetrachloride is 18-20g: 200-300mL: 25-30g: 30-40g.

8. The method for preparing a graphene-modified silicone rubber flexible self-cleaning bird-proof umbrella cover according to claim 1, characterized in that, The specific preparation steps for the graphene-silicone rubber composite are as follows: Self-cleaning composite graphene, methyl vinyl silicone rubber, and N,N-dimethylformamide were added to a reaction vessel and stirred for 20-30 minutes at 20-25℃ and 400-500 r / min. The mixture was then heated to 70-80℃, and ammonium persulfate was added. Under a nitrogen atmosphere, the mixture was stirred and reacted for 6-7 hours. After filtration, the filter cake was washed 2-4 times with petroleum ether and deionized water, respectively, and then vacuum dried at 60-70℃ for 1-2 hours to obtain the graphene-silicone rubber composite.

9. The method for preparing a flexible self-cleaning bird-proof umbrella cover of graphene-modified silicone rubber according to claim 8, characterized in that, The ratio of the self-cleaning composite graphene, methyl vinyl silicone rubber, N,N-dimethylformamide and ammonium persulfate is 15-20g: 300-400g: 700-800mL: 2-4g.

10. A flexible, self-cleaning bird-proof umbrella cover made of graphene-modified silicone rubber, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.