Carbon fiber pretreatment method, carbon fiber pretreatment product and application of carbon fiber pretreatment product and fully-wound gas cylinder

Abstract

The invention belongs to the technical field of materials, and particularly relates to a carbon fiber pretreatment method, a carbon fiber pretreatment product and application of a fully-wound gas cylinder. According to the technical scheme, the carbon fibers are subjected to pretreatment and plasma treatment, the surface activity of the carbon fibers is remarkably enhanced, and the interface bonding force between the carbon fibers and a resin matrix is improved by 30%-50%. The durability of the gas cylinder sample in a fatigue test is improved by more than 20%, and the phenomena of interface stripping and layering are avoided. And according to the requirements of the actual application environment, the technical scheme can flexibly adjust parameters such as treatment gas, time and power, and the optimal performance is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of coating materials, and specifically relates to a carbon fiber pretreatment method and a product thereof, and application of a fully wrapped gas cylinder. Background Art

[0002] As the global demand for clean energy continues to grow, hydrogen energy, as an efficient and environmentally friendly form of energy, has received widespread attention. The storage and transportation of hydrogen are key links in the application of hydrogen energy. As an important container for storing hydrogen, the performance and quality of hydrogen cylinders are crucial. Carbon fiber winding technology has been widely used in the manufacture of hydrogen cylinders due to its unique advantages.

[0003] The carbon fiber composite winding process is a process method in which continuous carbon fiber bundles or tapes are wound around a core mold according to a specific pattern, and then impregnated and cured with resin to form a composite product with a specific shape and performance. In the manufacture of hydrogen cylinders, a combination of circumferential winding and spiral winding is usually used. Circumferential winding is mainly used to withstand circumferential stress and improve the compression resistance of the cylinder; spiral winding is used to withstand axial stress and enhance the overall strength and stability of the cylinder. By reasonably designing the winding angle, number of layers and fiber distribution, the cylinder can have uniform strength and stiffness in different directions, thereby meeting the high requirements for hydrogen storage and transportation.

[0004] The carbon fiber composite winding process plays an important role in the manufacture of hydrogen cylinders, and its continuous development and innovation provide strong support for the application of hydrogen energy. The performance of carbon fiber wound hydrogen storage cylinders depends largely on the interfacial bonding strength between the carbon fiber and the resin matrix. Due to the chemical inertness of the carbon fiber surface, the interaction between the fiber and the resin is weak during the winding and curing process, which leads to problems such as delamination and peeling at the interface under high pressure. Therefore, improving the pretreatment technology of the carbon fiber surface to enhance the interfacial bonding strength has become the key to improving the overall mechanical properties of the cylinder. Summary of the invention

[0005] The present invention aims to provide a carbon fiber surface treatment process to enhance the interfacial bonding strength between the fiber and the resin, improve the compression resistance and fatigue resistance of the gas cylinder, and ensure the production efficiency and process stability.

[0006] The specific technical solutions are as follows:

[0007] A carbon fiber pretreatment method comprises the following steps:

[0008] 1) Preliminary cleaning of carbon fiber: Use cleaning solution to clean grease, dust and impurities on the surface of carbon fiber for 10-15 minutes, and dry the cleaned carbon fiber at 80℃-100℃ for 30-60 minutes;

[0009] 2) Plasma treatment: The cleaned carbon fiber is placed in a plasma reactor for plasma treatment at a temperature of -20°C to 0°C;

[0010] 3) Drying and moisture-proofing: The treated carbon fiber is immediately dried at 60℃-80℃ for 30-45 minutes, and the treated carbon fiber is stored under vacuum conditions. The treated carbon fiber is immediately dried and moisture-proofed to prevent surface oxidation or contamination. The treated fiber is stored in a vacuum packaging bag to prevent contact with moisture or other pollutants in the air.

[0011] Preferably, the cleaning liquid in step 1) is one or more of ethanol or acetone, and the mass concentration of the cleaning liquid is 90%-99%.

[0012] Preferably, the plasma treatment in step 2) is one or more of oxygen plasma treatment, nitrogen plasma treatment or argon plasma treatment.

[0013] Preferably, oxygen plasma treatment: gas flow rate: 50-100sccm, processing power: 100-150 watts, processing time: 3-10 minutes; nitrogen plasma treatment: gas flow rate: 60-120sccm, processing power: 120-180 watts, processing time: 5-15 minutes; argon plasma treatment: gas flow rate: 40-80sccm, processing power: 50-100 watts, processing time: 2-8 minutes.

[0014] Oxygen plasma treatment can improve the polarity of the fiber surface and enhance its reactivity with epoxy resin. Nitrogen plasma treatment can introduce active groups such as amino and amine groups to improve the polarity and wettability of the fiber surface. Argon plasma treatment can be used to remove surface pollutants and improve the fiber surface morphology.

[0015] After plasma treatment, the changes in the active groups and roughness of the fiber surface were detected by Fourier transform infrared spectroscopy and scanning electron microscopy to ensure that the surface treatment effect met the design requirements.

[0016] The carbon fiber is obtained according to the pretreatment method.

[0017] The application of the pre-treated carbon fiber fully wrapped gas cylinder includes the following steps:

[0018] 1) Select modified epoxy resin and add 1%-3%wt surfactant;

[0019] 2) Fiber winding: the winding angle is determined according to the cylinder structure, the winding angle is ±14° to ±90°, the winding speed is controlled at 15-35 m / min, the winding tension is controlled in the range of 30-50N, and the number of winding layers is 7-8;

[0020] 3) Curing: A step-by-step heating curing process is used. Primary curing: First, heat the wrapped carbon fiber to 120°C and keep it for 2 hours to ensure that the resin penetrates and cures. Secondary curing: Continue to increase the temperature to 160°C and keep it for 2 hours. Final curing: Continue to increase the temperature to 200°C and keep it for 4 hours to ensure that the gas cylinder reaches the final strength.

[0021] Preferably, according to the application of the pretreated carbon fiber fully wrapped gas cylinder, the modified epoxy resin in step 1) has a viscosity of 300-800 mPa·s (at 25°C), a suitable curing temperature of 120°C-200°C, and a suitable curing time of 8-9 hours. The pretreated carbon fiber can be fully combined with the matrix resin, and the resin system needs to have high wettability and reactivity.

[0022] Preferably, in the winding process step 1), the modified epoxy resin is one or more of polyurethane modified epoxy resin, acrylic modified epoxy resin, epoxy acrylate modified epoxy resin or phenolic modified epoxy resin, and the surfactant is sodium dodecyl sulfate or sodium dodecylbenzene sulfonate.

[0023] The beneficial effect of the present invention is that after the carbon fiber is pretreated by the technical solution of the present invention, the surface activity of the carbon fiber is significantly enhanced by plasma treatment technology, and the interfacial bonding strength between the carbon fiber and the resin matrix is ​​increased by 30%-50%. The durability of the gas cylinder sample in the fatigue test is improved by more than 20%, avoiding interface peeling and delamination. And according to the needs of the actual application environment, this technical solution can flexibly adjust the processing gas, time, power and other parameters to achieve optimal performance. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in combination with comparative examples and examples. It should be understood that the specific examples described herein are only used to explain the present invention and are not intended to limit the present invention.

[0025] Example 1

[0026] Carbon fiber pretreatment and wrapping gas cylinder process:

[0027] 1) Preliminary cleaning of carbon fiber: Use 90% ethanol cleaning solution to clean the grease, dust and impurities on the surface of T800 carbon fiber for 10 minutes, and dry the cleaned carbon fiber at 80°C for 40 minutes;

[0028] 2) Plasma treatment: The cleaned carbon fiber is placed in a low-temperature oxygen plasma reactor for plasma treatment, with a gas flow rate of 80 sccm, a processing power of 120 watts, and a processing time of 5 minutes; the plasma treatment temperature condition is -10°C;

[0029] 3) Drying and moisture-proofing: The treated carbon fiber is immediately dried at 70°C for 40 minutes and stored under vacuum conditions.

[0030] 4) The pre-treated carbon fiber is used for full wrapping of gas cylinders, including the following steps:

[0031] 4.1 Take acrylic acid modified epoxy resin, add 2%wt sodium dodecyl sulfate, and control the resin viscosity at 500mPa·s;

[0032] 4.2 Fiber winding: the winding angle is determined according to the cylinder structure, the winding angle is ±35°, the winding speed is controlled at 20 m / min, the winding tension is controlled within 35N range, and the number of winding layers is 7;

[0033] 4.3 Curing: A step-by-step heating curing process is used. Primary curing: First, heat the wrapped carbon fiber to 120°C and keep it for 2 hours to ensure that the resin penetrates and cures. Secondary curing: Continue to increase the temperature to 160°C and keep it for 2 hours. Final curing: Continue to increase the temperature to 200°C and keep it for 4 hours to ensure that the gas cylinder reaches the final strength.

[0034] Comparative Example 1

[0035] The difference from Example 1 is that the carbon fiber used in this example is not subjected to a pretreatment step and is directly used for winding gas cylinders. The winding process steps are the same as those in Example 1.

[0036] The compression strength and bonding strength tests of the wrapped gas cylinders of Example 1 and Comparative Example 1 show that the compression strength of the gas cylinders of Example 1 is increased by 20% and the interface bonding strength is increased by 50% compared with Comparative Example 1. The durability of the gas cylinder samples in fatigue tests is increased by 20%.

[0037] Example 2

[0038] Carbon fiber pretreatment and wrapping gas cylinder process:

[0039] 1) Preliminary cleaning of carbon fiber: Use 95% ethanol cleaning solution to clean the grease, dust and impurities on the surface of T800 carbon fiber for 10 minutes, and dry the cleaned carbon fiber at 90°C for 30 minutes;

[0040] 2) Plasma treatment: The cleaned carbon fiber is placed in a low-temperature nitrogen plasma reactor for plasma treatment, with a gas flow rate of 80 sccm, a processing power of 140 watts, and a processing time of 10 minutes; the plasma treatment temperature condition is -5°C;

[0041] 3) Drying and moisture-proofing: The treated carbon fiber is immediately dried at 80°C for 30 minutes and stored under vacuum conditions.

[0042] 4) The pre-treated carbon fiber is used for full wrapping of gas cylinders, including the following steps:

[0043] 4.1 Take epoxy acrylate modified epoxy resin and add 2%wt sodium dodecyl sulfate; the resin viscosity is controlled at 500mPa·s;

[0044] 4.2 Fiber winding, fiber winding, the winding angle is determined according to the cylinder structure, the winding angle is ±50°, the winding speed is controlled at 35 m / min, the winding tension is controlled within 50N range, and the number of winding layers is 8;

[0045] 4.3 Curing: A step-by-step heating curing process is used. Primary curing: First, heat the wrapped carbon fiber to 120°C and keep it for 2 hours to ensure that the resin penetrates and cures. Secondary curing: Continue to increase the temperature to 160°C and keep it for 2 hours. Final curing: Continue to increase the temperature to 200°C and keep it for 4 hours to ensure that the gas cylinder reaches the final strength.

[0046] Comparative Example 2

[0047] The difference from Example 2 is that the carbon fiber used in this example is not subjected to a pretreatment step and is directly used for winding gas cylinders. The winding process steps are the same as those in Example 2.

[0048] The compression strength and bonding strength tests of the wrapped gas cylinders of Example 2 and Comparative Example 2 showed that the compression strength of the gas cylinders of Example 2 was increased by 30% and the interface bonding strength was increased by 53% compared with Comparative Example 2. The durability of the gas cylinder samples in the fatigue test was increased by 23%.

[0049] Example 3

[0050] Carbon fiber pretreatment and wrapping gas cylinder process:

[0051] 1) Preliminary cleaning of carbon fiber: Use 95% ethanol cleaning solution to clean the grease, dust and impurities on the surface of T800 carbon fiber for 10 minutes, and dry the cleaned carbon fiber at 90°C for 30 minutes;

[0052] 2) Plasma treatment: The cleaned carbon fiber is placed in a low-temperature argon plasma treatment: gas flow rate: 40-80sccm, treatment power: 100 watts, treatment time: 4 minutes, and the plasma treatment temperature condition is -8°C;

[0053] 3) Drying and moisture-proofing: The treated carbon fiber is immediately dried at 80°C for 30 minutes and stored under vacuum conditions.

[0054] 4) The pre-treated carbon fiber is used for full wrapping of gas cylinders, including the following steps:

[0055] 4.1 Take epoxy acrylate modified epoxy resin and add 2%wt sodium dodecyl sulfate; the resin viscosity is controlled at 500mPa·s;

[0056] 4.2 Fiber winding: the winding angle is ±30° according to the cylinder structure, the winding speed is controlled at 20 m / min, the winding tension is controlled within 30N range, and the number of winding layers is 8;

[0057] 4.3 Curing: A step-by-step heating curing process is used. Primary curing: First, heat the wrapped carbon fiber to 120°C and keep it for 2 hours to ensure that the resin penetrates and cures. Secondary curing: Continue to increase the temperature to 160°C and keep it for 2 hours. Final curing: Continue to increase the temperature to 200°C and keep it for 4 hours to ensure that the gas cylinder reaches the final strength.

[0058] Comparative Example 3

[0059] The difference from Example 3 is that the carbon fiber used in this example is not subjected to a pretreatment step and is directly used for winding gas cylinders. The winding process steps are the same as those in Example 3.

[0060] The compression strength and bonding strength tests of the wrapped gas cylinders of Example 3 and Comparative Example 3 show that the compression strength of the gas cylinders of Example 3 is increased by 28% and the interface bonding strength is increased by 47% compared with Comparative Example 3. The durability of the gas cylinder samples in fatigue tests is increased by 21%.

[0061] The above examples verify that after the carbon fiber is pretreated by the technical solution of the present invention, the surface activity of the carbon fiber is significantly enhanced by plasma treatment technology, and the interfacial bonding strength between the carbon fiber and the resin matrix is ​​increased by 30%-50%. The durability of the gas cylinder sample in the fatigue test is increased by more than 20%, avoiding interface peeling and delamination.

Claims

1. A carbon fiber pretreatment method, characterized in that: The steps include: 1) Preliminary cleaning of carbon fiber: Use cleaning solution to clean grease, dust and impurities on the surface of carbon fiber for 10-15 minutes, and dry the cleaned carbon fiber at 80℃-100℃ for 30-60 minutes; 2) Plasma treatment: The cleaned carbon fiber is placed in a plasma reactor for plasma treatment at a temperature of -20°C to 0°C; 3) Drying and moisture-proofing: The treated carbon fiber is immediately dried at a temperature of 60°C-80°C for 30-45 minutes, and the treated carbon fiber is stored under vacuum conditions.

2. A carbon fiber pretreatment method according to claim 1, characterized in that: Step 1) The cleaning liquid is one or more of ethanol or acetone, and the mass concentration of the cleaning liquid is 90%-99%.

3. A carbon fiber pretreatment method according to claim 1, characterized in that: Step 2) The plasma treatment is one or more of oxygen plasma treatment, nitrogen plasma treatment or argon plasma treatment.

4. A carbon fiber pretreatment method according to claim 3, characterized in that: Oxygen plasma treatment: gas flow rate: 50-100sccm, processing power: 100-150 watts, processing time: 3-10 minutes; nitrogen plasma treatment: gas flow rate: 60-120sccm, processing power: 120-180 watts, processing time: 5-15 minutes; argon plasma treatment: gas flow rate: 40-80sccm, processing power: 50-100 watts, processing time: 2-8 minutes.

5. Carbon fiber obtained by the pretreatment method according to any one of claims 1 to 4.

6. Application of pre-treated carbon fiber fully wrapped gas cylinders, characterized in that: The steps include: 1) Select modified epoxy resin and add 1%-3%wt surfactant; 2) Fiber winding: the winding angle is determined according to the cylinder structure, the winding angle is ±14° to ±90°, the winding speed is controlled at 15-35 m / min, the winding tension is controlled in the range of 30-50N, and the number of winding layers is 7-8; 3) Curing: A step-by-step heating curing process is used. Primary curing: First, heat the wrapped carbon fiber to 120°C and keep it for 2 hours to ensure that the resin penetrates and cures. Secondary curing: Continue to increase the temperature to 160°C and keep it for 2 hours. Final curing: Continue to increase the temperature to 200°C and keep it for 4 hours to ensure that the gas cylinder reaches the final strength.

7. The use of the pretreated carbon fiber fully wrapped gas cylinder according to claim 6, characterized in that: Step 1) The modified epoxy resin has a viscosity of 300-800 mPa·s (at 25° C.), a suitable curing temperature of 120° C.-200° C., and a suitable curing time of 8-9 hours.

8. The use of the pretreated carbon fiber fully wrapped gas cylinder according to claim 7, characterized in that: Step 1) The modified epoxy resin is one or more of polyurethane modified epoxy resin, acrylic acid modified epoxy resin, epoxy acrylate modified epoxy resin or phenolic modified epoxy resin, and the surfactant is sodium dodecyl sulfate or sodium dodecylbenzene sulfonate.