A flame-retardant high-wear-resistant modified polyolefin material, a preparation method thereof and a valve

Abstract

The application belongs to the technical field of high polymer materials, and specifically provides a kind of flame-retardant high wear-resistant modified polyolefin material and its preparation method, valve.A kind of flame-retardant high wear-resistant modified polyolefin material includes the following raw materials: polypropylene, reinforcing fiber, multifunctional composite material and antioxidant;The reinforcing fiber is one of glass fiber, carbon fiber and basalt fiber;The multifunctional composite is prepared by polyionic liquid modified COFs, carbon nanotube and poly 3,4-ethylenedioxythiophene composite.The flame-retardant high wear-resistant modified polyolefin material prepared by the application has good flame-retardant, wear-resistant, antistatic advantages.

Description

Technical Field

[0001] This application belongs to the field of polymer materials technology, and in particular relates to a flame-retardant and highly wear-resistant modified polyolefin material and its preparation method, as well as a valve. Background Technology

[0002] Plastic valves are increasingly widely used in industry due to their lower cost and ease of maintenance. Polypropylene, as a general-purpose plastic, exhibits excellent heat resistance and chemical stability, demonstrating good corrosion resistance in common acid, alkali, and salt media and solvents, making it an ideal raw material for plastic valve manufacturing and enabling its application in corrosive conditions. However, polypropylene is prone to oxidation and aging in air, leading to a decline in mechanical properties over long-term use; its large coefficient of linear expansion makes it susceptible to dimensional deformation with temperature changes, resulting in valve sealing failure and fluid leakage; furthermore, its poor rigidity and low strength result in valves with weak impact resistance, and its poor wear resistance leads to easy wear of components during valve opening and closing, significantly shortening service life and increasing maintenance costs. In addition, plastic materials are prone to generating static electricity that is difficult to dissipate, posing a safety hazard. Polypropylene itself is flammable and has low pressure and impact resistance, making it difficult for plastic valves to safely and reliably replace metal valves in industrial scenarios involving high temperature, high pressure, strong corrosion, or flammable and explosive environments.

[0003] To address the above issues, current methods for improving the wear resistance of polypropylene often involve adding wear-resistant fillers such as reinforcing fibers; for flame retardancy, additive flame retardants such as halogenated and phosphorus-based flame retardants are often added; and for antistatic properties, a combination of organic and inorganic antistatic agents is frequently used. For example, patent application CN120365657A discloses a wear-resistant and high-toughness polypropylene material and its preparation method. This application uses polypropylene as the base material and compatibilizers, ethylene-octene block copolymers, and mullite functional agents as excipients. The wear-resistant and high-toughness polypropylene material is prepared through mixing and melt extrusion processes. The resulting material has higher hardness, thereby reducing the width of wear marks on the film surface and improving the wear resistance of the material.

[0004] The aforementioned document describes the use of branched macromolecular polymers to modify the surface of mullite. The presence of these macromolecular polymers improves the compatibility between mullite and the polypropylene matrix, and also allows for cross-linking with the polypropylene molecular chains. This helps mullite effectively exert its reinforcing effect and increases the structural density of the polypropylene material, resulting in higher hardness. However, this document only improves the wear resistance of the polypropylene material, without enhancing its flame retardant and antistatic properties, thus limiting its application range. Summary of the Invention

[0005] To address the aforementioned issues and further improve the flame retardant and wear-resistant properties of polypropylene, this application provides a flame-retardant and highly wear-resistant modified polyolefin material, its preparation method, and a valve.

[0006] This application first provides a flame-retardant and highly wear-resistant modified polyolefin material, comprising the following raw materials: polypropylene, reinforcing fibers, multifunctional composite materials, and antioxidants; The reinforcing fiber is one of glass fiber, carbon fiber, and basalt fiber; The multifunctional composite is prepared by combining polyionic liquid-modified COFs, carbon nanotubes, and poly(3,4-ethylenedioxythiophene).

[0007] Furthermore, the preparation method of the multifunctional composite includes the following steps: S1, dispersing dried COFs powder and polyionic liquid powder together in DMF, and after ultrasonic treatment and heating and stirring, filtering, washing and drying to obtain PIL@COFs composite material; S2, dispersing carbon nanotubes in ethanol to obtain dispersion A; dissolving 3,4-ethylenedioxythiophene monomer in deionized water to obtain solution B; dispersing PIL@COFs composite material in solution B, adding dispersion A, stirring evenly, adding FeCl3 solution, and reacting at room temperature to obtain the composite material.

[0008] Furthermore, in S2, the molar ratio of FeCl3 to 3,4-ethylenedioxythiophene monomer is (1.5-2.5):1.

[0009] Furthermore, the preparation method of the COFs includes the following steps: A1, under nitrogen protection, trifluoroacetic acid is added dropwise to hexamethylenetetramine and phloroglucinol, the mixture is heated to react, filtered, dried, and sublimed to obtain triformylphloroglucinol; A2, triformylphloroglucinol and melamine are reacted with dimethylacetamide under nitrogen atmosphere by heating and stirring to obtain COFs.

[0010] Furthermore, the preparation method of the polyionic liquid includes the following steps: B1, linear polystyrene reacts with paraformaldehyde, anhydrous zinc chloride, and acetyl chloride to obtain chloromethylated polystyrene; B2, chloromethylated polystyrene reacts with 1-vinylimidazole in DMF under nitrogen protection, and then is washed and dried to obtain the polyionic liquid.

[0011] Furthermore, in B2, the mass ratio of chloromethylated polystyrene to 1-vinylimidazole is 1:(0.6-1.2).

[0012] Furthermore, this application provides a method for preparing a flame-retardant and highly wear-resistant modified polyolefin material, comprising the following steps: placing polypropylene, reinforcing fiber, multifunctional composite and antioxidant in a high-speed mixer and mixing them evenly to obtain a mixture, and then melting and extruding the mixture through a twin-screw extruder, cooling and pelletizing it to obtain the final product.

[0013] Furthermore, the amount of the multifunctional complex added is 3-5 wt%.

[0014] Furthermore, this application provides a valve made from the aforementioned flame-retardant, high-wear-resistant modified polyolefin material by injection molding.

[0015] Furthermore, the injection molding process of the valve is as follows: temperature 160-180℃, pressure 100-120MPa, and time 15-50s.

[0016] Compared with the prior art, this application has the following beneficial effects: 1. Flame retardant properties: The porous structure of COFs materials can form a protective layer during combustion, preventing the flame from contacting the polymer matrix. At the same time, its stable structure absorbs heat, reducing heat transfer to the polymer and thus lowering the risk of combustion. Polyionic liquids can form a dense and stable char layer during combustion, isolating oxygen and heat, inhibiting the release of combustible gases, and thus interrupting combustion. Polyionic liquids loaded in the pores of COFs construct a PIL@COFs composite flame retardant system, which can synergistically form a dense and stable char layer during combustion, effectively isolating heat and oxygen and improving the flame retardant properties of polypropylene materials.

[0017] 2. Wear resistance: COFs have extremely high hardness and can effectively share and transfer loads in the polypropylene matrix; carbon nanotubes can reduce friction on the polypropylene matrix; polyionic liquids have good low-temperature fluidity and extremely high thermal stability, thus they can be used as high-performance, wide-temperature-range liquid lubricants to achieve excellent lubrication and wear resistance. The combination of these three factors enhances the wear resistance of polypropylene materials.

[0018] 3. Antistatic effect: Using two excellent conductive materials, poly(3,4-ethylenedioxythiophene) and carbon nanotubes, a coating layer is formed by in-situ polymerization on the surface of PIL@COFs, which constructs a conductive shell. This can quickly conduct the static charge accumulated on the surface of polypropylene materials and improve the antistatic performance of polypropylene materials. At the same time, this coating layer can better disperse the polyionic liquid in the channels of COFs, making the structure of the composite material more stable.

[0019] 4. The multifunctional composite integrates wear resistance, flame retardancy, and antistatic properties, solving the problems of poor compatibility, uneven dispersion, and mutual influence of performance when multiple single fillers are compounded, thus maintaining the good mechanical properties and processability of polypropylene materials. Detailed Implementation

[0020] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the tables. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] When using “including,” “having,” and “contains” as described herein, the intention is to cover non-exclusive inclusion, unless an explicit qualifying term such as “only,” “consisting of,” etc., is used, in which case another component may be added.

[0023] In this application, "at least one" means one or more, such as one, two, or more. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layered" means at least two layers, such as two layers, three layers, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0024] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0025] Unless otherwise specified, all steps in this application may be performed sequentially or randomly. For example, the method comprising steps (a) and (b) indicates that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order; for example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0026] The present application will be further illustrated by the following examples, but these examples do not limit the scope of the present application.

[0027] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in this application, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. All reagents or instruments whose manufacturers are not specified are conventional products that can be purchased commercially. In addition to the specific methods, equipment, and materials used in the embodiments, based on the knowledge of the prior art possessed by one of ordinary skill in the art and the description in this application, any prior art methods, equipment, and materials similar to or equivalent to those described, used, or made by the methods, equipment, and materials in the embodiments of this application may be used to implement this application.

[0028] Example 1 The preparation method of the multifunctional complex in this embodiment is as follows: S1, COFs powder was dried at 120℃ for 12 h. Polyionic liquid (PIL) was ground into powder. 1 g of activated COFs and 0.2 g of PIL were weighed and dispersed together in 50 mL of DMF. The mixture was ultrasonically treated for 30 min in an ultrasonic homogenizer. The suspension was transferred to a round-bottom flask and magnetically stirred at 60℃ for 24 h. After the reaction was complete, the mixture was filtered, and the solid product was collected. The filter cake was washed three times with 50 mL of ethyl acetate. The obtained solid product was vacuum dried at 60℃ for 48 h to remove residual solvent, yielding the PIL@COFs composite material.

[0029] S2, 100 mg of carbon nanotubes were ultrasonically dispersed in an ethanol solution to obtain dispersion A. 0.2 g of 3,4-ethylenedioxythiophene was dispersed in 20 mL of deionized water to obtain dispersion B. 1 g of PIL@COFs composite material was dispersed in dispersion B, and then dispersion A was added. After stirring evenly, an aqueous solution containing 0.34 g of FeCl3 was added, and the mixture was reacted at room temperature for 4 h to obtain a multifunctional composite.

[0030] The preparation method of COFs in this embodiment is as follows: In step A1, under nitrogen protection, 18.1 g of hexamethylenetetramine and 7.2 g of phloroglucinol were added sequentially to a three-necked flask. Then, 90 mL of trifluoroacetic acid was added dropwise with magnetic stirring. The mixture was gradually heated to 100 °C and maintained at this temperature for 2.5 h. Subsequently, 150 mL of 3M hydrochloric acid was added dropwise, and the reaction was continued at 100 °C for 1 h. After filtration, the filtrate was extracted three times with 50 mL of dichloromethane. The resulting organic layer was dried on magnesium sulfate and filtered. After concentration under reduced pressure, it was sublimated at 150 °C to obtain triformylphloroglucinol.

[0031] A2, 200 mL of dimethylacetamide was placed in a 250 mL three-necked flask and heated to 100 °C using an oil bath method, and stirred for 4 h to remove water. Then, 15 g of phloroglucinol and 9.45 g of melamine were placed in a three-necked flask containing the dehydrated dimethylacetamide, and the mixture was boiled to 180 °C under a nitrogen atmosphere and stirred for 72 h. After that, it was washed twice with tetrahydrofuran and dichloromethane, and after each wash, it was stirred on a magnetic stirrer for about 30 min. Finally, the washed product was vacuum dried at 60 °C to obtain COFs.

[0032] The preparation method of the polyionic liquid in this embodiment is as follows: B1. Weigh 1 g of linear polystyrene and dissolve it in 15 mL of anhydrous DMF. Stir until completely dissolved and transfer to a three-necked flask. Add 3.8 g of paraformaldehyde and 4 g of anhydrous zinc chloride. Place the three-necked flask in an ice-water bath and stir vigorously. Add 2.4 mL of acetyl chloride to a constant-pressure dropping funnel and slowly add it dropwise to the reaction mixture. After the addition is complete, continue stirring in the ice-water bath for 1 h, then slowly raise the temperature to 45 °C and continue the reaction for 24 h. After the reaction is complete, cool the reaction solution to room temperature and slowly add it dropwise to an ethanol / water mixture. Let it stand, discard the supernatant, wash twice, and dry the product for 48 h to obtain chloromethylated polystyrene.

[0033] B2, In a round-bottom flask, 10 g of chloromethylated polystyrene was dissolved in 150 mL of anhydrous DMF, followed by the addition of 6.8 g of 1-vinylimidazole. The reaction system was heated to 75°C under nitrogen protection and stirred for 48 h. After the reaction was completed, the reaction solution was cooled to room temperature, and diethyl ether was slowly added dropwise with vigorous stirring. After standing, the supernatant was decanted, washed twice, and the final solid product was dried at 40°C for 48 h.

[0034] The preparation method of the flame-retardant and highly wear-resistant modified polyolefin material in this embodiment is as follows: 70g of polypropylene (model T30s), 25g of basalt fiber (6mm in length), 3g of multifunctional composite and 0.15g of antioxidant 168 were placed in a high-speed mixer and mechanically mixed for 30 minutes to obtain a premix. The premix was then fed into a twin-screw extruder through a feed port. The temperature was controlled at 200℃ and the screw speed at 350r / min. The mixture was then melt-extruded, cooled, and pelletized to obtain a flame-retardant and highly wear-resistant modified polyolefin material.

[0035] The valve in this embodiment is prepared as follows: Flame-retardant and high-wear-resistant modified polyolefin material is heated and melted at 160°C using an injection molding machine. The molten liquid is then injected into a mold preheated to 60°C under a pressure of 100MPa. After holding the pressure and cooling for 20 seconds, the material is demolded to obtain the final product.

[0036] Example 2 The preparation method of the multifunctional complex in this embodiment is as follows: S1, COFs powder was dried at 120℃ for 12 h. Polyionic liquid (PIL) was ground into powder. 1 g of activated COFs and 0.5 g of PIL were weighed and dispersed together in 50 mL of DMF. The mixture was ultrasonically treated for 45 min in an ultrasonic homogenizer. The suspension was transferred to a round-bottom flask and magnetically stirred at 70℃ for 48 h. After the reaction was complete, the mixture was filtered, and the solid product was collected. The filter cake was washed three times with 50 mL of ethyl acetate. The obtained solid product was vacuum dried at 60℃ for 48 h to remove residual solvent, yielding the PIL@COFs composite material.

[0037] S2, 100 mg of carbon nanotubes were ultrasonically dispersed in an ethanol solution to obtain dispersion A. 0.2 g of 3,4-ethylenedioxythiophene was dispersed in 20 mL of deionized water to obtain dispersion B. 1 g of PIL@COFs composite material was dispersed in dispersion B, and then dispersion A was added. After stirring evenly, an aqueous solution containing 0.45 g of FeCl3 was added, and the mixture was reacted at room temperature for 4 h to obtain a multifunctional composite.

[0038] The preparation method of COFs in this embodiment is as follows: In step A1, under nitrogen protection, 18.1 g of hexamethylenetetramine and 7.2 g of phloroglucinol were added sequentially to a three-necked flask. Then, 90 mL of trifluoroacetic acid was added dropwise with magnetic stirring. The mixture was gradually heated to 100 °C and maintained at this temperature for 2.5 h. Subsequently, 150 mL of 3M hydrochloric acid was added dropwise, and the reaction was continued at 100 °C for 1 h. After filtration, the filtrate was extracted three times with 50 mL of dichloromethane. The resulting organic layer was dried on magnesium sulfate and filtered. After concentration under reduced pressure, it was sublimated at 150 °C to obtain triformylphloroglucinol.

[0039] A2, 200 mL of dimethylacetamide was placed in a 250 mL three-necked flask and heated to 100 °C using an oil bath method, and stirred for 4 h to remove water. Then, 15 g of phloroglucinol and 9.45 g of melamine were placed in a three-necked flask containing the dehydrated dimethylacetamide, and the mixture was boiled to 180 °C under a nitrogen atmosphere and stirred for 72 h. After that, it was washed twice with tetrahydrofuran and dichloromethane, and after each wash, it was stirred on a magnetic stirrer for about 30 min. Finally, the washed product was vacuum dried at 60 °C to obtain COFs.

[0040] The preparation method of the polyionic liquid in this embodiment is as follows: B1. Weigh 1 g of linear polystyrene and dissolve it in 15 mL of anhydrous DMF. Stir until completely dissolved and transfer to a three-necked flask. Add 3.8 g of paraformaldehyde and 4 g of anhydrous zinc chloride. Place the three-necked flask in an ice-water bath and stir vigorously. Add 2.4 mL of acetyl chloride to a constant-pressure dropping funnel and slowly add it dropwise to the reaction mixture. After the addition is complete, continue stirring in the ice-water bath for 1 h, then slowly raise the temperature to 45 °C and continue the reaction for 24 h. After the reaction is complete, cool the reaction solution to room temperature and slowly add it dropwise to an ethanol / water mixture. Let it stand, discard the supernatant, wash twice, and dry the product for 48 h to obtain chloromethylated polystyrene.

[0041] B2, In a round-bottom flask, 10 g of chloromethylated polystyrene was dissolved in 150 mL of anhydrous DMF, followed by the addition of 9 g of 1-vinylimidazole. The reaction system was heated to 75°C under nitrogen protection and stirred for 48 h. After the reaction was completed, the reaction solution was cooled to room temperature, and diethyl ether was slowly added dropwise with vigorous stirring. After standing, the supernatant was decanted, washed twice, and the final solid product was placed in a vacuum oven and dried at 40°C for 48 h.

[0042] The preparation method of the flame-retardant and highly wear-resistant modified polyolefin material in this embodiment is as follows: 70g of polypropylene (model T30s), 25g of glass fiber (3mm in length), 5g of multifunctional composite and 0.15g of antioxidant 168 were placed in a high-speed mixer and mechanically mixed for 30 minutes to obtain a premix. The premix was then fed into a twin-screw extruder through a feed port. The temperature was controlled at 200℃ and the screw speed at 350r / min. The mixture was then melt-extruded, cooled, and pelletized to obtain a flame-retardant and highly wear-resistant modified polyolefin material.

[0043] The valve in this embodiment is prepared as follows: Flame-retardant and high-wear-resistant modified polyolefin material is heated and melted at 180°C using an injection molding machine. The molten liquid is then injected into a mold preheated to 60°C under a pressure of 120MPa. After holding the pressure and cooling for 35 seconds, the material is demolded to obtain the final product.

[0044] Example 3 The preparation method of the multifunctional complex in this embodiment is as follows: S1, COFs powder was dried at 120℃ for 12 h. Polyionic liquid (PIL) was ground into powder. 1 g of activated COFs and 1 g of PIL were weighed and dispersed together in 50 mL of DMF. The mixture was ultrasonically treated in an ultrasonic homogenizer for 60 min. The suspension was transferred to a round-bottom flask and magnetically stirred at 80℃ for 24 h. After the reaction was complete, the mixture was filtered, and the solid product was collected. The filter cake was washed three times with 50 mL of ethyl acetate. The obtained solid product was vacuum dried at 60℃ for 48 h to remove residual solvent, yielding the PIL@COFs composite material.

[0045] S2, 100 mg of carbon nanotubes were ultrasonically dispersed in an ethanol solution to obtain dispersion A. 0.2 g of 3,4-ethylenedioxythiophene was dispersed in 20 mL of deionized water to obtain dispersion B. 1 g of PIL@COFs composite material was dispersed in dispersion B, and then dispersion A was added. After stirring evenly, an aqueous solution containing 0.57 g of FeCl3 was added, and the mixture was reacted at room temperature for 4 h to obtain a multifunctional composite.

[0046] The preparation method of COFs in this embodiment is as follows: In step A1, under nitrogen protection, 18.1 g of hexamethylenetetramine and 7.2 g of phloroglucinol were added sequentially to a three-necked flask. Then, 90 mL of trifluoroacetic acid was added dropwise with magnetic stirring. The mixture was gradually heated to 100 °C and maintained at this temperature for 2.5 h. Subsequently, 150 mL of 3M hydrochloric acid was added dropwise, and the reaction was continued at 100 °C for 1 h. After filtration, the filtrate was extracted three times with 50 mL of dichloromethane. The resulting organic layer was dried on magnesium sulfate and filtered. After concentration under reduced pressure, it was sublimated at 150 °C to obtain triformylphloroglucinol.

[0047] A2, 200 mL of dimethylacetamide was placed in a 250 mL three-necked flask and heated to 100 °C using an oil bath method, and stirred for 4 h to remove water. Then, 15 g of phloroglucinol and 9.45 g of melamine were placed in a three-necked flask containing the dehydrated dimethylacetamide, and the mixture was boiled to 180 °C under a nitrogen atmosphere and stirred for 72 h. After that, it was washed twice with tetrahydrofuran and dichloromethane, and after each wash, it was stirred on a magnetic stirrer for about 30 min. Finally, the washed product was vacuum dried at 60 °C to obtain COFs.

[0048] The preparation method of the polyionic liquid in this embodiment is as follows: B1. Weigh 1 g of linear polystyrene and dissolve it in 15 mL of anhydrous DMF. Stir until completely dissolved and transfer to a three-necked flask. Add 3.8 g of paraformaldehyde and 4 g of anhydrous zinc chloride. Place the three-necked flask in an ice-water bath and stir vigorously. Add 2.4 mL of acetyl chloride to a constant-pressure dropping funnel and slowly add it dropwise to the reaction mixture. After the addition is complete, continue stirring in the ice-water bath for 1 h, then slowly raise the temperature to 45 °C and continue the reaction for 24 h. After the reaction is complete, cool the reaction solution to room temperature and slowly add it dropwise to an ethanol / water mixture. Let it stand, discard the supernatant, wash twice, and dry the product for 48 h to obtain chloromethylated polystyrene.

[0049] B2, In a round-bottom flask, 10 g of chloromethylated polystyrene was dissolved in 150 mL of anhydrous DMF, followed by the addition of 11.3 g of 1-vinylimidazole. The reaction system was heated to 75°C under nitrogen protection and stirred for 48 h. After the reaction was completed, the reaction solution was cooled to room temperature, and diethyl ether was slowly added dropwise with vigorous stirring. After standing, the supernatant was decanted, washed twice, and the final solid product was placed in a vacuum oven and dried at 40°C for 48 h.

[0050] The preparation method of the flame-retardant and highly wear-resistant modified polyolefin material in this embodiment is as follows: 70g of polypropylene (model T30s), 25g of carbon fiber (6mm in length), 4g of multifunctional composite and 0.15g of antioxidant 168 were placed in a high-speed mixer and mechanically mixed for 30 minutes to obtain a premix. The premix was then fed into a twin-screw extruder through a feed port. The temperature was controlled at 200℃ and the screw speed at 350r / min. The mixture was then melt-extruded, cooled, and pelletized to obtain a flame-retardant and highly wear-resistant modified polyolefin material.

[0051] The valve in this embodiment is prepared as follows: Flame-retardant and high-wear-resistant modified polyolefin material is heated and melted at 170°C using an injection molding machine. The molten liquid is then injected into a mold preheated to 60°C under a pressure of 110MPa. After holding the pressure and cooling for 50 seconds, the material is demolded to obtain the final product.

[0052] Comparative Example 1 The preparation method of the multifunctional complex in this comparative example is as follows: COFs powder was dried at 120℃ for 12 h. Polyionic liquid (PIL) was ground into powder. 1 g of activated COFs and 0.5 g of PIL were weighed and dispersed together in 50 mL of DMF. The mixture was ultrasonically treated for 45 min in an ultrasonic homogenizer. The suspension was transferred to a round-bottom flask and magnetically stirred at 70℃ for 48 h. After the reaction was complete, the mixture was filtered, and the solid product was collected. The filter cake was washed three times with 50 mL of ethyl acetate. The resulting solid product was vacuum dried at 60℃ for 48 h to remove residual solvent, yielding the PIL@COFs composite material.

[0053] The preparation method of COFs in this comparative example is as follows: In step A1, under nitrogen protection, 18.1 g of hexamethylenetetramine and 7.2 g of phloroglucinol were added sequentially to a three-necked flask. Then, 90 mL of trifluoroacetic acid was added dropwise with magnetic stirring. The mixture was gradually heated to 100 °C and maintained at this temperature for 2.5 h. Subsequently, 150 mL of 3M hydrochloric acid was added dropwise, and the reaction was continued at 100 °C for 1 h. After filtration, the filtrate was extracted three times with 50 mL of dichloromethane. The resulting organic layer was dried on magnesium sulfate and filtered. After concentration under reduced pressure, it was sublimated at 150 °C to obtain triformylphloroglucinol.

[0054] A2, 200 mL of dimethylacetamide was placed in a 250 mL three-necked flask and heated to 100 °C using an oil bath method, and stirred for 4 h to remove water. Then, 15 g of phloroglucinol and 9.45 g of melamine were placed in a three-necked flask containing the dehydrated dimethylacetamide, and the mixture was boiled to 180 °C under a nitrogen atmosphere and stirred for 72 h. After that, it was washed twice with tetrahydrofuran and dichloromethane, and after each wash, it was stirred on a magnetic stirrer for about 30 min. Finally, the washed product was vacuum dried at 60 °C to obtain COFs.

[0055] The preparation method of the polyionic liquid in this comparative example is as follows: B1. Weigh 1 g of linear polystyrene and dissolve it in 15 mL of anhydrous DMF. Stir until completely dissolved and transfer to a three-necked flask. Add 3.8 g of paraformaldehyde and 4 g of anhydrous zinc chloride. Place the three-necked flask in an ice-water bath and stir vigorously. Add 2.4 mL of acetyl chloride to a constant-pressure dropping funnel and slowly add it dropwise to the reaction mixture. After the addition is complete, continue stirring in the ice-water bath for 1 h, then slowly raise the temperature to 45 °C and continue the reaction for 24 h. After the reaction is complete, cool the reaction solution to room temperature and slowly add it dropwise to an ethanol / water mixture. Let it stand, discard the supernatant, wash twice, and dry the product for 48 h to obtain chloromethylated polystyrene.

[0056] B2, In a round-bottom flask, 10 g of chloromethylated polystyrene was dissolved in 150 mL of anhydrous DMF, followed by the addition of 9 g of 1-vinylimidazole. The reaction system was heated to 75°C under nitrogen protection and stirred for 48 h. After the reaction was completed, the reaction solution was cooled to room temperature, and diethyl ether was slowly added dropwise with vigorous stirring. After standing, the supernatant was decanted, washed twice, and the final solid product was placed in a vacuum oven and dried at 40°C for 48 h.

[0057] The preparation method of the flame-retardant and high-wear-resistant modified polyolefin material in this comparative example is the same as that in Example 2.

[0058] The valve in this comparative example is prepared using the same method as in Example 2.

[0059] Comparative Example 2 The preparation method of the flame-retardant and highly wear-resistant modified polyolefin material in this comparative example is as follows: 70g of polypropylene (model T30s), 20g of glass fiber (3mm in length) and 0.15g of antioxidant 168 were placed in a high-speed mixer and mechanically mixed for 30 minutes to obtain a premix. The premix was then fed into a twin-screw extruder through a feed port. The temperature was controlled at 200℃ and the screw speed at 350r / min. The mixture was then melt-extruded, cooled, and pelletized to obtain a flame-retardant and highly wear-resistant modified polyolefin material.

[0060] The valve in this comparative example is prepared using the same method as in Example 2.

[0061] Performance testing Alcohol lamp combustion test: Tested according to MT113-1995 standard. The specimen size is 360mm×50mm×5mm. The vertical distance from the bottom of the specimen to the center of the alcohol lamp head is 19mm. Ignite for 15s and record the flame burning time of the specimen after the alcohol lamp is removed.

[0062] Limiting Oxygen Index (LOI) Test: According to GB / T 2406.2-2009, the sample is vertically inserted into the test tube of the oxygen index instrument, and a nitrogen-oxygen mixed gas flow (23±2℃) is introduced from the bottom. The initial oxygen concentration is set to ±2% of the estimated value, and the oxygen concentration gradient is adjusted to ±0.2%. The lowest oxygen concentration (LOI value) required for the sample to burn continuously for 3 minutes or for a burning length of 50 mm is recorded.

[0063] Surface resistance test: Tested according to MT113-1995 standard, the sample size is 360mm×300mm×5mm, the test voltage is 500±20V, and the surface resistance values ​​of the upper and lower surfaces of the sample are recorded.

[0064] Wear test: According to ASTM D1044 standard, a 10cm×10cm×8mm sample strip was placed on the grinding rotary test table, the rotation speed was set to 60r / min, the test sample was rubbed, the load was 1000g, the grinding wheel was SC10, and the wear of the test sample was tested after 5000 revolutions.

[0065] Mechanical properties: According to GB / T1040-2006, the tensile strength and bending strength were tested using a microcomputer-controlled electronic universal testing machine at a traction speed of 50 mm / min.

[0066] Table 1. Mechanical property test results of flame-retardant and high-wear-resistant modified polyolefin materials in Examples 1-3 and Comparative Examples 1-2. Table 2. Performance test results of flame-retardant and high-wear-resistant modified polyolefin materials in Examples 1-3 and Comparative Examples 1-2. Analysis of Examples 1-3 and Comparative Examples 1-2, combined with Table 1-2, shows that modifying COFs materials with polyionic liquids and coating them with poly(3,4-ethylenedioxythiophene) and carbon nanotubes, along with reinforcement with reinforcing fibers, gives polypropylene materials excellent wear resistance, antistatic properties, and flame retardancy. The flame-retardant, high-wear-resistant modified polyolefin material prepared in Comparative Example 1, compared to Examples 1-3, lacks the poly(3,4-ethylenedioxythiophene) and carbon nanotube coating on PIL@COFs, resulting in a lack of a conductive shell and inability to conduct surface static electricity in a timely manner. Consequently, the surface resistance of the flame-retardant, high-wear-resistant modified polyolefin material in Comparative Example 1 is significantly increased. The flame-retardant, high-wear-resistant modified polyolefin material prepared in Comparative Example 2, compared to Examples 1-3, does not contain a multifunctional composite, relying solely on reinforcing fibers for toughening. Lacking flame-retardant and antistatic materials, Comparative Example 2 exhibits an increased flaming time, a decreased LOI value, and an increased surface resistance.

[0067] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A flame-retardant and highly wear-resistant modified polyolefin material, characterized in that, It includes the following raw materials: polypropylene, reinforcing fibers, multifunctional composites, and antioxidants; The reinforcing fiber is one of glass fiber, carbon fiber, and basalt fiber; The preparation method of the multifunctional composite includes the following steps: S1, dry COFs powder and polyionic liquid powder are co-dispersed in DMF, and after ultrasonic treatment and heating and stirring, filtered, washed and dried to obtain PIL@COFs composite material; S2, carbon nanotubes are dispersed in ethanol to obtain dispersion A; 3,4-ethylenedioxythiophene monomer is dissolved in deionized water to obtain solution B; PIL@COFs composite material is dispersed in solution B, then dispersion A is added, stirred evenly, and FeCl3 solution is added, and reacted at room temperature to obtain the composite material. The preparation method of the COFs includes the following steps: A1, under nitrogen protection, trifluoroacetic acid is added dropwise to hexamethylenetetramine and phloroglucinol, the mixture is heated to react, filtered, dried, and sublimed to obtain triformylphloroglucinol; A2, triformylphloroglucinol and melamine are reacted with dimethylacetamide under nitrogen atmosphere by heating and stirring to obtain COFs. The preparation method of the polyionic liquid includes the following steps: B1, linear polystyrene reacts with paraformaldehyde, anhydrous zinc chloride and acetyl chloride to obtain chloromethylated polystyrene; B2, chloromethylated polystyrene reacts with 1-vinylimidazolium in DMF under nitrogen protection, and then is washed and dried to obtain the polyionic liquid.

2. The flame-retardant and highly wear-resistant modified polyolefin material according to claim 1, characterized in that, In S2, the molar ratio of FeCl3 to 3,4-ethylenedioxythiophene monomer is (1.5-2.5):

1.

3. The flame-retardant and highly wear-resistant modified polyolefin material according to claim 1, characterized in that, In B2, the mass ratio of chloromethylated polystyrene to 1-vinylimidazole is 1:(0.6-1.2).

4. A method for preparing the flame-retardant and highly wear-resistant modified polyolefin material as described in claim 1, characterized in that, The process includes the following steps: placing polypropylene, reinforcing fibers, multifunctional composites and antioxidants in a high-speed mixer and mixing them evenly to obtain a mixture; then melting and extruding the mixture using a twin-screw extruder, cooling and pelletizing it to obtain the final product.

5. The method for preparing a flame-retardant and highly wear-resistant modified polyolefin material according to claim 4, characterized in that, The amount of the multifunctional complex added is 3-5 wt%.

6. A valve, characterized in that, The flame-retardant and highly wear-resistant modified polyolefin material as described in any one of claims 1-3 is obtained by injection molding.

7. A valve according to claim 6, characterized in that, The injection molding process for the valve is as follows: temperature 160-180℃, pressure 100-120MPa, time 15-50s.

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