Halogen corrosion-resistant composite material and preparation method thereof

Abstract

The present invention belongs to the technical field of composite materials, and specifically relates to a halogen-resistant composite material and a preparation method thereof. The halogen-resistant composite material comprises the following components by weight: 60-70 parts of nylon 56, 10-20 parts of semi-aromatic nylon, 25-35 parts of modified carbon fibers, 5-10 parts of graphene oxide, and 1-3 parts of a pentaerythritol-based polyol; the modified carbon fibers are carbon fibers modified using an acidic solution. The oxygen-containing functional groups on the surface of the modified carbon fibers can form strong chemical bonds or hydrogen bonds with the oxygen-containing groups on the surface of the graphene oxide, the polyhydroxy structures on the pentaerythritol, and the amide groups on the nylon 56, thereby tightly bonding the fillers. The linear carbon fibers combined with the lamellar graphene oxide are more conducive to enhancing the barrier effect and improving the halogen-resistant corrosion performance of the composite material.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite materials, and in particular relates to a halogen corrosion resistant composite material and a preparation method thereof. Background Art

[0002] In chemical production processes, especially those producing halogenated compounds like trichlorotrifluoroethane, the primary agents of corrosion for equipment like condensers, evaporators, and distillation towers are halides and their salts found in organic matter. Halogenated acids (such as hydrochloric acid and hydrofluoric acid) are particularly corrosive, often causing corrosion and perforation of some equipment after only a few months of use, resulting in significant production losses. Therefore, research into corrosion-resistant materials is essential for the chemical production of halogenated compounds like trichlorotrifluoroethane. A material's chemical and mineral composition significantly influences its corrosion resistance. Materials that react readily with acids, bases, salts, oxygen, or certain chemicals, or materials that are easily soluble in water or certain solvents, exhibit poor corrosion resistance.

[0003] Some metal materials resistant to halides and their salts, such as Hastelloy B, have alloy contents exceeding 70%, which not only increases material cost but also significantly degrades processing performance. Titanium alloys offer excellent corrosion resistance, particularly in strong acid and alkaline environments, but also face the challenge of high cost. Therefore, it is necessary to identify corrosion-resistant, low-cost materials to meet the requirements of chemical production equipment. The first step is material selection: choosing appropriate corrosion-resistant materials based on the characteristics of the media encountered during chemical production. The second step is structural design, avoiding dead corners and crevices, as these areas are prone to accumulating corrosive media and causing localized corrosion. Equipment wall thickness should be appropriately designed to meet strength requirements while also taking into account corrosion margins to prevent corrosion failure during the equipment's service life. Maintainability is also important, ensuring ease of routine inspection, cleaning, and repair. Furthermore, necessary corrosion protection measures, such as coatings and linings, should be implemented.

[0004] Nylon polymers have good corrosion resistance and excellent processing properties, and can simultaneously meet the performance requirements of corrosion resistance and easy processing in chemical production. Nylon is a type of high molecular polymer that contains repeating unit amide bonds. Nylon is widely used in the fields of engineering plastics and fiber materials because of its good heat resistance, chemical corrosion resistance, wear resistance, and excellent mechanical properties. For example, the manufacture of engineering plastic products such as mechanical parts, automotive parts, electrical equipment housings, and some special-purpose aerospace products can also be made into common nylon fiber-type fiber materials due to its mechanical and heat resistance properties. Some bio-based nylons can also be used to manufacture medical devices, medical materials, and packaging materials due to their biocompatibility and chemical resistance. Nylon is a key and important class of polymer materials with a wide range of applications. It plays a key role in engineering construction, spinning and textiles, chemical equipment, and packaging.

[0005] Nylon can be divided into three main categories based on its molecular structure: aliphatic, semi-aromatic, and fully aromatic. Aliphatic nylon was the first nylon to achieve industrialized production. Its main chain contains no other groups besides methylene and amide groups, resulting in better processability. With the increase in aromatic ring structures in the main chain, the material's thermodynamic properties, rigidity, and mechanical strength also increase, while also exhibiting corrosion resistance. Fully aromatic nylon also has some disadvantages, such as a high melting point and poor solubility in organic solvents, resulting in poor processability, increased processing costs, and thus limited applications. Among them, bio-based aliphatic nylon, due to its good processability and low cost, is the material with the most promising application prospects. Chinese invention patent application publication number CN119307093A provides a highly alcoholysis-resistant glass fiber-reinforced nylon material. By adding a small amount of mica to the matrix raw material, the insulation and heat resistance of the prepared glass fiber-reinforced nylon material are improved to a certain extent, expanding the range of products that can be made from the material and improving the stability of the products, thereby helping the products resist corrosion from strong acids and alkalis. However, bio-based aliphatic nylon has poor salt corrosion resistance, which limits its further application. Summary of the Invention

[0006] The purpose of the present invention is to provide a halogen corrosion resistant composite material and a preparation method thereof. The halogen corrosion resistant composite material has excellent corrosion resistance and expands its application in the production process of halogen-containing compounds such as trichlorotrifluoroethane.

[0007] In order to achieve the above object, the first aspect of the present invention provides a halogen corrosion-resistant composite material, comprising the following components in parts by weight:

[0008] 60-70 parts of nylon 56, 10-20 parts of semi-aromatic nylon, 25-35 parts of modified carbon fiber, 5-10 parts of graphene oxide, and 1-3 parts of pentaerythritol-based polyol; the modified carbon fiber is a carbon fiber modified by an acidic solution.

[0009] Nylon 56 is a new type of bio-based polyamide. Its monomer, bio-based 1,5-pentanediamine, is derived from glucose. Glucose is fermented to produce lysine, which is then decarboxylated by lysine decarboxylase to produce bio-based 1,5-pentanediamine. Subsequently, bio-based 1,5-pentanediamine, containing an odd number of carbon atoms, and petroleum-based adipic acid, containing an even number of carbon atoms, are melt-polycondensed to produce bio-based nylon 56. Bio-based nylon 56 has superior melt flow properties compared to PA66, making it more suitable for use in complex workpieces such as engineering equipment. However, compared to other types of aliphatic nylons, bio-based nylon 56 has poor halogen corrosion resistance and low mechanical strength due to the odd-even effect. To improve its corrosion resistance, the present invention adds a certain amount of semi-aromatic nylon. The presence of benzene rings in semi-aromatic nylon not only improves the mechanical strength of the composite material but also provides excellent barrier properties, reducing the odd-even effect of nylon 56 and preventing the intrusion of corrosive substances, thereby improving the corrosion resistance of the composite material.

[0010] However, as an aliphatic nylon, nylon 56 still has lower mechanical properties than aromatic nylon. In order to further improve its mechanical strength while meeting its halogen corrosion resistance, the present invention adds a certain amount of modified carbon fiber, graphene oxide and pentaerythritol.

[0011] Carbon fiber is a fiber material with a carbon content exceeding 90%. It is typically made from organic polymer precursors such as polyacrylonitrile, asphalt, phenolic formaldehyde, and viscose, followed by spinning, pre-oxidation, carbonization, and graphitization, resulting in a high-performance fiber material with a turbostratic graphite structure. Carbon fiber boasts excellent properties such as high specific strength, high specific modulus, high-temperature resistance, friction resistance, corrosion resistance, and high thermal conductivity, making it widely used as a reinforcement for high-performance composite materials. Despite the significant advantages of carbon fiber-reinforced nylon 56-based composites, several challenges remain in their preparation and application, hindering the development of nylon 56 resin-based composites. Nylon 56 resin typically has a high viscosity, while carbon fiber exhibits high surface inertness. This makes it difficult to achieve two-phase impregnation during composite preparation, making it difficult to simultaneously prepare the composite and improve interfacial strength. Furthermore, the high viscosity of nylon 56 makes it difficult to evenly distribute the carbon fibers within the matrix, resulting in a low density composite and difficulty improving halogen corrosion resistance. To address this issue, the present invention utilizes a corrosive acidic solution to treat the carbon fiber surface. This treatment has two effects. First, after oxidation treatment, the surface of the carbon fiber usually has structural morphologies such as grooves or pits. When the carbon fiber is embedded in the matrix, the surface roughness of the carbon fiber can mechanically interlock the fiber and the matrix, thereby enhancing the interfacial bonding between the two phases. Secondly, the oxidation treatment can produce a large number of oxygen-containing groups on the surface of the carbon fiber, improve the surface inertness of the carbon fiber, and enhance the wettability and bonding strength between the carbon fiber and the resin matrix. More importantly, the oxygen-containing functional groups on the surface of the carbon fiber can form strong chemical bonds or hydrogen bonds with the oxygen-containing groups on the surface of graphene oxide, the polyhydroxy structure on pentaerythritol, and the amide groups on nylon 56, so that the fillers are closely linked together. The linear structure of carbon fiber combined with the lamellar structure of graphene oxide is more conducive to improving the barrier effect and improving the halogen corrosion resistance of the composite material. Pentaerythritol can not only serve as a link between the modified carbon fiber and graphene oxide, but also improve the processing performance of the composite material, promote the dispersion of inorganic fillers, improve the density of the composite material, and overcome the negative defects such as porosity and looseness caused by the grooves on the surface of the modified carbon fiber.

[0012] In particular, the semi-aromatic nylon is one or more of nylon 6T, nylon 6I, nylon 6T / 66, nylon 6T / 6, and nylon 6T / 6I. These semi-aromatic nylons offer both processability and barrier properties, improving the melt flowability of nylon 56 resin to meet the requirements for fabricating complex workpieces while also enhancing the corrosion resistance of the composite material.

[0013] In particular, the specific preparation process of the modified carbon fiber is: placing the cleaned carbon fiber into a concentrated nitric acid solution, ultrasonically modifying the carbon fiber, taking it out and washing it to neutrality, thereby obtaining the modified carbon fiber.

[0014] Specifically, the cleaning is performed using a mixed solution of ethanol and acetone, with the concentrated nitric acid solution having a concentration of 60-70wt%. Etching with concentrated nitric acid not only removes impurities from the carbon fiber surface but also introduces oxygen-containing functional groups, such as carboxyl (COOH) and hydroxyl (OH), onto the surface. These functional groups increase the polarity of the carbon fiber surface, making it easier to bond with the nylon 56 resin matrix, thereby improving the interfacial strength and overall performance of the composite material.

[0015] Particularly, the temperature of the ultrasonic modification treatment is 40-50° C., and the time is 0.5-1.5 h.

[0016] Particularly, the pentaerythritol-based polyol is one or more of monopentaerythritol, dipentaerythritol, and tripentaerythritol.

[0017] Particularly, the halogen corrosion resistant composite material further comprises an additive.

[0018] Particularly, the auxiliary agent is one or more of a lubricant, a coupling agent, an antioxidant, a release agent, a nucleating agent, a flow modifier, and a colorant.

[0019] Specifically, the lubricant is one or more of polytetrafluoroethylene, zinc stearate, calcium stearate, talc, silicone oil, and polyethylene wax. Lubricants significantly improve the processing performance of nylon 56 composite materials by reducing friction, torque, and die buildup, thereby increasing production efficiency. Lubricants also enhance the product's surface gloss and smoothness, lowering the coefficient of friction and improving durability and user experience.

[0020] Particularly, the coupling agent is one or more of a silane coupling agent, a titanate coupling agent, a phosphate coupling agent, and an aluminate coupling agent.

[0021] A second aspect of the present invention provides a method for preparing a halogen corrosion-resistant composite material, comprising the following steps:

[0022] (1) Weigh each component by weight;

[0023] (2) All raw materials except modified carbon fiber are pre-mixed and fed into the twin-screw extruder through the main feed port, and the modified carbon fiber is fed into the twin-screw extruder through the side feed port;

[0024] (3) Melting, extrusion and granulation to obtain a halogen-resistant composite material.

[0025] A twin-screw extruder is used to process the material. As the material advances through the screws, a heating device external to the barrel heats the material, while the rotation of the screws simultaneously generates shear and frictional heat. These two heat sources combine to gradually transform the material from a solid state to a molten state, achieving plasticization. Typically, the screw speed of a twin-screw extruder is 400-500 rpm. The melt extrusion temperature is not specifically limited but can be adjusted based on the type of semi-aromatic nylon and its melting point, specifically 280-320°C.

[0026] Beneficial effects:

[0027] The present invention provides a halogen-resistant composite material and a preparation method thereof. The halogen-resistant composite material has excellent corrosion resistance and expands its application in the production process of halogen-containing compounds such as trichlorotrifluoroethane. Bio-based nylon 56 also has better melt flow properties than PA66, which is more conducive to its application in complex workpiece fields such as engineering equipment. The addition of modified carbon fiber, graphene oxide and pentaerythritol further improves its mechanical strength on the basis of meeting its halogen corrosion resistance. After oxidation treatment, the surface of the carbon fiber usually has structural morphology such as grooves or pits, which enhances the interfacial bonding between the two phases. The oxygen-containing functional groups on the surface of the carbon fiber can form strong chemical bonds or hydrogen bonds with the oxygen-containing groups on the surface of the graphene oxide, the polyhydroxy structure on the pentaerythritol and the amide group on the nylon 56, so that they are closely linked together. The linear structure of carbon fiber combined with the lamellar structure of graphene oxide is more conducive to improving the barrier effect and the halogen corrosion resistance of the composite material. Pentaerythritol can not only serve as a link between modified carbon fibers and graphene oxide, but also improve the processing performance of the composite material, promote the dispersion of inorganic fillers, increase the density of the composite material, and overcome the negative defects caused by grooves on the surface of the modified carbon fibers. DETAILED DESCRIPTION

[0028] The following describes the specific embodiments of the present disclosure in detail. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present disclosure, and are not intended to limit the present disclosure.

[0029] The endpoints and any values of the endpoint values disclosed in this disclosure are not limited to the precise ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, the endpoint values of each range and the individual point values, and the individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0030] Example 1

[0031] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0032] 60 parts of nylon 56, 12 parts of semi-aromatic nylon 6T / 66, 25 parts of modified carbon fiber, 5 parts of graphene oxide, 1 part of dipentaerythritol, and 1 part of polytetrafluoroethylene;

[0033] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 40°C, and the time is 1.5h.

[0034] Example 2

[0035] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0036] 70 parts of nylon 56, 16 parts of semi-aromatic nylon 6T / 66, 35 parts of modified carbon fiber, 10 parts of graphene oxide, 3 parts of dipentaerythritol, and 5 parts of talc;

[0037] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 68wt%; the temperature of the ultrasonic modification treatment is 50°C and the time is 0.5h.

[0038] Example 3

[0039] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0040] 60 parts of nylon 56, 16 parts of semi-aromatic nylon 6T / 66, 25 parts of modified carbon fiber, 10 parts of graphene oxide, 3 parts of dipentaerythritol, and 1 part of polytetrafluoroethylene;

[0041] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 40°C and the time is 0.8h.

[0042] Example 4

[0043] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0044] 66 parts of nylon 56, 10 parts of semi-aromatic nylon 6T / 66, 30 parts of modified carbon fiber, 8 parts of graphene oxide, 2 parts of dipentaerythritol, and 3 parts of talc;

[0045] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 46°C, and the time is 1.1h.

[0046] Example 5

[0047] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0048] 62 parts of nylon 56, 13 parts of semi-aromatic nylon 6T / 66, 28 parts of modified carbon fiber, 6 parts of graphene oxide, 1.5 parts of dipentaerythritol, and 2.5 parts of polytetrafluoroethylene;

[0049] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 68wt%; the temperature of the ultrasonic modification treatment is 43°C, and the time is 1.2h.

[0050] Example 6

[0051] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0052] 68 parts of nylon 56, 15 parts of semi-aromatic nylon 6T / 66, 33 parts of modified carbon fiber, 9 parts of graphene oxide, 2.6 parts of dipentaerythritol, and 4.2 parts of talc;

[0053] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 48°C, and the time is 0.8h.

[0054] Example 7

[0055] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0056] 66 parts of nylon 56, 20 parts of semi-aromatic nylon 6T / 66, 30 parts of modified carbon fiber, 8 parts of graphene oxide, 2 parts of dipentaerythritol, and 3 parts of talc;

[0057] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 46°C, and the time is 1.1h.

[0058] Example 8

[0059] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0060] 64 parts of nylon 56, 15.5 parts of semi-aromatic nylon 6T / 66, 28 parts of modified carbon fiber, 8.5 parts of graphene oxide, 2.3 parts of dipentaerythritol, and 3.5 parts of polytetrafluoroethylene;

[0061] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 68wt%; the temperature of the ultrasonic modification treatment is 43°C, and the time is 0.9h.

[0062] Example 9

[0063] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0064] 67.5 parts of nylon 56, 14.5 parts of semi-aromatic nylon 6T / 66, 31 parts of modified carbon fiber, 7.5 parts of graphene oxide, 2.2 parts of dipentaerythritol, and 3.5 parts of talc;

[0065] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 45°C, and the time is 0.7h.

[0066] Example 10

[0067] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0068] 66 parts of nylon 56, 14 parts of semi-aromatic nylon 6T / 66, 30 parts of modified carbon fiber, 8 parts of graphene oxide, 2 parts of dipentaerythritol, and 3 parts of talc;

[0069] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 46°C, and the time is 1.1h.

[0070] Comparative Example 1

[0071] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0072] 66 parts of nylon 56, 14 parts of semi-aromatic nylon 6T / 66, 30 parts of modified carbon fiber, 0 parts of graphene oxide, 10 parts of dipentaerythritol, and 3 parts of talc;

[0073] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 46°C, and the time is 1.1h.

[0074] Comparative Example 2

[0075] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0076] 66 parts of nylon 56, 14 parts of semi-aromatic nylon 6T / 66, 30 parts of modified carbon fiber, 10 parts of graphene oxide, 0 parts of dipentaerythritol, and 3 parts of talc;

[0077] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 46°C, and the time is 1.1h.

[0078] Comparative Example 3

[0079] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0080] 66 parts of nylon 56, 14 parts of semi-aromatic nylon 6T / 66, 30 parts of cleaned carbon fibers, 8 parts of graphene oxide, 2 parts of dipentaerythritol, and 3 parts of talc;

[0081] The specific preparation process of the cleaned carbon fiber is: using a mixed solution of ethanol and acetone to clean the carbon fiber.

[0082] Comparative Example 4

[0083] A halogen corrosion-resistant composite material comprises the following components in parts by weight:

[0084] 66 parts of nylon 56, 14 parts of semi-aromatic nylon 6T / 66, 30 parts of modified carbon fiber, 8 parts of graphene oxide, 5 parts of dipentaerythritol, and 3 parts of talc;

[0085] The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, ultrasonically modified, and then taken out and washed until neutral to obtain the modified carbon fiber; the cleaning is performed using a mixed solution of ethanol and acetone, and the concentration of the concentrated nitric acid solution is 65wt%; the temperature of the ultrasonic modification treatment is 46°C, and the time is 1.1h.

[0086] The preparation processes of the halogen corrosion-resistant composite materials in the above embodiment and comparative example are the same, specifically:

[0087] (1) Weigh each component by weight;

[0088] (2) All raw materials except the modified carbon fiber (cleaned carbon fiber in comparative example 3) were pre-mixed and fed into the main feed port of the twin-screw extruder. The modified carbon fiber (cleaned carbon fiber in comparative example 3) was fed into the side feed port.

[0089] (3) Melting, extruding, and granulating to obtain a halogen-resistant composite material; the screw speed of the twin-screw extruder is 450 rpm; and the melt extrusion temperature is 300°C.

[0090] Performance Testing: Using deionized water as the solvent, a 3.8 mol / L hydrochloric acid solution was prepared. Accelerated aging testing was conducted on the halogen-resistant composite materials at 45°C under sealed conditions. Specifically, the halogen-resistant composite materials prepared in the above examples and comparative examples were prepared into standard samples. Their initial tensile strength (MPa, ISO 527) and initial flexural strength (MPa, ISO 178) were tested. The tensile and flexural strengths after immersion in a 3.8 mol / L hydrochloric acid solution at 45°C for 10 days were also tested under sealed conditions. The tensile and flexural strength retention rates were calculated. The results are shown in Tables 1 and 2.

[0091] Table 1 Properties of halogen corrosion resistant composite materials prepared in Examples 1 to 7

[0092]

[0093] Table 2 Properties of halogen corrosion resistant composite materials prepared in Examples 8-10 and Comparative Examples 1-4

[0094]

[0095] As can be seen from Tables 1 and 2, the addition of modified carbon fiber, graphene oxide and pentaerythritol further improves its mechanical strength on the basis of meeting its halogen corrosion resistance. After oxidation treatment, the surface of the carbon fiber usually has structural morphologies such as grooves or pits, which enhances the interfacial bonding of the two phases. The oxygen-containing functional groups on the surface of the carbon fiber can form strong chemical bonds or hydrogen bonds with the oxygen-containing groups on the surface of the graphene oxide, the polyhydroxy structure on the pentaerythritol and the amide group on the nylon 56, making them closely linked together. The linear structure of carbon fiber combined with the lamellar structure of graphene oxide is more conducive to improving the barrier effect and improving the halogen corrosion resistance of the composite material. Pentaerythritol can not only serve as a link connecting the modified carbon fiber and graphene oxide, but also improve the processing performance of the composite material, promote the dispersion of inorganic fillers, improve the density of the composite material, overcome the negative defects caused by the grooves on the surface of the modified carbon fiber, improve the halogen acid corrosion resistance of the composite material, and have a higher mechanical strength retention rate.

[0096] Compared with Example 10, Comparative Examples 1 and 2 lack graphene oxide or pentaerythritol, and their halogen corrosion resistance is greatly reduced. This further illustrates that the oxygen-containing functional groups on the surface of the carbon fibers can form strong chemical bonds or hydrogen bonds with the oxygen-containing groups on the surface of graphene oxide, the polyhydroxy structures on pentaerythritol, and the amide groups on nylon 56, thereby improving the halogen corrosion resistance of the composite material. Comparative Example 3 does not oxidize the carbon fibers, and thus cannot form structural morphologies such as grooves or pits on the surface of the carbon fibers, nor can it introduce oxygen-containing functional groups to enhance the interaction with graphene oxide and dipentaerythritol. The composite material has a loose structure and is not conducive to blocking the erosion of corrosive substances. Comparative Example 4 uses too much pentaerythritol. Although the initial mechanical properties are not significantly affected, as a small molecule additive, excessive use of pentaerythritol may cause technical problems such as precipitation, which is not only detrimental to the processing of the composite material, but also causes surface defects in the product, making it easy to cause rapid corrosion as a corrosion site.

[0097] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A halogen corrosion resistant composite material, characterized in that: The composition comprises the following components in parts by weight: 60-70 parts of nylon 56, 10-20 parts of semi-aromatic nylon, 25-35 parts of modified carbon fiber, 5-10 parts of graphene oxide, and 1-3 parts of pentaerythritol-based polyol; The modified carbon fiber is a carbon fiber modified by an acidic solution; The specific preparation process of the modified carbon fiber is as follows: the cleaned carbon fiber is placed in a concentrated nitric acid solution, subjected to ultrasonic modification treatment, taken out and washed until neutral, thereby obtaining the modified carbon fiber; The concentration of the concentrated nitric acid solution is 60-70 wt %.

2. The halogen-resistant composite material according to claim 1, wherein: The semi-aromatic nylon is one or more of nylon 6T, nylon 6I, nylon 6T / 66, nylon 6T / 6, and nylon 6T / 6I.

3. The halogen-resistant composite material according to claim 1, wherein: The cleaning is performed using a mixed solution of ethanol and acetone.

4. The halogen-resistant composite material according to claim 1, wherein: The temperature of the ultrasonic modification treatment is 40-50° C., and the time is 0.5-1.5 h.

5. The halogen-resistant composite material according to claim 1, wherein: The pentaerythritol-based polyol is one or more of monopentaerythritol, dipentaerythritol, and tripentaerythritol.

6. The halogen corrosion resistant composite material according to claim 1, characterized in that: The halogen corrosion resistant composite material further comprises an auxiliary agent.

7. The halogen corrosion resistant composite material according to claim 6, characterized in that: The auxiliary agent is one or more of a lubricant, a coupling agent, an antioxidant, a release agent, a nucleating agent, a flow modifier, and a colorant.

8. The halogen corrosion resistant composite material according to claim 7, characterized in that: The lubricant is one or more of polytetrafluoroethylene, zinc stearate, calcium stearate, talc, silicone oil, and polyethylene wax.

9. The method for preparing a halogen corrosion-resistant composite material according to claim 1, wherein: The following steps are involved: (1) Weigh each component by weight; (2) All raw materials except modified carbon fiber are pre-mixed and fed into the twin-screw extruder through the main feed port, and the modified carbon fiber is fed into the twin-screw extruder through the side feed port; (3) Melting, extrusion and granulation to obtain a halogen-resistant composite material.

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