Wear-resistant polyethylene composite pipe material and method for manufacturing the same

Abstract

The application relates to the technical field of high polymer materials, and particularly discloses a wear-resistant polyethylene composite pipe material and a preparation method thereof.A wear-resistant polyethylene composite pipe material is prepared from the following raw materials: high-density polyethylene, chlorinated polyethylene, grafted nano silicon carbide whiskers, a composite lubricating phase, a toughening agent, a compatibilizer, an antioxidant and a lubricant; the grafted nano silicon carbide whiskers are silicon carbide whiskers grafted with high-density polyethylene on the surface; and the composite lubricating phase is sodium dodecyl sulfonate intercalation modified magnesium-aluminum layered double hydroxide loaded with nano molybdenum disulfide sheet layers.The composite pipe material can be used for wear-resistant conveying pipes in the industrial fields of petroleum, chemical industry, mining and electric power, and has excellent wear resistance.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and more specifically, it relates to a wear-resistant polyethylene composite pipe material and its preparation method. Background Technology

[0002] Polyethylene composite pipes are widely used in slurry transportation pipelines due to their lightweight, corrosion resistance, and low fluid resistance, especially suitable for slurry transportation conditions with high abrasiveness and corrosiveness. In the mining industry, operations such as tailings discharge, slag transportation, and underground backfilling all require the long-distance transportation of large quantities of high-concentration solid particle slurries. These slurries contain a large number of hard solid particles such as quartz, feldspar, and metal oxides, and are often accompanied by acidic or alkaline mineral slurry media, exerting a strong dual effect of abrasive wear and chemical corrosion on the inner wall of the pipe. Traditional metal pipes suffer from severe wear and corrosion, short service life, and high maintenance costs under these conditions. In contrast, polyethylene pipes, with their excellent chemical corrosion resistance and self-lubricating properties, have gradually become one of the mainstream choices for tailings and slurry transportation pipelines in mines.

[0003] In existing technologies, the overall performance of polyethylene pipes is often improved by modifying the matrix or adding fillers. For example, patent document CN118931011B discloses a method for preparing a multifunctional polyethylene pipe for lined composite pipes. This polyethylene pipe includes the following raw materials: high-density polyethylene, boron nitride reinforcing material, composite antibacterial additive, crosslinking agent, antioxidant, and lubricant. Using high-density polyethylene as the matrix material, the addition of boron nitride reinforcing material enhances the interaction and bonding force with the polyethylene matrix, absorbs and disperses external impact energy, hinders crack propagation, and improves the mechanical properties and toughness of the polyethylene pipe. The addition of composite antibacterial additive improves the antibacterial properties of the polyethylene pipe, thereby extending its service life. However, in the actual application of tailings and high-concentration abrasive slurry transportation in the aforementioned mines, the hard solid particles such as quartz and metallic slag contained in the slurry continuously act on the inner wall of the pipe in multiple forms such as cutting, impact, and chiseling over a long period of time. The existing technical solutions only use conventional boron nitride as a reinforcing filler. Although its plate-like structure can improve the strength and toughness of the matrix to a certain extent, it does not perform targeted optimization of the wear-resistant phase for abrasive wear conditions. Furthermore, the interfacial bonding strength between the filler and the polyethylene matrix in ordinary physical blend systems is limited. Under long-term high-frequency abrasive impact and shearing, the surface filler of the pipe is prone to peeling off, and the matrix material experiences rapid wear, resulting in a fast wear rate on the inner wall of the pipe, easy local wear-through and groove damage, and a service life that cannot meet the requirements of long-term stable operation in mines. Therefore, the existing polyethylene pipes still have the defects of poor wear resistance and inability to serve stably for a long time in the transportation of highly abrasive slurries. Summary of the Invention

[0004] To enhance the wear resistance of polyethylene composite pipes, this application provides a wear-resistant polyethylene composite pipe material and its preparation method.

[0005] This application provides a wear-resistant polyethylene composite pipe material, which adopts the following technical solution: A wear-resistant polyethylene composite pipe material comprises the following raw materials in parts by weight: 90-100 parts of high-density polyethylene; 5-10 parts of chlorinated polyethylene; 6-10 parts of grafted nano-silicon carbide whiskers; 3-8 parts of composite lubricating phase; 2-5 parts toughening agent; 3-6 parts compatibilizer; Antioxidant 0.3-1 part; 0.5-1.5 parts lubricant; The grafted nano silicon carbide whiskers are silicon carbide whiskers with high-density polyethylene grafted onto their surfaces. The composite lubricating phase is a sodium dodecyl sulfonate intercalated modified magnesium-aluminum layered double hydroxide supported on nano-molybdenum disulfide sheets.

[0006] The technical solution of this application uses high-density polyethylene as the main matrix, introduces grafted nano-silicon carbide whiskers as a hard wear-resistant load-bearing phase, and a composite lubricating phase as a friction-reducing barrier phase. It is combined with chlorinated polyethylene, toughening agent and compatibilizer to construct a multi-phase synergistic system. While maintaining the basic mechanical properties of the pipe, it simultaneously improves the wear resistance performance of the material from multiple dimensions such as interface strengthening, wear resistance, friction reduction and lubrication and corrosion barrier, effectively adapting to the long-cycle operation requirements of conveying highly abrasive slurries.

[0007] Grafted nano-silicon carbide whiskers, as the core wear-resistant functional phase, can form deep molecular entanglement and interfacial compatibility with the polyethylene matrix through surface covalent grafting of high-density polyethylene molecular chains. This upgrades the weak interfacial bonding of traditional physical blending systems to strong interfacial action at the molecular level, fundamentally eliminating the failure factor of filler easily peeling off from the matrix during wear, and avoiding the vicious cycle of pits formed by filler detachment and secondary abrasive particles aggravating wear. At the same time, silicon carbide whiskers themselves have high hardness and a one-dimensional needle-like structure. After being uniformly dispersed in the matrix, they can form a spatial bearing network, directly resisting the cutting and chiseling action of hard solid particles in the slurry, significantly reducing the ploughing damage of abrasive particles to the matrix and the material removal rate, and improving the material's resistance to abrasive wear.

[0008] The composite lubricating phase adopts a structural design of sodium dodecyl sulfonate intercalated modified magnesium-aluminum layered double hydroxide loaded with nano-molybdenum disulfide sheets. On the one hand, the layered structure of nano-molybdenum disulfide has low shear slip characteristics, which can form a continuous solid lubrication transfer film on the wear surface of the inner wall of the pipe, effectively reducing the friction coefficient between abrasive particles and material surface, reducing shear wear, and forming a synergistic wear-resistant mechanism of "hard load-bearing-soft lubrication" with hard silicon carbide whiskers. On the other hand, the hydrophobically intercalated modified layered double hydroxide sheets can be uniformly peeled and dispersed in the matrix, constructing a tortuous medium penetration path, hindering the diffusion of acid and alkali ions and high mineralization components in the slurry into the material interior, weakening the deterioration effect of corrosion on the interface and matrix, effectively inhibiting the synergistic acceleration of wear and corrosion, and extending the service life of the pipe under complex slurry conditions.

[0009] The chlorinated polyethylene and toughening agent compounded in the system can further optimize the toughness and weather resistance of the matrix, offset the material embrittlement problem that may be caused by the introduction of hard fillers, and ensure that the pipe has excellent impact resistance and stress cracking resistance, meeting the requirements for long-term stable service of mine slurry transportation pipelines.

[0010] Optionally, the grafted silicon carbide nano whiskers are prepared using the following method: A1. Immerse nano-silicon carbide whiskers in hydrogen peroxide solution, stir and reflux at 80-100℃ for 2-4 hours, then wash, filter and vacuum dry to obtain hydroxylated silicon carbide whiskers. A2. Disperse hydroxylated silicon carbide whiskers in an ethanol solution, add silane coupling agent KH-570, adjust the pH to 3.5-4.5 with glacial acetic acid, stir and react at 60-80℃ for 4-6 hours, and after the reaction is completed, centrifuge, wash and vacuum dry to obtain silane coupling agent modified silicon carbide whiskers. A3. Silane coupling agent modified silicon carbide whiskers and high-density polyethylene are added to a mixer, and then benzoyl peroxide is added. The mixture is melt-blended at 160-190℃ and 30-60 r / min for 10-20 min. The reaction product is then pulverized to obtain grafted nano silicon carbide whiskers.

[0011] A stable covalent grafted structure can be constructed on the surface of silicon carbide whiskers through a stepwise reaction path of hydroxylation pretreatment, silane coupling agent modification, and melt grafting. The hydroxylation step introduces sufficient active reaction sites to the whisker surface, the silane coupling agent modification builds a reaction bridge between the inorganic whiskers and the organic polymer, and the melt blending grafting achieves chemical bonding between the polyethylene molecular chains and the whisker surface. This preparation path allows for controllable reaction conditions and is suitable for industrial-scale production, ensuring the uniformity and stability of the grafting effect and avoiding insufficient interfacial bonding strength due to inadequate grafting. This provides a structural basis for the batch stability of the wear resistance performance of the pipe.

[0012] Optionally, in step A1, the mass concentration of the hydrogen peroxide solution is 25%-35%, and the mass ratio of the nano-silicon carbide whiskers to the hydrogen peroxide solution is 1:(8-12).

[0013] Optionally, in step A2, the mass concentration of the ethanol solution is 80%-90%, and the mass ratio of the hydroxylated silicon carbide whiskers, the ethanol solution, and the silane coupling agent KH-570 is 1:(12-18):(0.08-0.12).

[0014] Optionally, in step A2, the mass ratio of the silane coupling agent-modified silicon carbide whiskers to high-density polyethylene is 1:(2-5), and the amount of benzoyl peroxide added is 0.5%-1.5% of the mass of high-density polyethylene.

[0015] By adopting the above technical solution and adjusting the mass ratio of whiskers to high-density polyethylene, the thickness of the polyethylene graft layer on the whisker surface can be precisely controlled. This allows the grafted segments to form sufficient molecular entanglement with the matrix to strengthen the interface, while preventing the filler from agglomerating due to excessive graft layer thickness. The appropriate amount of initiator can ensure the sufficiency of the melt grafting reaction, while avoiding excessive cross-linking side reactions caused by excessive initiator, ultimately achieving the optimal balance between filler interfacial bonding strength and dispersion performance.

[0016] Optionally, the composite lubricating phase is prepared using the following method: B1. Prepare a mixed salt solution by mixing magnesium nitrate hexahydrate and aluminum nitrate nonahydrate according to the magnesium-aluminum ratio. Separately prepare a mixed alkaline solution of sodium hydroxide and sodium dodecyl sulfonate. Add the mixed salt solution and the mixed alkaline solution dropwise into the reaction vessel in a parallel stream. Raise the temperature to 60-70℃ and crystallize for 12-18 hours. After the reaction is completed, filter, wash and vacuum dry to obtain sodium dodecyl sulfonate intercalated magnesium-aluminum layered double hydroxide. B2. Disperse sodium dodecyl sulfonate intercalated magnesium aluminum layered double hydroxide in deionized water to prepare a suspension with a mass fraction of 3%-5%. Then add sodium molybdate dihydrate and thioacetamide. After ultrasonic dispersion for 20-30 min, transfer to a polytetrafluoroethylene hydrothermal reactor and react at 180-200℃ for 12-16 h. After naturally cooling to room temperature, filter, wash with water, and vacuum dry to obtain the composite lubricating phase.

[0017] By adopting the above technical solution, sodium dodecyl sulfonate is first used to intercalate and modify magnesium-aluminum layered double hydroxides through a co-precipitation process. Then, nano-molybdenum disulfide is generated in situ through a hydrothermal reaction and loaded onto the surface of the sheets. This process allows the molybdenum disulfide sheets to be uniformly attached to the surface and interlayer of the layered double hydroxides, effectively solving the problem of easy self-agglomeration of nano-molybdenum disulfide. At the same time, the intercalation modification can transform the hydrophilic inorganic sheets into oleophilic sheets, significantly improving the compatibility of the composite filler with the polyethylene matrix and ensuring that the lubrication and barrier functions are uniformly performed in the matrix.

[0018] Optionally, in step B1, the molar ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate is (2-3):1; the total metal ion concentration of the mixed salt solution is 0.5-1.0 mol / L; the sodium hydroxide concentration in the mixed alkali solution is 1.0-1.5 mol / L, and the sodium dodecyl sulfonate concentration is 0.2-0.3 mol / L; the mass ratio of the mixed salt solution to the mixed alkali solution is 1:(0.9-1.1).

[0019] Optionally, in step B2, the amount of sodium molybdate dihydrate added is 30%-40% of the mass of sodium dodecyl sulfonate intercalated magnesium aluminum layered double hydroxide; the amount of thioacetamide added is 60%-90% of the mass of sodium dodecyl sulfonate intercalated magnesium aluminum layered double hydroxide.

[0020] By adopting the above technical solution, an appropriate loading amount can enable molybdenum disulfide sheets to form a continuous lubricating phase on the surface of layered double hydroxides, giving full play to the friction-reducing effect of layered slip, while avoiding the stacking and agglomeration of sheets caused by excessive loading amount; the matching sulfur source ratio can ensure that the molybdenum source is fully converted into molybdenum disulfide, reduce the generation of by-products, and ensure the stable friction-reducing effect of the composite lubricating phase.

[0021] Optionally, the toughening agent is EPDM rubber powder.

[0022] This application also provides a method for preparing a wear-resistant polyethylene composite pipe material, using the following technical solution: A method for preparing a wear-resistant polyethylene composite pipe material includes the following steps: S1. High-density polyethylene, chlorinated polyethylene, grafted nano-silicon carbide whiskers, composite lubricating phase, toughening agent, compatibilizer, antioxidant, and lubricant are added to a high-speed mixer, heated to 80-100℃, and mixed at 1000-1500 rpm for 8-12 minutes to obtain a uniform premix. The premix is ​​then added to a twin-screw extruder, and after melt blending, extrusion, water cooling, air drying, and pelletizing, wear-resistant polyethylene composite masterbatch is obtained. S2. Add the wear-resistant polyethylene composite masterbatch into the pipe extruder, and after melting and plasticizing, extrusion through the die head, cooling and sizing by the vacuum sizing sleeve, further cooling by the cooling water tank, traction by the traction machine, and cutting to a fixed length, the wear-resistant polyethylene composite pipe material is obtained.

[0023] By adopting the above technical solution, the step-by-step processing can avoid the uneven dispersion and agglomeration defects caused by direct extrusion of fillers into pipes, and ensure that the grafted wear-resistant phase and the composite lubricating phase are evenly distributed in the cross section of the pipe wall. This allows the wear-resistant, friction-reducing, and barrier effects to be uniformly exerted throughout the inner wall of the pipe, ensuring the uniformity of the overall wear resistance performance of the pipe. At the same time, the process is compatible with existing industrial production lines for polyethylene pipes and has good engineering feasibility.

[0024] In summary, this application has the following beneficial effects: 1. This application employs grafted nano-silicon carbide whiskers as the core wear-resistant functional phase. Addressing the shortcomings of existing polyethylene pipes, such as weak interfacial bonding between filler and matrix, and the tendency for filler to peel off during wear, leading to secondary abrasive wear and accelerated failure, this application covalently grafts polyethylene molecular chains onto the whisker surface. This upgrades the weak interfacial bonding of traditional physical blending to a strong molecular-level interfacial effect, eliminating the core failure factor of filler peeling at its source and preventing the vicious cycle of filler detachment forming pits that exacerbate wear. Simultaneously, the silicon carbide whiskers, with their high hardness and one-dimensional needle-like structure, can construct a spatial load-bearing network within the matrix, directly resisting the cutting and chiseling effects of hard particles in the slurry. This significantly reduces the ploughing damage and material removal rate caused by abrasive particles, greatly improving the material's resistance to abrasive wear.

[0025] 2. This application employs a composite lubricating phase of nano-molybdenum disulfide supported by sodium dodecyl sulfonate-intercalated modified magnesium-aluminum layered double hydroxide. Addressing the problems of easy agglomeration of existing lubricating fillers and accelerated failure due to synergistic abrasion under slurry conditions, this application utilizes the layered carrier of the layered double hydroxide to achieve uniform dispersion of molybdenum disulfide, solving the technical challenge of easy self-agglomeration of the nano-lubricating phase. The layered slip characteristics of molybdenum disulfide can form a continuous solid lubricant transfer film on the wear surface, effectively reducing the friction coefficient and shear wear, forming a synergistic wear-resistant mechanism with the hard wear-resistant phase. Simultaneously, the hydrophobic intercalated layers can construct tortuous penetration paths, hindering the diffusion of acid and alkali ions from the slurry into the material interior, weakening the deteriorating effect of corrosion on the interface and matrix, suppressing the synergistic abrasion effect, and extending the service life of the pipe.

[0026] 3. This application utilizes a compound system of chlorinated polyethylene, toughening agent, and compatibilizer combined with a stepwise extrusion process. Addressing the shortcomings of hard wear-resistant fillers, such as matrix embrittlement and uneven distribution of wear resistance in pipes, this application leverages the synergistic toughening effect of chlorinated polyethylene and the toughening agent to effectively counteract the embrittlement side effects of hard fillers. This improves the pipe's impact resistance and stress cracking resistance, ensuring that the pipe wall is less prone to microcracks under long-term slurry impact. The compatibilizer further strengthens the interphase interface bonding. Combined with the stepwise process of premixing, granulation, and pipe extrusion, this achieves uniform dispersion of the functional filler in the matrix, preventing agglomeration and the formation of wear-prone weak points. This ensures that the wear-resistant, friction-reducing, and barrier functions are uniformly applied throughout the pipe wall, maintaining the overall mechanical properties of the pipe while improving wear resistance. Detailed Implementation

[0027] The present application will be further described in detail below with reference to the embodiments.

[0028] Preparation example of grafted silicon carbide nano whiskers Preparation Example 1 Grafted silicon carbide nano whiskers were prepared using the following method: A1. Weigh 100g of nano-silicon carbide whiskers and add them to 800g of 25% hydrogen peroxide solution to completely submerge the whiskers. Turn on the stirrer and heat to 80℃, then stir and reflux for 2 hours. After the reaction is complete, allow the mixture to cool naturally, filter it, and wash it repeatedly with deionized water until the filtrate is neutral. Place the filter cake in an 80℃ vacuum drying oven and dry it for 12 hours to obtain hydroxylated silicon carbide whiskers.

[0029] A2. Weigh 100g of the above hydroxylated silicon carbide whiskers and add them to 1200g of 90% ethanol solution. Disperse the mixture by ultrasonication for 20min to form a uniform suspension. Add 8g of silane coupling agent KH-570 and adjust the pH of the system to 3.5 by adding glacial acetic acid. Heat the mixture to 60℃ and stir for 4h. After the reaction is complete, centrifuge the mixture, wash the precipitate three times with anhydrous ethanol, and dry it under vacuum at 80℃ to obtain silane coupling agent modified silicon carbide whiskers.

[0030] A3. Weigh 100g of silane coupling agent modified silicon carbide whiskers and 200g of high-density polyethylene and add them to a mixer. Then add 1g of benzoyl peroxide (0.5% of the mass of high-density polyethylene). Set the mixing temperature to 160℃ and the speed to 30r / min. Melt and blend for 10min. After discharge, allow to cool naturally and then crush and sieve the mixture to obtain grafted nano silicon carbide whiskers.

[0031] Preparation Example 2 Grafted silicon carbide nano whiskers were prepared using the following method: A1. Weigh 100g of nano-silicon carbide whiskers and add them to 1000g of 30% hydrogen peroxide solution. Turn on the stirring and heat to 90℃. Stir and reflux for 3h. After the reaction is complete, cool, filter, wash until the filtrate is neutral, and dry under vacuum at 80℃ for 12h to obtain hydroxylated silicon carbide whiskers.

[0032] A2. Weigh 100g of hydroxylated silicon carbide whiskers and add them to 1500g of 85% ethanol solution. Disperse the mixture by ultrasonication for 25min to form a uniform suspension. Add 10g of silane coupling agent KH-570 and adjust the pH of the system to 4.0 by adding glacial acetic acid. Heat the mixture to 70℃ and stir for 5h. After the reaction is complete, centrifuge the mixture, wash it three times with anhydrous ethanol, and dry it under vacuum at 80℃ to obtain silane coupling agent modified silicon carbide whiskers.

[0033] A3. Weigh 100g of silane coupling agent modified silicon carbide whiskers and 350g of high-density polyethylene and add them to a mixer. Then add 3.5g of benzoyl peroxide (accounting for 1.0% of the mass of high-density polyethylene). Set the mixing temperature to 175℃ and the rotation speed to 45r / min. Melt and blend for 15min. After cooling, pulverize and sieve to obtain grafted nano silicon carbide whiskers.

[0034] Preparation Example 3 Grafted silicon carbide nano whiskers were prepared using the following method: A1. Weigh 100g of nano-silicon carbide whiskers and add them to 1200g of 35% hydrogen peroxide solution. Turn on the stirring and heat to 100℃. Stir and reflux for 4h. After the reaction is complete, cool, filter, wash until the filtrate is neutral, and dry under vacuum at 80℃ for 12h to obtain hydroxylated silicon carbide whiskers.

[0035] A2. Weigh 100g of hydroxylated silicon carbide whiskers and add them to 1800g of 80% ethanol solution. Disperse the mixture by ultrasonication for 30min to form a uniform suspension. Add 12g of silane coupling agent KH-570 and adjust the pH of the system to 4.5 by adding glacial acetic acid. Heat the mixture to 80℃ and stir for 6h. After the reaction is complete, centrifuge the mixture, wash it three times with anhydrous ethanol, and dry it under vacuum at 80℃ to obtain silane coupling agent modified silicon carbide whiskers.

[0036] A3. Weigh 100g of silane coupling agent modified silicon carbide whiskers and 500g of high-density polyethylene and add them to a mixer. Then add 7.5g of benzoyl peroxide (accounting for 1.5% of the mass of high-density polyethylene). Set the mixing temperature to 190℃ and the rotation speed to 60r / min. Melt and blend for 20min. After cooling, pulverize and sieve to obtain grafted nano silicon carbide whiskers.

[0037] Preparation example of composite lubricating phase Preparation Example 4 The composite lubricating phase was prepared using the following method: B1. Weigh magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, and prepare a mixed salt solution with a total metal ion concentration of 0.5 mol / L at a magnesium-to-aluminum molar ratio of 2:1. Separately prepare a mixed alkaline solution of sodium hydroxide and sodium dodecyl sulfonate, wherein the sodium hydroxide concentration is 1.0 mol / L and the sodium dodecyl sulfonate concentration is 0.2 mol / L. Under nitrogen protection and continuous stirring, add the mixed salt solution and the mixed alkaline solution dropwise into the reaction vessel at a mass ratio of 1:0.9, and control the pH of the system to be stable at 9.0-10.0. After the addition is complete, raise the temperature to 60℃ and crystallize at a constant temperature for 12 hours. After the reaction is completed, filter, wash with deionized water until the filtrate is neutral, and dry under vacuum at 80℃ to obtain sodium dodecyl sulfonate intercalated magnesium-aluminum layered double hydroxide.

[0038] B2. Weigh 100g of the above intercalation product and add it to deionized water to prepare a suspension with a mass fraction of 3%. Disperse the suspension by sonication for 20min. Add 30g of sodium molybdate dihydrate and 60g of thioacetamide. Continue to disperse by sonication for 20min and then transfer the mixture to a polytetrafluoroethylene hydrothermal reactor. Set the temperature to 180℃ and perform a hydrothermal reaction for 12h. After naturally cooling to room temperature, filter the mixture, wash it three times with deionized water, and vacuum dry it at 60℃ to obtain the composite lubricating phase.

[0039] Preparation Example 5 The composite lubricating phase was prepared using the following method: B1. Weigh magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, and prepare a mixed salt solution with a total metal ion concentration of 0.75 mol / L at a magnesium-to-aluminum molar ratio of 2.5:1. Separately prepare a mixed alkaline solution of sodium hydroxide and sodium dodecyl sulfonate, wherein the concentration of sodium hydroxide is 1.25 mol / L and the concentration of sodium dodecyl sulfonate is 0.25 mol / L. Under nitrogen protection and continuous stirring, add the mixed salt solution and the mixed alkaline solution dropwise into the reaction vessel at a mass ratio of 1:1.0, and control the pH of the system to be stable at 9.0-10.0. After the addition is complete, raise the temperature to 65℃ and crystallize at a constant temperature for 15 hours. After the reaction is completed, filter, wash until neutral, and dry under vacuum at 80℃ to obtain sodium dodecyl sulfonate intercalated magnesium-aluminum layered double hydroxide.

[0040] B2. Weigh 100g of the above intercalation product and add it to deionized water to prepare a suspension with a mass fraction of 4%. Disperse the suspension by sonication for 25min. Add 35g of sodium molybdate dihydrate (35% of the mass of the intercalation product) and 75g of thioacetamide (75% of the mass of the intercalation product). Continue to disperse the suspension by sonication for 25min and then transfer it to a hydrothermal reactor. Set the temperature to 190℃ and perform a hydrothermal reaction for 14h. After natural cooling, filter, wash, and vacuum dry at 60℃ to obtain the composite lubricating phase.

[0041] Preparation Example 6 The composite lubricating phase was prepared using the following method: B1. Weigh magnesium nitrate hexahydrate and aluminum nitrate nonahydrate, and prepare a mixed salt solution with a total metal ion concentration of 1.0 mol / L at a magnesium-to-aluminum molar ratio of 3:1. Separately prepare a mixed alkaline solution of sodium hydroxide and sodium dodecyl sulfonate, wherein the sodium hydroxide concentration is 1.5 mol / L and the sodium dodecyl sulfonate concentration is 0.3 mol / L. Under nitrogen protection and continuous stirring, add the mixed salt solution and the mixed alkaline solution dropwise into the reaction vessel at a mass ratio of 1:1.1, and control the pH of the system to be stable at 9.0-10.0. After the addition is complete, raise the temperature to 70℃ and crystallize at a constant temperature for 18 hours. After the reaction is completed, filter, wash until neutral, and dry under vacuum at 80℃ to obtain sodium dodecyl sulfonate intercalated magnesium-aluminum layered double hydroxide.

[0042] B2. Weigh 100g of the above intercalation product and add it to deionized water to prepare a suspension with a mass fraction of 5%. Disperse the suspension by sonication for 30min. Add 40g of sodium molybdate dihydrate (40% of the mass of the intercalation product) and 90g of thioacetamide (90% of the mass of the intercalation product). Continue to disperse the suspension by sonication for 30min and then transfer it to a hydrothermal reactor. Set the temperature to 200℃ and perform a hydrothermal reaction for 16h. After natural cooling, filter, wash, and vacuum dry at 60℃ to obtain the composite lubricating phase.

[0043] Example Example 1 A wear-resistant polyethylene composite pipe material, the raw material composition and dosage of which are shown in Table 1, wherein the density of high-density polyethylene is 0.955 g / cm³. 3 The molecular weight is 250,000, and the molecular weight of chlorinated polyethylene is 100,000; the grafted silicon carbide nano whiskers are selected from those prepared in Preparation Example 1; the composite lubricating phase is selected from those prepared in Preparation Example 4; the toughening agent is EPDM rubber powder; the compatibilizer is maleic anhydride grafted polyethylene compatibilizer; the antioxidant is antioxidant 1010 and antioxidant 168 compounded in a mass ratio of 1:1; and the lubricant is paraffin wax.

[0044] A method for preparing a wear-resistant polyethylene composite pipe material includes the following steps: S1. High-density polyethylene, chlorinated polyethylene, grafted nano-silicon carbide whiskers, composite lubricating phase, toughening agent, compatibilizer, antioxidant, and lubricant are added to a high-speed mixer, heated to 80°C, and mixed at 1000 rpm for 8 minutes to obtain a uniform premix. The premix is ​​then added to a twin-screw extruder, and after melt blending, extrusion, water cooling, air drying, and pelletizing, wear-resistant polyethylene composite masterbatch is obtained. S2. Add the wear-resistant polyethylene composite masterbatch into the pipe extruder, and after melting and plasticizing, extrusion through the die head, cooling and sizing by the vacuum sizing sleeve, further cooling by the cooling water tank, traction by the traction machine, and cutting to a fixed length, the wear-resistant polyethylene composite pipe material is obtained.

[0045] Example 2 A wear-resistant polyethylene composite pipe material, the raw material composition and dosage of which are shown in Table 1, wherein the density of high-density polyethylene is 0.955 g / cm³. 3 The molecular weight is 250,000, and the molecular weight of chlorinated polyethylene is 100,000; the grafted silicon carbide nano whiskers are selected from those prepared in Preparation Example 2; the composite lubricating phase is selected from those prepared in Preparation Example 5; the toughening agent is EPDM rubber powder; the compatibilizer is maleic anhydride grafted polyethylene compatibilizer; the antioxidant is antioxidant 1010 and antioxidant 168 compounded in a mass ratio of 1:1; and the lubricant is paraffin wax.

[0046] A method for preparing a wear-resistant polyethylene composite pipe material includes the following steps: S1. High-density polyethylene, chlorinated polyethylene, grafted nano-silicon carbide whiskers, composite lubricating phase, toughening agent, compatibilizer, antioxidant, and lubricant are added to a high-speed mixer, heated to 90°C, and mixed at 1250 rpm for 10 minutes to obtain a uniform premix. The premix is ​​then added to a twin-screw extruder, and after melt blending, extrusion, water cooling, air drying, and pelletizing, wear-resistant polyethylene composite masterbatch is obtained. S2. Add the wear-resistant polyethylene composite masterbatch into the pipe extruder, and after melting and plasticizing, extrusion through the die head, cooling and sizing by the vacuum sizing sleeve, further cooling by the cooling water tank, traction by the traction machine, and cutting to a fixed length, the wear-resistant polyethylene composite pipe material is obtained.

[0047] Example 3 A wear-resistant polyethylene composite pipe material, the raw material composition and dosage of which are shown in Table 1, wherein the density of high-density polyethylene is 0.955 g / cm³. 3 The molecular weight is 250,000, and the molecular weight of chlorinated polyethylene is 100,000; the grafted silicon carbide nano whiskers are selected from those prepared in Preparation Example 3; the composite lubricating phase is selected from those prepared in Preparation Example 6; the toughening agent is EPDM rubber powder; the compatibilizer is maleic anhydride grafted polyethylene compatibilizer; the antioxidant is antioxidant 1010 and antioxidant 168 compounded in a mass ratio of 1:1; and the lubricant is paraffin wax.

[0048] A method for preparing a wear-resistant polyethylene composite pipe material includes the following steps: S1. High-density polyethylene, chlorinated polyethylene, grafted nano-silicon carbide whiskers, composite lubricating phase, toughening agent, compatibilizer, antioxidant, and lubricant are added to a high-speed mixer, heated to 100℃, and mixed at 1500 rpm for 12 minutes to obtain a uniform premix. The premix is ​​then added to a twin-screw extruder, and after melt blending, extrusion, water cooling, air drying, and pelletizing, wear-resistant polyethylene composite masterbatch is obtained. S2. Add the wear-resistant polyethylene composite masterbatch into the pipe extruder, and after melting and plasticizing, extrusion through the die head, cooling and sizing by the vacuum sizing sleeve, further cooling by the cooling water tank, traction by the traction machine, and cutting to a fixed length, the wear-resistant polyethylene composite pipe material is obtained.

[0049] Table 1. Raw material composition and proportions (kg) of polyethylene composite pipe materials in Examples 1-3

[0050] Example 4 A wear-resistant polyethylene composite pipe material differs from Example 3 in that: in this example, the grafted nano-silicon carbide whiskers are selected from the grafted nano-silicon carbide whiskers prepared in Preparation Example 1; and the composite lubricating phase is selected from the composite lubricating phase prepared in Preparation Example 5.

[0051] Example 5 A wear-resistant polyethylene composite pipe material differs from Example 3 in that: in this example, the grafted nano-silicon carbide whiskers are selected from the grafted nano-silicon carbide whiskers prepared in Example 2; and the composite lubricating phase is selected from the composite lubricating phase prepared in Example 4.

[0052] Example 6 A wear-resistant polyethylene composite pipe material, which differs from Example 3 in that the molecular weight of the high-density polyethylene in this example is 150,000.

[0053] Comparative Example Comparative Example 1 A polyethylene pipe was prepared according to Example 1 in the patent document with announcement number CN118931011B and titled "Preparation Method of Multifunctional Polyethylene Pipe for Lined Composite Pipe".

[0054] Comparative Example 2 A wear-resistant polyethylene composite pipe material differs from Example 3 in that: in this comparative example, grafted nano-silicon carbide whiskers and composite lubricating phases were not added, and high-density polyethylene was used instead.

[0055] Comparative Example 3 A wear-resistant polyethylene composite pipe material, which differs from Example 3 in that: in this comparative example, an equal amount of nano-silicon carbide whiskers is used instead of grafted nano-silicon carbide whiskers.

[0056] Comparative Example 4 A wear-resistant polyethylene composite pipe material, which differs from Example 3 in that: in this comparative example, an equal amount of graphite powder is used instead of the composite lubricating phase.

[0057] Performance testing Test samples: The polyethylene composite pipe materials prepared in Examples 1-6 and Comparative Examples 1-4 were made into standard test samples.

[0058] Test items: 1. Notched impact strength test of simply supported beam The test was conducted in accordance with GB / T1043.1-2008 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test".

[0059] 2. Abrasive wear performance testing was conducted using an MLS-23 wet sand rubber wheel wear testing machine to simulate the abrasive wear conditions of mining slurry. The sample size was 70mm × 25mm × 6mm. Test parameters were: rubber wheel Shore hardness A60, rotation speed 240 r / min, normal load 100 N; the abrasive used was 40-70 mesh quartz sand, mixed with deionized water to prepare a slurry with a mass fraction of 30%, and a slurry flow rate of 300 mL / min, continuously rinsing the sample surface for 30 minutes. Before the test, the sample was dried in an 80℃ vacuum oven to constant weight, and the initial mass was recorded. After the test, the sample was removed, cleaned with anhydrous ethanol to remove surface residue, and dried to constant weight. The mass after wear was recorded, and the volumetric wear was calculated based on the material density. A smaller volumetric wear indicates better abrasive wear resistance.

[0060] 3. The test was conducted using an MM-200 ring-block friction and wear testing machine, in accordance with GB / T3960-2016 "Test Method for Sliding Friction and Wear of Plastics". The mating part was a 45# quenched steel ring, the test load was 200N, the sliding speed was 0.42m / s, and the steady-state dynamic friction coefficient of the sample was tested under dry friction conditions.

[0061] Experimental results: see Table 2.

[0062] Table 2 Experimental Results

[0063] As shown in Table 2, the test data of this application demonstrate that, compared with all comparative examples, each embodiment exhibits superior anti-abrasive wear and frictional lubrication performance, effectively solving the core defects of existing polyethylene pipes in mining abrasive slurry conditions, such as rapid wear rate and short service life. In Examples 1-3, as the filler dosage in the formulation increases within the protected range, the volumetric wear decreases slightly, and the friction coefficient gradually decreases, with a stable and controllable performance gradient. This proves that the optimized formulation system of this application has strong range adaptability and high process stability, and can stably exert the effect of wear resistance and friction reduction. Through the synergistic effect of grafted nano-silicon carbide whiskers and composite lubricating phases, each embodiment significantly inhibits the cutting and chiseling wear of hard mineral slurry particles on the inner wall of the pipe. Compared with the prior art comparative example 1 and pure matrix comparative example 2, the volumetric wear is reduced by more than 55%, and the improvement in wear resistance is extremely significant.

[0064] The advantages of the modified composite lubricating phase have been fully verified in the experimental data. Comparative Example 4 used conventional graphite powder as the lubricating filler, and the friction coefficient and wear amount were both at a high level. This application uses a composite lubricating phase of magnesium-aluminum layered double hydroxide supported on nano-molybdenum disulfide. Relying on the layered structure of the carrier, the nano-lubricating components are uniformly dispersed, effectively avoiding the agglomeration defects of nano-fillers. It can form a continuous and dense solid lubricating transfer film on the wear surface of the pipe, continuously reducing the interfacial friction and shearing. At the same time, the modified intercalation structure can effectively block the penetration of acid and alkali corrosive media, inhibit the synergistic failure effect of wear and corrosion, and further improve the long-term wear resistance of the pipe under complex mining slurry conditions.

[0065] Furthermore, the variable control experiments in Examples 4-6 demonstrate that the formulation system of this application has wide adaptability and high tolerance. Minor adjustments to the filler preparation process and small changes in the molecular weight of the matrix do not cause significant performance fluctuations, further proving that the overall structure of the technical solution of this application is stable and the process is highly repeatable. Compared to the shortcomings of existing technologies with single reinforcement and non-directional wear-resistant design, this application achieves simultaneous optimization of the wear resistance and comprehensive mechanical properties of polyethylene pipes through multi-dimensional synergistic modification of interface strengthening, hard load-bearing, lubrication and friction reduction, and corrosion barrier, possessing excellent engineering application value.

[0066] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A wear-resistant polyethylene composite pipe material, characterized in that, The raw materials include the following parts by weight: 90-100 parts of high-density polyethylene; 5-10 parts of chlorinated polyethylene; 6-10 parts of grafted nano-silicon carbide whiskers; 3-8 parts of composite lubricating phase; 2-5 parts toughening agent; 3-6 parts compatibilizer; Antioxidant 0.3-1 part; 0.5-1.5 parts lubricant; The grafted nano silicon carbide whiskers are silicon carbide whiskers with high-density polyethylene grafted onto their surfaces. The composite lubricating phase is a sodium dodecyl sulfonate intercalated modified magnesium-aluminum layered double hydroxide supported on nano-molybdenum disulfide sheets.

2. The wear-resistant polyethylene composite pipe material according to claim 1, characterized in that, The grafted silicon carbide nano whiskers were prepared using the following method: A1. Immerse nano-silicon carbide whiskers in hydrogen peroxide solution, stir and reflux at 80-100℃ for 2-4 hours, then wash, filter and vacuum dry to obtain hydroxylated silicon carbide whiskers. A2. Disperse hydroxylated silicon carbide whiskers in an ethanol solution, add silane coupling agent KH-570, adjust the pH to 3.5-4.5 with glacial acetic acid, stir and react at 60-80℃ for 4-6 hours, and after the reaction is completed, centrifuge, wash and vacuum dry to obtain silane coupling agent modified silicon carbide whiskers. A3. Silane coupling agent modified silicon carbide whiskers and high-density polyethylene are added to a mixer, and then benzoyl peroxide is added. The mixture is melt-blended at 160-190℃ and 30-60 r / min for 10-20 min. The reaction product is then pulverized to obtain grafted nano silicon carbide whiskers.

3. The wear-resistant polyethylene composite pipe material according to claim 1, characterized in that, In step A1, the mass concentration of the hydrogen peroxide solution is 25%-35%, and the mass ratio of the nano-silicon carbide whiskers to the hydrogen peroxide solution is 1:(8-12).

4. The wear-resistant polyethylene composite pipe material according to claim 1, characterized in that, In step A2, the mass concentration of the ethanol solution is 80%-90%, and the mass ratio of the hydroxylated silicon carbide whiskers, the ethanol solution, and the silane coupling agent KH-570 is 1:(12-18):(0.08-0.12).

5. The wear-resistant polyethylene composite pipe material according to claim 1, characterized in that, In step A2, the mass ratio of the silane coupling agent-modified silicon carbide whiskers to high-density polyethylene is 1:(2-5), and the amount of benzoyl peroxide added is 0.5%-1.5% of the mass of high-density polyethylene.

6. The wear-resistant polyethylene composite pipe material according to claim 1, characterized in that, The composite lubricating phase was prepared using the following method: B1. Prepare a mixed salt solution by mixing magnesium nitrate hexahydrate and aluminum nitrate nonahydrate according to the magnesium-aluminum ratio. Separately prepare a mixed alkaline solution of sodium hydroxide and sodium dodecyl sulfonate. Add the mixed salt solution and the mixed alkaline solution dropwise into the reaction vessel in a parallel stream. Raise the temperature to 60-70℃ and crystallize for 12-18 hours. After the reaction is completed, filter, wash and vacuum dry to obtain sodium dodecyl sulfonate intercalated magnesium-aluminum layered double hydroxide. B2. Disperse sodium dodecyl sulfonate intercalated magnesium aluminum layered double hydroxide in deionized water to prepare a suspension with a mass fraction of 3%-5%. Then add sodium molybdate dihydrate and thioacetamide. After ultrasonic dispersion for 20-30 min, transfer to a polytetrafluoroethylene hydrothermal reactor and react at 180-200℃ for 12-16 h. After naturally cooling to room temperature, filter, wash with water, and vacuum dry to obtain the composite lubricating phase.

7. The wear-resistant polyethylene composite pipe material according to claim 6, characterized in that, In step B1, the molar ratio of magnesium nitrate hexahydrate to aluminum nitrate nonahydrate is (2-3):1; the total metal ion concentration of the mixed salt solution is 0.5-1.0 mol / L; the sodium hydroxide concentration in the mixed alkali solution is 1.0-1.5 mol / L, and the sodium dodecyl sulfonate concentration is 0.2-0.3 mol / L; the mass ratio of the mixed salt solution to the mixed alkali solution is 1:(0.9-1.1).

8. The wear-resistant polyethylene composite pipe material according to claim 6, characterized in that, In step B2, the amount of sodium molybdate dihydrate added is 30%-40% of the mass of sodium dodecyl sulfonate intercalated magnesium aluminum layered double hydroxide; the amount of thioacetamide added is 60%-90% of the mass of sodium dodecyl sulfonate intercalated magnesium aluminum layered double hydroxide.

9. The wear-resistant polyethylene composite pipe material according to claim 1, characterized in that, The toughening agent is EPDM rubber powder.

10. A method for preparing a wear-resistant polyethylene composite pipe material according to any one of claims 1-9, characterized in that, Includes the following steps: S1. High-density polyethylene, chlorinated polyethylene, grafted nano-silicon carbide whiskers, composite lubricating phase, toughening agent, compatibilizer, antioxidant, and lubricant are added to a high-speed mixer, heated to 80-100℃, and mixed at 1000-1500 rpm for 8-12 minutes to obtain a uniform premix. The premix is ​​then added to a twin-screw extruder, and after melt blending, extrusion, water cooling, air drying, and pelletizing, wear-resistant polyethylene composite masterbatch is obtained. S2. Add the wear-resistant polyethylene composite masterbatch into the pipe extruder, and after melting and plasticizing, extrusion through the die head, cooling and sizing by the vacuum sizing sleeve, further cooling by the cooling water tank, traction by the traction machine, and cutting to a fixed length, the wear-resistant polyethylene composite pipe material is obtained.

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