Carbon fiber surface rapid desizing and etching method

Abstract

The invention discloses a carbon fiber surface rapid desizing and etching method. The method comprises the following steps: preparing a composite solvent; the method comprises the following steps: immersing carbon fibers to be treated into a composite solvent, and treating at 40-80 DEG C for 2-20 minutes; directly introducing oxidizing mixed gas into the composite solvent to form a gas-liquid micro-interface reaction field; and heating to 180-400 DEG C at a certain rate, synchronously regulating and controlling the flow of the oxidizing mixed gas, and completing etching on the surface of the carbon fiber. According to the method, the slurry on the surface of the carbon fiber is efficiently removed through the compound solvent, the surfactant and the initiator, the oxidizing mixed gas is introduced into the compound solvent, a gas-liquid micro-interface reaction field is formed, and etching on the surface of the carbon fiber is completed, so that the roughness is improved, the treatment efficiency is greatly improved, the production cost is reduced, damage to the carbon fiber is small, and the method is suitable for industrial production. The original performance of the carbon fiber can be kept, quality guarantee is provided for subsequent composite material preparation, and the method has wide applicability.

Description

Technical Field

[0001] The invention belongs to the technical field of carbon fiber surface treatment, and particularly relates to a method for rapid desizing and etching the surface of a carbon fiber. Background Art

[0002] During the production and application of carbon fiber, a layer of slurry is usually applied to its surface to protect it and improve its processing performance. However, in certain specific applications, this slurry layer needs to be quickly and thoroughly removed for subsequent surface treatment or composite with other materials. Traditional slurry removal methods often have problems such as long processing time, low efficiency, and easy damage to the carbon fiber. Therefore, it is particularly important to develop a method that can quickly and effectively remove the slurry from the carbon fiber surface with minimal damage to the carbon fiber. Summary of the Invention

[0003] In order to solve the problems in the prior art, the purpose of the present invention is to provide a method for rapid desizing and etching of carbon fiber surface.

[0004] In order to achieve the above-mentioned purpose and the above-mentioned technical effect, the technical solution adopted by the present invention is:

[0005] A method for rapid desizing and etching of carbon fiber surface, comprising the following steps:

[0006] Step 1: prepare a composite solvent and store it in a container;

[0007] Step 2: Immerse the carbon fiber to be treated in a composite solvent and treat it at 40-80°C for 2-20 minutes to complete rapid desizing of the carbon fiber surface;

[0008] Step 3: introducing an oxidizing mixed gas into the composite solvent to form a gas-liquid microinterface reaction field;

[0009] Step 4: Raise the temperature to 180-400°C at a certain rate, and simultaneously adjust the flow rate of the oxidizing mixed gas to complete etching on the carbon fiber surface.

[0010] Furthermore, in step 1, the composite solvent includes a solvent, a surfactant and an initiator, and the weight percentages of the solvent, the surfactant and the initiator are 95-99.8:0.1-3:0.1-2.

[0011] Furthermore, the solvent is prepared by mixing ethyl acetate and acetone in a volume ratio of 1-3:3-8.

[0012] Furthermore, the surfactant contains an amino group or a carboxyl group.

[0013] Furthermore, the initiator is persulfate or organic peroxide.

[0014] Furthermore, the initiator is potassium persulfate.

[0015] Furthermore, in step three, the oxidizing mixed gas includes ozone, nitrogen dioxide and an inert gas.

[0016] Furthermore, the inert gas is argon or nitrogen.

[0017] Furthermore, in step 4, the temperature is raised to 180-400° C. at a rate of 1-12° C. / min, and the flow rate of the oxidizing mixed gas is simultaneously regulated to 1-10 L / min to complete etching on the carbon fiber surface.

[0018] Furthermore, in step 4, etching is completed on the carbon fiber surface in two stages:

[0019] Stage I: 180-250°C, gas flow rate 1-5 L / min, preferential oxidation of grain boundary defects;

[0020] Stage II: 250-400°C, gas flow rate 5-10 L / min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention discloses a method for rapid desizing and etching of carbon fiber surfaces. The method realizes efficient removal of slurry on the carbon fiber surface by compounding a solvent, a surfactant and an initiator. An oxidizing mixed gas is introduced into the composite solvent to form a gas-liquid microinterface reaction field, thereby achieving etching on the carbon fiber surface. The method greatly improves processing efficiency, reduces production costs, causes little damage to the carbon fiber, can maintain the original properties of the carbon fiber, and provides quality assurance for the subsequent preparation of composite materials. The method is suitable for carbon fibers of different types and specifications and has wide applicability. DETAILED DESCRIPTION

[0023] The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more precise definition of the protection scope of the present invention.

[0024] The following is a brief summary of one or more aspects to provide a basic understanding of these aspects. This summary is not an exhaustive overview of all conceivable aspects and is neither intended to identify key or critical elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that will be provided later.

[0025] A method for rapid desizing and etching of carbon fiber surface, comprising the following steps:

[0026] Step 1: prepare a composite solvent and store it in a container;

[0027] The composite solvent comprises a solvent, a surfactant and an initiator, wherein the weight percentages of the solvent, the surfactant and the initiator are 95-99.8:0.1-3:0.1-2, the solvent is ethyl acetate and acetone compounded in a volume ratio of 1-3:3-8, the surfactant contains an amino group or a carboxyl group, and the initiator is a persulfate or an organic peroxide;

[0028] Step 2: Immerse the carbon fiber to be treated in a composite solvent and treat it at 40-80°C for 2-20 minutes; ethyl acetate is a medium-polar ester with a solubility parameter of 9.1, which matches the solubility parameter of the slurry of 9.3 and can swell the epoxy resin slurry. Acetone is a strong polar ketone. The combination of ethyl acetate and acetone is beneficial to the removal of the slurry. Persulfate can decompose at 40-80°C to generate sulfate radicals, which can oxidize and degrade the long polymer chains in the slurry, thereby reducing its relative molecular weight (to below 5000). By combining the solvent, initiator and surfactant, efficient removal of the slurry is achieved;

[0029] Step 3: An oxidizing mixed gas is introduced into the composite solvent to form a gas-liquid microinterface reaction field. The gas contacts the carbon fiber surface in the form of a microbubble group with a bubble diameter of ≤45 μm. At high temperature, the gas etches the carbon fiber, while increasing the surface roughness. The residual ethyl acetate decomposes at high temperature to form free radicals, increasing activity and enhancing binding force, thereby further improving the etching effect.

[0030] The oxidizing mixed gas includes ozone, nitrogen dioxide, and an inert gas, and the inert gas is argon or nitrogen. Step 4: Raise the temperature to 180-400°C at a rate of 1-12°C / min, and simultaneously adjust the flow rate of the oxidizing mixed gas to 1-10L / min to complete etching on the carbon fiber surface to improve the surface roughness.

[0031] Stage I: 180-250℃, gas flow rate 1-5L / min, time 5-15min, preferential oxidation at the carbon fiber grain boundary to form a pyramidal base pit, which is based on the carbon fiber grain boundary defects (dangling bonds, dislocations) and has the highest reaction activity;

[0032] Stage II: 250-400°C, gas flow rate 5-10 L / min, time 10-20 min, selective etching occurs, inducing axial growth of the cone;

[0033] During the etching stage of this step, the carboxyl / amino groups in the surfactant can be anchored at the carbon fiber lattice defect sites such as dislocations, edge carbon, etc., and can act as a morphology directing agent.

[0034] Example 1

[0035] A method for rapid desizing and etching of carbon fiber surface, comprising the following steps:

[0036] Step 1: prepare a composite solvent and store it in a container;

[0037] The composite solvent includes a solvent, a surfactant and an initiator, the weight percentage of the solvent, the surfactant and the initiator is 95:3:2, the solvent is ethyl acetate and acetone in a volume ratio of 1:3, the surfactant contains an amino group, and an amino acid surfactant can be used, and the initiator is potassium persulfate;

[0038] Step 2: Immerse the carbon fiber to be treated in a composite solvent and treat it at 60°C for 10 minutes. Ethyl acetate is a medium-polar ester with a solubility parameter of 9.1, which matches the solubility parameter of the slurry of 9.3 and can swell the epoxy resin slurry. Acetone is a strong polar ketone. The combination of ethyl acetate and acetone is beneficial to the removal of the slurry. Potassium persulfate can decompose at 60°C to generate sulfate radicals, which can oxidize and degrade the long polymer chains in the slurry, thereby reducing its relative molecular weight (to below 5000). By combining the solvent, initiator and surfactant, efficient removal of the slurry is achieved.

[0039] Step 3: introducing an oxidizing mixed gas into the composite solvent to form a gas-liquid microinterface reaction field. The gas penetrates the solvent in the form of microbubble groups and contacts the carbon fiber surface. The bubble diameter is 40 μm.

[0040] The oxidizing mixed gas includes ozone, nitrogen dioxide, and inert gas, and the ozone concentration is 100g / cm 3 , the inert gas is argon;

[0041] Step 4: Raise the temperature to 350°C at a rate of 5°C / min, and simultaneously adjust the flow rate of the oxidizing mixed gas to 1-10L / min to complete etching on the carbon fiber surface and improve the surface roughness:

[0042] Stage I: 180-250°C, gas flow rate 3L / min, time 14min, preferential oxidation at the carbon fiber grain boundaries to facilitate the formation of pits;

[0043] Phase II: 250-350°C, gas flow rate of 6 L / min, time of 20 min, selective etching occurs, inducing axial growth of the cones, the final cone height is 450 nm, and the distance between cones is 100 nm.

[0044] Example 2

[0045] A method for rapid desizing and etching of carbon fiber surface, comprising the following steps:

[0046] Step 1: prepare a composite solvent and store it in a container;

[0047] The composite solvent includes a solvent, a surfactant and an initiator, the weight percentage of the solvent, the surfactant and the initiator is 99.8:0.1:0.1, the solvent is ethyl acetate and acetone in a volume ratio of 1:3, the surfactant is an amino acid surfactant, and the initiator is potassium persulfate;

[0048] Step 2: Immerse the carbon fiber to be treated in a composite solvent and treat it at 60°C for 20 minutes. Ethyl acetate is a medium-polar ester with a solubility parameter of 9.1, which matches the solubility parameter of the slurry of 9.3 and can swell the epoxy resin slurry. Acetone is a strong polar ketone. The combination of ethyl acetate and acetone is beneficial to the removal of the slurry. Potassium persulfate can decompose at 60°C to generate sulfate radicals, which can oxidize and degrade the long polymer chains in the slurry, thereby reducing its relative molecular weight (to below 5000). By combining the solvent, initiator and surfactant, efficient removal of the slurry is achieved.

[0049] Step 3: introducing an oxidizing mixed gas into the composite solvent to form a gas-liquid microinterface reaction field. The gas penetrates the solvent in the form of microbubble groups and contacts the carbon fiber surface. The bubble diameter is 45 μm.

[0050] The oxidizing mixed gas includes ozone, nitrogen dioxide, and inert gas, with an ozone concentration of 90g / cm 3 , the inert gas is nitrogen;

[0051] Step 4: Raise the temperature to 400°C at a rate of 10°C / min, and simultaneously adjust the flow rate of the oxidizing mixed gas to 1-10L / min to complete etching on the carbon fiber surface and improve the surface roughness:

[0052] Stage I: 180-250°C, gas flow rate 2L / min, time 7min, preferential oxidation at the carbon fiber grain boundaries;

[0053] Stage II: 250-400°C, gas flow rate of 10 L / min, time of 15 min, selective etching occurs to induce axial growth of the cone.

[0054] The rest is the same as Example 1.

[0055] Example 3

[0056] A method for rapid desizing and etching of carbon fiber surface, comprising the following steps:

[0057] Step 1: prepare a composite solvent and store it in a container;

[0058] The composite solvent includes a solvent, a surfactant, and an initiator, wherein the weight percentage of the solvent, the surfactant, and the initiator is 96:2:2, the solvent is ethyl acetate and acetone in a volume ratio of 3:8, the surfactant contains an amino group, and the initiator is potassium persulfate;

[0059] Step 2: Immerse the carbon fiber to be treated in a composite solvent and treat it at 80°C for 15 minutes. Ethyl acetate is a medium-polar ester with a solubility parameter of 9.1, which matches the solubility parameter of the slurry of 9.3. It can swell the epoxy resin slurry. Acetone is a strong polar ketone. The combination of ethyl acetate and acetone is beneficial to the removal of the slurry. Potassium persulfate can decompose at 80°C to generate sulfate radicals, which can oxidize and degrade the long polymer chains in the slurry, thereby reducing its relative molecular weight (to below 5000). By combining solvents, initiators and surfactants, efficient removal of the slurry is achieved.

[0060] Step 3: introducing an oxidizing mixed gas into the composite solvent to form a gas-liquid microinterface reaction field. The gas penetrates the solvent in the form of microbubble groups and contacts the carbon fiber surface. The bubble diameter is 45 μm.

[0061] The oxidizing mixed gas includes ozone, nitrogen dioxide, and inert gas, and the ozone concentration is 120g / cm 3 , the inert gas is nitrogen;

[0062] Step 4: Raise the temperature to 400°C at a rate of 12°C / min, and simultaneously adjust the flow rate of the oxidizing mixed gas to 1-10L / min to complete etching on the carbon fiber surface and improve the surface roughness:

[0063] Stage I: 180-250°C, gas flow rate 3 L / min, time 5.83 min, preferential oxidation at the carbon fiber grain boundaries, facilitating the formation of pits;

[0064] Stage II: 250-400°C, gas flow rate of 8 L / min, time of 12.5 min, selective etching occurs, inducing axial growth of the cone.

[0065] The rest is the same as in Example 1.

[0066] Parts or structures not specifically described in the present invention may be adopted from existing technologies or existing products and will not be described in detail here. The above description is only an embodiment of the present invention and does not limit the scope of the patent of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification, or directly or indirectly applied to other related technical fields, are also included in the scope of patent protection of the present invention.

Claims

1. A method for rapid desizing and etching of carbon fiber surface, characterized in that: The following steps are involved: Step 1: prepare a composite solvent and store it in a container; Step 2: Immerse the carbon fiber to be treated in a composite solvent and treat it at 40-80°C for 2-20 minutes to complete rapid desizing of the carbon fiber surface; Step 3: introducing an oxidizing mixed gas into the composite solvent to form a gas-liquid microinterface reaction field; Step 4: Raise the temperature to 180-400°C at a certain rate, and simultaneously adjust the flow rate of the oxidizing mixed gas to complete etching on the carbon fiber surface.

2. A method for rapid desizing and etching of carbon fiber surface according to claim 1, characterized in that: In step 1, the composite solvent includes a solvent, a surfactant and an initiator, and the weight percentages of the solvent, the surfactant and the initiator are 95-99.8:0.1-3:0.1-2.

3. The method for rapid desizing and etching of carbon fiber surface according to claim 2, characterized in that: The solvent is prepared by mixing ethyl acetate and acetone in a volume ratio of 1-3:3-8.

4. The method for rapid desizing and etching of carbon fiber surface according to claim 2, characterized in that: The surfactant contains an amino group or a carboxyl group.

5. The method for rapid desizing and etching of carbon fiber surface according to claim 2, characterized in that: The initiator is persulfate or organic peroxide.

6. A method for rapid desizing and etching of carbon fiber surface according to claim 5, characterized in that: The initiator is potassium persulfate.

7. The method for rapid desizing and etching of carbon fiber surface according to claim 1, characterized in that: In step three, the oxidizing mixed gas includes ozone, nitrogen dioxide and an inert gas.

8. A method for rapid desizing and etching of carbon fiber surface according to claim 7, characterized in that: The inert gas is argon or nitrogen.

9. The method for rapid desizing and etching of carbon fiber surface according to claim 1, characterized in that: In step 4, the temperature is raised to 180-400°C at a rate of 1-12°C / min, and the flow rate of the oxidizing mixed gas is simultaneously adjusted to 1-10 L / min to complete etching on the carbon fiber surface.

10. The method for rapid desizing and etching of carbon fiber surface according to claim 1, characterized in that: In step 4, etching is completed on the carbon fiber surface in two stages: Stage I: 180-250°C, gas flow rate 1-5 L / min, preferential oxidation of grain boundary defects; Stage II: 250-400°C, gas flow rate 5-10 L / min.