Carbon fiber reinforced nylon material and preparation method thereof

Abstract

The invention relates to a carbon fiber reinforced nylon material and a preparation method thereof, and belongs to the technical field of high polymer materials. The carbon fiber reinforced nylon material is prepared from nylon and modified carbon fibers, wherein the mass ratio of the nylon to the modified carbon fibers is 100: (10-15); the modified carbon fiber is prepared by reacting epoxy grafted carbon fiber with maleic anhydride grafted nylon and then reacting with 1, 1-cyclohexyl diacetic anhydride; the surface of the carbon fiber is grafted with a PA66 chain segment and a cyclohexyl diethyl chain segment, the PA66 chain segment and the cyclohexyl diethyl chain segment can endow the surface of the carbon fiber with good lipophilicity, and carboxyl groups contained in the PA66 chain segment and the cyclohexyl diethyl chain segment can effectively improve the polarity of the carbon fiber, so that the carbon fiber has good surface activity, the dispersity of the carbon fiber is improved, and the carbon fiber has good mechanical properties. And moreover, the cyclohexyl diethyl chain segment has relatively large steric hindrance, so that winding of the PA66 chain segment can be avoided, the extensibility of the PA66 chain segment is improved, and the overall performance of the material is further improved.

Description

Technical Field

[0001] This invention relates to a carbon fiber reinforced nylon material and its preparation method, belonging to the field of polymer materials technology. Background Technology

[0002] Currently, vehicle exhaust is causing serious pollution to the global environment. Studies have shown that reducing the weight of a vehicle can reduce fuel consumption and carbon dioxide emissions. Therefore, lightweighting of vehicles is of great significance, and lightweighting and high performance are among the development directions for automotive materials.

[0003] Nylon 66 (PA66) is a partially crystalline thermoplastic material with excellent mechanical properties, chemical resistance, heat resistance, and self-lubricating properties. Through reinforcement and toughening modification, it can replace metal materials in the manufacture of high-strength, heat-resistant components such as intake manifolds, gears, and front-end frames, and has been widely used in automobiles.

[0004] Compared to glass fiber, carbon fiber has higher strength and modulus, and is often used in the preparation of advanced composite materials. Carbon fiber composites are a promising new type of composite material with advantages such as high strength, high toughness, high plasticity, and impact resistance, and are widely used in aerospace, automotive, and other fields. Carbon fiber reinforced nylon materials can significantly improve the mechanical and abrasion properties of nylon. Compared to glass fiber reinforced nylon, carbon fiber has a better reinforcement effect and lower density, making it suitable for manufacturing moving parts such as gears and guide rails. However, the poor compatibility between carbon fiber and the nylon matrix leads to uneven dispersion of carbon fiber in the nylon matrix, resulting in a limited improvement in the performance of nylon materials. Summary of the Invention

[0005] The purpose of this invention is to provide a carbon fiber reinforced nylon material and its preparation method, so as to solve the problem of poor reinforcement caused by the poor compatibility between carbon fiber and nylon when using carbon fiber modified nylon materials.

[0006] This invention provides a carbon fiber reinforced nylon material, which is composed of nylon and modified carbon fiber, wherein the mass ratio of nylon to modified carbon fiber is 100:10~15; the modified carbon fiber is prepared by reacting epoxy-grafted carbon fiber and maleic anhydride-grafted nylon, and then reacting them with 1,1-cyclohexyldiacetic anhydride.

[0007] Preferably, the preparation method of the epoxy-grafted carbon fiber is as follows: carbon fiber, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol and water are heated to reflux, and then mixed and refluxed for 25~28h to obtain epoxy-grafted carbon fiber.

[0008] Preferably, the mass ratio of the carbon fiber, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol and water is 1:2~3:80~90:8~10.

[0009] Preferably, the carbon fiber has an average length of 3-5 mm and an average diameter of 5-8 μm.

[0010] Preferably, the reaction method of epoxy-grafted carbon fiber and maleic anhydride-grafted nylon is as follows: epoxy-grafted carbon fiber and maleic anhydride-grafted nylon are mixed and then melt-extruded to obtain nylon-grafted carbon fiber, wherein the molar ratio of epoxy groups in the epoxy-grafted carbon fiber to the molar ratio of maleic anhydride in the maleic anhydride-grafted nylon is 1:1; and the maleic anhydride grafting rate of the maleic anhydride-grafted nylon is 1.2~1.5%.

[0011] Preferably, the temperature for melt extrusion of epoxy-grafted carbon fiber and maleic anhydride-grafted nylon after mixing is 235~240℃.

[0012] Preferably, the method for reacting with 1,1-cyclohexyldiacetic anhydride is as follows: Nylon grafted carbon fibers and 1,1-cyclohexyldiacetic anhydride are mixed and then melt-extruded to obtain modified carbon fibers, wherein the molar ratio of hydroxyl groups to 1,1-cyclohexyldiacetic anhydride in the nylon grafted carbon fibers is 1:1.

[0013] Preferably, the temperature for melt extrusion after mixing nylon grafted carbon fiber and 1,1-cyclohexyldiacetic anhydride is 235~240℃.

[0014] Preferably, the nylon is PA66; the maleic anhydride-grafted nylon is maleic anhydride-grafted PA66.

[0015] A method for preparing carbon fiber reinforced nylon material as described above includes the following steps: mixing the raw materials of carbon fiber reinforced nylon material according to the specified ratio and then performing melt extrusion to obtain carbon fiber reinforced nylon material.

[0016] The beneficial effects of this invention are as follows: The carbon fiber reinforced nylon material of this invention is composed of nylon and modified carbon fiber. The carbon fiber surface is grafted with PA66 segments and cyclohexyldiethyl segments. The PA66 segments and cyclohexyldiethyl segments can impart good oleophilicity to the carbon fiber surface, while the carboxyl groups contained in the PA66 segments and cyclohexyldiethyl segments can effectively improve the polarity of the carbon fiber, thereby giving the carbon fiber better surface activity and improving its dispersibility. In addition, the cyclohexyldiethyl segments have greater steric hindrance, which can prevent PA66 segments from entangled and improve the extensibility of PA66 segments, thereby improving the overall performance of the material. Detailed Implementation

[0017] The following examples are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the present invention.

[0018] The PA66 used in Examples 1-3 and Comparative Examples 1-5 came from the same batch of products manufactured by the same company. Example

[0019] The carbon fiber reinforced nylon material of this embodiment is composed of PA66 and modified carbon fiber, with a mass ratio of PA66 to modified carbon fiber of 100:10. The preparation method of modified carbon fiber is as follows: carbon fiber (average length 3 mm, average diameter 5 μm), γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol and deionized water in a mass ratio of 1:2:80:8 are added to a reaction vessel, heated to reflux, and then reacted under stirring and reflux conditions for 25 h. After cooling to room temperature, the mixture is filtered, and the filter cake is washed successively with ethanol and deionized water. After drying, epoxy-grafted carbon fiber is obtained. Then, epoxy grafted... Carbon fiber and maleic anhydride-grafted PA66 (with a maleic anhydride grafting rate of 1.2%) were mixed evenly and then added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain PA66-grafted carbon fiber. The molar ratio of epoxy groups in the epoxy-grafted carbon fiber to the molar ratio of maleic anhydride in the maleic anhydride-grafted PA66 was 1:1. Then, PA66-grafted carbon fiber and 1,1-cyclohexyldiacetic anhydride were mixed evenly and added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain modified carbon fiber. The molar ratio of hydroxyl groups in the PA66-grafted carbon fiber to the molar ratio of 1,1-cyclohexyldiacetic anhydride was 1:1. Example

[0020] The carbon fiber reinforced nylon material of this embodiment is composed of PA66 and modified carbon fiber, with a mass ratio of PA66 to modified carbon fiber of 100:12. The preparation method of modified carbon fiber is as follows: carbon fiber (average length 4 mm, average diameter 6 μm), γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol and deionized water in a mass ratio of 1:3:85:9 are added to a reaction vessel, heated to reflux, and then reacted under stirring and reflux conditions for 27 h. After cooling to room temperature, the mixture is filtered, and the filter cake is washed successively with ethanol and deionized water. After drying, epoxy-grafted carbon fiber is obtained. Then, epoxy grafted... Carbon fiber and maleic anhydride-grafted PA66 (with a maleic anhydride grafting rate of 1.3%) were mixed evenly and then added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain PA66-grafted carbon fiber. The molar ratio of epoxy groups in the epoxy-grafted carbon fiber to the molar ratio of maleic anhydride in the maleic anhydride-grafted PA66 was 1:1. Then, PA66-grafted carbon fiber and 1,1-cyclohexyldiacetic anhydride were mixed evenly and added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain modified carbon fiber. The molar ratio of hydroxyl groups in the PA66-grafted carbon fiber to the molar ratio of 1,1-cyclohexyldiacetic anhydride was 1:1. Example

[0021] The carbon fiber reinforced nylon material of this embodiment is composed of PA66 and modified carbon fiber, with a mass ratio of PA66 to modified carbon fiber of 100:15. The preparation method of modified carbon fiber is as follows: carbon fiber (average length 5 mm, average diameter 8 μm), γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol and deionized water in a mass ratio of 1:3:90:10 are added to a reaction vessel, heated to reflux, and then reacted under stirring and reflux conditions for 28 h. After cooling to room temperature, the mixture is filtered, and the filter cake is washed successively with ethanol and deionized water. After drying, epoxy-grafted carbon fiber is obtained. Then, the epoxy grafting... After uniform mixing of epoxy-grafted carbon fibers and maleic anhydride-grafted PA66 (with a maleic anhydride grafting rate of 1.5%), the mixture was added to a twin-screw extruder and melt-extruded at 235°C to obtain PA66-grafted carbon fibers. The molar ratio of epoxy groups in the epoxy-grafted carbon fibers to the molar ratio of maleic anhydride in the maleic anhydride-grafted PA66 was 1:1. Then, PA66-grafted carbon fibers and 1,1-cyclohexyldiacetic anhydride were mixed uniformly and added to a twin-screw extruder, and melt-extruded at 235°C to obtain modified carbon fibers. The molar ratio of hydroxyl groups in the PA66-grafted carbon fibers to the molar ratio of 1,1-cyclohexyldiacetic anhydride was 1:1.

[0022] Comparative Example 1 The carbon fiber reinforced nylon material of this comparative example is composed of PA66 and modified carbon fiber, with a mass ratio of PA66 to modified carbon fiber of 100:10. The preparation method of the modified carbon fiber is as follows: carbon fiber (average length 3 mm, average diameter 5 μm), γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol, and deionized water in a mass ratio of 1:2:80:8 are added to a reaction vessel, heated to reflux, and then reacted under stirring and reflux conditions for 25 h. After cooling to room temperature, the mixture is filtered, and the filter cake is washed successively with ethanol and deionized water. After drying, epoxy-grafted carbon fiber is obtained. Then, epoxy-grafted carbon fiber and maleic anhydride-grafted PA66 (with a maleic anhydride grafting rate of 1.2%) were stirred evenly and added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain PA66-grafted carbon fiber. The molar ratio of epoxy groups in the epoxy-grafted carbon fiber to the molar ratio of maleic anhydride in the maleic anhydride-grafted PA66 was 1:1. Then, PA66-grafted carbon fiber and nadic anhydride were stirred evenly and added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain modified carbon fiber. The molar ratio of hydroxyl groups in the PA66-grafted carbon fiber to the molar ratio of nadic anhydride was 1:1.

[0023] Comparative Example 2 The carbon fiber reinforced nylon material in this comparative example is composed of PA66 and modified carbon fiber, with a mass ratio of PA66 to modified carbon fiber of 100:10. The modified carbon fiber is prepared as follows: carbon fiber (average length 3 mm, average diameter 5 μm), γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol, and deionized water in a mass ratio of 1:2:80:8 are added to a reaction vessel, heated to reflux, and then reacted under stirring and reflux conditions for 25 h. After cooling to room temperature, the mixture is filtered, and the filter cake is washed successively with ethanol and deionized water. After drying, epoxy-grafted carbon fiber is obtained. Epoxy-grafted carbon fibers and maleic anhydride-grafted PA66 (with a maleic anhydride grafting rate of 1.2%) were mixed evenly and then added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain PA66-grafted carbon fibers. The molar ratio of epoxy groups in the epoxy-grafted carbon fibers to the molar ratio of maleic anhydride in the maleic anhydride-grafted PA66 was 1:1. Then, PA66-grafted carbon fibers and methylhexahydrophthalic anhydride were mixed evenly and added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain modified carbon fibers. The molar ratio of hydroxyl groups in the PA66-grafted carbon fibers to the molar ratio of methylhexahydrophthalic anhydride was 1:1.

[0024] Comparative Example 3 The carbon fiber reinforced nylon material in this comparative example is composed of PA66 and modified carbon fiber, with a mass ratio of PA66 to modified carbon fiber of 100:10. The modified carbon fiber is prepared as follows: carbon fiber (average length 3 mm, average diameter 5 μm), γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol, and deionized water in a mass ratio of 1:2:80:8 are added to a reaction vessel, heated to reflux, and then reacted under stirring and reflux conditions for 25 h. After cooling to room temperature, the mixture is filtered, and the filter cake is washed successively with ethanol and deionized water. After drying, epoxy-grafted carbon fiber is obtained. Epoxy-grafted carbon fibers and maleic anhydride-grafted PA66 (with a maleic anhydride grafting rate of 1.2%) were mixed evenly and then added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain PA66-grafted carbon fibers. The molar ratio of epoxy groups in the epoxy-grafted carbon fibers to the molar ratio of maleic anhydride in the maleic anhydride-grafted PA66 was 1:1. Then, PA66-grafted carbon fibers and phthalic anhydride were mixed evenly and added to a twin-screw extruder. The mixture was melt-extruded at 235°C to obtain modified carbon fibers. The molar ratio of hydroxyl groups in the PA66-grafted carbon fibers to the molar ratio of phthalic anhydride was 1:1.

[0025] Comparative Example 4 The carbon fiber reinforced nylon material of this comparative example is composed of PA66, epoxy-grafted carbon fiber, and maleic anhydride-grafted PA66. The epoxy-grafted carbon fiber is the same as that prepared in Example 1, and the maleic anhydride-grafted PA66 is the same as that in Example 1. The molar ratio of epoxy groups in the epoxy-grafted carbon fiber to the molar ratio of maleic anhydride in the maleic anhydride-grafted PA66 is 1:1, and the mass ratio of PA66 to the sum of the masses of epoxy-grafted carbon fiber and maleic anhydride-grafted PA66 is 100:10.

[0026] Comparative Example 5 The carbon fiber reinforced nylon material of this comparative example is composed of PA66, PA66 grafted carbon fiber and 1,1-cyclohexyldiacetic anhydride. The PA66 grafted carbon fiber is the same as the PA66 grafted carbon fiber prepared in Example 1. The molar ratio of hydroxyl groups to 1,1-cyclohexyldiacetic anhydride in the PA66 grafted carbon fiber is 1:1.

[0027] Experimental Example To evaluate the performance differences of the carbon fiber reinforced nylon materials in the various embodiments and comparative examples, the raw materials of the carbon fiber reinforced nylon materials in the various embodiments and comparative examples were mixed according to the specified proportions and then added to a twin-screw extruder. The mixture was heated to 240°C for melt extrusion to obtain the carbon fiber reinforced nylon materials. The carbon fiber reinforced nylon materials were then made into standard samples for performance testing, including tensile strength, elongation at break, flexural strength, impact strength, and abrasion resistance. Tensile strength and elongation at break were tested according to standard GB / T1040-2006, flexural strength according to standard GB / T9341-2008, and cantilever beam notched impact strength according to standard GB / T1843-2008. Abrasion resistance was measured using a friction loss tester. After the test, the mass loss rate of the sample was used to characterize the abrasion resistance. The mass loss rate is equal to the ratio of the mass lost by the sample during the friction loss test to the initial mass of the sample. The test results of tensile strength, elongation at break, flexural strength, impact strength, and abrasion resistance of the carbon fiber reinforced nylon materials in the various embodiments and comparative examples are shown in Table 1.

[0028] Table 1. Tensile strength of carbon fiber reinforced nylon materials Elongation at break, flexural strength, impact strength and abrasion resistance Carbon fiber reinforced nylon materials Tensile strength (MPa) Elongation at break (%) Flexural strength (MPa) Impact strength (kJ / m 2 ) Mass loss rate (%) Example 1 218 17.1 285 14.7 2.1 Example 2 215 16.8 282 14.1 2.4 Example 3 217 16.9 284 14.5 2.2 Comparative Example 1 159 5.4 253 10.2 9.1 Comparative Example 2 155 5.7 251 9.8 8.8 Comparative Example 3 158 5.5 256 9.5 9.3 Comparative Example 4 161 5.9 252 10.1 9.4 Comparative Example 5 164 6.1 254 10.4 9.2 As shown in Table 1, the carbon fiber reinforced nylon material of the present invention possesses excellent mechanical and abrasion resistance properties. This is because the carbon fiber surface in the material is grafted with PA66 segments and cyclohexyldiethyl segments. The PA66 and cyclohexyldiethyl segments impart good oleophilicity to the carbon fiber surface, while the carboxyl groups contained in the PA66 and cyclohexyldiethyl segments effectively improve the polarity of the carbon fiber, thereby giving the carbon fiber better surface activity and improving its dispersibility. Furthermore, the cyclohexyldiethyl segments have greater steric hindrance, which can prevent PA66 segments from entangled, improve the flexibility of PA66 segments, and thus improve the overall performance of the material.

[0029] As can be seen from Example 1 and Comparative Examples 1-3, when the 1,1-cyclohexyl diacetic anhydride used in the preparation of modified carbon fibers is replaced with nadic anhydride, methyl hexahydrophthalic anhydride or phthalic anhydride, the rigidity of the groups increases or the degree of branching decreases, resulting in a weakening of the steric hindrance effect, thereby affecting the improvement of material properties.

[0030] As can be seen from Example 1 and Comparative Example 4, when a mixture of epoxy-grafted carbon fiber and maleic anhydride-grafted PA66 is used, the carbon fiber reinforcement effect is poor due to the incomplete reaction between maleic anhydride-grafted PA66 and epoxy-grafted carbon fiber, the poor dispersibility of epoxy-grafted carbon fiber, and the lack of cyclohexyldiethyl segments.

[0031] As can be seen from Example 1 and Comparative Example 5, when a mixture of PA66 grafted carbon fiber and 1,1-cyclohexyldiacetic anhydride is used, the hydroxyl groups of 1,1-cyclohexyldiacetic anhydride and PA66 grafted carbon fiber do not react completely, and the carbon fiber surface lacks cyclohexyldiethyl segments, which causes PA66 segments to entangle and accumulate on the carbon fiber surface, affecting the reinforcing effect of the carbon fiber.

Claims

1. A carbon fiber reinforced nylon material, characterized in that, It is composed of nylon and modified carbon fiber, wherein the mass ratio of nylon to modified carbon fiber is 100:10~15; the modified carbon fiber is prepared by reacting epoxy-grafted carbon fiber and maleic anhydride-grafted nylon, and then reacting them with 1,1-cyclohexyldiacetic anhydride.

2. The carbon fiber reinforced nylon material as described in claim 1, characterized in that, The preparation method of the epoxy-grafted carbon fiber is as follows: carbon fiber, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol and water are heated to reflux, and then mixed and refluxed for 25~28h to obtain epoxy-grafted carbon fiber.

3. The carbon fiber reinforced nylon material as described in claim 2, characterized in that, The mass ratio of the carbon fiber, γ-(2,3-epoxypropoxy)propyltrimethoxysilane, ethanol and water is 1:2~3:80~90:8~10.

4. The carbon fiber reinforced nylon material as described in claim 2, characterized in that, The carbon fibers have an average length of 3-5 mm and an average diameter of 5-8 μm.

5. The carbon fiber reinforced nylon material according to any one of claims 1-4, characterized in that, The reaction method of epoxy-grafted carbon fiber and maleic anhydride-grafted nylon is as follows: epoxy-grafted carbon fiber and maleic anhydride-grafted nylon are mixed and then melt-extruded to obtain nylon-grafted carbon fiber. The molar ratio of epoxy groups in the epoxy-grafted carbon fiber to the molar ratio of maleic anhydride in the maleic anhydride-grafted nylon is 1:

1. The maleic anhydride grafting rate of the maleic anhydride-grafted nylon is 1.2~1.5%.

6. The carbon fiber reinforced nylon material as described in claim 5, characterized in that, The temperature for melt extrusion of epoxy-grafted carbon fiber and maleic anhydride-grafted nylon is 235~240℃.

7. The carbon fiber reinforced nylon material as described in claim 1, characterized in that, The method for reacting with 1,1-cyclohexyldiacetic anhydride is as follows: Nylon grafted carbon fibers and 1,1-cyclohexyldiacetic anhydride are mixed and then melt-extruded to obtain modified carbon fibers. The molar ratio of hydroxyl groups to 1,1-cyclohexyldiacetic anhydride in the nylon grafted carbon fibers is 1:

1.

8. The carbon fiber reinforced nylon material as described in claim 7, characterized in that, The temperature for melt extrusion of nylon grafted carbon fiber and 1,1-cyclohexyldiacetic anhydride is 235~240℃.

9. The carbon fiber reinforced nylon material as described in claim 1, characterized in that, The nylon is PA66; the maleic anhydride-grafted nylon is maleic anhydride-grafted PA66.

10. A method for preparing a carbon fiber reinforced nylon material as described in any one of claims 1-9, characterized in that, Includes the following steps: The raw materials for carbon fiber reinforced nylon are mixed in a certain proportion and then melt-extruded to obtain carbon fiber reinforced nylon material.