Anti-aging polymer plate and preparation method thereof

Abstract

The invention discloses an anti-aging polymer plate and a preparation method thereof, and relates to the technical field of materials. The anti-aging polymer plate prepared by the invention comprises modified polyethylene and modified functional particles, the modified polyethylene is obtained by grafting polyethylene with benzimidazole-carboxylic acid ethyl ester, then carrying out quaternization and aminolysis and then reacting with aniline; the modified functional particles are obtained by reacting shell-core functional particles with polyacrylate as a core and styrene and acrylamide polymer as a shell with 3-hydroxy-2-(hydroxymethyl) propionaldehyde and DOPO (9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) and then reacting with phosphoric acid; the anti-aging polymer plate prepared by the invention has good antibacterial, anti-aging, impact-resistant and flame-retardant properties.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to an anti-aging polymer sheet and its preparation method. Background Technology

[0002] Polymer sheets are sheet materials with specific shapes and properties, made primarily from synthetic polymer compounds through processing and molding. Their essence lies in utilizing the long-chain molecular structure of polymers to impart comprehensive properties such as strength, toughness, and plasticity. Common types include polyethylene (PE) sheets, polypropylene (PP) sheets, polyvinyl chloride (PVC) sheets, and polycarbonate (PC) sheets, which are widely used in building decoration (advertising signage, packaging containers, industrial equipment linings, and furniture manufacturing), etc.

[0003] Polyethylene sheets are widely used due to their excellent chemical stability, low water absorption, good electrical insulation, and ease of processing. However, their inherent defects limit their long-term use in harsher environments. Firstly, the polyethylene molecular chain contains tertiary carbon atoms, making it extremely sensitive to ultraviolet radiation and oxygen. Under outdoor sunlight exposure, it is highly susceptible to photo-oxidative degradation, and molecular chain breakage leads to surface powdering, discoloration, embrittlement, and a significant decrease in strength, resulting in poor weather resistance. Therefore, modification is urgently needed to impart superior anti-aging properties to extend its outdoor service life. Secondly, polyethylene lacks impact toughness at low temperatures or high strain rates, exhibiting a tendency towards brittle fracture. It is prone to cracking and breakage under external impact or dynamic loads, requiring modification to improve its impact resistance.

[0004] Furthermore, polyethylene is a hydrocarbon polymer with a low limiting oxygen index, making it highly flammable. This poses a significant safety hazard in fire-resistant applications such as construction and transportation. Therefore, flame-retardant modification is necessary to improve its flame retardancy rating and inhibit flame propagation and molten droplet formation. In addition, polyethylene sheets are prone to microbial growth and biofilm formation in humid, nutrient-rich environments (such as food packaging, kitchens, bathrooms, and medical areas), leading to material degradation and potential hygiene problems. Therefore, it is essential to endow them with effective antibacterial properties.

[0005] In summary, developing a modified polyethylene sheet that integrates multiple functions such as anti-aging, high impact resistance, efficient flame retardancy, and long-lasting antibacterial properties, and exploring its preparation method for large-scale production, has significant technical and commercial value for expanding the application of polyethylene sheets in high-end, demanding, and hygienic outdoor and indoor scenarios. Summary of the Invention

[0006] The purpose of this invention is to provide an anti-aging polymer board and its preparation method to solve the problems existing in the prior art.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A method for preparing an anti-aging polymer board includes the following preparation steps: (1) 1H-benzimidazole-6-carboxylic acid ethyl ester and 4-bromo-1-butene were reacted to obtain modified benzimidazole; benzimidazole was grafted onto polyethylene to obtain imidazole-based polyethylene; and imidazole-based polyethylene was quaternized to obtain quaternized polyethylene. (2) Quaternized polyethylene and aniline are reacted to obtain pre-modified polyethylene; pre-modified polyethylene and aniline are reacted to obtain modified polyethylene; (3) The butyl acrylate emulsion was polymerized to obtain an emulsion; (4) The emulsion is then polymerized with styrene and acrylamine emulsion to obtain functional particles; (5) The functional particles were reacted sequentially with 3-hydroxy-2-(hydroxymethyl)propionaldehyde, DOPO, and phosphoric acid to obtain modified functional particles; (6) The modified polyethylene and modified functional particles are mixed and hot-pressed by a flat vulcanizing machine to obtain an anti-aging polymer board.

[0008] As an optimization, the preparation method of the quaternized polyethylene in step (1) is as follows: polyethylene and xylene are mixed and heated to 100-110℃ and stirred for 30-40 min, then initiator and modified benzimidazole are added, and the mixture is reacted at 100-110℃ for 6-8 h to obtain imidazole-based polyethylene; the mass ratio of polyethylene, xylene, initiator and modified benzimidazole is 1:(30-40):(0.01-0.02):(0.2-0.3); Imidazole polyethylene is ground into powder; imidazole polyethylene powder, xylene, and bromododecane are mixed in a mass ratio of 1:(20-30):(0.3-0.4) and heated to 90-100℃ for 5-6 hours to obtain quaternized polyethylene.

[0009] As an optimization, the preparation method of the modified benzimidazole is as follows: 1H-benzimidazole-6-carboxylic acid ethyl ester, 4-bromo-1-butene, 18-crown ether-6, potassium hydroxide, and benzene are mixed and refluxed at 105-115℃ for 6-8 hours to obtain modified benzimidazole; the molar ratio of 1H-benzimidazole-6-carboxylic acid ethyl ester, 4-bromo-1-butene, 18-crown ether-6, and potassium hydroxide is 1:(1.01-1.05):(3-3.5):(3-3.5); the mass of benzene is 10-12 times that of benzimidazole.

[0010] As an optimization, the preparation method of the pre-modified polyethylene in step (2) is as follows: quaternized polyethylene, xylene, aniline and sodium methoxide are mixed and heated to 105-115℃ for 8-10h to obtain pre-modified polyethylene; the mass ratio of quaternized polyethylene, xylene, aniline and sodium methoxide is 1:(30-40):(0.3-0.4):(0.01-0.02); Premodified polyethylene, xylene, and nano copper oxide are mixed and heated to 80-90℃ and stirred for 30-40 minutes. Aniline is then added and reacted for 4-6 hours to obtain modified polyethylene. The mass ratio of premodified polyethylene, xylene, nano copper oxide, and aniline is 1:(30-40):(0.01-0.02):(0.3-0.4).

[0011] As an optimization, the preparation method of the emulsion in step (3) is as follows: Weigh the following raw materials: by mass parts, emulsifier A1 0.02-0.03 parts, pure water 150-200 parts, initiator solution 30-35 parts, emulsifier solution A2 20-25 parts, mixed monomer M1 30-35 parts, mixed monomer M2 130-150 parts; Mix emulsifier A1 with pure water and dissolve at 60-70℃. Add mixed monomer M1 and 1 / 2 of the initiator solution. After reacting for 30-40 minutes, add 1 / 3 of the emulsifier solution A2 and mixed monomer M2. Heat to 75-85℃ and react for 1-2 hours. Then add 1 / 4 of the initiator solution and 1 / 3 of the emulsifier solution A2 and react for 1-2 hours. Finally, add the remaining 1 / 4 of the initiator solution and 1 / 3 of the emulsifier solution A2 and react at a constant temperature for 2-3 hours to obtain the emulsion. As an optimization, the preparation method of the functional particles in step (4) is as follows: weigh the following raw materials: by mass parts, 200-250 parts of emulsion, 30-35 parts of pure water, 60-65 parts of mixed monomer M3, 1-2 parts of initiator potassium persulfate, and 0.6-0.8 parts of emulsifier sodium dodecylbenzenesulfonate; Mix the emulsion and pure water, heat to 60℃, add 1 / 3 of the mixed monomer M3 and 1 / 3 of the initiator, react for 30-40 min, add 1 / 3 of the emulsifier, add 2 / 3 of the mixed monomer M3 dropwise, and continue the reaction for 1-2 h. The mixed monomer M3 is obtained by mixing styrene and acrylamine in a mass ratio of 3:1. Add 1 / 3 of the initiator and 1 / 3 of the emulsifier, react for 1-2 h, add the remaining 1 / 3 of the initiator and 1 / 3 of the emulsifier, and react at a constant temperature for 3-4 h. Cool and discharge the material, and add the material dropwise to a 5wt% magnesium sulfate solution at 85-90℃, stirring at a constant temperature for 2-3 h to obtain functional particles; the mass ratio of the 5wt% magnesium sulfate solution to the material is (4-5):1.

[0012] As an optimization, the initiator solution is obtained by mixing initiator and pure water at a mass ratio of 1:3, the emulsifier solution A2 is obtained by mixing emulsifier and pure water at a mass ratio of 1:20, the mixed monomer M1 is obtained by mixing butyl acrylate and crosslinking agent at a mass ratio of 10:0.1, and the mixed monomer M2 is obtained by mixing butyl acrylate and crosslinking agent at a mass ratio of 10:0.2.

[0013] As an optimization, the preparation method of the modified functional particles in step (5) is as follows: the functional particles are ultrasonically dispersed in anhydrous ethanol, 3-hydroxy-2-(hydroxymethyl)propanal is added, the temperature is raised to 70-80℃ and stirred for 20-30 min, the temperature is raised to 80-90℃ and stirred for 4-5 h, DOPO is added, the temperature is raised to 110℃ and refluxed for 6-7 h to obtain pre-modified functional particles; the mass ratio of functional particles, 3-hydroxy-2-(hydroxymethyl)propanal, DOPO and anhydrous ethanol is 1:(0.5-0.7):(0.5-0.7):(15-20); The pre-modified functional particles, phosphoric acid, and xylene are reacted at 120-130℃ for 4-5 hours in a mass ratio of 1:(0.6-0.8):(15-20). Then, urea at 2-3 times the mass of phosphoric acid is added and the reaction continues for 1-2 hours to obtain the modified functional particles.

[0014] As an optimization, the mass ratio of modified polyethylene to modified functional particles in step (6) is 1:(0.2-0.3).

[0015] The present invention also provides an anti-aging polymer board prepared according to any one of the above preparation methods.

[0016] Compared with the prior art, the beneficial effects achieved by the present invention are: The anti-aging polymer board prepared by this invention comprises modified polyethylene and modified functional particles; the modified polyethylene is obtained by grafting benzimidazole-ethyl carboxylate onto polyethylene, followed by quaternization, aminolysis, and reaction with aniline; the modified functional particles are obtained by reacting core-shell functional particles with polyacrylate as the core and styrene and acrylamine polymer as the shell with 3-hydroxy-2-(hydroxymethyl)propionaldehyde, and then with phosphoric acid. First, vinylbenzimidazole containing a double bond is prepared by nucleophilic substitution of 1H-benzimidazole-6-carboxylate and 4-bromo-1-butene. In the presence of an initiator, the vinylbenzimidazole is grafted onto the side chain of polyethylene. Then, through reaction with bromododecane, a benzimidazole quaternary ammonium salt with antibacterial properties is generated on the side chain. 1H-benzimidazole-6-carboxylate and aniline are subjected to aminolysis to generate benzamide functional groups. Copper oxide is used as a Lewis acid catalyst to activate the carbonyl oxygen of the amide, enhancing the electrophilicity of carbon. The nitrogen atom of aniline / ammonia nucleophilically attacks the carbonyl carbon, forming a C=N bond (amidine structure) after dehydration, generating a benzamide derivative. The extended conjugated π electron system of the benzamide derivative and benzimidazole absorbs ultraviolet light and converts light energy into heat energy, thereby significantly reducing the destructive effect of ultraviolet light on the polymer backbone and endowing the material with excellent resistance to ultraviolet aging. Secondly, functional particles with a core-shell structure were prepared using polyacrylate as the core and styrene and acrylamine polymers as the shell. The acrylate polymer has strong impact resistance and good weather resistance, styrene has excellent molding and processing performance, and acrylamine provides amino functional groups for subsequent reactions. The core-shell structured functional particles synthesized by emulsion polymerization effectively combine the properties of the three reactive monomers, giving the material good impact resistance. The amino group of acrylamine and 3-hydroxy-2-(hydroxymethyl)propanal form an imine bond, and the PH bond of DOPO undergoes nucleophilic addition to the imine bond (C=N) to generate an intermediate containing a PN bond. The polyhydroxy group of 3-hydroxy-2-(hydroxymethyl)propanal reacts with phosphoric acid to finally obtain a PN synergistic flame-retardant structure, giving the material good flame-retardant properties. Finally, modified polyethylene and modified functional particles were mixed to prepare polymer sheets. The negatively charged phosphate groups on the surface of the functional particles and the positively charged quaternary ammonium salt groups on the polyethylene side chains significantly enhanced the interfacial bonding force between the modified polyethylene matrix and the modified functional particles through electrostatic interaction. This strong interfacial bonding facilitates stress transfer, reduces interfacial defects, and synergistically leverages the advantages of the two modified components (UV resistance, antibacterial properties, flame retardancy, and impact resistance), thereby improving the overall performance and long-term stability (aging resistance) of the final sheet. Detailed Implementation

[0017] 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.

[0018] The polyethylene grade described in the following examples and comparative examples is DJM1820, purchased from Sinopec Yangzi Petrochemical Co., Ltd.; the nano-copper oxide particles have a diameter of 50 nm and were purchased from Nanjing Jike Biotechnology Co., Ltd.; the emulsifier A1 is sodium dodecylbenzenesulfonate, the initiator solution is obtained by mixing potassium persulfate and pure water at a mass ratio of 1:3, the emulsifier solution A2 is obtained by mixing sodium dodecylbenzenesulfonate and pure water at a mass ratio of 1:20, the mixed monomer M1 is obtained by mixing butyl acrylate and crosslinking agent diallyl phthalate at a mass ratio of 10:0.1, the mixed monomer M2 is obtained by mixing butyl acrylate and crosslinking agent diallyl phthalate at a mass ratio of 10:0.2, and the mixed monomer M3 is obtained by mixing styrene and acrylamine at a mass ratio of 3:1; the DOPO is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.

[0019] Example 1: This embodiment describes a method for preparing anti-aging polymer boards, including the following steps: (1) Ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown ether-6, potassium hydroxide, and benzene were mixed and refluxed at 115°C for 8 hours. The mixture was filtered and the filtrate was retained. Benzene was removed under reduced pressure to obtain modified benzenemidazole. The molar ratio of ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown ether-6, and potassium hydroxide was 1:1.01:3:3. The mass of benzene was 10 times that of benzenemidazole. Polyethylene and xylene were mixed and heated to 110℃ and stirred for 40 min. Initiator and modified benzimidazole were added, and the mixture was reacted at 110℃ for 8 h. After precipitation with ethanol, filtration, washing and drying, imidazole-based polyethylene was obtained. The mass ratio of polyethylene, xylene, initiator benzoyl peroxide and modified benzimidazole was 1:30:0.01:0.2. Imidazole polyethylene was ground into 200-mesh powder; the imidazole polyethylene powder, xylene, and bromododecane were mixed at a mass ratio of 1:20:0.3 and heated to 100℃ for 6 hours. After cooling to room temperature, the mixture was precipitated with ethanol, washed with ethanol and acetone, and dried under vacuum to obtain quaternized polyethylene. (2) Quaternized polyethylene, xylene, aniline and sodium methoxide were mixed and heated to 115°C for 10 h. After cooling to room temperature, xylene was removed by rotary evaporation under reduced pressure. The mixture was then washed successively with 1M hydrochloric acid solution, saturated sodium bicarbonate solution and saturated sodium chloride solution and dried under vacuum to obtain pre-modified polyethylene. The mass ratio of quaternized polyethylene, xylene, aniline and sodium methoxide was 1:30:0.3:0.01. Pre-modified polyethylene, xylene, and nano-copper oxide were ultrasonically mixed and heated to 90°C with stirring for 40 min. Aniline was then added and the reaction continued for 6 h. After cooling to room temperature, the mixture was precipitated with acetone, filtered, washed, and vacuum dried to obtain modified polyethylene. The mass ratio of pre-modified polyethylene, xylene, nano-copper oxide, and aniline was 1:30:0.01:0.3. (3) Weigh the following raw materials: by mass parts, emulsifier A1 0.02 parts, pure water 150 parts, initiator solution 30 parts, emulsifier solution A2 20 parts, mixed monomer M1 30 parts, mixed monomer M2 130 parts; Emulsifier A1 was mixed with pure water and dissolved at 70°C. Mixed monomer M1 and half of the initiator solution were added. After reacting for 40 minutes, half of the emulsifier solution A2 was added, followed by the dropwise addition of mixed monomer M2. The temperature was raised to 85°C, and the reaction continued for 2 hours after the dropwise addition was completed. Then, half of the initiator solution and half of the emulsifier solution A2 were added, and the reaction continued for 2 hours. Finally, the remaining half of the initiator solution and half of the emulsifier solution A2 were added, and the reaction was carried out at a constant temperature for 3 hours to obtain an emulsion with a particle size of 100 nm. The initiator solution and emulsifier solution were added in three batches. (4) Weigh the following raw materials: by mass, 200 parts emulsion, 30 parts pure water, 360 parts mixed monomer M3, 1 part potassium persulfate initiator, and 0.6 parts sodium dodecylbenzene sulfonate emulsifier; The emulsion and pure water were mixed and heated to 60°C. One-third of the mixed monomer M3 and one-third of the initiator were added, and the reaction was allowed to proceed for 40 minutes. One-third of the emulsifier was then added, followed by the dropwise addition of two-thirds of the mixed monomer M3. After the dropwise addition was complete, the reaction continued for 1-2 hours. One-third of the initiator and one-third of the emulsifier were then added, and the reaction was allowed to proceed for 2 hours. The remaining one-third of the initiator and one-third of the emulsifier were then added in three batches. After the addition was complete, the reaction was kept at a constant temperature for 4 hours. The mixture was then cooled and discharged. The solution was added dropwise to a 5 wt% magnesium sulfate solution at 90°C, and stirred at a constant temperature for 3 hours. After filtration, washing with water (60°C hot water), and drying (60°C vacuum drying), functional particles were obtained. The mass ratio of the 5 wt% magnesium sulfate solution to the solution was 4:1. (5) The functional particles were ultrasonically dispersed in anhydrous ethanol, 3-hydroxy-2-(hydroxymethyl)propanal was added, the temperature was raised to 80℃ and stirred for 30 min, the temperature was raised to 90℃ and stirred for 5 h, DOPO was added, the temperature was raised to 110℃ and refluxed for 7 h, and the mixture was filtered, washed with anhydrous ethanol and pure water and dried to obtain the pre-modified functional particles; the mass ratio of functional particles, 3-hydroxy-2-(hydroxymethyl)propanal, DOPO and anhydrous ethanol was 1:0.5:0.5:15; The pre-modified functional particles, phosphoric acid, and xylene were refluxed at 130℃ for 5 hours at a mass ratio of 1:0.6:15. Urea with a mass of twice that of phosphoric acid was added and the reaction was continued for 2 hours. After filtration, washing with acetone and drying, the modified functional particles were obtained. (6) Mix modified polyethylene and modified functional particles at a mass ratio of 1:0.2, place them in a mold, and hot press them with a flat vulcanizing machine to obtain anti-aging polymer sheets; the mold size is 300mm×300mm; the parameters of the flat vulcanizing machine are 6MPa, 180℃, and the hot pressing time is 45min.

[0020] Example 2: This embodiment describes a method for preparing anti-aging polymer boards, including the following steps: (1) Ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown ether-6, potassium hydroxide, and benzene were mixed and refluxed at 110°C for 7 hours. The mixture was filtered and the filtrate was retained. Benzene was removed under reduced pressure to obtain modified benzeneimidazole. The molar ratio of ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown ether-6, and potassium hydroxide was 1:1.02:3.2:3.2. The mass of benzene was 11 times that of benzeneimidazole. Polyethylene and xylene were mixed and heated to 105℃ and stirred for 35 min. Initiator and modified benzimidazole were added, and the mixture was reacted at 105℃ for 7 h. After precipitation with ethanol, filtration, washing and drying, imidazole-based polyethylene was obtained. The mass ratio of polyethylene, xylene, initiator benzoyl peroxide and modified benzimidazole was 1:35:0.01:0.25. Imidazole polyethylene was ground into 200-mesh powder; the imidazole polyethylene powder, xylene, and bromododecane were mixed at a mass ratio of 1:25:0.35 and heated to 95°C for 5.5 h. After cooling to room temperature, the mixture was precipitated with ethanol, washed with ethanol and acetone, and dried under vacuum to obtain quaternized polyethylene. (2) Quaternized polyethylene, xylene, aniline and sodium methoxide were mixed and heated to 100°C for 9 hours. After cooling to room temperature, xylene was removed by rotary evaporation under reduced pressure. The mixture was then washed successively with 1M hydrochloric acid solution, saturated sodium bicarbonate solution and saturated sodium chloride solution and dried under vacuum to obtain pre-modified polyethylene. The mass ratio of quaternized polyethylene, xylene, aniline and sodium methoxide was 1:35:0.35:0.01. Premodified polyethylene, xylene, and nano copper oxide were ultrasonically mixed and heated to 85°C and stirred for 35 min. Aniline was added and the reaction continued for 5 h. After cooling to room temperature, the mixture was precipitated with acetone, filtered, washed, and vacuum dried to obtain modified polyethylene. The mass ratio of premodified polyethylene, xylene, nano copper oxide, and aniline was 1:35:0.01:0.35. (3) Weigh the following raw materials: by mass parts, emulsifier A1 0.025 parts, pure water 170 parts, initiator solution 33 parts, emulsifier solution A2 22 parts, mixed monomer M1 32 parts, mixed monomer M2 140 parts; Emulsifier A1 was mixed with pure water and dissolved at 65°C. Mixed monomer M1 and half of the initiator solution were added. After reacting for 35 minutes, one-third of the emulsifier solution A2 was added, followed by dropwise addition of mixed monomer M2. The temperature was raised to 80°C, and the reaction continued until the addition was complete. After 1.5 hours, one-quarter of the initiator solution and one-third of the emulsifier solution A2 were added, and the reaction continued for another 1.5 hours. The remaining one-quarter of the initiator solution and one-third of the emulsifier solution A2 were then added, and the reaction was maintained at a constant temperature for 2.5 hours to obtain an emulsion with a particle size of 100 nm. (The initiator solution and emulsifier solution were added in three batches.) (4) Weigh the following raw materials: by mass parts, 230 parts emulsion, 32 parts pure water, 363 parts mixed monomer M3, 1.5 parts potassium persulfate initiator, and 0.7 parts sodium dodecylbenzene sulfonate emulsifier; The emulsion and pure water were mixed and heated to 60°C. One-third of the mixed monomer M3 and one-third of the initiator were added, and the reaction was allowed to proceed for 35 minutes. One-third of the emulsifier was then added, followed by the dropwise addition of two-thirds of the mixed monomer M3. After the dropwise addition was complete, the reaction continued for 1.5 hours. One-third of the initiator and one-third of the emulsifier were then added, and the reaction was allowed to proceed for another 1.5 hours. The remaining one-third of the initiator and one-third of the emulsifier were then added (the initiator and emulsifier were added in three batches). After the addition was complete, the reaction was kept at a constant temperature for 3.5 hours. The mixture was then cooled and discharged. The solution was added dropwise to a 5 wt% magnesium sulfate solution at 87°C, and stirred at a constant temperature for 2.5 hours. The mixture was then filtered, washed with water (60°C hot water), and dried (60°C vacuum drying) to obtain functional particles. The mass ratio of the 5 wt% magnesium sulfate solution to the solution was 4.5:1. (5) The functional particles were ultrasonically dispersed in anhydrous ethanol, 3-hydroxy-2-(hydroxymethyl)propanal was added, the temperature was raised to 75°C and stirred for 25 min, the temperature was raised to 85°C and stirred for 4.5 h, DOPO was added, the temperature was raised to 110°C and refluxed for 6.5 h, and the mixture was filtered, washed with anhydrous ethanol and pure water and dried to obtain the pre-modified functional particles; the mass ratio of functional particles, 3-hydroxy-2-(hydroxymethyl)propanal, DOPO and anhydrous ethanol was 1:0.6:0.6:17; The pre-modified functional particles, phosphoric acid, and xylene were refluxed at 125°C for 4.5 h at a mass ratio of 1:0.7:17. Then, urea at 2.5 times the mass of phosphoric acid was added and the reaction was continued for another 1.5 h. After filtration, washing with acetone, and drying, the modified functional particles were obtained. (6) Mix modified polyethylene and modified functional particles at a mass ratio of 1:0.25, place them in a mold, and hot press them with a flat vulcanizing machine to obtain anti-aging polymer sheets; the mold size is 300mm×300mm; the parameters of the flat vulcanizing machine are 6MPa, 180℃, and the hot pressing time is 45min.

[0021] Example 3: This embodiment describes a method for preparing anti-aging polymer boards, including the following steps: (1) Ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown ether-6, potassium hydroxide, and benzene were mixed and refluxed at 105℃ for 6 hours. The mixture was filtered and the filtrate was retained. Benzene was removed under reduced pressure to obtain modified benzeneimidazole. The molar ratio of ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown ether-6, and potassium hydroxide was 1:1.05:3.5:3.5. The mass of benzene was 12 times that of benzeneimidazole. Polyethylene and xylene were mixed and heated to 100℃ and stirred for 30 min. Initiator and modified benzimidazole were added, and the mixture was reacted at 100℃ for 6 h. After precipitation with ethanol, filtration, washing and drying, imidazole-based polyethylene was obtained. The mass ratio of polyethylene, xylene, initiator benzoyl peroxide and modified benzimidazole was 1:40:0.02:0.3. Imidazole polyethylene was ground into 200-mesh powder; the imidazole polyethylene powder, xylene, and bromododecane were mixed at a mass ratio of 1:30:0.4 and heated to 90°C for 5 hours. After cooling to room temperature, the mixture was precipitated with ethanol, washed with ethanol and acetone, and dried under vacuum to obtain quaternized polyethylene. (2) Quaternized polyethylene, xylene, aniline and sodium methoxide were mixed and heated to 105℃ for 8-h. After cooling to room temperature, xylene was removed by rotary evaporation under reduced pressure. The mixture was then washed successively with 1M hydrochloric acid solution, saturated sodium bicarbonate solution and saturated sodium chloride solution and dried under vacuum to obtain pre-modified polyethylene. The mass ratio of quaternized polyethylene, xylene, aniline and sodium methoxide was 1:40:0.4:0.02. Pre-modified polyethylene, xylene, and nano-copper oxide were ultrasonically mixed and heated to 80°C with stirring for 30 min. Aniline was then added and the reaction continued for 4 h. After cooling to room temperature, the mixture was precipitated with acetone, filtered, washed, and vacuum dried to obtain modified polyethylene. The mass ratio of pre-modified polyethylene, xylene, nano-copper oxide, and aniline was 1:40:0.02:0.4. (3) Weigh the following raw materials: by mass parts, 0.03 parts of emulsifier A1, 200 parts of pure water, 35 parts of initiator solution, 25 parts of emulsifier solution A2, 35 parts of mixed monomer M1, and 150 parts of mixed monomer M2; Emulsifier A1 was mixed with pure water and dissolved at 60°C. Mixed monomer M1 and half of the initiator solution were added. After reacting for 30 minutes, one-third of the emulsifier solution A2 was added, followed by the dropwise addition of mixed monomer M2. The temperature was raised to 75°C, and the reaction continued for 1 hour after the dropwise addition was completed. Then, one-quarter of the initiator solution and one-third of the emulsifier solution A2 were added, and the reaction was carried out for 1 hour. Finally, the remaining one-quarter of the initiator solution and one-third of the emulsifier solution A2 were added, and the reaction was carried out at a constant temperature for 2 hours to obtain an emulsion with a particle size of 100 nm. The initiator solution and emulsifier solution were added in three batches. (4) Weigh the following raw materials: by mass parts, 250 parts emulsion, 35 parts pure water, 365 parts mixed monomer M, 2 parts potassium persulfate initiator, and 0.8 parts sodium dodecylbenzene sulfonate emulsifier; The emulsion and pure water were mixed and heated to 60°C. One-third of the mixed monomer M3 and one-third of the initiator were added, and the reaction was allowed to proceed for 30 minutes. One-third of the emulsifier was then added, followed by the dropwise addition of two-thirds of the mixed monomer M3. After the dropwise addition was complete, the reaction continued for 1 hour. One-third of the initiator and one-third of the emulsifier were then added, and the reaction was allowed to proceed for another hour. The remaining one-third of the initiator and one-third of the emulsifier were then added in three batches. After the addition was complete, the reaction was kept at a constant temperature for 3 hours. The mixture was then cooled and discharged. The solution was added dropwise to a 5 wt% magnesium sulfate solution at 85°C, and stirred at a constant temperature for 2 hours. After filtration, washing with water (60°C hot water), and drying (60°C vacuum drying), functional particles were obtained. The mass ratio of the 5 wt% magnesium sulfate solution to the solution was 5:1. (5) The functional particles were ultrasonically dispersed in anhydrous ethanol, 3-hydroxy-2-(hydroxymethyl)propanal was added, the temperature was raised to 70℃ and stirred for 20 min, the temperature was raised to 80℃ and stirred for 4 h, DOPO was added, the temperature was raised to 110℃ and refluxed for 6 h, and the mixture was filtered, washed with anhydrous ethanol and pure water and dried to obtain the pre-modified functional particles; the mass ratio of functional particles, 3-hydroxy-2-(hydroxymethyl)propanal, DOPO and anhydrous ethanol was 1:0.7:0.7:20; The pre-modified functional particles, phosphoric acid, and xylene were refluxed at 120℃ for 4 hours at a mass ratio of 1:0.8:20. Urea with a mass of 3 times that of phosphoric acid was added and the reaction was continued for 1 hour. After filtration, washing with acetone and drying, the modified functional particles were obtained. (6) Mix modified polyethylene and modified functional particles at a mass ratio of 1:0.3, place them in a mold, and hot press them with a flat vulcanizing machine to obtain anti-aging polymer sheets; the mold size is 300mm×300mm; the parameters of the flat vulcanizing machine are 6MPa, 180℃, and the hot pressing time is 45min.

[0022] Comparative Example 1: The difference between the preparation method of the anti-aging polymer sheet in Comparative Example 1 and Example 2 is that the polyethylene is not modified. Specifically, steps (1) and (2) are omitted. Step (6) is modified to mix polyethylene and modified functional particles at a mass ratio of 1:0.25, place them in a mold, and hot press them in a flat vulcanizing machine to obtain the anti-aging polymer sheet. The mold size is 300mm×300mm. The parameters of the flat vulcanizing machine are 6MPa, 180℃, and the hot pressing time is 45min. The remaining steps are the same as in Example 2.

[0023] Comparative Example 2: The difference between the preparation method of the anti-aging polymer board in Comparative Example 2 and Example 2 is that the functional particles are not modified. Specifically, step (5) is omitted, and step (6) is modified as follows: the modified polyethylene and functional particles are mixed at a mass ratio of 1:0.25, placed in a mold, and hot-pressed by a flat vulcanizing machine to obtain the anti-aging polymer board; the mold size is 300mm×300mm; the parameters of the flat vulcanizing machine are 6MPa, 180℃, and the hot-pressing time is 45min. The remaining steps are the same as in Example 2.

[0024] Comparative Example 3: The preparation method of the anti-aging polymer sheet in Comparative Example 3 differs from that in Example 2 in that it does not contain modified functional particles, specifically steps (3) to (5) are omitted. Step (6) is modified as follows: the modified polyethylene is placed in a mold and hot-pressed by a flat vulcanizing machine to obtain the anti-aging polymer sheet; the mold size is 300mm×300mm; the parameters of the flat vulcanizing machine are 6MPa, 180℃, and the hot-pressing time is 45min. The remaining steps are the same as in Example 2.

[0025] Test Example 1: Antibacterial performance testing: Test method: The boards prepared in the examples and comparative examples were cut into small pieces and ground into powder with a particle size of 200 mesh. The antibacterial rate was tested according to standard GB / T 21510-2017. The results are shown in Table 1. A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 1 shows that the material prepared by the present invention has good antibacterial properties.

[0026] The antibacterial properties of Examples 1-3 are superior to those of the comparative examples, indicating that firstly, vinylbenzimidazole containing double bonds is prepared by nucleophilic substitution of 1H-benzimidazole-6-carboxylic acid ethyl ester and 4-bromo-1-butene. In the presence of an initiator, the vinylbenzimidazole is grafted onto the side chain of polyethylene. Then, by reacting with bromododecane, a benzimidazole quaternary ammonium salt with antibacterial properties is generated on the side chain, which can endow the material with good antibacterial properties.

[0027] Test Example 2: Impact resistance testing: Test method: The impact resistance was tested according to standard GB / T 1843–2008. The plates prepared in the examples and comparative examples were cut into specimens with a size of 80mm×10mm×4mm. The pendulum pre-lift angle was 150° and the impact energy was 5.5J. The results are shown in Table 2.

[0028] Anti-aging performance testing: Test method: The sample was placed in a UV aging chamber for 720 hours. The test conditions were: UVB-313 lamp as the light source, with an irradiance of 0.72 W / m². 2 The blackboard temperature was 60℃. The aged samples were tested according to the mechanical property testing methods. The impact strength retention rate before and after aging was calculated; the results are shown in Table 2. A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 2 reveals that the material prepared by the present invention has good mechanical properties and anti-aging properties.

[0029] The mechanical properties of Examples 1-3 are superior to those of the Comparative Example, and the anti-aging properties of Examples 1-3 are superior to those of the Comparative Example. This is because ethyl 1H-benzimidazole-6-carboxylate and 4-bromo-1-butene are nucleophilically substituted to obtain vinylbenzimidazole containing a double bond. In the presence of an initiator, the vinylbenzimidazole is grafted onto the side chain of polyethylene. ethyl 1H-benzimidazole-6-carboxylate and aniline undergo an aminolysis reaction to generate a benzamide functional group. Copper oxide acts as a Lewis acid catalyst, activating the carbonyl oxygen of the amide and enhancing the electrophilicity of carbon. The nitrogen atom of aniline / ammonia nucleophilically attacks the carbonyl carbon, forming a C=N bond (amidinium structure) after dehydration, generating a benzamide derivative. The extended conjugated π-electron system of the benzamide derivative and benzamide absorbs ultraviolet light, converting light energy into heat energy, thereby significantly reducing the destructive effect of ultraviolet light on the polymer backbone and endowing the material with excellent anti-ultraviolet aging ability. Secondly, functional particles with a core-shell structure were prepared using polyacrylate as the core and styrene and acrylamine polymers as the shell. The acrylate polymer has strong impact resistance and good weather resistance, styrene has excellent molding and processing performance, and acrylamine provides amino functional groups for subsequent reactions. The core-shell structured functional particles synthesized by emulsion polymerization effectively combine the properties of the three reactive monomers, giving the material good impact resistance.

[0030] Test Example 3: Flame retardant performance testing: Test method: The polymer sheet was cut into strips of 100.0mm × 10.0mm × 4.0mm. The limiting oxygen index was tested using an M606B digital oxygen index tester according to GB / T2406.2-2009 standard. The results are shown in Table 3. A comparison of the experimental data of Examples 1-3 and Comparative Examples 1-3 in Table 3 shows that the material prepared by the present invention has good flame retardant properties.

[0031] The flame retardant properties of Examples 1-3 are superior to those of the comparative examples, indicating that functional particles with a core-shell structure are prepared by using polyacrylate as the core and styrene and acrylamine polymers as the shell. Acrylamine provides amino functional groups for subsequent reactions. The amino group of acrylamine and 3-hydroxy-2-(hydroxymethyl)propanal form an imine bond, and the PH bond of DOPO undergoes nucleophilic addition to the imine bond (C=N) to generate an intermediate containing a PN bond. The polyhydroxy group of 3-hydroxy-2-(hydroxymethyl)propanal reacts with phosphoric acid to finally obtain a PN-synergistic flame retardant structure, which endows the material with good flame retardant properties.

[0032] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing an anti-aging polymer board, characterized by, The preparation steps include: (1) reacting ethyl 1H-benzimidazole-6-carboxylate and 4-bromo-1-butene to obtain modified benzimidazole; grafting polyethylene with the modified benzimidazole to obtain imidazole-based polyethylene; and quaternizing the imidazole-based polyethylene to obtain quaternized polyethylene; (2) reacting the quaternized polyethylene and aniline to obtain pre-modified polyethylene; and reacting the pre-modified polyethylene and aniline to obtain modified polyethylene; (3) emulsion polymerization of butyl acrylate to obtain an emulsion; (4) emulsion polymerization of the emulsion, styrene and propylene amine to obtain functional particles; (5) reacting the functional particles with 3-hydroxy-2-(hydroxymethyl)propanal, DOPO and phosphoric acid in sequence to obtain modified functional particles; (6) mixing the modified polyethylene and the modified functional particles, and hot pressing by a flat vulcanizing machine to obtain an anti-aging polymer plate.

2. The method for preparing the anti-aging polymer board according to claim 1, characterized in that, In step (1), the quaternized polyethylene is prepared by mixing polyethylene and xylene at 100-110°C for 30-40 min, adding an initiator and modified benzimidazole, and reacting at 100-110°C for 6-8 h; the mass ratio of polyethylene, xylene, initiator and modified benzimidazole is 1:(30-40):(0.01-0.02):(0.2-0.3). The imidazole-based polyethylene is ground into powder; the imidazole-based polyethylene powder, xylene and bromododecane are mixed at a mass ratio of 1:(20-30):(0.3-0.4), heated to 90-100°C and reacted for 5-6 h to obtain the quaternized polyethylene.

3. The method for preparing the anti-aging polymer board according to claim 2, characterized in that, The modified benzimidazole is prepared by mixing ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown-6 ether, potassium hydroxide and benzene, heating to 105-115°C and refluxing for 6-8 h; the molar ratio of ethyl 1H-benzimidazole-6-carboxylate, 4-bromo-1-butene, 18-crown-6 ether and potassium hydroxide is 1:(1.01-1.05):(3-3.5):(3-3.5); the mass of benzene is 10-12 times that of benzimidazole.

4. The method for preparing the anti-aging polymer board according to claim 1, characterized in that, In step (2), the pre-modified polyethylene is prepared by mixing the quaternized polyethylene, xylene, aniline and sodium methoxide, heating to 105-115°C and reacting for 8-10 h; the mass ratio of the quaternized polyethylene, xylene, aniline and sodium methoxide is 1:(30-40):(0.3-0.4):(0.01-0.02). The pre-modified polyethylene, xylene and nano copper oxide are mixed, heated to 80-90°C and stirred for 30-40 min, aniline is added and reacted for 4-6 h to obtain the modified polyethylene; the mass ratio of the pre-modified polyethylene, xylene, nano copper oxide and aniline is 1:(30-40):(0.01-0.02):(0.3-0.4). The pre-modified polyethylene, xylene and nano copper oxide are mixed, heated to 80-90°C and stirred for 30-40 min, aniline is added and reacted for 4-6 h to obtain the modified polyethylene; the mass ratio of the pre-modified polyethylene, xylene, nano copper oxide and aniline is 1:(30-40):(0.01-0.02):(0.3-0.4).

5. The method for preparing the anti-aging polymer board according to claim 1, characterized in that, The preparation method of the emulsion in step (3) is as follows: the following raw materials are weighed: 0.02-0.03 parts of emulsifier A1, 150-200 parts of pure water, 30-35 parts of initiator solution, 20-25 parts of emulsifier solution A2, 30-35 parts of mixed monomer M1, and 130-150 parts of mixed monomer M2, in terms of mass fraction; The emulsifier A1 and the pure water are mixed and dissolved at 60-70℃, 1 / 2 of the initiator solution and the mixed monomer M1 are added, after 30-40 min of reaction, 1 / 3 of the emulsifier solution A2 and the mixed monomer M2 are added, and the temperature is raised to 75-85℃, after 1-2 h of reaction, 1 / 4 of the initiator solution and 1 / 3 of the emulsifier solution A2 are added, and after 1-2 h of reaction, the remaining 1 / 4 of the initiator solution and 1 / 3 of the emulsifier solution A2 are added, and constant temperature reaction is carried out for 2-3 h to obtain the emulsion.

6. The method for preparing the anti-aging polymer board according to claim 1, characterized in that, The preparation method of the functional particles in step (4) is as follows: the following raw materials are weighed: 200-250 parts of emulsion, 30-35 parts of pure water, 60-65 parts of mixed monomer M3, 1-2 parts of initiator, and 0.6-0.8 parts of emulsifier, in terms of mass fraction; The emulsion and the pure water are mixed and the temperature is raised to 60℃, 1 / 3 of the mixed monomer M3 and 1 / 3 of the initiator are added, and after 30-40 min of reaction, 1 / 3 of the emulsifier is added, 2 / 3 of the mixed monomer M3 is added dropwise, and the reaction is continued for 1-2 h, the mixed monomer M3 is obtained by mixing styrene and propylene amine in a mass ratio of 3:1, 1 / 3 of the initiator and 1 / 3 of the emulsifier are added, and after 1-2 h of reaction, the remaining 1 / 3 of the initiator and 1 / 3 of the emulsifier are added, and after the addition is completed, constant temperature reaction is carried out for 3-4 h, and the product is cooled and discharged, the emulsion is added dropwise into a 5wt% magnesium sulfate solution at 85-90℃, and constant temperature stirring is carried out for 2-3 h to obtain the functional particles; the mass ratio of the 5wt% magnesium sulfate solution to the emulsion is (4-5):

1.

7. The method for preparing the anti-aging polymer board according to claim 5, characterized in that, The initiator solution is obtained by mixing the initiator and pure water in a mass ratio of 1:3, the emulsifier solution A2 is obtained by mixing the emulsifier and pure water in a mass ratio of 1:20, the mixed monomer M1 is obtained by mixing butyl acrylate and a crosslinking agent in a mass ratio of 10:0.1, and the mixed monomer M2 is obtained by mixing butyl acrylate and a crosslinking agent in a mass ratio of 10:0.

2.

8. The method for preparing the anti-aging polymer board according to claim 1, characterized in that, The preparation method of the modified functional particles in step (5) is as follows: the functional particles are dispersed in anhydrous ethanol, 3-hydroxy-2-(hydroxymethyl) propionaldehyde is added, the temperature is raised to 70-80℃, and stirring is carried out for 20-30 min, the temperature is raised to 80-90℃, and stirring is carried out for 4-5 h, DOPO is added, the temperature is raised to 110℃, and reflux reaction is carried out for 6-7 h to obtain the pre-modified functional particles; the mass ratio of the functional particles, 3-hydroxy-2-(hydroxymethyl) propionaldehyde, DOPO, and anhydrous ethanol is 1:(0.5-0.7):(0.5-0.7):(15-20); The pre-modified functional particles, phosphoric acid, and dimethylbenzene are reacted at 120-130℃ for 4-5 h, and urea in an amount of 2-3 times the mass of the phosphoric acid is added to continue the reaction for 1-2 h to obtain the modified functional particles.

9. The method for preparing the anti-aging polymer board according to claim 1, characterized in that, The mass ratio of the modified polyethylene and the modified functional particles in step (6) is 1:(0.2-0.3).

10. An anti-aging polymer board prepared by the method according to any one of claims 1-9.

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