High-strength corrosion-resistant PA66 as well as preparation method and application thereof

Abstract

The invention relates to high-strength corrosion-resistant PA66 and a preparation method and application thereof, and belongs to the technical field of high polymer materials, the high-strength corrosion-resistant PA66 comprises the following raw materials: 55-65 parts of a PA66 base material, 20-25 parts of multifunctional modified glass fibers, 0.5-1.5 parts of an antioxidant, 1-2 parts of a lubricant, 0.1-0.5 part of a coupling agent and 2-4 parts of a flexibilizer; according to the technical scheme, the silane modified glass fiber is obtained by combining the nano material with the glass fiber and then grafting the silane coupling agent; combining the silane modified glass fiber, diamine and fluorinated dianhydride to obtain an anhydride-terminated compound; combining the anhydride-terminated compound with amphiphilic hyperbranched polyester to obtain the multifunctional modified glass fiber; mixing the PA66 base material, the multifunctional modified glass fiber, an antioxidant, a lubricant, a coupling agent and a flexibilizer, and performing extrusion granulation to obtain the high-strength corrosion-resistant PA66. The corrosion resistance, the thermal stability and the mechanical property of the PA66 are integrally improved.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials technology, specifically relating to a high-strength corrosion-resistant PA66, its preparation method, and its applications. Background Technology

[0002] As the global automotive industry moves towards greater efficiency and environmental friendliness, the demands on material performance are increasing. Polyamide 66 (PA66), as a high-performance engineering plastic, has been widely used in automotive manufacturing due to its excellent mechanical properties, wear resistance, and good processing performance. For example, PA66 is widely used in key components such as engine peripheral parts, cooling system water chambers, and interior structural parts. However, with automotive design trending towards lightweighting and electrification, higher demands are placed on the performance of PA66 materials. It not only needs high strength to withstand greater mechanical loads but also excellent corrosion resistance to maintain stable physical and chemical properties under harsh conditions such as humidity and chemical corrosion, ensuring product lifespan and safety. Therefore, there is an urgent need to develop a high-strength, corrosion-resistant PA66 material to meet the pressing needs of the modern automotive industry for high-performance materials.

[0003] In existing technologies, high-strength, corrosion-resistant PA66 materials are typically prepared by adding glass fibers. However, due to the poor interfacial bonding between glass fibers and the PA66 matrix, and the uneven distribution of fibers within the matrix, debonding and crack propagation easily occur at the interface under stress, thus weakening the overall mechanical strength of PA66. Furthermore, although glass fibers themselves possess a certain degree of chemical corrosion resistance, prolonged contact with acidic or alkaline solutions or other corrosive media accelerates the hydrolysis and degradation of the PA66 matrix, leading to a decrease in its corrosion resistance and shortening its service life. Summary of the Invention

[0004] The purpose of this invention is to provide a high-strength, corrosion-resistant PA66, its preparation method, and its application. The invention involves combining nanomaterials with glass fibers and then grafting a silane coupling agent to obtain silane-modified glass fibers. The silane-modified glass fibers from step S1 are combined with diamine and fluorinated dianhydride to obtain an anhydride-terminated composite. The anhydride-terminated composite from step S2 is then combined with an amphiphilic hyperbranched polyester to obtain multifunctional modified glass fibers. PA66 base material, multifunctional modified glass fibers, antioxidants, lubricants, coupling agents, and toughening agents are mixed and extruded to granulate, finally yielding high-strength, corrosion-resistant PA66. The multifunctional modified glass fibers significantly improve the corrosion resistance, thermal stability, and mechanical properties of PA66, thereby enhancing its overall performance and extending its service life.

[0005] The technical problem this invention aims to solve is as follows: In the prior art, high-strength, corrosion-resistant PA66 materials are typically prepared by adding glass fibers. However, due to the poor interfacial bonding between the glass fibers and the PA66 matrix, and the uneven distribution of the fibers within the matrix, debonding and crack propagation easily occur at the interface under stress, thus weakening the overall mechanical strength of PA66. Furthermore, although glass fibers themselves possess a certain degree of chemical corrosion resistance, prolonged contact with acidic or alkaline solutions or other corrosive media accelerates the hydrolysis and degradation of the PA66 matrix, leading to a decrease in its corrosion resistance and shortening its service life.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A high-strength, corrosion-resistant PA66 comprises the following raw materials in parts by weight: 55-65 parts PA66 base material, 20-25 parts multifunctional modified glass fiber, 0.5-1.5 parts antioxidant, 1-2 parts lubricant, 0.1-0.5 parts coupling agent, and 2-4 parts toughening agent;

[0008] The preparation method of the multifunctional modified glass fiber includes the following steps:

[0009] S1: By combining nanomaterials with glass fibers and then grafting silane coupling agents, silane-modified glass fibers are obtained.

[0010] S2: Combine the silane-modified glass fiber, diamine, and fluorinated dianhydride from step S1 to obtain an anhydride-terminated complex;

[0011] S3: Combine the anhydride-capped composite from step S2 with an amphiphilic hyperbranched polyester to obtain multifunctional modified glass fiber.

[0012] Furthermore, step S1 specifically includes:

[0013] A1: Glass fiber was added to a Tris-HCl buffer solution and sonicated. Dopamine hydrochloride was then added and the mixture was stirred. After the reaction was completed, the mixture was filtered, washed with deionized water, and finally vacuum dried to obtain coated glass fiber. The coated glass fiber was added to a Tris-HCl buffer solution and sonicated. Then, nanomaterials were added and the mixture was stirred. After the reaction was completed, the mixture was filtered, washed with deionized water, and finally vacuum dried to obtain modified glass fiber.

[0014] A2: Add the silane coupling agent to a mixed solution of anhydrous ethanol and deionized water and stir. Then adjust the pH of the system to 4.5-5.5 with dilute hydrochloric acid solution. Then add the modified glass fiber from step A1 and reflux the reaction. After the reaction is complete, filter the solution, wash it with anhydrous ethanol, and finally vacuum dry it to obtain silane-modified glass fiber.

[0015] In the above reaction process, in step A1, dopamine hydrochloride undergoes an oxidative self-polymerization reaction to generate polydopamine, which can coat the surface of glass fibers to obtain coated glass fibers. The coated glass fibers contain amino and hydroxyl groups, while the nanomaterials contain hydroxyl, carboxyl, and epoxy groups. The coated glass fibers and nanomaterials are mainly combined through hydrogen bonding to obtain modified glass fibers. In step A2, the surface of the modified glass fibers has oxygen-containing functional groups (such as hydroxyl, carboxyl, and epoxy groups). The silane coupling agent is hydrolyzed to produce silanol groups, which can react and combine with the oxygen-containing functional groups on the surface of the modified glass fibers to graft the silane coupling agent onto the surface of the modified glass fibers, finally obtaining silane-modified glass fibers.

[0016] Further, in step A1, the mass ratio of the glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride is 0.45-0.55: 90-110: 0.05-0.15.

[0017] Furthermore, in step A1, the stirring reaction takes 22-24 hours and is carried out at room temperature.

[0018] Further, in step A1, the mass ratio of the coated glass fiber, Tris-HCl buffer solution, and nanomaterial is 0.45-0.55: 90-110: 0.15-0.25.

[0019] Furthermore, the nanomaterial is composed of graphene oxide and multi-walled carbon nanotubes mixed in a mass ratio of 0.9-1.1:0.6-0.8.

[0020] Further, in step A2, the mass ratio of the silane coupling agent, the mixed solution of anhydrous ethanol and deionized water, and the modified glass fiber is 0.08-0.12:90-110:4.9-5.1.

[0021] Furthermore, the silane coupling agent is 3-aminopropyltriethoxysilane.

[0022] Furthermore, in step A2, the reflux reaction is carried out at a temperature of 80-90°C for 1.5-2.5 hours.

[0023] Furthermore, in step A2, the vacuum drying temperature is 75-85℃ and the time is 12h.

[0024] Furthermore, step S2 specifically includes:

[0025] Fluorinated dianhydride, silane-modified glass fiber from step S1, benzoic acid, and acetic acid were mixed evenly and stirred under nitrogen protection. Then, diamine was added and the reaction was continued with stirring. After the reaction was completed, the mixture was cooled to room temperature and then poured into hexane for precipitation. The precipitate was collected by filtration, washed with anhydrous ethanol and deionized water, and finally dried under vacuum to obtain the anhydride-terminated complex.

[0026] In the above reaction process, fluorinated dianhydride has anhydride and carboxyl groups, while silane-modified glass fiber and diamine both have amino groups. The amino groups in silane-modified glass fiber and diamine can react and combine with the anhydride and carboxyl groups in fluorinated dianhydride, thus combining silane-modified glass fiber, diamine and fluorinated dianhydride together to finally obtain anhydride-terminated complex.

[0027] Furthermore, the mass ratio of the fluorinated dianhydride, silane-modified glass fiber, benzoic acid, acetic acid, and diamine is 15.5-16.5:2-3:0.8-1.2:140-160:7-8.

[0028] Furthermore, the fluorinated dianhydride is composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.7-0.8:0.5-0.6.

[0029] Furthermore, the diamine is 1,3-bis(4'-aminophenoxy)benzene.

[0030] Furthermore, the stirring temperature is 95-105℃, and the stirring time is 2-3 hours.

[0031] Furthermore, the temperature for the continued stirring reaction is 125-135℃, and the time is 8-10h.

[0032] Furthermore, the vacuum drying temperature is 115-125℃, and the time is 24 hours.

[0033] Furthermore, step S3 specifically includes:

[0034] The anhydride-capped complex and amphiphilic hyperbranched polyester in step S2 were mixed evenly, acetone was added, and ultrasonic dispersion was performed. Then, the catalyst was added, and the reaction was stirred under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature and then poured into ethanol for precipitation. After filtration, the mixture was washed with ethanol and finally vacuum dried to obtain multifunctional modified glass fiber.

[0035] In the above reaction process, the anhydride-terminated composite contains anhydride groups, and the amphiphilic hyperbranched polyester contains hydroxyl groups. The anhydride groups in the anhydride-terminated composite can react and combine with the hydroxyl groups in the amphiphilic hyperbranched polyester, thus combining the anhydride-terminated composite and the amphiphilic hyperbranched polyester to finally obtain multifunctional modified glass fiber.

[0036] Furthermore, the mass ratio of the anhydride-capped complex, the amphiphilic hyperbranched polyester, acetone, and the catalyst is 9.8-10.2:1.2-1.4:50-70:0.01-0.03.

[0037] Furthermore, the catalyst is triethylamine.

[0038] Furthermore, the ultrasonic dispersion time is 25-35 min.

[0039] Furthermore, the temperature of the stirring reaction is 105-115℃, and the time is 6-8h.

[0040] Furthermore, the vacuum drying temperature is 70-80℃, and the time is 24 hours.

[0041] Furthermore, the preparation method of the amphiphilic hyperbranched polyester includes the following steps:

[0042] Hydroxyl-terminated hyperbranched polyester and tetrahydrofuran were mixed evenly and stirred under nitrogen protection. Then stearic acid was added and stirred evenly. 4-Dimethylaminopyridine was then added and stirred under nitrogen protection. After the reaction was completed, tetrahydrofuran was removed by rotary evaporation to obtain amphiphilic hyperbranched polyester.

[0043] In the above reaction process, the hydroxyl-terminated hyperbranched polyester has hydroxyl groups and the stearic acid has carboxyl groups. Some of the hydroxyl groups in the hydroxyl-terminated hyperbranched polyester can react and combine with some of the carboxyl groups in the stearic acid, thereby combining a portion of the hydroxyl-terminated hyperbranched polyester with a portion of the stearic acid, and finally obtaining an amphiphilic hyperbranched polyester.

[0044] Furthermore, the mass ratio of the terminal hydroxyl hyperbranched polyester, tetrahydrofuran, stearic acid, and 4-dimethylaminopyridine is 60:80:30:0.03.

[0045] Furthermore, the stirring temperature is 58-62℃, and the stirring time is 1.5-2h.

[0046] Furthermore, the temperature of the stirring reaction is 58-62℃, and the time is 5.5-6h.

[0047] A method for preparing high-strength, corrosion-resistant PA66 includes the following steps:

[0048] Weigh out the raw materials by weight, mix PA66 base material, antioxidant, lubricant, coupling agent and toughening agent, and stir for 10-15 minutes to obtain a mixture. Add the mixture and multifunctional modified glass fiber to a twin-screw extruder, and after extrusion and granulation, cool and pelletize to obtain high-strength corrosion-resistant PA66.

[0049] Furthermore, the antioxidant is at least one of tris(2,4-di-tert-butylphenyl) phosphite, antioxidant 1098, and dodecyl thiodipropionate.

[0050] Furthermore, the lubricant is at least one of calcium stearate, polyethylene wax, and oleamide.

[0051] Furthermore, the coupling agent is composed of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and N-β-aminoethyl-γ-aminopropyltrimethoxysilane in a mass ratio of 1-2:1.

[0052] Furthermore, the toughening agent is composed of ethylene-octene copolymer and glycidyl methacrylate mixed in a mass ratio of 1:1.

[0053] Furthermore, the twin-screw extruder has a screw speed of 400-500 rpm and an extrusion temperature of 270-280℃.

[0054] A high-strength corrosion-resistant PA66 is prepared by the above-described method for preparing high-strength corrosion-resistant PA66.

[0055] The beneficial effects of this invention are:

[0056] (1) In the technical solution of this invention, silane-modified glass fiber is obtained by combining nanomaterials with glass fiber and then grafting silane coupling agent; wherein, the nanomaterials are composed of graphene oxide and multi-walled carbon nanotubes, which can play a synergistic role, not only having a good bonding force with glass fiber, but also effectively improving the overall rigidity and strength of PA66. In addition, the dense layer formed by graphene oxide and multi-walled carbon nanotubes can serve as an effective physical barrier to prevent corrosive media (such as water, oxygen, etc.) from penetrating into the interior, thereby protecting the PA66 matrix from external environmental erosion and further improving the corrosion resistance of PA66; by grafting modified glass fiber with silane coupling agent, not only can the dispersibility of modified glass fiber be enhanced and its agglomeration prevented, but the silane coupling agent can also provide reaction sites for subsequent reactions, further improving the mechanical properties and corrosion resistance of PA66. Performance: A silane-modified glass fiber, diamine, and fluorinated dianhydride are combined to obtain an anhydride-terminated composite. The fluorinated dianhydride is composed of a mixture of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane, exhibiting a good synergistic effect that effectively improves the heat resistance, chemical stability, and hydrophobicity of PA66. The chemical combination of silane-modified glass fiber, diamine, and fluorinated dianhydride not only enhances their binding force but also forms an imide oligomer, further improving the mechanical properties and thermal stability of PA66. Additionally, it provides reaction sites for subsequent reactions, increases the dispersibility of silane-modified glass fiber in PA66, prevents aggregation, enhances the interfacial compatibility between silane-modified glass fiber and PA66, and effectively improves the processing performance of PA66, further enhancing its corrosion resistance, thermal stability, and mechanical properties.

[0057] (2) In the technical solution of the present invention, the anhydride end-capping complex is combined with the amphiphilic hyperbranched polyester to obtain multifunctional modified glass fiber; the amphiphilic hyperbranched polyester is obtained by combining the terminal hydroxyl hyperbranched polyester and stearic acid; a portion of the hydroxyl groups in the terminal hydroxyl hyperbranched polyester and a portion of the carboxyl groups in the stearic acid are combined to obtain an amphiphilic hyperbranched polyester containing hydroxyl groups and long aliphatic chains, which can effectively improve the mechanical properties and flowability of PA66. Combining the anhydride end-capping complex with the amphiphilic hyperbranched polyester not only enhances the interfacial compatibility between it and PA66, but also further improves the strength, toughness and melt flowability of PA66; the PA66 base material, multifunctional modified glass fiber, antioxidant, lubricant, coupling agent and toughening agent are mixed and extruded and granulated to finally obtain high-strength corrosion-resistant PA66. The multifunctional modified glass fiber effectively improves the overall performance of PA66.

[0058] (3) In the technical solution of the present invention, nanomaterials are combined with glass fibers, then silane coupling agents are grafted, then diamine and fluorinated dianhydride are combined, and then amphiphilic hyperbranched polyester is combined to obtain multifunctional modified glass fibers. PA66 base material, multifunctional modified glass fibers, antioxidants, lubricants, coupling agents and toughening agents are mixed, and then extruded and granulated to finally obtain high-strength corrosion-resistant PA66. The corrosion resistance, thermal stability, fluidity and mechanical properties of PA66 are improved as a whole, and the service life of PA66 is extended. The overall comprehensive performance is good. Detailed Implementation

[0059] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0060] The specific parameters of the raw materials used in this invention are as follows:

[0061] Graphene oxide, product code XF002-2, provided by Jiangsu Xianfeng Nanomaterials Technology Co., Ltd.; Multi-walled carbon nanotubes, product code S33198, particle size 10-20nm, preferably 20nm, provided by Shanghai Yuanye Biotechnology Co., Ltd.; Glass fiber, fiber diameter 9-13μm, preferably 9μm, provided by Shandong Tonghui Glass Fiber Co., Ltd.; Hexafluorodianhydride, CAS number: 1107-00-2, product code: H810819, provided by Shanghai Maclean Biochemical Technology Co., Ltd.; 2,2-bis(4-carboxyphenyl)hexafluoropropane, CAS number: 1171-47-7, provided by Hubei Langbowan Biomedical Co., Ltd.; Hydroxyl-terminated hyperbranched polyester, molecular weight 2400g / mol, hydroxyl number 24mol, hydroxyl value 560mg. KOH / g, provided by Wuhan Hyperbranched Resin Technology Co., Ltd.; Polyethylene wax, molecular weight 1500-5000, preferably 3000, provided by Shandong Baolilai Plastic Additives Co., Ltd.; Ethylene-octene copolymer, grade: 8401, provided by Guangzhou Jiushun New Materials Co., Ltd.; PA66 base material, brand: Lanxess (Germany), density: 1.14 g / cm³. 3 Provided by Shanghai Xincheng Hongtai Plastic Technology Co., Ltd.

[0062] Example 1

[0063] The specific steps for preparing multifunctional modified glass fibers are as follows:

[0064] S1: Preparation of silane-modified glass fibers, the specific steps are as follows:

[0065] A1: Glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride were added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) at a mass ratio of 0.45:90:0.05. The solution was ultrasonically treated for 15 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz), then dopamine hydrochloride was added, and the mixture was stirred and reacted at room temperature for 22 h. After the reaction, the mixture was filtered, washed three times with deionized water (each time the deionized water mass was 15% of the Tris-HCl buffer solution mass), and finally vacuum dried at 75℃ for 12 h to obtain coated glass fiber. The mass ratio of solution to nanomaterials was 0.45:90:0.15. Coated glass fibers were added to a 0.01 mol / L Tris-HCl buffer solution (pH=8.5) and sonicated for 10 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then, nanomaterials were added and the mixture was stirred and reacted at room temperature for 22 h. After the reaction was completed, the mixture was filtered and washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution). Finally, the mixture was vacuum dried at 75 °C for 16 h to obtain modified glass fibers. The nanomaterials were composed of graphene oxide and multi-walled carbon nanotubes mixed in a mass ratio of 0.9:0.6.

[0066] A2: Following a mass ratio of 0.08:90:4.9 for a mixed solution of 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water, and modified glass fiber, 3-aminopropyltriethoxysilane was added to the mixed solution of anhydrous ethanol and deionized water (volume ratio of anhydrous ethanol to deionized water was 9:1). The mixture was stirred at room temperature for 30 min, and the pH of the system was adjusted to 4.5 with 0.1 mol / L dilute hydrochloric acid solution. Then, the modified glass fiber from step A1 was added, and the mixture was refluxed at 80°C for 2.5 h under nitrogen protection. After the reaction, the mixture was filtered, washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 20% of the mass of the mixed solution of anhydrous ethanol and deionized water), and finally vacuum dried at 75°C for 12 h to obtain silane-modified glass fiber.

[0067] S2: Fluorinated dianhydride, silane-modified glass fiber, benzoic acid, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed evenly according to a mass ratio of 15.5:2:0.8:140:7. The mixture was stirred at 95°C for 3 hours under nitrogen protection. Then, 1,3-bis(4'-aminophenoxy)benzene was added, and the reaction was continued at 125°C for 10 hours. After the reaction was completed, the mixture was cooled to room temperature. Then, hexane (hexane mass is twice the mass of acetic acid) is added for precipitation. After filtration, the precipitate is collected and washed three times each with anhydrous ethanol and deionized water (each time the mass of anhydrous ethanol is 25% of the mass of acetic acid, and each time the mass of deionized water is 30% of the mass of acetic acid). Finally, it is vacuum dried at 115℃ for 24 hours to obtain the anhydride-terminated complex. In this complex, the fluorinated dianhydride is composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.7:0.5.

[0068] S3: According to the mass ratio of anhydride-capped complex, amphiphilic hyperbranched polyester, acetone, and triethylamine of 9.8:1.2:50:0.01, the anhydride-capped complex and amphiphilic hyperbranched polyester in step S2 were mixed evenly, then acetone was added, and the mixture was ultrasonically dispersed for 25 min (ultrasonic power of 100 W and ultrasonic frequency of 40 kHz). Then triethylamine was added, and the mixture was stirred and reacted at 105 °C for 8 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, and then precipitated in ethanol (ethanol mass was 5 times the mass of acetone). After filtration, the mixture was washed 3 times with ethanol (each time the ethanol mass was 40% of the acetone mass). Finally, the mixture was vacuum dried at 70 °C for 24 h to obtain multifunctional modified glass fiber.

[0069] The preparation method of amphiphilic hyperbranched polyester includes the following steps:

[0070] The hydroxyl-terminated hyperbranched polyester and tetrahydrofuran were mixed evenly according to the mass ratio of 59.5:78:42:0.028 of stearic acid, 4-dimethylaminopyridine, and stirred at 58°C for 2 hours under nitrogen protection. Then stearic acid was added and stirred evenly. 4-dimethylaminopyridine was then added and stirred at 58°C for 6 hours under nitrogen protection. After the reaction was completed, tetrahydrofuran was removed by rotary evaporation at 60°C to obtain amphiphilic hyperbranched polyester.

[0071] A high-strength, corrosion-resistant PA66 comprises the following raw materials in parts by weight: 55 parts PA66 base material, 20 parts multifunctional modified glass fiber, 0.5 parts tris(2,4-di-tert-butylphenyl) phosphite, 1 part calcium stearate, 0.1 parts coupling agent, and 2 parts toughening agent;

[0072] The preparation method includes the following steps:

[0073] Weigh out the raw materials by weight, mix PA66 base material, tris(2,4-di-tert-butylphenyl) phosphite, calcium stearate, coupling agent, and toughening agent, and stir at 450 rpm for 15 min to obtain a mixture. Add the mixture and multifunctional modified glass fiber to a twin-screw extruder through a loss-in-weight feeding system. The screw speed of the twin-screw extruder is 400 rpm, and the extrusion temperature is 270℃. The mixture is added from the main feed port, and the multifunctional modified glass fiber is added from the side feed port. After extrusion, granulation, cooling, and pelletizing, high-strength corrosion-resistant PA66 is obtained. The coupling agent is composed of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and N-β-aminoethyl-γ-aminopropyltrimethoxysilane in a mass ratio of 1:1; the toughening agent is composed of ethylene-octene copolymer and glycidyl methacrylate in a mass ratio of 1:1.

[0074] Example 2

[0075] The specific steps for preparing multifunctional modified glass fibers are as follows:

[0076] S1: Preparation of silane-modified glass fibers, the specific steps are as follows:

[0077] A1: Glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride were added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) at a mass ratio of 0.5:100:0.1, and ultrasonicated for 20 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Dopamine hydrochloride was then added, and the mixture was stirred at room temperature for 23 h. After the reaction, the mixture was filtered, washed three times with deionized water (each time the deionized water mass was 15% of the Tris-HCl buffer solution mass), and finally vacuum dried at 80℃ for 12 h to obtain coated glass fiber. The coated glass fiber was then further processed according to the mass ratio of Tris-HCl buffer solution... The mass ratio of the solution to the nanomaterials was 0.5:100:0.2. The coated glass fiber was added to a 0.01 mol / L Tris-HCl buffer solution (pH=8.5) and sonicated for 12 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then the nanomaterials were added and the mixture was stirred at room temperature for 23 h. After the reaction was completed, the mixture was filtered and washed three times with deionized water (each time the mass of deionized water was 20% of the mass of the Tris-HCl buffer solution). Finally, it was vacuum dried at 80 °C for 16 h to obtain the modified glass fiber. The nanomaterials were composed of graphene oxide and multi-walled carbon nanotubes mixed in a mass ratio of 1:0.7.

[0078] A2: Following the mass ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water mixed solution to modified glass fiber of 0.1:100:5, 3-aminopropyltriethoxysilane was added to the anhydrous ethanol and deionized water mixed solution (volume ratio of anhydrous ethanol to deionized water was 9:1), and stirred at room temperature for 35 min. The pH of the system was then adjusted to 5 with 0.1 mol / L dilute hydrochloric acid solution. The modified glass fiber from step A1 was then added, and the reaction was carried out under nitrogen protection and refluxed at 85°C for 2 h. After the reaction was completed, the mixture was filtered and washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 20% of the mass of the anhydrous ethanol and deionized water mixed solution). Finally, the mixture was vacuum dried at 80°C for 12 h to obtain silane-modified glass fiber.

[0079] S2: Fluorinated dianhydride, silane-modified glass fiber, benzoic acid, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed evenly according to a mass ratio of 16:2.5:1:150:7.5. The mixture was stirred at 100°C for 2.5 h under nitrogen protection. Then, 1,3-bis(4'-aminophenoxy)benzene was added, and the reaction was continued at 130°C for 9 h. After the reaction was completed, the mixture was cooled to room temperature. Then, hexane (hexane mass is twice the mass of acetic acid) is added for precipitation. After filtration, the precipitate is collected and washed three times each with anhydrous ethanol and deionized water (each time the mass of anhydrous ethanol is 25% of the mass of acetic acid, and each time the mass of deionized water is 30% of the mass of acetic acid). Finally, it is vacuum dried at 120℃ for 24 hours to obtain the anhydride-terminated complex. In this complex, the fluorinated dianhydride is composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.75:0.55.

[0080] S3: According to the mass ratio of anhydride-terminated complex, amphiphilic hyperbranched polyester, acetone, and triethylamine of 10:1.3:60:0.02, the anhydride-terminated complex and amphiphilic hyperbranched polyester in step S2 were mixed evenly, then acetone was added, and the mixture was ultrasonically dispersed for 30 min (ultrasonic power of 100 W and ultrasonic frequency of 40 kHz). Then triethylamine was added, and the mixture was stirred and reacted at 110 °C for 7 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, and then ethanol (ethanol mass was 5 times the mass of acetone) was poured in for precipitation. After filtration, the mixture was washed 3 times with ethanol (each time the ethanol mass was 40% of the acetone mass). Finally, the mixture was vacuum dried at 75 °C for 24 h to obtain multifunctional modified glass fiber.

[0081] The preparation method of amphiphilic hyperbranched polyester includes the following steps:

[0082] The hydroxyl-terminated hyperbranched polyester, tetrahydrofuran, stearic acid, and 4-dimethylaminopyridine were mixed evenly in a mass ratio of 60:80:42.5:0.03. The mixture was stirred at 60°C under nitrogen protection for 1.8 h. Then, stearic acid was added and stirred evenly. 4-dimethylaminopyridine was then added and the mixture was stirred at 60°C under nitrogen protection for 5.8 h. After the reaction was completed, tetrahydrofuran was removed by rotary evaporation at 65°C to obtain the amphiphilic hyperbranched polyester.

[0083] A high-strength, corrosion-resistant PA66 comprises the following raw materials in parts by weight: 60 parts PA66 base material, 23 parts multifunctional modified glass fiber, 1 part antioxidant 1098, 1.5 parts polyethylene wax, 0.3 parts coupling agent, and 3 parts toughening agent;

[0084] The preparation method includes the following steps:

[0085] Weigh out the raw materials by weight, mix PA66 base material, antioxidant 1098, polyethylene wax, coupling agent and toughening agent, and stir at 500 rpm for 12 min to obtain a mixture. Add the mixture and multifunctional modified glass fiber to a twin-screw extruder through a loss-in-weight feeding system. The screw speed of the twin-screw extruder is 450 rpm and the extrusion temperature is 275℃. The mixture is added from the main feed port and the multifunctional modified glass fiber is added from the side feed port. After extrusion and granulation, the mixture is cooled and pelletized to obtain high-strength corrosion-resistant PA66. The coupling agent is composed of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and N-β-aminoethyl-γ-aminopropyltrimethoxysilane in a mass ratio of 1.5:1. The toughening agent is composed of ethylene-octene copolymer and glycidyl methacrylate in a mass ratio of 1:1.

[0086] Example 3

[0087] The specific steps for preparing multifunctional modified glass fibers are as follows:

[0088] S1: Preparation of silane-modified glass fibers, the specific steps are as follows:

[0089] A1: Glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride were added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) at a mass ratio of 0.55:110:0.15. The solution was ultrasonically treated for 25 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Dopamine hydrochloride was then added, and the mixture was stirred and reacted at room temperature for 24 h. After the reaction, the mixture was filtered, washed three times with deionized water (each time the deionized water mass was 15% of the Tris-HCl buffer solution mass), and finally vacuum dried at 85℃ for 12 h to obtain coated glass fiber. The mass ratio of solution to nanomaterials was 0.55:110:0.25. Coated glass fibers were added to a 0.01 mol / L Tris-HCl buffer solution (pH=8.5) and sonicated for 15 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then, nanomaterials were added and the mixture was stirred and reacted at room temperature for 24 h. After the reaction was completed, the mixture was filtered and washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution). Finally, it was vacuum dried at 85 °C for 16 h to obtain modified glass fibers. The nanomaterials were composed of graphene oxide and multi-walled carbon nanotubes mixed in a mass ratio of 1.1:0.8.

[0090] A2: Following the mass ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water mixed solution to modified glass fiber of 0.12:110:5.1, 3-aminopropyltriethoxysilane was added to the anhydrous ethanol and deionized water mixed solution (volume ratio of anhydrous ethanol to deionized water was 9:1), and stirred at room temperature for 40 min. The pH of the system was then adjusted to 5.5 with 0.1 mol / L dilute hydrochloric acid solution. The modified glass fiber from step A1 was then added, and the reaction was carried out under nitrogen protection and refluxed at 90 °C for 1.5 h. After the reaction was completed, the mixture was filtered and washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 20% of the mass of the anhydrous ethanol and deionized water mixed solution). Finally, the mixture was vacuum dried at 85 °C for 12 h to obtain silane-modified glass fiber.

[0091] S2: Fluorinated dianhydride, silane-modified glass fiber, benzoic acid, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed evenly according to a mass ratio of 16.5:3:1.2:160:8. The mixture was stirred at 105°C for 2 hours under nitrogen protection. Then, 1,3-bis(4'-aminophenoxy)benzene was added, and the reaction was continued at 135°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature. Then, hexane (hexane mass is twice the mass of acetic acid) is added for precipitation. After filtration, the precipitate is collected and washed three times each with anhydrous ethanol and deionized water (each time the mass of anhydrous ethanol is 25% of the mass of acetic acid, and each time the mass of deionized water is 30% of the mass of acetic acid). Finally, it is vacuum dried at 125℃ for 24 hours to obtain the anhydride-terminated complex. In this complex, the fluorinated dianhydride is composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.8:0.6.

[0092] S3: According to the mass ratio of anhydride end-capping complex, amphiphilic hyperbranched polyester, acetone, and triethylamine of 10.2:1.4:70:0.03, the anhydride end-capping complex and amphiphilic hyperbranched polyester in step S2 were mixed evenly, then acetone was added, and the mixture was ultrasonically dispersed for 35 min (ultrasonic power of 100 W and ultrasonic frequency of 40 kHz). Then triethylamine was added, and the mixture was stirred and reacted at 115 °C for 6 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature, and then ethanol (ethanol mass was 5 times the mass of acetone) was poured in for precipitation. After filtration, the mixture was washed 3 times with ethanol (each time the ethanol mass was 40% of the acetone mass). Finally, the mixture was vacuum dried at 80 °C for 24 h to obtain multifunctional modified glass fiber.

[0093] The preparation method of amphiphilic hyperbranched polyester includes the following steps:

[0094] The hydroxyl-terminated hyperbranched polyester, tetrahydrofuran, stearic acid, and 4-dimethylaminopyridine were mixed evenly in a mass ratio of 60.5:82:43:0.032. The mixture was stirred at 62°C under nitrogen protection for 1.5 h, then stearic acid was added and stirred evenly. 4-dimethylaminopyridine was then added and the mixture was stirred at 62°C under nitrogen protection for 5.5 h. After the reaction was completed, tetrahydrofuran was removed by rotary evaporation at 70°C to obtain the amphiphilic hyperbranched polyester.

[0095] A high-strength, corrosion-resistant PA66 comprises the following raw materials in parts by weight: 65 parts PA66 base material, 25 parts multifunctional modified glass fiber, 1.5 parts dodecyl thiodipropionate, 2 parts oleamide, 0.5 parts coupling agent, and 4 parts toughening agent.

[0096] The preparation method includes the following steps:

[0097] Weigh out the raw materials by weight, mix PA66 base material, disodecyl thiodipropionate, oleamide, coupling agent and toughening agent, and stir at 550 rpm for 10 min to obtain a mixture. Add the mixture and multifunctional modified glass fiber to a twin-screw extruder through a loss-in-weight feeding system. The screw speed of the twin-screw extruder is 500 rpm and the extrusion temperature is 280℃. The mixture is added from the main feed port and the multifunctional modified glass fiber is added from the side feed port. After extrusion and granulation, the mixture is cooled and pelletized to obtain high-strength corrosion-resistant PA66. The coupling agent is composed of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and N-β-aminoethyl-γ-aminopropyltrimethoxysilane in a mass ratio of 2:1. The toughening agent is composed of ethylene-octene copolymer and glycidyl methacrylate in a mass ratio of 1:1.

[0098] Comparative Example 1

[0099] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step A1, the nanomaterials are replaced with graphene oxide by an equal mass, while the remaining steps and raw materials are the same as in Example 3.

[0100] A1: Glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride were added to a 0.01 mol / L Tris-HCl buffer solution (pH=8.5) at a mass ratio of 0.55:110:0.15. The solution was ultrasonically treated for 25 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Dopamine hydrochloride was then added, and the mixture was stirred and reacted at room temperature for 24 h. After the reaction, the mixture was filtered, washed three times with deionized water (each time the deionized water mass was 15% of the Tris-HCl buffer solution mass), and finally vacuum dried at 85℃ for 12 h to obtain coated glass fiber. The coated glass fiber, Tris-HCl buffer solution, and graphene oxide were mixed in a mass ratio of 0.55:110:0.25. The coated glass fiber was added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) and sonicated for 15 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then, graphene oxide was added and the mixture was stirred at room temperature for 24 h. After the reaction was completed, the mixture was filtered and washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution). Finally, it was vacuum dried at 85 °C for 16 h to obtain the modified glass fiber.

[0101] Comparative Example 2

[0102] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step A1, the nanomaterials are replaced by multi-walled carbon nanotubes of equal mass, while the remaining steps and raw materials are the same as in Example 3.

[0103] A1: Glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride were added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) at a mass ratio of 0.55:110:0.15. The solution was ultrasonically treated for 25 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Dopamine hydrochloride was then added, and the mixture was stirred and reacted at room temperature for 24 h. After the reaction, the mixture was filtered, washed three times with deionized water (each time the deionized water mass was 15% of the Tris-HCl buffer solution mass), and finally vacuum dried at 85℃ for 12 h to obtain coated glass fiber. The mass ratio of coated glass fiber, Tris-HCl buffer solution, and multi-walled carbon nanotubes was 0.55:110:0.25. The coated glass fiber was added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) and sonicated for 15 min (ultrasonic power of 100 W, ultrasonic frequency of 40 kHz). Then, multi-walled carbon nanotubes were added, and the mixture was stirred and reacted at room temperature for 24 h. After the reaction was completed, the mixture was filtered and washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution). Finally, it was vacuum dried at 85 °C for 16 h to obtain modified glass fiber.

[0104] Comparative Example 3

[0105] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step S2, the silane modified glass fiber is replaced by the modified glass fiber in step A1 by the same mass, and the original step A2 is deleted. The remaining steps and raw materials are the same as in Example 3.

[0106] S1: Glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride were added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) at a mass ratio of 0.55:110:0.15. The solution was ultrasonically treated for 25 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Dopamine hydrochloride was then added, and the mixture was stirred and reacted at room temperature for 24 h. After the reaction, the mixture was filtered, washed three times with deionized water (each time the deionized water mass was 15% of the Tris-HCl buffer solution mass), and finally vacuum dried at 85℃ for 12 h to obtain coated glass fiber. The ratio of coated glass fiber to Tris-HCl buffer solution was then adjusted. The mass ratio of solution to nanomaterials was 0.55:110:0.25. Coated glass fibers were added to a 0.01 mol / L Tris-HCl buffer solution (pH=8.5) and sonicated for 15 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then, nanomaterials were added and the mixture was stirred and reacted at room temperature for 24 h. After the reaction was completed, the mixture was filtered and washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution). Finally, it was vacuum dried at 85 °C for 16 h to obtain modified glass fibers. The nanomaterials were composed of graphene oxide and multi-walled carbon nanotubes mixed in a mass ratio of 1.1:0.8.

[0107] S2: Fluorinated dianhydride, modified glass fiber, benzoic acid, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed uniformly according to a mass ratio of 16.5:3:1.2:160:8. The mixture was stirred at 105°C for 2 hours under nitrogen protection. Then, 1,3-bis(4'-aminophenoxy)benzene was added, and the reaction was continued at 135°C for 8 hours. After the reaction was complete, the mixture was cooled to room temperature. The mixture was poured into hexane (hexane mass was twice the mass of acetic acid) to precipitate the precipitate. After filtration, the precipitate was collected and washed three times each with anhydrous ethanol and deionized water (each time anhydrous ethanol mass was 25% of the mass of acetic acid, and each time deionized water mass was 30% of the mass of acetic acid). Finally, the mixture was vacuum dried at 125℃ for 24 h to obtain the anhydride-terminated complex. The fluorinated dianhydride was composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.8:0.6.

[0108] Comparative Example 4

[0109] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step S2, fluorinated dianhydride is replaced by hexafluorodianhydride by the same mass, while the remaining steps and raw materials are the same as in Example 3.

[0110] S2: Hexafluorodianhydride, silane-modified glass fiber, benzoic acid, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed evenly according to a mass ratio of 16.5:3:1.2:160:8. The mixture was stirred at 105°C for 2 hours under nitrogen protection. Then, 1,3-bis(4'-aminophenoxy)benzene was added, and the mixture was stirred at 135°C for another 8 hours. After the reaction was completed, the mixture was cooled to room temperature and then precipitated in hexane (hexane mass was twice the mass of acetic acid). The precipitate was collected by filtration and washed three times each with anhydrous ethanol and deionized water (each time the mass of anhydrous ethanol was 25% of the mass of acetic acid, and each time the mass of deionized water was 30% of the mass of acetic acid). Finally, the mixture was vacuum dried at 125°C for 24 hours to obtain the anhydride-capped complex.

[0111] Comparative Example 5

[0112] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step S2, fluorinated dianhydride is replaced by 2,2-bis(4-carboxyphenyl)hexafluoropropane by mass, while the remaining steps and raw materials are the same as in Example 3.

[0113] S2: 2,2-bis(4-carboxyphenyl)hexafluoropropane, silane-modified glass fiber, benzoic acid, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed uniformly in a mass ratio of 16.5:3:1.2:160:8. The mixture was stirred at 105°C for 2 hours under nitrogen protection. Then, 1,3-bis(4'-aminophenoxy)benzene was added, and the mixture was stirred at 135°C for another 8 hours. After the reaction was completed, the mixture was cooled to room temperature and then precipitated in hexane (hexane mass was twice the mass of acetic acid). The precipitate was collected by filtration and washed three times each with anhydrous ethanol and deionized water (each time the mass of anhydrous ethanol was 25% of the mass of acetic acid, and each time the mass of deionized water was 30% of the mass of acetic acid). Finally, the mixture was vacuum dried at 125°C for 24 hours to obtain the anhydride-capped complex.

[0114] Comparative Example 6

[0115] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step S2, fluorinated dianhydride, silane-modified glass fiber and diamine are directly mixed, while the remaining steps and raw materials are the same as in Example 3.

[0116] S2: Fluorinated dianhydride, silane-modified glass fiber, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed evenly in a mass ratio of 16.5:3:160:8. The mixture was stirred at room temperature for 2 hours, then 1,3-bis(4'-aminophenoxy)benzene was added and stirred at room temperature for another 8 hours. After stirring, the mixture was cooled to room temperature and then precipitated in hexane (hexane mass was twice the mass of acetic acid). The precipitate was collected by filtration and washed three times each with anhydrous ethanol and deionized water (each time anhydrous ethanol mass was 25% of the acetic acid mass, and each time deionized water mass was 30% of the acetic acid mass). Finally, the mixture was vacuum dried at 125℃ for 24 hours to obtain the anhydride-terminated complex. The fluorinated dianhydride was composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.8:0.6.

[0117] Comparative Example 7

[0118] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step S2, fluorinated dianhydride and silane modified glass fiber are combined, while the remaining steps and raw materials are the same as in Example 3.

[0119] S2: Fluorinated dianhydride, benzoic acid, acetic acid, and silane-modified glass fiber were mixed evenly according to a mass ratio of 16.5:1.2:160:11. The mixture was stirred at 105°C for 2 hours under nitrogen protection. Then, silane-modified glass fiber was added, and the mixture was stirred at 135°C for another 8 hours. After the reaction was completed, the mixture was cooled to room temperature and then precipitated in hexane (hexane mass was twice the mass of acetic acid). The precipitate was collected by filtration and washed three times each with anhydrous ethanol and deionized water (each time the mass of anhydrous ethanol was 25% of the mass of acetic acid, and each time the mass of deionized water was 30% of the mass of acetic acid). Finally, the mixture was vacuum dried at 125°C for 24 hours to obtain the anhydride-terminated complex. The fluorinated dianhydride was composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.8:0.6.

[0120] Comparative Example 8

[0121] The difference between this comparative example and Example 3 is that, in the preparation of multifunctional modified glass fiber, in step S3, the amphiphilic hyperbranched polyester is replaced by an equal mass of terminal hydroxyl hyperbranched polyester, while the remaining steps and raw materials are the same as in Example 3.

[0122] S3: The anhydride-capped complex, hydroxyl-terminated hyperbranched polyester, acetone, and triethylamine were mixed evenly in a mass ratio of 10.2:1.4:70:0.03. Acetone was then added, and the mixture was ultrasonically dispersed for 35 min (ultrasonic power of 100 W and ultrasonic frequency of 40 kHz). Triethylamine was then added, and the mixture was stirred and reacted at 115 °C for 6 h under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature and then precipitated in ethanol (ethanol mass was 5 times the mass of acetone). After filtration, the mixture was washed three times with ethanol (each time the ethanol mass was 40% of the acetone mass). Finally, the mixture was vacuum dried at 80 °C for 24 h to obtain multifunctional modified glass fiber.

[0123] Comparative Example 9

[0124] The difference between this comparative example and Example 3 is that, when preparing the multifunctional modified glass fiber, amphiphilic hyperbranched polyester was not added, and the original step S3 was deleted. The remaining steps and raw materials were the same as in Example 3.

[0125] S1: Preparation of silane-modified glass fibers, the specific steps are as follows:

[0126] A1: Glass fiber, Tris-HCl buffer solution, and dopamine hydrochloride were added to 0.01 mol / L Tris-HCl buffer solution (pH=8.5) at a mass ratio of 0.55:110:0.15. The solution was ultrasonically treated for 25 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Dopamine hydrochloride was then added, and the mixture was stirred and reacted at room temperature for 24 h. After the reaction, the mixture was filtered, washed three times with deionized water (each time the deionized water mass was 15% of the Tris-HCl buffer solution mass), and finally vacuum dried at 85℃ for 12 h to obtain coated glass fiber. The mass ratio of solution to nanomaterials was 0.55:110:0.25. Coated glass fibers were added to a 0.01 mol / L Tris-HCl buffer solution (pH=8.5) and sonicated for 15 min (ultrasonic power 100 W, ultrasonic frequency 40 kHz). Then, nanomaterials were added and the mixture was stirred and reacted at room temperature for 24 h. After the reaction was completed, the mixture was filtered and washed three times with deionized water (each time the mass of deionized water was 20% of the mass of Tris-HCl buffer solution). Finally, it was vacuum dried at 85 °C for 16 h to obtain modified glass fibers. The nanomaterials were composed of graphene oxide and multi-walled carbon nanotubes mixed in a mass ratio of 1.1:0.8.

[0127] A2: Following the mass ratio of 3-aminopropyltriethoxysilane, anhydrous ethanol, and deionized water mixed solution to modified glass fiber of 0.12:110:5.1, 3-aminopropyltriethoxysilane was added to the anhydrous ethanol and deionized water mixed solution (volume ratio of anhydrous ethanol to deionized water was 9:1), and stirred at room temperature for 40 min. The pH of the system was then adjusted to 5.5 with 0.1 mol / L dilute hydrochloric acid solution. The modified glass fiber from step A1 was then added, and the reaction was carried out under nitrogen protection and refluxed at 90 °C for 1.5 h. After the reaction was completed, the mixture was filtered and washed three times with anhydrous ethanol (each time the mass of anhydrous ethanol was 20% of the mass of the anhydrous ethanol and deionized water mixed solution). Finally, the mixture was vacuum dried at 85 °C for 12 h to obtain silane-modified glass fiber.

[0128] S2: Fluorinated dianhydride, silane-modified glass fiber, benzoic acid, acetic acid, and 1,3-bis(4'-aminophenoxy)benzene were mixed evenly according to a mass ratio of 16.5:3:1.2:160:8. The mixture was stirred at 105°C for 2 hours under nitrogen protection. Then, 1,3-bis(4'-aminophenoxy)benzene was added, and the reaction was continued at 135°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature. The mixture was then added to hexane (hexane mass was twice the mass of acetic acid) for precipitation. After filtration, the precipitate was collected and washed three times each with anhydrous ethanol and deionized water (each time anhydrous ethanol mass was 25% of the mass of acetic acid, and each time deionized water mass was 30% of the mass of acetic acid). Finally, it was vacuum dried at 125℃ for 24 hours to obtain multifunctional modified glass fiber. The fluorinated dianhydride was composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.8:0.6.

[0129] The high-strength, corrosion-resistant PA66 prepared in Examples 1-3 and Comparative Examples 1-9 were tested for mechanical and corrosion resistance. Mechanical property testing: Tensile strength was tested according to GB / T 1040.2-2019 standard, using Type II specimens with dimensions (mm): 115 (length) × (6±0.04) (width of the parallel middle section) × 2 (thickness), and a tensile speed of 50 mm / min. Bending strength was tested according to GB / T 9341-2008 standard, with specimen dimensions (mm): (80±0.4) × (10±0.1) × (4±0.02), and a bending speed of 20 mm / min. According to ASTM... The D256-2010 standard is used for notched impact strength testing; corrosion resistance testing: ethylene glycol and water are mixed in a mass ratio of 1:1 to form a mixed solution. The high-strength corrosion-resistant PA66 prepared in Examples 1-3 and Comparative Examples 1-9 are added to the mixed solution respectively, and the corrosion resistance is tested under the conditions of 135℃ for 300h. Samples are taken every 150h for testing.

[0130] The test results are shown in Tables 1 and 2 below:

[0131] Table 1 Mechanical property parameters of high-strength corrosion-resistant PA66

[0132] Table 2 Corrosion resistance parameters of high-strength corrosion-resistant PA66

[0133] As shown in Tables 1 and 2 above, and comparing Comparative Examples 1-3 and Example 3, replacing the nanomaterials with graphene oxide or multi-walled carbon nanotubes by the same mass, or replacing the silane-modified glass fiber with the modified glass fiber in step A1 by the same mass, the test results of the final high-strength and corrosion-resistant PA66 are worse than those of Example 3. This indicates that the nanomaterials composed of graphene oxide and multi-walled carbon nanotubes can play a synergistic role, effectively improving the mechanical properties and corrosion resistance of PA66. Grafting the silane coupling agent onto the surface of the modified glass fiber can not only improve its dispersibility, but also increase the bonding force between the modified glass fiber and fluorinated dianhydride and diamine, further improving the mechanical strength and corrosion resistance of PA66.

[0134] Comparing Comparative Examples 4-7 and Example 3, it can be seen that replacing fluorinated dianhydride with hexafluorodianhydride or 2,2-bis(4-carboxyphenyl)hexafluoropropane by mass, or directly mixing fluorinated dianhydride, silane-modified glass fiber, and diamine, or combining fluorinated dianhydride and silane-modified glass fiber, ultimately producing high-strength, corrosion-resistant PA66, yielded worse test results compared to Example 3. This indicates that the fluorinated dianhydride composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane has a synergistic effect, effectively improving the hydrophobicity and corrosion resistance of PA66. Combining fluorinated dianhydride, silane-modified glass fiber, and diamine through a chemical reaction enhances their bonding strength and further improves the mechanical properties and corrosion resistance of PA66. The anhydride-terminated composite prepared by combining fluorinated dianhydride, diamine, and silane-modified glass fiber can significantly improve the mechanical strength, thermal stability, and corrosion resistance of PA66.

[0135] Comparing Comparative Examples 8-9 and Example 3, it can be seen that replacing the amphiphilic hyperbranched polyester with an equal mass of terminal hydroxyl hyperbranched polyester, or not adding amphiphilic hyperbranched polyester, resulted in a high-strength corrosion-resistant PA66 with worse test results compared to Example 3. This indicates that combining terminal hydroxyl hyperbranched polyester with stearic acid to prepare amphiphilic hyperbranched polyester, and then combining the amphiphilic hyperbranched polyester with an anhydride end-capping complex, can not only enhance its bonding strength, but also further improve the corrosion resistance, thermal stability, and mechanical properties of PA66.

[0136] As shown in Tables 1 and 2 above, the high-strength corrosion-resistant PA66 prepared in Examples 1-3, compared to the high-strength corrosion-resistant PA66 prepared in Comparative Examples 1-9, achieves superior performance by combining nanomaterials with glass fibers, grafting silane coupling agents, combining with diamines and fluorinated dianhydrides, and then combining with amphiphilic hyperbranched polyesters to obtain multifunctional modified glass fibers. The PA66 base material, multifunctional modified glass fibers, antioxidants, lubricants, coupling agents, and toughening agents are mixed, extruded, and granulated to obtain high-strength corrosion-resistant PA66, meeting the performance requirements. In contrast, the high-strength corrosion-resistant PA66 prepared in Comparative Examples 1-9 did not meet the performance requirements. This indicates that the high-strength corrosion-resistant PA66 prepared in this invention not only possesses better corrosion resistance, thermal stability, and mechanical properties, but also extends the service life of PA66, demonstrating excellent overall performance.

[0137] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0138] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined by the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high-strength, corrosion-resistant PA66, characterized in that, The raw materials include the following parts by weight: 55-65 parts PA66 base material, 20-25 parts multifunctional modified glass fiber, 0.5-1.5 parts antioxidant, 1-2 parts lubricant, 0.1-0.5 parts coupling agent and 2-4 parts toughening agent; The preparation method of the multifunctional modified glass fiber includes the following steps: S1: By combining nanomaterials with glass fibers and then grafting silane coupling agents, silane-modified glass fibers are obtained. S2: Combine the silane-modified glass fiber, diamine, and fluorinated dianhydride from step S1 to obtain an anhydride-terminated complex; S3: Combine the anhydride-capped composite from step S2 with an amphiphilic hyperbranched polyester to obtain multifunctional modified glass fiber.

2. The high-strength corrosion-resistant PA66 according to claim 1, characterized in that, Step S1 is as follows: A1: Glass fiber was added to a Tris-HCl buffer solution and sonicated. Dopamine hydrochloride was then added and the mixture was stirred. After the reaction was completed, the mixture was filtered, washed with deionized water, and finally vacuum dried to obtain coated glass fiber. The coated glass fiber was added to a Tris-HCl buffer solution and sonicated. Then, nanomaterials were added and the mixture was stirred. After the reaction was completed, the mixture was filtered, washed with deionized water, and finally vacuum dried to obtain modified glass fiber. A2: Add the silane coupling agent to a mixed solution of anhydrous ethanol and deionized water and stir. Then adjust the pH of the system to 4.5-5.5 with dilute hydrochloric acid solution. Then add the modified glass fiber from step A1 and reflux the reaction. After the reaction is complete, filter the solution, wash it with anhydrous ethanol, and finally vacuum dry it to obtain silane-modified glass fiber.

3. The high-strength corrosion-resistant PA66 according to claim 2, characterized in that, In step A1, the nanomaterial is composed of graphene oxide and multi-walled carbon nanotubes mixed in a mass ratio of 0.9-1.1:0.6-0.

8.

4. The high-strength corrosion-resistant PA66 according to claim 1, characterized in that, Step S2 is as follows: Fluorinated dianhydride, silane-modified glass fiber from step S1, benzoic acid, and acetic acid were mixed evenly and stirred under nitrogen protection. Then, diamine was added and the reaction was continued with stirring. After the reaction was completed, the mixture was cooled to room temperature and then poured into hexane for precipitation. The precipitate was collected by filtration, washed with anhydrous ethanol and deionized water, and finally dried under vacuum to obtain the anhydride-terminated complex.

5. The high-strength corrosion-resistant PA66 according to claim 4, characterized in that, The fluorinated dianhydride is composed of hexafluorodianhydride and 2,2-bis(4-carboxyphenyl)hexafluoropropane in a mass ratio of 0.7-0.8:0.5-0.

6.

6. The high-strength corrosion-resistant PA66 according to claim 1, characterized in that, Step S3 is as follows: The anhydride-capped complex and amphiphilic hyperbranched polyester in step S2 were mixed evenly, acetone was added, and ultrasonic dispersion was performed. Then, the catalyst was added, and the reaction was stirred under nitrogen protection. After the reaction was completed, the mixture was cooled to room temperature and then poured into ethanol for precipitation. After filtration, the mixture was washed with ethanol and finally vacuum dried to obtain multifunctional modified glass fiber.

7. The high-strength corrosion-resistant PA66 according to claim 6, characterized in that, The preparation method of the amphiphilic hyperbranched polyester includes the following steps: Hydroxyl-terminated hyperbranched polyester and tetrahydrofuran were mixed evenly and stirred under nitrogen protection. Then stearic acid was added and stirred evenly. 4-Dimethylaminopyridine was then added and stirred under nitrogen protection. After the reaction was completed, tetrahydrofuran was removed by rotary evaporation to obtain amphiphilic hyperbranched polyester.

8. The high-strength corrosion-resistant PA66 according to claim 1, characterized in that, The coupling agent is composed of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and N-β-aminoethyl-γ-aminopropyltrimethoxysilane in a mass ratio of 1-2:

1.

9. A method for preparing high-strength corrosion-resistant PA66 as described in any one of claims 1-8, characterized in that, Includes the following steps: Weigh out the raw materials by weight, mix PA66 base material, antioxidant, lubricant, coupling agent and toughening agent, and stir for 10-15 minutes to obtain a mixture. Add the mixture and multifunctional modified glass fiber to a twin-screw extruder, and after extrusion and granulation, cool and pelletize to obtain high-strength corrosion-resistant PA66.

10. The application of high-strength corrosion-resistant PA66 as described in any one of claims 1-8 in automotive parts.

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