Corrosion-resistant composite material, method of manufacture and use thereof in gears

Abstract

The application belongs to the technical field of nylon composite materials, and specifically provides a corrosion-resistant composite material, a preparation method and application of the corrosion-resistant composite material in a gear.A corrosion-resistant composite material comprises the following components: modified nylon 6, reinforcing filler and auxiliary agent; the modified nylon 6 is formed by in-situ polymerization of boron nitride nanosheets coated with polydopamine, amphiphilic ion-modified polyrotaxan and monomer caprolactam; and the reinforcing filler is composed of glass fibers modified by a silane coupling agent and SiCw.The corrosion-resistant composite material prepared by the application has the advantages of high thermal conductivity, high strength and good toughness, and is suitable for preparing a composite nylon gear.

Description

Technical Field

[0001] This application belongs to the field of nylon composite material technology, and in particular relates to a corrosion-resistant composite material, its preparation method, and its application in gears. Background Technology

[0002] As a lightweight and high-strength material, nylon gears are gradually replacing traditional metal gears in the electric vehicle industry. Nylon gears possess excellent comprehensive properties, including lightweight, good self-lubrication, strong fatigue resistance, and a low coefficient of friction, which can improve the range of electric vehicles and reduce noise and cost. However, nylon gears alone have drawbacks such as high water absorption, temperature sensitivity, insufficient heat resistance, and poor thermal conductivity, leading to easy expansion and deformation, and reduced strength, thus affecting their dimensional stability and mechanical properties. In addition, nylon gears still have limited wear resistance and insufficient mechanical strength, making it difficult to meet the requirements for long service life and high stability.

[0003] To improve the overall performance of nylon gears, nanomaterials and other fillers are commonly used for reinforcement and modification. For example, patent application CN119350846A discloses a low-moisture-absorbing nylon composite material and its preparation method. This invention's low-moisture-absorbing nylon composite material comprises the following raw materials: nylon 66, modified nylon 6, reinforcing filler, lubricant, and antioxidant. This invention's low-moisture-absorbing nylon composite material is prepared by mixing and extruding granulation with nylon 66 and modified nylon 6 as base materials, adding reinforcing filler and other additives. The introduction of modified nylon 6 improves the toughness of the composite material and reduces its water absorption rate; while the introduction of reinforcing filler utilizes the synergistic effect of halloysite and boron nitride to improve the flame retardant properties of the composite material and further reduce its water absorption rate.

[0004] While the method described in the aforementioned document, which involves directly incorporating polydopamine-modified halloysite nanotubes and boron nitride nanosheets into a nylon matrix, is convenient, it relies solely on mechanical stirring and lacks covalent or strong hydrogen bonding interactions. This results in low stress transfer efficiency at the filler-nylon matrix interface. When the material is subjected to external forces, the stress is difficult to transfer uniformly from the nylon matrix to the filler, preventing the filler from fully exerting its reinforcing effect and significantly reducing the mechanical properties of the composite material. Summary of the Invention

[0005] To address the aforementioned issues and further improve the interfacial compatibility between the filler and nylon, as well as enhance the mechanical properties and multifunctional synergistic effect of the composite nylon material, this application provides a corrosion-resistant composite material, its preparation method, and its application in gears.

[0006] In a first aspect, this application provides a corrosion-resistant composite material, which adopts the following technical solution:

[0007] A corrosion-resistant composite material, characterized in that it comprises the following components: modified nylon 6, reinforcing filler, compatibilizer, and antioxidant;

[0008] The modified nylon 6 was prepared by in-situ polymerization of caprolactam, modified boron nitride nanosheets, and modified polyrotaxane.

[0009] The modified boron nitride nanosheets were prepared by coating boron nitride nanosheets with polydopamine.

[0010] Preferably, the method for preparing the modified polyrotaxane includes the following steps: S1, polyethylene glycol is modified with p-toluenesulfonyl chloride to obtain PEG-Ts; S2, PEG-Ts are self-assembled with cyclodextrin to obtain Pre-PR; S3, Pre-PR is reacted with (3-aminopropyl)trimethoxysilane and dialyzed to obtain NH2-Pre-PR; S4, NH2-Pre-PR is reacted with 1,3-propanesulfonyl lactone and N,N-diisopropylethylamine and dialyzed to obtain SBMA-Pre-PR; S5, SBMA-Pre-PR is reacted with 3,5-dimethylphenol in K2CO3 / DMF to obtain the modified polyrotaxane.

[0011] Preferably, the method for preparing the modified boron nitride nanosheets includes the following steps: ultrasonically dispersing hexagonal boron nitride in deionized water to obtain a boron nitride nanosheet dispersion; then adding dopamine hydrochloride to the boron nitride nanosheet dispersion and performing a polymerization reaction to obtain modified boron nitride nanosheets.

[0012] Preferably, the reinforcing filler comprises modified glass fiber and modified SiCw.

[0013] Preferably, the method for preparing the modified glass fiber includes the following steps: reacting glass fiber with a silane coupling agent in an ethanol solution to obtain the modified glass fiber.

[0014] Preferably, the preparation method of the modified SiCw includes the following steps: ultrasonically dispersing a silane coupling agent into a mixture of water and ethanol to obtain a silane coupling agent dispersion; then adding SiCw to the silane coupling agent dispersion, stirring and drying to obtain modified SiCw.

[0015] Preferably, a method for preparing a corrosion-resistant composite material is characterized by comprising the following steps: 1) Modified boron nitride nanosheets and modified polyrotaxane composite: modified boron nitride nanosheets are ultrasonically dispersed in DMF to obtain dispersion A; modified polyrotaxane is ultrasonically dispersed in DMF to obtain dispersion B; dispersion B is slowly poured into dispersion A, and dried after vacuum distillation to obtain composite PB; 2) In-situ polymerization of nylon matrix: caprolactam and composite PB are subjected to anionic ring-opening polymerization under nitrogen protection to obtain modified nylon 6; 3) Modified nylon 6, along with reinforcing filler, antioxidant, and compatibilizer, are added to a twin-screw extruder, and melt-extruded to granulate to obtain the corrosion-resistant composite material.

[0016] Preferably, the temperature settings of the twin-screw extruder are: 220℃ in zone 1, 250℃ in zone 2, 260℃ in zone 3, 255℃ in zone 4, and 250℃ in zone 5; the main feed port speed is 300-500 r / min; and the side feed port speed is 180-200 r / min.

[0017] Secondly, this application provides a composite nylon gear, which is made by injection molding of the aforementioned corrosion-resistant composite material.

[0018] Preferably, the injection molding process is as follows: temperature 250-270℃, pressure 100-120MPa, and time 20-30s.

[0019] Compared with the prior art, this application has the following beneficial effects:

[0020] 1. In the preparation of corrosion-resistant composite materials, the polydopamine coating layer in the modified boron nitride nanosheets reduces the agglomeration of boron nitride nanosheets through physical barrier effect; at the same time, the amino and phenolic hydroxyl groups on the surface of polydopamine interact with the amide groups of the nylon 6 matrix, improving the compatibility between boron nitride nanosheets and nylon 6 matrix, thereby improving the dispersibility of boron nitride nanosheets in nylon 6 matrix.

[0021] 2. The amphiphilic sulfonate betaine in modified polyrotaxane can form hydrogen bonds or electrostatic interactions with the phenolic hydroxyl and quinone groups on the surface of polydopamine, and can also interact with the amide groups of nylon 6. This improves the interfacial compatibility between polyrotaxane and modified boron nitride nanosheets and nylon 6 matrix, which is beneficial for stress transfer and avoids stress concentration. At the same time, the sliding crosslinking structure of cyclodextrin in polyrotaxane can effectively absorb and disperse stress, inhibit the initiation and propagation of microcracks, and improve the toughness and life of corrosion-resistant composite materials.

[0022] 3. Boron nitride nanosheets possess a honeycomb-like planar layer formed by alternating sp² hybrid covalent bonds, exhibiting high bond energy and an ordered lattice structure, thus endowing them with excellent in-plane thermal conductivity. After modification with polydopamine, the dispersion of boron nitride nanosheets in the nylon matrix can be improved, reducing the breakage of thermal conductivity pathways caused by the aggregation of boron nitride nanosheets, thereby more fully utilizing their high in-plane thermal conductivity. Modified SiCw establishes axial heat dissipation channels by bridging modified boron nitride nanosheets with different orientations. The two fillers form a continuous thermal conductivity pathway in the nylon matrix, significantly improving the thermal conductivity of the corrosion-resistant composite material. At the same time, the inherent low coefficient of thermal expansion and interlayer hydrophobic properties of modified boron nitride nanosheets are utilized to synergistically reduce the thermal expansion of the corrosion-resistant composite material, achieving synergistic optimization of thermal conductivity and dimensional stability.

[0023] 4. Modified glass fibers introduce amino groups that crosslink with the amide groups of the nylon matrix, bearing the main mechanical load. Modified SiCw introduces epoxy groups that crosslink with the amide groups of the nylon matrix, bridging the fiber gaps to transfer stress, improving load transfer efficiency, and thus improving the strength and toughness of the nylon composite material. Attached Figure Description

[0024] Figure 1 The images show SEM images of boron nitride nanosheets and modified boron nitride nanosheets from Example 2, with boron nitride nanosheets on the left and modified boron nitride nanosheets on the right.

[0025] Figure 2 The images show SEM images of glass fiber and modified glass fiber from Example 2, with glass fiber on the left and modified glass fiber on the right.

[0026] Figure 3 The images show SEM images of SiCw and modified SiCw from Example 2, with SiCw on the left and modified SiCw on the right.

[0027] Figure 4 The image shows a cross-sectional SEM image of the corrosion-resistant composite material, with the left side showing Comparative Example 2 and the right side showing Example 2. Detailed Implementation

[0028] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0029] The present application will be further described in detail below with reference to the embodiments.

[0030] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0031] Example 1

[0032] The corrosion-resistant composite material of this embodiment is composed of the following weight components: 100g modified nylon 6, 25g modified glass fiber, 3g modified SiCw, 1.5g compatibilizer (POE-g-MAH), and 0.1g antioxidant (0.05g antioxidant 1010 and 0.05g antioxidant 168).

[0033] The modified polyrotaxane is prepared using the following method in this embodiment:

[0034] (1) Weigh 12g of polyethylene glycol (molecular weight 4000) and place it in a vacuum oven at 85℃ overnight. Under argon protection, add the polyethylene glycol to a 250mL three-necked flask and add 50mL of anhydrous THF to dissolve the polyethylene glycol. Then, add 2.4mL of TEA and 4.29g of p-toluenesulfonyl chloride and stir at room temperature for 24h. After the reaction is complete, remove the THF by rotary evaporator. Dissolve the crude product in 50mL of DCM and pour it into 500mL of diethyl ether to precipitate. Filter to collect the purified product and dry it at 85℃ to obtain PEG-Ts.

[0035] (2) Dissolve the PEG-Ts product from the previous step and 47.4 g of α-cyclodextrin in 240 mL and 360 mL of deionized water, respectively. Mix the two solutions and sonicate for 1 h, then stir at room temperature for 24 h and remove water by rotary evaporation. Dry the product in a vacuum oven at 85 °C for 36 h to obtain Pre-PR. Dissolve the Pre-PR powder in 100 mL of deionized water, add 21.57 g of (3-aminopropyl)trimethoxysilane, adjust the pH to 8-9 with 0.1 M NaOH, and stir at 40 °C for 12 h. Then cool to 4 °C in an ice bath, add 1 mL of acetic acid to adjust the pH to 5-6. Put the reaction solution into a dialysis bag with a molecular weight cutoff of 3500 Da, dialyze with deionized water for 48 h, and freeze-dry to obtain NH2-Pre-PR. The product from the previous step, NH2-Pre-PR, 292.5 mg of 1,3-propanesulfonyl lactone, and 412.5 μL of N,N-diisopropylethylamine were dissolved in 3.45 mL of dehydrated DMF, and the solution was stirred at room temperature for 24 h. After the reaction, the solution was purified by dialyzing at 4°C and lyophilized to obtain SBMA-Pre-PR.

[0036] (3) Dissolve 12.9 g of 3,5-dimethylphenol in 90 mL of anhydrous DMF and add it to a 250 mL three-necked flask. Slowly add 1.742 g of K2CO3 in an ice bath and stir for 0.5 h. Then, slowly add SBMA-Pre-PR powder under vigorous stirring and dilute with 25 mL of anhydrous DMF. After thorough stirring, transfer the system to 30 °C and react for 24 h. Pour the crude product into 1200 mL of methanol to precipitate and wash twice. Centrifuge to remove methanol. Mix the precipitate with 30 mL of DMSO, add 30 mL of deionized water to form a dispersion, dialyze for 48 h, remove water by rotary evaporation, and dry the product to obtain modified polyrotaxane.

[0037] The modified boron nitride nanosheets in this embodiment were prepared as follows: 6 g of hexagonal boron nitride and 75 mL of Tris buffer (0.064 g / mL) were weighed and added to a flask containing 250 mL of deionized water, and sonicated for 30 min. Subsequently, diluted NaOH solution was added until the pH reached 8.5, and 6 g of dopamine hydrochloride was added to the flask. The mixture was stirred at room temperature for 16 h. After the reaction, the mixture was washed several times with deionized water until the pH of the centrifuged solution became neutral. Finally, the modified boron nitride nanosheets were vacuum dried at 80°C for 24 h.

[0038] The modified glass fiber in this embodiment is prepared as follows: 50g of glass fiber (3mm in length, aspect ratio 20) is added to a 1000mL three-necked flask, and acetone is added to cover the glass fiber. The mixture is refluxed at 70℃ for 2h. After the reaction is completed, the mixture is filtered and dried at 80℃ for 24h to obtain purified glass fiber. Then, 1000mL of 2% KH550 ethanol solution is prepared, and the purified glass fiber is added to the above solution. The mixture is refluxed at 80℃ for 2h, filtered, washed, and dried at 120℃ for 12h to obtain modified glass fiber.

[0039] The modified SiCw in this embodiment is prepared as follows: a deionized water and anhydrous ethanol solution with a volume ratio of 1:2 is prepared, and 1 mL of KH560 is added to the solution and sonicated for 10 min. 10 g of SiCw (length 25 μm, aspect ratio 50) is added to the solution, stirred at 45 °C for 30 min, and then dried at 80 °C for 3 h to obtain modified SiCw.

[0040] The method for preparing the corrosion-resistant composite material in this embodiment is as follows:

[0041] (1) Take 1.5g of modified boron nitride nanosheets and add them to DMF. Disperse them by ultrasonication for 30 min to obtain dispersion A. Take 3g of modified polyrotaxane and add it to DMF. Disperse it by ultrasonication for 30 min to obtain dispersion B. Slowly pour dispersion B into dispersion A and stir at 800r / min for 2h. Then remove the solvent by vacuum distillation and dry to obtain composite PB.

[0042] (2) 100g caprolactam was heated to 80℃ to melt, 4.5g of complex PB was added, and the mixture was stirred and sonicated for 30min, and then vacuumed for 30min to remove water to obtain a mixed melt. Under nitrogen protection, 0.05g antioxidant 1010 and 0.05g antioxidant 168 were added to the mixed melt, and after stirring for 5min, 0.375g NaOH was added. After magnetic stirring for 5min, vacuuming was performed for 15min, and finally 1.7mL TDI was added. The temperature was raised to 220℃ and the polymerization reaction was carried out for 2h. After the reaction was completed, modified nylon 6 was obtained by water cooling and granulation.

[0043] (3) 3g of modified SiCw and 1.5g of POE-g-MAH were premixed at 100rpm for 20min, and then mixed with 100g of modified nylon 6 and fed into a twin-screw extruder through the main feed port. 25g of modified glass fiber was fed into the extruder through the side feed port (located after the screw melting section) and extruded into granules. The temperatures of the five zones of the extruder were set to 220℃, 250℃, 260℃, 255℃ and 250℃ respectively, and slightly adjusted according to the actual production conditions on site. The rotation speed of the main feed port was 350 r / min and the rotation speed of the side feed port was 180 r / min. The extruded granules were dried in an oven at 130℃ for 5 h to obtain a corrosion-resistant composite material.

[0044] The preparation method of the composite nylon gear in this embodiment is as follows: 100g of corrosion-resistant composite material is weighed and put into the hopper of the injection molding machine. Under the action of the screw rotation, it is fed into the barrel heated at 240℃. After being mixed evenly, it is injected into the injection mold with an iron core and injection molding is performed. The injection temperature is 250℃, the pressure is 100MPa, the injection time is 20s, and after the injection is completed, it is dried at 110℃ for 3h to obtain the composite nylon gear.

[0045] Example 2

[0046] The corrosion-resistant composite material of this embodiment is composed of the following weight components: 105g modified nylon 6, 23g modified glass fiber, 6g modified SiCw, 2g compatibilizer (POE-g-MAH), and 0.2g antioxidant (0.15g antioxidant 1010 and 0.05g antioxidant 168).

[0047] The modified polyrotaxane is prepared using the following method in this embodiment:

[0048] (1) Weigh 12g of polyethylene glycol (molecular weight 4000) and place it in a vacuum oven at 85℃ overnight. Under argon protection, add the polyethylene glycol to a 250mL three-necked flask and add 50mL of anhydrous THF to dissolve the polyethylene glycol. Then, add 2.4mL of TEA and 4.29g of p-toluenesulfonyl chloride and stir at room temperature for 24h. After the reaction is complete, remove the THF by rotary evaporator. Dissolve the crude product in 50mL of DCM and pour it into 500mL of diethyl ether to precipitate. Filter to collect the purified product and dry it at 85℃ to obtain PEG-Ts.

[0049] (2) Dissolve the PEG-Ts product from the previous step and 47.4 g of α-cyclodextrin in 240 mL and 360 mL of deionized water, respectively. Mix the two solutions and sonicate for 1 h, then stir at room temperature for 24 h and remove water by rotary evaporation. Dry the product in a vacuum oven at 85 °C for 36 h to obtain Pre-PR. Dissolve the Pre-PR powder in 100 mL of deionized water, add 21.57 g of (3-aminopropyl)trimethoxysilane, adjust the pH to 8-9 with 0.1 M NaOH, and stir at 40 °C for 12 h. Then cool to 4 °C in an ice bath, add 1 mL of acetic acid to adjust the pH to 5-6. Put the reaction solution into a dialysis bag with a molecular weight cutoff of 3500 Da, dialyze with deionized water for 48 h, and freeze-dry to obtain NH2-Pre-PR. The product from the previous step, NH2-Pre-PR, 292.5 mg of 1,3-propanesulfonyl lactone, and 412.5 μL of N,N-diisopropylethylamine were dissolved in 3.45 mL of dehydrated DMF, and the solution was stirred at room temperature for 24 h. After the reaction, the solution was purified by dialyzing at 4°C and lyophilized to obtain SBMA-Pre-PR.

[0050] (3) Dissolve 12.9 g of 3,5-dimethylphenol in 90 mL of anhydrous DMF and add it to a 250 mL three-necked flask. Slowly add 1.742 g of K2CO3 in an ice bath and stir for 0.5 h. Then, slowly add SBMA-Pre-PR powder under vigorous stirring and dilute with 25 mL of anhydrous DMF. After thorough stirring, transfer the system to 30 °C and react for 24 h. Pour the crude product into 1200 mL of methanol to precipitate and wash twice. Centrifuge to remove methanol. Mix the precipitate with 30 mL of DMSO, add 30 mL of deionized water to form a dispersion, dialyze for 48 h, remove water by rotary evaporation, and dry the product to obtain modified polyrotaxane.

[0051] The modified boron nitride nanosheets in this embodiment were prepared as follows: 6 g of hexagonal boron nitride and 75 mL of Tris buffer (0.064 g / mL) were weighed and added to a flask containing 250 mL of deionized water, and sonicated for 30 min. Subsequently, diluted NaOH solution was added until the pH reached 8.5, and 6 g of dopamine hydrochloride was added to the flask. The mixture was stirred at room temperature for 16 h. After the reaction, the mixture was washed several times with deionized water until the pH of the centrifuged solution became neutral. Finally, the modified boron nitride nanosheets were vacuum dried at 80°C for 24 h.

[0052] The modified glass fiber in this embodiment is prepared as follows: 50g of glass fiber (3mm in length, aspect ratio 20) is added to a 1000mL three-necked flask, and acetone is added to cover the glass fiber. The mixture is refluxed at 70℃ for 2h. After the reaction is completed, the mixture is filtered and dried at 80℃ for 24h to obtain purified glass fiber. Then, 1000mL of 2% KH550 ethanol solution is prepared, and the purified glass fiber is added to the above solution. The mixture is refluxed at 80℃ for 2h, filtered, washed, and dried at 120℃ for 12h to obtain modified glass fiber.

[0053] The modified SiCw in this embodiment is prepared as follows: a deionized water and anhydrous ethanol solution with a volume ratio of 1:2 is prepared, and 1 mL of KH560 is added to the solution and sonicated for 10 min. 10 g of SiCw (length 25 μm, aspect ratio 50) is added to the solution, stirred at 45 °C for 30 min, and then dried at 80 °C for 3 h to obtain modified SiCw.

[0054] The method for preparing the corrosion-resistant composite material in this embodiment is as follows:

[0055] (1) Take 1.5g of modified boron nitride nanosheets and add them to DMF. Disperse them by ultrasonication for 30 min to obtain dispersion A. Take 4g of modified polyrotaxane and add it to DMF. Disperse it by ultrasonication for 30 min to obtain dispersion B. Slowly pour dispersion B into dispersion A and stir at 800r / min for 2h. Then remove the solvent by vacuum distillation and dry to obtain composite PB.

[0056] (2) 105g caprolactam was heated to 80℃ to melt, 5.5g of complex PB was added, and the mixture was stirred and sonicated for 30min, and then vacuumed for 30min to remove water to obtain a mixed melt. Under nitrogen protection, 0.15g antioxidant 1010 and 0.05g antioxidant 168 were added to the mixed melt, and after stirring for 5min, 0.375g NaOH was added. After magnetic stirring for 5min, vacuuming was performed for 15min, and finally 1.7mL TDI was added. The temperature was raised to 220℃ and the polymerization reaction was carried out for 2h. After the reaction was completed, modified nylon 6 was obtained by water cooling and granulation.

[0057] (3) 6g of modified SiCw and 2g of POE-g-MAH were premixed at 100rpm for 20min, and then mixed with 105g of modified nylon 6 and fed into a twin-screw extruder through the main feed port. 23g of modified glass fiber was fed into the extruder through the side feed port (located after the screw melting section) and extruded into granules. The temperatures of the five zones of the extruder were set to 220℃, 250℃, 260℃, 255℃ and 250℃ respectively, and slightly adjusted according to the actual production conditions on site. The rotation speed of the main feed port was 300 r / min and the rotation speed of the side feed port was 200 r / min. The extruded granules were dried in an oven at 130℃ for 5 h to obtain a corrosion-resistant composite material.

[0058] The preparation method of the composite nylon gear in this embodiment is as follows: 105g of corrosion-resistant composite material is weighed and put into the hopper of the injection molding machine. Under the action of the screw rotation, it is fed into the barrel heated at 240℃. After being mixed evenly, it is injected into the injection mold with an iron core and injection molded. The injection temperature is 260℃, the pressure is 110MPa, and the injection time is 25s. After the injection is completed, it is dried at 110℃ for 3 hours to obtain the composite nylon gear.

[0059] Example 3

[0060] The corrosion-resistant composite material of this embodiment is composed of the following weight components: 115g modified nylon 6, 20g modified glass fiber, 3g modified SiCw, 2.5g compatibilizer (POE-g-MAH), and 0.3g antioxidant (0.2g antioxidant 1010 and 0.1g antioxidant 168).

[0061] The modified polyrotaxane is prepared using the following method in this embodiment:

[0062] (1) Weigh 12g of polyethylene glycol (molecular weight 4000) and place it in a vacuum oven at 85℃ overnight. Under argon protection, add the polyethylene glycol to a 250mL three-necked flask and add 50mL of anhydrous THF to dissolve the polyethylene glycol. Then, add 2.4mL of TEA and 4.29g of p-toluenesulfonyl chloride and stir at room temperature for 24h. After the reaction is complete, remove the THF by rotary evaporator. Dissolve the crude product in 50mL of DCM and pour it into 500mL of diethyl ether to precipitate. Filter to collect the purified product and dry it at 85℃ to obtain PEG-Ts.

[0063] (2) Dissolve the PEG-Ts product from the previous step and 47.4 g of α-cyclodextrin in 240 mL and 360 mL of deionized water, respectively. Mix the two solutions and sonicate for 1 h, then stir at room temperature for 24 h and remove water by rotary evaporation. Dry the product in a vacuum oven at 85 °C for 36 h to obtain Pre-PR. Dissolve the Pre-PR powder in 100 mL of deionized water, add 21.57 g of (3-aminopropyl)trimethoxysilane, adjust the pH to 8-9 with 0.1 M NaOH, and stir at 40 °C for 12 h. Then cool to 4 °C in an ice bath, add 1 mL of acetic acid to adjust the pH to 5-6. Put the reaction solution into a dialysis bag with a molecular weight cutoff of 3500 Da, dialyze with deionized water for 48 h, and freeze-dry to obtain NH2-Pre-PR. The product from the previous step, NH2-Pre-PR, 292.5 mg of 1,3-propanesulfonyl lactone, and 412.5 μL of N,N-diisopropylethylamine were dissolved in 3.45 mL of dehydrated DMF, and the solution was stirred at room temperature for 24 h. After the reaction, the solution was purified by dialyzing at 4°C and lyophilized to obtain SBMA-Pre-PR.

[0064] (3) Dissolve 12.9 g of 3,5-dimethylphenol in 90 mL of anhydrous DMF and add it to a 250 mL three-necked flask. Slowly add 1.742 g of K2CO3 in an ice bath and stir for 0.5 h. Then, slowly add SBMA-Pre-PR powder under vigorous stirring and dilute with 25 mL of anhydrous DMF. After thorough stirring, transfer the system to 30 °C and react for 24 h. Pour the crude product into 1200 mL of methanol to precipitate and wash twice. Centrifuge to remove methanol. Mix the precipitate with 30 mL of DMSO, add 30 mL of deionized water to form a dispersion, dialyze for 48 h, remove water by rotary evaporation, and dry the product to obtain modified polyrotaxane.

[0065] The modified boron nitride nanosheets in this embodiment were prepared as follows: 6 g of hexagonal boron nitride and 75 mL of Tris buffer (0.064 g / mL) were weighed and added to a flask containing 250 mL of deionized water, and sonicated for 30 min. Subsequently, diluted NaOH solution was added until the pH reached 8.5, and 6 g of dopamine hydrochloride was added to the flask. The mixture was stirred at room temperature for 16 h. After the reaction, the mixture was washed several times with deionized water until the pH of the centrifuged solution became neutral. Finally, the modified boron nitride nanosheets were vacuum dried at 80°C for 24 h.

[0066] The modified glass fiber in this embodiment is prepared as follows: 50g of glass fiber (3mm in length, aspect ratio 20) is added to a 1000mL three-necked flask, and acetone is added to cover the glass fiber. The mixture is refluxed at 70℃ for 2h. After the reaction is completed, the mixture is filtered and dried at 80℃ for 24h to obtain purified glass fiber. Then, 1000mL of 2% KH550 ethanol solution is prepared, and the purified glass fiber is added to the above solution. The mixture is refluxed at 80℃ for 2h, filtered, washed, and dried at 120℃ for 12h to obtain modified glass fiber.

[0067] The modified SiCw in this embodiment is prepared as follows: a deionized water and anhydrous ethanol solution with a volume ratio of 1:2 is prepared, and 1 mL of KH560 is added to the solution and sonicated for 10 min. 10 g of SiCw (length 25 μm, aspect ratio 50) is added to the solution, stirred at 45 °C for 30 min, and then dried at 80 °C for 3 h to obtain modified SiCw.

[0068] The method for preparing the corrosion-resistant composite material in this embodiment is as follows:

[0069] (1) Take 1g of modified boron nitride nanosheets and add them to DMF. Disperse them by ultrasonication for 30 min to obtain dispersion A. Take 2g of modified polyrotaxane and add it to DMF. Disperse it by ultrasonication for 30 min to obtain dispersion B. Slowly pour dispersion B into dispersion A and stir at 800r / min for 2h. Then remove the solvent by vacuum distillation and dry to obtain composite PB.

[0070] (2) 115g caprolactam was heated to 80℃ to melt, 3g of complex PB was added, and the mixture was stirred and sonicated for 30min, and then vacuumed for 30min to remove water to obtain a mixed melt. Under nitrogen protection, 0.2g antioxidant 1010 and 0.1g antioxidant 168 were added to the mixed melt, and after stirring for 5min, 0.375g NaOH was added. After magnetic stirring for 5min, vacuuming was carried out for 15min, and finally 1.7mLTDI was added. The temperature was raised to 220℃ and the polymerization reaction was carried out for 2h. After the reaction was completed, modified nylon 6 was obtained by water cooling and granulation.

[0071] (3) 3g of modified SiCw and 2.5g of POE-g-MAH were premixed at 100rpm for 20min, and then mixed with 115g of modified nylon 6 and fed into a twin-screw extruder through the main feed port. 20g of modified glass fiber was fed into the extruder through the side feed port (located after the screw melting section) for extrusion granulation. The temperatures of the five zones of the extruder were set to 220℃, 250℃, 260℃, 255℃ and 250℃ respectively, and slightly adjusted according to the actual production conditions on site. The rotation speed of the main feed port was 400 r / min and the rotation speed of the side feed port was 180 r / min. The extruded granules were dried in an oven at 130℃ for 5 h to obtain corrosion-resistant composite materials.

[0072] The preparation method of the composite nylon gear in this embodiment is as follows: 115g of corrosion-resistant composite material is weighed and put into the hopper of the injection molding machine. Under the action of the screw rotation, it is fed into the barrel heated at 240℃. After being mixed evenly, it is injected into the injection mold with an iron core and injection molding is performed. The injection temperature is 270℃, the pressure is 120MPa, and the injection time is 30s. After the injection is completed, it is dried at 110℃ for 3h to obtain the composite nylon gear.

[0073] Comparative Example 1

[0074] The corrosion-resistant composite material of this comparative example consists of the following weight components: 105g modified nylon 6, 23g modified glass fiber, 6g modified SiCw, 2g compatibilizer (POE-g-MAH), and 0.2g antioxidant (0.15g antioxidant 1010 and 0.05g antioxidant 168).

[0075] The method for preparing the corrosion-resistant composite material in this comparative example is as follows:

[0076] (1) 105g caprolactam was heated to 80℃ to melt, 1.5g modified boron nitride nanosheets were added, and the mixture was stirred and sonicated for 30min, and then vacuumed for 30min to remove water to obtain a mixed melt. Under nitrogen protection, 0.15g antioxidant 1010 and 0.05g antioxidant 168 were added to the mixed melt, and after stirring for 5min, 0.375g NaOH was added. After magnetic stirring for 5min, vacuuming was performed for 15min, and finally 1.7mL TDI was added. The temperature was raised to 220℃ and the polymerization reaction was carried out for 2h. After the reaction was completed, modified nylon 6 was obtained by water cooling and granulation.

[0077] (2) 6g of modified SiCw and 2g of POE-g-MAH were premixed at 100rpm for 20min, and then mixed with 105g of modified nylon 6 and fed into a twin-screw extruder through the main feed port. 23g of modified glass fiber was fed into the extruder through the side feed port (located after the screw melting section) and extruded into granules. The temperatures of the five zones of the extruder were set to 220℃, 250℃, 260℃, 255℃ and 250℃ respectively, and slightly adjusted according to the actual production conditions on site. The rotation speed of the main feed port was 300 r / min and the rotation speed of the side feed port was 200 r / min. The extruded granules were dried in an oven at 130℃ for 5 h to obtain a corrosion-resistant composite material.

[0078] The preparation method of the modified boron nitride nanosheets in this comparative example is the same as that in Example 2.

[0079] The preparation method of the modified glass fiber in this comparative example is the same as that in Example 2.

[0080] The preparation method of the modified SiCw in this comparative example is the same as that in Example 2.

[0081] The preparation method of the composite nylon gear in this comparative example is the same as that in Example 2.

[0082] Comparative Example 2

[0083] The corrosion-resistant composite material of this comparative example consists of the following weight components: 105g modified nylon 6, 23g modified glass fiber, 6g modified SiCw, 2g compatibilizer (POE-g-MAH), and 0.2g antioxidant (0.15g antioxidant 1010 and 0.05g antioxidant 168).

[0084] The method for preparing the corrosion-resistant composite material in this comparative example is as follows:

[0085] (1) 105g caprolactam was heated to 80℃ to melt, 1.5g boron nitride nanosheets and 4g polyrotaxane were added, and the mixture was stirred and sonicated for 30min and then vacuumed for 30min to remove water to obtain a mixed melt. Under nitrogen protection, 0.15g antioxidant 1010 and 0.05g antioxidant 168 were added to the mixed melt, and after stirring for 5min, 0.375g NaOH was added. After magnetic stirring for 5min, vacuuming was performed for 15min, and finally 1.7mL TDI was added. The temperature was raised to 220℃ and the polymerization reaction was carried out for 2h. After the reaction was completed, modified nylon 6 was obtained by water cooling and granulation.

[0086] (2) 6g of modified SiCw and 2g of POE-g-MAH were premixed at 100rpm for 20min, and then mixed with 105g of modified nylon 6 and fed into a twin-screw extruder through the main feed port. 23g of modified glass fiber was fed into the extruder through the side feed port (located after the screw melting section) and extruded into granules. The temperatures of the five zones of the extruder were set to 220℃, 250℃, 260℃, 255℃ and 250℃ respectively, and slightly adjusted according to the actual production conditions on site. The rotation speed of the main feed port was 300 r / min and the rotation speed of the side feed port was 200 r / min. The extruded granules were dried in an oven at 130℃ for 5 h to obtain a corrosion-resistant composite material.

[0087] The preparation method of the modified glass fiber in this comparative example is the same as that in Example 2.

[0088] The preparation method of the modified SiCw in this comparative example is the same as that in Example 2.

[0089] The preparation method of the composite nylon gear in this comparative example is the same as that in Example 2.

[0090] Performance testing

[0091] The samples were injection molded into standard specimens according to GB / T1703.1-2019; tensile strength was tested according to GB / T1040.1-2018 at a tensile rate of 50 mm / min; flexural strength was tested according to GB / T9341-2018 at a test speed of 2 mm / min; frictional properties were tested according to GB / T3960-2016; cantilever beam notched impact strength was tested according to GB / T1843-2008 with a pendulum impact energy of 5.5 J; heat distortion temperature was tested according to Method A in GB / T 1634.2-2019, with a specimen length of 80 mm, width of 10 mm, thickness of 4 mm, heating rate of 2 ℃ / min, and weight load of 1.8 MPa. Each composite material was tested in parallel three times, and the final results were averaged. The test results are shown in Table 1.

[0092] Table 1 Test data of composite materials in Examples 1-3 and Comparative Examples 1-2

[0093]

[0094] Analyze Examples 1-3 and Comparative Examples 1-2, in conjunction with Table 1 and Figures 1-4 It can be seen that the corrosion-resistant composite material with modified boron nitride nanosheets, modified polyrotaxane, modified glass fiber, and modified SiCw has good mechanical and thermal properties. In Comparative Example 1, the modified nylon 6 prepared in Comparative Example 1, compared with Examples 1-3, did not contain modified polyrotaxane, lacked a dynamic pulley structure, and had limited ability to alleviate stress concentration, thus reducing the impact strength and toughness of the corrosion-resistant composite material in Comparative Example 1. In Comparative Example 2, the modified nylon 6 prepared in Comparative Example 2, compared with Examples 1-3, did not modify boron nitride nanosheets and polyrotaxane, resulting in reduced dispersion of boron nitride nanosheets and reduced bonding force between polyrotaxane and nylon, thus reducing the strength, toughness, and thermal conductivity of the corrosion-resistant composite material in Comparative Example 2.

[0095] The boron nitride nanosheets and polydopamine-modified boron nitride nanosheets in Example 2 were subjected to SEM morphology observation and analysis, and the results are as follows: Figure 1 As shown. From Figure 1 As can be seen, boron nitride nanosheets are stacked, while boron nitride nanosheets coated with polydopamine are dispersed. This is because the polydopamine coating layer acts as a physical barrier, reducing the aggregation of boron nitride nanosheets.

[0096] The cross-sections of the corrosion-resistant composite materials prepared in Example 2 and Comparative Example 2 were observed and analyzed using SEM. The results are as follows: Figure 4 As shown. From Figure 4As can be seen from the data, compared with Comparative Example 2, most of the voids in the corrosion-resistant composite material in Example 2 were removed. This is because the boron nitride nanosheets were modified with polydopamine and the polyrotaxane was modified with sulfonate betaine, which made the two more dispersed in the nylon matrix and significantly improved the interfacial compatibility with the nylon matrix.

[0097] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this invention.

Claims

1. A corrosion resistant composite material, characterized by, The composition comprises modified nylon 6, reinforcing filler, compatibilizer and antioxidant. The modified nylon 6 is prepared by in-situ polymerization of caprolactam, modified boron nitride nanosheet and modified polyrotaxane. The modified boron nitride nanosheet is prepared by modifying boron nitride nanosheet coated with polydopamine. The preparation method of the modified polyrotaxane comprises the following steps: S1, polyethylene glycol is modified by p-toluenesulfonyl chloride to obtain PEG-Ts; S2, PEG-Ts is self-assembled with cyclodextrin to obtain Pre-PR; S3, Pre-PR is reacted with (3-aminopropyl) trimethoxysilane, and NH2-Pre-PR is obtained after dialysis; S4, NH2-Pre-PR is reacted with 1, 3-propanesultone and N, N-diisopropylethylamine, and SBMA-Pre-PR is obtained after dialysis; and S5, SBMA-Pre-PR is reacted with 3, 5-dimethylphenol in K2CO3 / DMF to obtain modified polyrotaxane.

2. A corrosion resistant composite material according to claim 1, wherein The preparation method of the modified boron nitride nanosheet comprises the following steps: hexagonal boron nitride is ultrasonically dispersed into deionized water to obtain a boron nitride nanosheet dispersion liquid; then, dopamine hydrochloride is added into the boron nitride nanosheet dispersion liquid, and a modified boron nitride nanosheet is prepared through polymerization reaction.

3. A corrosion resistant composite material according to claim 1, wherein The reinforcing filler comprises modified glass fiber and modified SiCw.

4. A corrosion resistant composite material according to claim 3, wherein The preparation method of the modified glass fiber comprises the following steps: glass fiber is reacted with silane coupling agent in an ethanol solution to obtain modified glass fiber.

5. A corrosion resistant composite material according to claim 3, wherein The preparation method of the modified SiCw comprises the following steps: a silane coupling agent is ultrasonically dispersed into a mixture of water and ethanol to obtain a silane coupling agent dispersion liquid; then, SiCw is added into the silane coupling agent dispersion liquid, and the modified SiCw is obtained after stirring and drying.

6. A method of producing a corrosion-resistant composite material, characterized by, The method comprises the following steps: 1) modified boron nitride nanosheet and modified polyrotaxane are compounded: the modified boron nitride nanosheet is ultrasonically dispersed in DMF to obtain a dispersion liquid A; the modified polyrotaxane is ultrasonically dispersed in DMF to obtain a dispersion liquid B; the dispersion liquid B is slowly poured into the dispersion liquid A, and the compound PB is obtained after vacuum distillation and drying; 2) nylon matrix is in-situ polymerized: caprolactam and the compound PB are in-situ polymerized through anionic ring-opening polymerization under the protection of nitrogen to obtain modified nylon 6; 3) the modified nylon 6, the reinforcing filler, the antioxidant and the compatibilizer are added into a double-screw extruder, and the corrosion-resistant composite material is obtained through melt extrusion and granulation; The modified boron nitride nanosheet is prepared by modifying boron nitride nanosheet coated with polydopamine; The preparation method of the modified polyrotaxane comprises the following steps: S1, polyethylene glycol is modified by p-toluenesulfonyl chloride to obtain PEG-Ts; S2, PEG-Ts is self-assembled with cyclodextrin to obtain Pre-PR; S3, Pre-PR is reacted with (3-aminopropyl) trimethoxysilane, and NH2-Pre-PR is obtained after dialysis; S4, NH2-Pre-PR is reacted with 1, 3-propanesultone and N, N-diisopropylethylamine, and SBMA-Pre-PR is obtained after dialysis; and S5, SBMA-Pre-PR is reacted with 3, 5-dimethylphenol in K2CO3 / DMF to obtain modified polyrotaxane.

7. A method of making a corrosion resistant composite material according to claim 6, wherein, The temperature of the double screw extruder is set as: 220 DEG C in the first zone, 250 DEG C in the second zone, 260 DEG C in the third zone, 255 DEG C in the fourth zone, 250 DEG C in the fifth zone, the rotation speed of the main feeding port is 300-500 r / min, and the rotation speed of the side feeding port is 180-200 r / min.

8. Use of a corrosion-resistant composite material as claimed in any one of claims 1-5 for the production of a gear, characterized in that, The corrosion-resistant composite material is prepared into a composite nylon gear through injection molding.

9. Use according to claim 8, characterized in that, The injection molding process of the composite nylon gear is as follows: the temperature is 250-270 DEG C, the pressure is 100-120 MPa, and the time is 20-30 s.

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