阅读说明：本技术 一种具有复合机械互锁结构界面的改性碳纤维及其复合材料 (Modified carbon fiber with composite mechanical interlocking structure interface and composite material thereof ) 是由 邹华维 邱宝伟 梁梅 孙通 陈洋 于 2020-07-27 设计创作，主要内容包括：本发明公开了一种具有复合机械互锁结构界面的改性碳纤维及其复合材料。该改性碳纤维是以氧化石墨烯、羧甲基纤维素或其盐作为改性剂,对碳纤维进行改性后制得的材料。与单独采用氧化石墨烯或羧甲基纤维素进行改性制得的改性碳纤维相比,本发明氧化石墨烯/羧甲基纤维素改性碳纤维的表面粗糙度明显增大,微机械互锁强度和润湿性显著提高。与单独采用氧化石墨烯或羧甲基纤维素对碳纤维进行改性后所得的复合材料相比,本发明氧化石墨烯/羧甲基纤维素改性碳纤维增强复合材料的层间剪切强度和界面剪切强度显著提高,界面性能取得了协同增强效果,可以用来制备高性能结构制件,在航空航天、汽车、轨道交通、舰船以及运动器材等领域应用前景广阔。(The invention discloses modified carbon fiber with a composite mechanical interlocking structure interface and a composite material thereof. The modified carbon fiber is a material prepared by modifying carbon fiber by using graphene oxide, carboxymethyl cellulose or salt thereof as a modifier. Compared with the modified carbon fiber prepared by singly adopting the graphene oxide or the carboxymethyl cellulose for modification, the surface roughness of the graphene oxide/carboxymethyl cellulose modified carbon fiber is obviously increased, and the micro-mechanical interlocking strength and the wettability are obviously improved. Compared with the composite material obtained by singly adopting the graphene oxide or the carboxymethyl cellulose to modify the carbon fiber, the graphene oxide/carboxymethyl cellulose modified carbon fiber reinforced composite material provided by the invention has the advantages that the interlaminar shear strength and the interface shear strength are obviously improved, the interface performance obtains a synergistic enhancement effect, the graphene oxide/carboxymethyl cellulose modified carbon fiber reinforced composite material can be used for preparing high-performance structural parts, and the application prospect in the fields of aerospace, automobiles, rail transit, ships, sports equipment and the like is wide.)

1. A graphene oxide/carboxymethyl cellulose modified carbon fiber is characterized in that: the carbon fiber modified graphene oxide/carboxymethyl cellulose composite material is prepared by modifying carbon fibers by using graphene oxide and carboxymethyl cellulose or salts thereof as modifiers.

2. The graphene oxide/carboxymethyl cellulose modified carbon fiber according to claim 1, wherein: the salt of the carboxymethyl cellulose is a metal salt of the carboxymethyl cellulose, preferably sodium carboxymethyl cellulose;

and/or the carbon fiber is polyacrylonitrile-based carbon fiber.

3. The graphene oxide/carboxymethyl cellulose modified carbon fiber according to claim 2, wherein: the mass ratio of the graphene oxide to the carboxymethyl cellulose or the salt thereof is (0.01-0.25): 1, preferably 0.06: 1;

and/or the ratio of the mass of the carboxymethyl cellulose or the salt thereof to the length of the carbon fiber is 0.05 g: (3-7) m, preferably 0.05 g: 5 m; the diameter of the carbon fiber is 3-10 μm, and preferably 7 μm.

4. A method for preparing the graphene oxide/carboxymethyl cellulose modified carbon fiber according to any one of claims 1 to 3, wherein: the method comprises the steps of immersing carbon fibers into a sizing agent, taking out the carbon fibers and drying the carbon fibers to obtain the carbon fibers; the sizing agent consists of graphene oxide, carboxymethyl cellulose or salt thereof and a solvent.

5. The method of claim 4, wherein: in the sizing agent, the concentration of the graphene oxide is 0.01-0.05 g/L, preferably 0.03g/L, and the concentration of the carboxymethyl cellulose or the salt thereof is 0.2-0.8 g/L, preferably 0.5 g/L;

and/or, the solvent is water;

and/or the immersion time is 5-30 minutes, preferably 10 minutes;

and/or the drying temperature is 25-50 ℃, preferably 40 ℃;

and/or, the sizing agent is prepared by the following method: adding graphene oxide and carboxymethyl cellulose or salts thereof into a solvent, uniformly stirring, and then carrying out ultrasonic treatment to obtain the graphene oxide-carboxymethyl cellulose composite material; the ultrasonic time is 10-50 minutes, preferably 30 minutes, and the ultrasonic power is 400-600W, preferably 500W.

6. A carbon fiber reinforced composite material characterized by: the graphene oxide/carboxymethyl cellulose modified carbon fiber is prepared from the graphene oxide/carboxymethyl cellulose modified carbon fiber of any one of claims 1 to 3, a resin matrix and a curing agent serving as raw materials.

7. The carbon fiber-reinforced composite material according to claim 6, characterized in that: the resin matrix is epoxy resin, preferably E51;

and/or the curing agent is an aromatic amine epoxy curing agent, preferably 4, 4-diaminodiphenylmethane;

and/or the mass ratio of the resin matrix to the curing agent is 100 (20-30), preferably 100: 28;

and/or the volume ratio of the resin matrix to the graphene oxide/carboxymethyl cellulose modified carbon fiber is 3: (1.5-2.5), preferably 3: 2.

8. A method for producing the carbon fiber-reinforced composite material as recited in any one of claims 6 to 7, characterized in that: the method comprises the following steps: and uniformly mixing the resin matrix and the curing agent to obtain a resin sizing agent, uniformly coating the resin sizing agent on the surface of the graphene oxide/carboxymethyl cellulose modified carbon fiber, then placing the carbon fiber into a mold, and curing to obtain the graphene oxide/carboxymethyl cellulose modified carbon fiber.

9. The method of claim 8, wherein: the mixing mode is stirring, preferably stirring for 5 minutes at 70-85 ℃;

and/or the curing conditions are as follows: firstly, preserving heat and pressure for 1-3 h under the conditions of 8-12 Mpa and 120-150 ℃, and then preserving heat and pressure for 1-3 h under the conditions of 8-12 Mpa and 150-190 ℃; preferably, the curing conditions are: the heat preservation and pressure maintaining are carried out for 2h under the conditions of 10Mpa and 135 ℃, and then the heat preservation and pressure maintaining are carried out for 2h under the conditions of 10Mpa and 175 ℃.

10. Use of the carbon fiber reinforced composite material according to any one of claims 6 to 7 for the manufacture of structural parts for aerospace, automotive, rail transit, ship and/or sports equipment.

Technical Field

The invention belongs to the field of composite materials, and particularly relates to a modified carbon fiber with a composite mechanical interlocking structure interface and a composite material thereof.

Background

Carbon fibers have high specific strength, high modulus, low density and excellent heat resistance, are ideal reinforcing materials for advanced polymer composite materials, are widely concerned at present in carbon fiber reinforced composite materials (CFRPs) reinforced by the carbon fibers, and are already applied to the fields of aerospace, vehicle engineering, chemical industry and the like. However, the carbon fiber reinforced composite material has the problem of poor mechanical properties at present, and the application of the carbon fiber reinforced composite material is greatly limited. The key factor influencing the mechanical property of the carbon fiber reinforced composite material is the interface property between the carbon fiber and the matrix, the untreated carbon fiber is composed of a large amount of inert graphite microcrystals, the surface of the untreated carbon fiber is nonpolar, the surface energy is low and smooth, and chemical active functional groups are lacked, so that the interface bonding between the carbon fiber and the matrix is very weak, the load is difficult to be effectively transferred onto the carbon fiber from the matrix, the interface between the carbon fiber and the matrix becomes a stress concentration area, and the mechanical property of the carbon fiber composite material is greatly weakened. Therefore, it is very important to modify carbon fibers to improve the interfacial bond strength between the carbon fibers and the matrix.

In recent years, researchers have proposed many methods for improving the interfacial bond strength between the fiber and the substrate, which can be divided into physical methods (including coating, sizing, plasma treatment, high energy irradiation, etc.) and chemical methods (including oxidative etching, chemical grafting, electrophoretic deposition, etc.). Wherein, the sizing method has been widely used due to the characteristics of good controllability, high stability, high efficiency, strong design strength and the like.

Graphene Oxide (GO) is a novel two-dimensional layered structured nanomaterial, the single layer of which is a hexagonal sp2 bonded carbon atom and contains various oxygen functional groups (such as epoxy, hydroxyl, carboxyl, and the like). Researches show that the graphene oxide is added into the composite material, so that the elastic property, fatigue resistance, thermal stability and hardness of the composite material can be effectively improved, and a wider prospect is provided for the research of the composite material.

The literature "preparation of graphene oxide reinforced carbon fiber/epoxy composite material and research on mechanical properties thereof, yoho morning positive" describes a carbon fiber modified by graphene oxide and a composite material formed by the modified carbon fiber and epoxy resin. The research finds that the carbon fiber treated by graphene oxide can improve the surface structure of the carbon fiber, and after treatment, the surface energy of the carbon fiber is increased, the wettability and cohesiveness between a reinforcement body and a matrix are improved, so that the interlaminar shear performance of the composite material is improved. And when the concentration of the graphene oxide solution is 0.3 wt%, the interlaminar shear strength of the obtained composite material is improved to the maximum extent, and is improved by 12.9% compared with the unmodified carbon fiber composite material. However, in order to meet the practical application requirements of the diversification of composite materials, the interlaminar shear strength needs to be further improved.

Yuan et al (underfluence of differential surface treatments on the interfacial surface of graphene oxide/carbon fiber/epoxy compositions. appl Surf Sci.2018; 458: 996-.

In summary, it is still difficult to obtain carbon fibers with excellent interfacial properties and further difficult to obtain composite materials with excellent properties by modifying carbon fibers by graphene sizing, and further improvement is needed.

Disclosure of Invention

The invention aims to provide modified carbon fibers with a composite mechanical interlocking structure interface, and a composite material which is prepared by taking the modified carbon fibers as a reinforcement and has remarkably improved interlaminar shear strength and interface shear strength.

The invention provides a graphene oxide/carboxymethyl cellulose modified carbon fiber, which is a material prepared by modifying carbon fibers by using graphene oxide, carboxymethyl cellulose or salt thereof as a modifier.

Further, the salt of carboxymethyl cellulose is a metal salt of carboxymethyl cellulose, preferably sodium carboxymethyl cellulose;

and/or the carbon fiber is polyacrylonitrile-based carbon fiber.

Further, the mass ratio of the graphene oxide to the carboxymethyl cellulose or the salt thereof is (0.01-0.25): 1, preferably 0.06: 1;

and/or the ratio of the mass of the carboxymethyl cellulose or the salt thereof to the length of the carbon fiber is 0.05 g: (3-7) m, preferably 0.05 g: 5 m; the diameter of the carbon fiber is 3-10 μm, and preferably 7 μm.

The invention also provides a method for preparing the graphene oxide/carboxymethyl cellulose modified carbon fiber, which comprises the steps of immersing the carbon fiber into a sizing agent, taking out and drying; the sizing agent consists of graphene oxide, carboxymethyl cellulose or salt thereof and a solvent.

Furthermore, in the sizing agent, the concentration of the graphene oxide is 0.01-0.05 g/L, preferably 0.03g/L, and the concentration of the carboxymethyl cellulose or the salt thereof is 0.2-0.8 g/L, preferably 0.5 g/L;

and/or, the solvent is water;

and/or the immersion time is 5-30 minutes, preferably 10 minutes;

and/or the drying temperature is 25-50 ℃, preferably 40 ℃;

and/or, the sizing agent is prepared by the following method: adding graphene oxide and carboxymethyl cellulose or salts thereof into a solvent, uniformly stirring, and then carrying out ultrasonic treatment to obtain the graphene oxide-carboxymethyl cellulose composite material; the ultrasonic time is 10-50 minutes, preferably 30 minutes, and the ultrasonic power is 400-600W, preferably 500W.

The invention also provides a carbon fiber reinforced composite material which is prepared by taking the graphene oxide/carboxymethyl cellulose modified carbon fiber, a resin matrix and a curing agent as raw materials.

Further, the resin matrix is epoxy resin, preferably E51;

and/or the curing agent is an aromatic amine epoxy curing agent, preferably 4, 4-diaminodiphenylmethane;

and/or the mass ratio of the resin matrix to the curing agent is 100 (20-30), preferably 100: 28;

and/or the volume ratio of the resin matrix to the graphene oxide/carboxymethyl cellulose modified carbon fiber is 3: (1.5-2.5), preferably 3: 2.

The invention also provides a preparation method of the carbon fiber reinforced composite material, which comprises the following steps: and uniformly mixing the resin matrix and the curing agent to obtain a resin sizing agent, uniformly coating the resin sizing agent on the surface of the graphene oxide/carboxymethyl cellulose modified carbon fiber, then placing the carbon fiber into a mold, and curing to obtain the graphene oxide/carboxymethyl cellulose modified carbon fiber.

Further, the mixing mode is stirring, preferably stirring for 5 minutes at 70-85 ℃;

and/or the curing conditions are as follows: firstly, preserving heat and pressure for 1-3 h under the conditions of 8-12 Mpa and 120-150 ℃, and then preserving heat and pressure for 1-3 h under the conditions of 8-12 Mpa and 150-190 ℃; preferably, the curing conditions are: the heat preservation and pressure maintaining are carried out for 2h under the conditions of 10Mpa and 135 ℃, and then the heat preservation and pressure maintaining are carried out for 2h under the conditions of 10Mpa and 175 ℃.

The invention also provides application of the carbon fiber reinforced composite material in preparing structural parts of aerospace, automobiles, rail traffic, ships and/or sports equipment.

The mechanical interlocking structure is an embedded mechanical interlocking structure formed by the resin matrix and the reinforcement body after cooling and solidification, and can improve the binding force between the reinforcement body and the resin matrix. The micromechanical interlocking structure means that the formed mechanical interlocking structure is in a micro-nano scale.

Carboxymethyl Cellulose (CMC), a water-soluble Cellulose ether obtained by chemically modifying natural Cellulose. Because of the poor water solubility of the acid structure of carboxymethylcellulose, its Sodium salt, namely Sodium carboxymethylcellulose (CMC-Na), is commonly used in order to better utilize it.

The invention provides a graphene oxide/carboxymethyl cellulose modified carbon fiber and also provides a carbon fiber reinforced composite material prepared by taking the graphene oxide/carboxymethyl cellulose modified carbon fiber as a raw material. Experiments prove that compared with the modified carbon fiber obtained by modifying the carbon fiber by singly adopting the graphene oxide or the carboxymethyl cellulose, the surface roughness of the graphene oxide/carboxymethyl cellulose modified carbon fiber obtained by the invention is obviously increased, and the micro-mechanical interlocking strength and the wettability are obviously improved; compared with the composite material obtained by singly adopting the graphene oxide or the carboxymethyl cellulose to modify the carbon fiber, the graphene oxide/carboxymethyl cellulose modified carbon fiber reinforced composite material prepared by the invention has the advantages that the interlaminar shear strength and the interface shear strength are obviously improved, the interface performance obtains a synergistic enhancement effect, and the graphene oxide/carboxymethyl cellulose modified carbon fiber reinforced composite material can be used for preparing high-performance structural parts and has wide application prospects in the fields of aerospace, automobiles, rail transit, ships, sports equipment and the like.

The preparation method is simple, low in raw material cost and suitable for expanded production.

Obviously, many modifications, substitutions, and variations are possible in light of the above teachings of the invention, without departing from the basic technical spirit of the invention, as defined by the following claims.

The present invention will be described in further detail with reference to the following examples. This should not be understood as limiting the scope of the above-described subject matter of the present invention to the following examples. All the technologies realized based on the above contents of the present invention belong to the scope of the present invention.

Drawings

Fig. 1 is a schematic diagram of a preparation process of graphene oxide/carboxymethyl cellulose modified carbon fiber and a corresponding carbon fiber reinforced composite material.

FIG. 2 is a schematic representation of the reaction of CMC or CMC-Na with GO to form hydrogen bonds.

FIG. 3 FTIR spectra of individual carbon fiber samples.

Fig. 4 Raman spectra of each carbon fiber sample: (a) summary, (b) CF, (c) CF/GO, (d) CF/CMC, and (e) CF/GO/CMC.

Figure 5 XPS spectra of each carbon fiber sample: (a) summary, (b) CF, (c) CF/GO, (d) CF/CMC, and (e) CF/GO/CMC.

FIG. 6 shows SEM ((a) CF, (b) CF/GO, (c) CF/CMC, (d) CF/GO/CMC) and AFM ((a ') CF, (b') CF/GO, (c ') CF/CMC, (d') CF/GO/CMC) test results for each carbon fiber sample.

Fig. 7 contact angle test results for each carbon fiber sample: (a) CF, (b) CF/GO, (c) CF/CMC, and (d) CF/GO/CMC.

FIG. 8 shows SEM test results for longitudinal sections ((a) CF, (b) CF/GO, (c) CF/CMC, (d) CF/GO/CMC) and transverse sections ((a ') CF, (b') CF/GO, (c ') CF/CMC, (d') CF/GO/CMC) of each of the carbon fiber reinforced composites.

Fig. 9 shows the results of interlaminar shear strength tests of the respective carbon fiber-reinforced composite materials.

Fig. 10 shows the results of the interfacial shear strength test of each carbon fiber-reinforced composite material.

Detailed Description

The raw materials and equipment used in the invention are known products and are obtained by purchasing commercial products.

The raw materials include polyacrylonitrile-based carbon fibers (average diameter 7 μm, density 1.78 g/cc), sodium carboxymethylcellulose (CMC-Na,50-100MPa · s, DS ═ 0.7), graphene oxide (GO, particle size 0.5-10 μm, weight ratio C/O ═ 1.67), bisphenol a type epoxy resin (E51, epoxy value 0.49-0.54mol/100g), curing agent 4, 4-diaminodiphenylmethane (DDM), etc.