Self-repairing type carbon fiber intelligent sizing agent and preparation method thereof

Abstract

The invention discloses a self-repairing type carbon fiber intelligent sizing agent and a preparation method thereof, and belongs to the technical field of carbon fiber surface modification. According to the invention, the repairing agent is coated, and the photo-thermal material is added to obtain the photo-thermal self-repairing particles; the water-soluble sizing agent base solution, the surfactant, the silane coupling agent, the lubricant, the adhesive and the antistatic agent are mixed to obtain the self-repairing sizing agent. And after the carbon fibers are damaged, the photo-thermal self-repairing particles crack, and the repairing agent in the particles can flow out to cure and repair cracks under the condition of natural light, so that the effect of intelligent response is achieved, and manual damage detection and repairing are not needed.

Description

Technical Field

[0001] The present invention belongs to the technical field of carbon fiber surface modification, and particularly relates to a self-healing carbon fiber intelligent sizing agent and a preparation method thereof. Background Art

[0002] Carbon fiber is an important reinforcing material and is widely used in various fields. Due to its advantages such as high specific strength, specific modulus, high temperature resistance, chemical resistance, small friction coefficient, and good electrical conductivity, carbon fiber can be used to enhance the material properties. Carbon fiber composites can be applied to various fields, for example, aerospace, aviation, sports goods, civil construction, electronic products, medical devices, etc.

[0003] The sizing agent is an important auxiliary agent to improve the performance of carbon fiber. Coating the sizing agent on the surface of carbon fiber to form a protective film with a thickness of dozens of nanometers to hundreds of nanometers and a mass fraction of 0.8%-1.5% can greatly reduce the adverse phenomena generated during fiber processing such as fiber fuzzing, filament breakage, or deformation, making the fiber easy to bundle, improving its reprocessing performance, and at the same time ensuring that the fiber itself is not damaged.

[0004] At present, the processability of carbon fiber is affected because the carbon fiber has a low elongation rate and is brittle. During the processing of carbon fiber, fuzz or filament breakage will occur due to mechanical friction, reducing the strength of carbon fiber. Moreover, in subsequent use, carbon fiber composites will be affected by mechanical loads, environmental factors, etc. and generate microcracks, interface debonding and other damages. At present, although there are methods and products for repairing damages, generally, it is necessary to manually use a repair agent or perform light irradiation or heat treatment, and it is difficult to detect and repair small damages.

[0005] Therefore, the self-healing sizing agent can automatically release the repair agent to fill and repair these damages without manual intervention, thereby significantly extending the service life of the composite material. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a self-healing carbon fiber intelligent sizing agent and a preparation method thereof. After the carbon fiber is damaged, the photo-thermal self-healing particles will also crack, and the repair agent therein can flow out and be cured in natural light to repair the crack, achieving the effect of intelligent response, without the need for manual detection of damage and then repair.

[0007] To achieve the above purpose, the present invention provides the following technical solutions:

[0008] In the first aspect, the present invention provides a self-healing carbon fiber intelligent sizing agent, comprising the following components in parts by mass:

[0009] 100 parts of water-soluble sizing agent base liquid, 5 - 8 parts of photothermal self-healing particles, 1 - 5 parts of surfactant, 0.1 - 3 parts of silane coupling agent, 0.1 - 3 parts of lubricant, 0.1 - 5 parts of adhesive, 0.1 - 3 parts of antistatic agent.

[0010] Preferably, the water-soluble sizing agent base liquid is composed of 1 - 10% of water-based resin, and the balance is deionized water.

[0011] Preferably, the water-based resin includes water-based epoxy resin, water-soluble phenolic epoxy resin, and sulfonated water-based epoxy resin.

[0012] Preferably, the preparation method of the photothermal self-healing particles is as follows:

[0013] S1. Heat and mix graphene oxide, photocurable repair agent, initiator, and solvent evenly to obtain a mixed solution;

[0014] S2. Mix the mixed solution with an aqueous solution of water-soluble resin and emulsify to form an emulsion;

[0015] S3. Mix and stir the emulsion with melamine-formaldehyde resin monomer for reaction. After the reaction is completed, filter and dry at normal temperature under vacuum to obtain microcapsules;

[0016] S4. Mix the microcapsules, zinc oxide, polyvinyl alcohol, and water, disperse them evenly by ultrasonic wave, then filter, wash, and dry to obtain photothermal self-healing particles.

[0017] It is found in the present invention that currently, the damaged carbon fiber is usually repaired by using a repair agent to cure under the conditions of light or heat, so as to fill the gap and complete the repair; however, it usually requires artificial application of reagents or reaction conditions, and a large amount of time is required to detect the damage. In the present invention, the repair agent is encapsulated by microcapsules. After cracking and damage caused by reasons such as wear occur, the microcapsules are damaged, so that the internal repair liquid flows out, and then the damaged place is repaired.

[0018] Further preferably, in S1, the mass ratio of graphene oxide, photocurable repair agent, initiator, and solvent is (1 - 5):100:(0.1 - 5):100;

[0019] The particle size of the graphene oxide is 10 - 20 μm;

[0020] The photocurable repair agent is epoxy acrylate, polyurethane acrylate resin;

[0021] The initiator is benzophenone;

[0022] The solvent is ethyl acetate.

[0023] By adopting the above technical solution, the present invention uses graphene oxide, a photocuring repair agent, and an initiator as the core materials. Among them, the photocuring repair agent and the initiator will cure and repair the gap under natural light after flowing out. The graphene oxide first acts as a nanoscale filler for filling to firmly repair the gap, and the graphene oxide will generate heat under light conditions to further promote the curing speed and prevent the loss of the repair agent.

[0024] Further preferably, in the step S2, the volume ratio of the mixed liquid to the aqueous solution of the water-soluble resin is 1:1;

[0025] The aqueous solution of the water-soluble resin is a polyvinyl alcohol solution with a concentration of 3-10 wt%.

[0026] Further preferably, in the step S3, the mass ratio of the emulsion to the melamine-formaldehyde resin monomer is 10:(0.5-1);

[0027] In the melamine-formaldehyde resin monomer, the molar ratio of melamine to formaldehyde is 3:1.

[0028] Further preferably, in the step S4, the mass ratio of the microcapsule, zinc oxide, polyvinyl alcohol, and water is 1:(1-3):(0.05-0.1):(1-3). By adopting the above technical solution, the present invention prevents the premature occurrence of photocuring by loading a light-blocking zinc oxide layer on the surface of the microcapsule.

[0029] Preferably, the surfactant is one or more of sodium dodecyl sulfonate, sodium dodecyl sulfate, and the Tween series;

[0030] The lubricant is one or more of polyoxyethylene ether, higher fatty alcohol, and higher fatty ester;

[0031] The binder is one or more of carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose, and polyacrylamide;

[0032] The antistatic agent is one or more of polyether ester amide, polyether ester acetylamide, and propylene oxide copolymer.

[0033] In a second aspect, the present invention provides a method for preparing the above self-healing carbon fiber intelligent sizing agent, comprising the following steps:

[0034] Weigh the raw materials according to the said weight parts;

[0035] Mix the raw materials evenly to obtain the self-healing carbon fiber intelligent sizing agent.

[0036] It has at least the following beneficial technical effects:

[0037] The present invention coats a repair agent and adds a photothermal material to obtain photothermal self-healing particles; and a self-healing sizing agent is obtained by mixing a water-soluble sizing agent base liquid, a surfactant, a silane coupling agent, a lubricant, an adhesive, and an antistatic agent. After the carbon fiber is damaged, the photothermal self-healing particles are also cracked, and the repair agent therein can flow out and be cured to repair the crack under natural light, achieving the effect of intelligent response, without the need for artificial detection of damage and then repair. Detailed Description of the Invention

[0038] The various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be construed as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0039] It should be understood that the terms used in the present invention are only for describing specific embodiments and are not intended to limit the present invention. In addition, for the numerical ranges in the present invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each intermediate value within any stated value or stated range, as well as each smaller range between any other stated value or intermediate value within the stated range, is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0040] Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention pertains. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In case of conflict with any incorporated document, the content of this specification shall prevail.

[0041] Without departing from the scope or spirit of the present invention, various improvements and changes can be made to the specific embodiments of the present invention specification, which are obvious to those skilled in the art. Other embodiments obtained from the specification of the present invention are obvious to those skilled in the art. The specification and examples of this application are merely exemplary.

[0042] Regarding the terms "comprising", "including", "having", "containing", etc. used herein, they are all open-ended terms, meaning including but not limited to.

[0043] As used in the present invention, "room temperature" and "normal temperature" are both calculated as 25 ± 2°C unless otherwise specified.

[0044] Unless otherwise specified, the raw materials or instruments used in the following examples of the present invention are all obtained commercially.

[0045] Example 1

[0046] This embodiment provides a self-healing carbon fiber intelligent sizing agent, and the preparation steps are as follows:

[0047] (1) Prepare photothermal self-healing particles:

[0048] S1. Heat and mix graphene oxide with a particle size of 15 μm, a photocuring repair agent (epoxy acrylate), benzophenone, and ethyl acetate in a mass ratio of 3:100:3:100 to obtain a homogeneous mixture;

[0049] S2. Mix the mixture with a 6 wt% polyvinyl alcohol solution in a volume ratio of 1:1 and emulsify to form an emulsion;

[0050] S3. Mix the emulsion with melamine-formaldehyde resin monomer (molar ratio of melamine to formaldehyde 3:1) in a mass ratio of 10:0.8, stir and react at 80 °C for 2 h. After the reaction is completed, filter and dry at room temperature under vacuum to obtain microcapsules with a particle size of 35 μm;

[0051] S4. Mix the microcapsules, zinc oxide, polyvinyl alcohol, and water in a mass ratio of 1:2:0.08:2, disperse them evenly by ultrasonic treatment, then filter, wash, and dry to obtain photothermal self-healing particles.

[0052] (2) Weigh 100 parts of a water-soluble sizing agent base liquid (5% aqueous epoxy resin solution), 6 parts of photothermal self-healing particles, 3 parts of a surfactant (sodium dodecyl sulfate), 2 parts of a silane coupling agent, 2 parts of a lubricant (polyoxyethylene ether), 3 parts of a binder (carboxymethyl cellulose), and 2 parts of an antistatic agent (polyether ester amide) by weight.

[0053] Example 2

[0054] Mix the above raw materials evenly to obtain a self-healing carbon fiber intelligent sizing agent.

[0055] (1) Prepare photothermal self-healing particles:

[0056] S1. Heat and mix graphene oxide with a particle size of 10 μm, a photocuring repair agent (polyurethane acrylate), benzophenone, and ethyl acetate in a mass ratio of 1:100:0.1:100 to obtain a homogeneous mixture;

[0057] S2. Mix the mixture with a 3 wt% polyvinyl alcohol solution in a volume ratio of 1:1 and emulsify to form an emulsion;

[0058] S3. Mix the emulsion with melamine-formaldehyde resin monomer (molar ratio of melamine to formaldehyde 3:1) in a mass ratio of 10:0.5, stir and react at 80 °C for 2 h. After the reaction is completed, filter and dry at room temperature under vacuum to obtain microcapsules with a particle size of 30 μm;

[0059] S4. Mix the microcapsules, zinc oxide, polyvinyl alcohol, and water in a mass ratio of 1:1:0.05:1, then ultrasonically disperse them evenly, and then filter, wash, and dry to obtain the photothermal self-healing particles.

[0060] (2) Weigh 100 parts of the water-soluble sizing agent base liquid (1% aqueous solution of water-soluble phenolic epoxy resin), 5 parts of the photothermal self-healing particles, 1 part of the surfactant (sodium dodecyl sulfate), 0.1 part of the silane coupling agent, 0.1 part of the lubricant (higher fatty alcohol), 0.1 part of the binder (hydroxyethyl cellulose), and 0.1 part of the antistatic agent (polyether ester acetamide) by weight.

[0061] Example 3

[0062] Mix the above raw materials evenly to obtain the self-healing carbon fiber intelligent sizing agent.

[0063] (1) Prepare the photothermal self-healing particles:

[0064] S1. Heat and mix 20-μm graphene oxide, photo-curable repair agent (polyurethane acrylate resin), benzophenone, and ethyl acetate in a mass ratio of 5:100:5:100 to obtain a mixed solution;

[0065] S2. Mix the mixed solution with a 10 wt% polyvinyl alcohol solution in a volume ratio of 1:1, and then emulsify to form an emulsion;

[0066] S3. Mix the emulsion with melamine-formaldehyde resin monomer (molar ratio of melamine to formaldehyde is 3:1) in a mass ratio of 10:1, stir and react at 80 °C for 2 h. After the reaction, filter and vacuum dry at room temperature to obtain microcapsules with a particle size of 40 μm;

[0067] S4. Mix the microcapsules, zinc oxide, polyvinyl alcohol, and water in a mass ratio of 1:3:0.1:3, then ultrasonically disperse them evenly, and then filter, wash, and dry to obtain the photothermal self-healing particles.

[0068] (2) Weigh 100 parts of the water-soluble sizing agent base liquid (10% aqueous solution of sulfonated waterborne epoxy resin), 8 parts of the photothermal self-healing particles, 5 parts of the surfactant (Tween-80), 3 parts of the silane coupling agent, 3 parts of the lubricant (polyoxyethylene ether), 5 parts of the binder (polyacrylamide), and 3 parts of the antistatic agent (propylene oxide copolymer) by weight.

[0069] Mix the above raw materials evenly to obtain the self-healing carbon fiber intelligent sizing agent.

[0070] Comparative Example 1

[0071] This comparative example has the same preparation method as Example 1, except that in step (1), it does not contain graphene oxide.

[0072] Comparative Example 2

[0073] This comparative example has the same preparation method as Example 1, except that in step (1), it does not contain zinc oxide.

[0074] Experimental Example

[0075] The sizing agent prepared above was placed in a sizing tank. The unsized carbon fiber was impregnated through the sizing tank to complete wire feeding and sizing, and the impregnation time was 30 s; the sized carbon fiber was dried by blowing, the drying temperature was 100 °C, and the dried sized carbon fiber was obtained after winding. The sized carbon fiber was made into cracks by friction, and then it was observed whether self-repair was completed under natural light, and the time was recorded, as shown in Table 1.

[0076] Table 1

[0077] Case Self-repair completion time min Example 1 232 Example 2 259 Example 3 283 Comparative Example 1 496 Comparative Example 2 -

[0078] Therefore, it can be seen from Table 1 that the sizing agent prepared by the present invention has an obvious self-repairing function, can repair itself without artificial detection of damage, and has a short repair time; the repair time of Comparative Example 1 increased significantly, indicating that graphene oxide can accelerate the repair speed; in Comparative Example 2, self-repair could not be achieved because photocuring occurred too early.

[0079] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A self-repairing carbon fiber intelligent sizing agent, characterized in that: The composition comprises the following components in parts by weight: 100 parts of water-soluble sizing agent base liquid, 5-8 parts of photothermal self-repairing particles, 1-5 parts of surfactant, 0.1-3 parts of silane coupling agent, 0.1-3 parts of lubricant, 0.1-5 parts of adhesive, and 0.1-3 parts of antistatic agent.

2. The self-repairing carbon fiber intelligent sizing agent according to claim 1, characterized in that: The water-soluble sizing agent base liquid is composed of 1-10% water-based resin, and the remainder is deionized water.

3. The self-repairing carbon fiber intelligent sizing agent according to claim 1, characterized in that: The water-based resin includes water-based epoxy resin, water-soluble phenolic epoxy resin, and sulfonated water-based epoxy resin.

4. The self-repairing carbon fiber intelligent sizing agent according to claim 1, characterized in that: The preparation method of the photothermal self-repairing particles is as follows: S1. heating and mixing graphene oxide, a light-curing repair agent, an initiator, and a solvent to obtain a mixed solution; S2. The mixed solution is mixed with an aqueous solution of a water-soluble resin and then emulsified to form an emulsion; S3. The emulsion is mixed with melamine - formaldehyde resin monomer and stirred to react, and after the reaction is completed, filtered and dried at room temperature in vacuum to obtain microcapsules; S4. The microcapsules, zinc oxide, polyvinyl alcohol and water are mixed and evenly dispersed by ultrasonication, and then filtered, washed and dried to obtain photothermal self-healing particles.

5. The self-repairing carbon fiber intelligent sizing agent according to claim 4, characterized in that: The mass ratio of graphene oxide, photocuring repair agent, initiator and solvent in S1 is (1-5):100:(0.1-5):100; The particle size of the graphene oxide is 10-20 μm; The light-curing repair agent is epoxy acrylate or polyurethane acrylic resin; The initiator is benzophenone; The solvent is ethyl acetate.

6. The self-repairing carbon fiber intelligent sizing agent according to claim 4, characterized in that: The volume ratio of the mixed liquid in S2 to the water-soluble resin aqueous solution is 1:1; The water-soluble resin aqueous solution is a 3-10 wt % polyvinyl alcohol solution.

7. The self-repairing carbon fiber intelligent sizing agent according to claim 4, characterized in that: The mass ratio of the S3 emulsion to the melamine-formaldehyde resin monomer is 10:(0.5-1); The molar ratio of melamine to formaldehyde in the melamine-formaldehyde resin monomer is 3:

1.

8. The self-repairing carbon fiber intelligent sizing agent according to claim 4, characterized in that: The mass ratio of microcapsules, zinc oxide, polyvinyl alcohol and water in S4 is 1:(1-3):(0.05-0.1):(1-3).

9. The self-repairing carbon fiber intelligent sizing agent according to claim 1, characterized in that: The surfactant is one or more of sodium dodecyl sulfonate, sodium dodecyl sulfate, and Tween series; The lubricant is one or more of polyoxyethylene ether, higher fatty alcohol, and higher fatty ester; The binder is one or more of carboxymethyl cellulose, ethyl cellulose, hydroxyethyl cellulose and polyacrylamide; The antistatic agent is one or more of polyether ester amide, polyether ester acetamide and propylene oxide copolymer.

10. The method for preparing the self-repairing carbon fiber intelligent sizing agent according to any one of claims 1 to 9, characterized in that: The following steps are involved: Weigh the raw materials according to the weight parts; The raw materials are mixed evenly to obtain a self-repairing carbon fiber intelligent sizing agent.