Modified ultra-high molecular weight polyethylene fiber and preparation method thereof

Abstract

The invention belongs to the technical field of modification of ultra-high molecular weight polyethylene fibers, and particularly relates to a modified ultra-high molecular weight polyethylene fiber and a preparation method thereof.The preparation method comprises the following steps that the ultra-high molecular weight polyethylene fiber is sequentially washed with absolute ethyl alcohol and water and then dried; then soaking the dried ultra-high molecular weight polyethylene fibers in a tannic acid mixed solution to obtain tannic acid modified ultra-high molecular weight polyethylene fibers; the tannic acid mixed solution comprises Tris, tannic acid, barium sulfate, sodium chloride and water; then placing the tannic acid modified ultra-high molecular weight polyethylene fiber in a cyanuric chloride solution, reacting in an inert atmosphere, taking out and drying; then putting into a phenylenediammonium solution, and reacting in an inert atmosphere; and finally, cleaning, drying, and repeating the process for at least one time to obtain the modified ultra-high molecular weight polyethylene fiber. According to the invention, the tensile breaking strength and the interfacial shear strength after bonding with epoxy resin are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of modification of ultra-high molecular weight polyethylene fibers, and in particular relates to a modified ultra-high molecular weight polyethylene fiber and a preparation method thereof. Background Art

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fiber resin-based composites are widely used in many fields due to their many excellent properties. Although UHMWPE fibers have excellent properties, such as high strength and stiffness, chemical resistance, light weight, and good mechanical properties at low temperatures, their surface is inert and their adhesion to polar polymers (such as epoxy resins) is poor, which limits their application areas. Generally, ultra-high molecular weight polyethylene fibers need to be modified.

[0003] Common surface modification methods include chemical oxidation treatment, plasma treatment, radiation grafting treatment and corona discharge treatment.

[0004] CN 108395675 A discloses a method for preparing a tannic acid-modified ultra-high molecular weight polyethylene fiber and a composite material thereof, wherein the ultra-high molecular weight polyethylene fiber is used as a raw material and a tannic acid-NaCl-Tris mixed solution is used as a modifier. The ultra-high molecular weight polyethylene fiber is immersed in a tannic acid-NaCl-Tris solution, and the tannic acid and NaCl are chelated to form a modified ultra-high molecular weight polyethylene fiber. + Reaction to form TA-Na + ; Then, through the action of electrostatic force, covalent bond and non-covalent bond, a coating is formed on the surface of the ultra-high molecular weight polyethylene fiber. After the tannic acid coating, the bonding ability between the ultra-high molecular weight polyethylene fiber and the resin matrix is ​​improved, and the mechanical properties of the obtained composite material are enhanced. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a modified ultra-high molecular weight polyethylene fiber and a preparation method thereof, so as to improve the tensile breaking strength and the interface shear strength after combining with epoxy resin.

[0006] The embodiment of the present invention provides a method for preparing a modified ultra-high molecular weight polyethylene fiber, comprising the following steps: The ultra-high molecular weight polyethylene fiber is washed with anhydrous ethanol and water in sequence, and then dried; Then, the dried ultra-high molecular weight polyethylene fiber is immersed in a tannic acid mixed solution to obtain tannic acid-modified ultra-high molecular weight polyethylene fiber; the tannic acid mixed solution comprises Tris, tannic acid, barium sulfate, sodium chloride and water; Then, the tannic acid-modified ultra-high molecular weight polyethylene fiber is placed in a cyanuric chloride solution, reacted under an inert atmosphere, taken out and dried; Then it is placed in a phenyldiammonium solution and reacted under an inert atmosphere; Finally, the fiber is cleaned and dried, and the above process is repeated at least once to obtain modified ultra-high molecular weight polyethylene fiber.

[0007] Preferably, in the tannic acid mixed solution, the mass concentration of Tris is 0.1-0.2%, the mass concentration of tannic acid is 0.2-0.4%, the mass concentration of barium sulfate is 0.4-0.6%, and the mass concentration of sodium chloride is 1.4-1.7%.

[0008] Preferably, in the tannic acid mixed solution, the mass concentration of Tris is 0.1-0.12%, the mass concentration of tannic acid is 0.25-0.35%, the mass concentration of barium sulfate is 0.45-0.55%, and the mass concentration of sodium chloride is 1.5-1.6%.

[0009] Preferably, the dried ultra-high molecular weight polyethylene fiber is immersed in a tannic acid mixed solution, the temperature of the solution is 30-40° C., and during the immersion, a shaking method is used to increase the immersion degree.

[0010] Preferably, when the ultra-high molecular weight polyethylene fiber is cleaned with anhydrous ethanol, ultrasonic vibration is performed, and the drying temperature after cleaning is 80-90°C.

[0011] Preferably, the solvent of the cyanuric chloride solution is tetrahydrofuran, the mass concentration of cyanuric chloride is 0.2-0.4%, and the temperature of the cyanuric chloride solution is -5-5°C.

[0012] Preferably, the inert gas used in the inert atmosphere is nitrogen, and the drying temperature is 70-90°C.

[0013] Preferably, the solvent of the phenylenediamine solution is isopropanol, the phenylenediamine is m-phenylenediamine or p-phenylenediamine, and the temperature of the phenylenediamine solution is 60-70°C.

[0014] Preferably, in the phenyldiammonium solution, the concentration of phenyldiammonium is 5-7 mg / mL.

[0015] The embodiment of the present invention provides a modified ultra-high molecular weight polyethylene fiber, which is obtained by adopting the preparation method.

[0016] The beneficial effect of the present invention is that barium sulfate is added to the tannic acid mixed solution, and the addition of barium ions significantly improves the tensile fracture strength and the interface shear strength after combining with the epoxy resin. Compared with not adding any metal ions or adding copper ions, the performance improvement is more obvious, the tensile fracture strength is increased by 27%, and the interface shear strength after combining with the epoxy resin is increased by 80%. DETAILED DESCRIPTION

[0017] Example 1 A method for preparing modified ultra-high molecular weight polyethylene fiber comprises the following steps: 1. Preparation of tannic acid modified ultra-high molecular weight polyethylene fiber 1) The UHMWPE fiber bundle was slowly passed through an anhydrous ethanol solution through multiple round rollers, ultrasonically vibrated for 15 minutes, and then washed multiple times with multiple rounds of deionized water, and then dried in an oven at a drying temperature of 90°C.

[0018] 2) Add a certain amount of tris(hydroxymethyl)aminomethane (Tris), tannic acid, BaSO4 and sodium chloride to a certain volume of deionized water (the ratio of each raw material is 500ml deionized water: 0.6g tris(hydroxymethyl)aminomethane: 1.5g tannic acid: 2.5g BaSO4: 8g sodium chloride) to prepare a tannic acid mixed solution.

[0019] 3) The pretreated UHMWPE fiber of step 1) is immersed in the prepared tannic acid mixed solution of step 2), placed in a rocking device, and rocked at 40° C. for 10 hours to obtain tannic acid modified ultrahigh molecular weight polyethylene fiber (TA-UPE).

[0020] 2. Polyamine step-by-step grafting modification of UHMWPE fiber 4) Take a certain amount of tetrahydrofuran as solvent, add a certain amount of cyanuric chloride (the ratio of each raw material is 500 ml tetrahydrofuran: 1.2 g cyanuric chloride), adjust the temperature to 0°C, place TA-UPE in the above solution, react under nitrogen for 24 hours, and then place in an 80°C oven to dry.

[0021] 5) Place the above fiber in a certain amount of isopropanol solution, add a certain amount of m-phenylenediamine (the amount of each raw material is 750 ml isopropanol, 6 mg / ml m-phenylenediamine), adjust the temperature to 60°C, and react in nitrogen for 12 hours.

[0022] 6) After the reaction is completed, the fiber is washed with anhydrous ethanol and deionized water for multiple times, and then dried in an oven at 90°C. The above process is repeated twice to obtain modified ultra-high molecular weight polyethylene fiber.

[0023] Comparative Example 1 Compared with Example 1, in Comparative Example 1, BaSO4 is not added, and the rest is the same as Example 1.

[0024] Comparative Example 2 Compared with Example 1, in Comparative Example 2, BaSO4 is replaced by CuSO4, and the rest is the same as Example 1.

[0025] The tensile strength at break and the interfacial shear strength after combining with epoxy resin of Example 1 and Comparative Examples 1-2 were measured, and it was found that the modified ultra-high molecular weight polyethylene fiber of Example 1 had a 27% increase in tensile strength at break and an 80% increase in interfacial shear strength after combining with epoxy resin compared to the unmodified ultra-high molecular weight polyethylene fiber.

[0026] The modified ultra-high molecular weight polyethylene fiber of Comparative Example 1 has a 12% higher tensile strength at break and a 35% higher interfacial shear strength after bonding with epoxy resin than the unmodified ultra-high molecular weight polyethylene fiber.

[0027] The modified ultra-high molecular weight polyethylene fiber of Comparative Example 2 has a 17% higher tensile strength at break and a 46% higher interfacial shear strength after bonding with epoxy resin than the unmodified ultra-high molecular weight polyethylene fiber.

[0028] A person skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of protection of the present application is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0029] One or more embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the present application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of one or more embodiments of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a modified ultra-high molecular weight polyethylene fiber, characterized in that: The following steps are included: The ultra-high molecular weight polyethylene fiber is washed with anhydrous ethanol and water in sequence, and then dried; Then, the dried ultra-high molecular weight polyethylene fiber is immersed in a tannic acid mixed solution to obtain tannic acid-modified ultra-high molecular weight polyethylene fiber; the tannic acid mixed solution comprises Tris, tannic acid, barium sulfate, sodium chloride and water; Then, the tannic acid-modified ultra-high molecular weight polyethylene fiber is placed in a cyanuric chloride solution, reacted under an inert atmosphere, taken out and dried; Then it is placed in a phenyldiammonium solution and reacted under an inert atmosphere; Finally, the fiber is cleaned and dried, and the above process is repeated at least once to obtain modified ultra-high molecular weight polyethylene fiber.

2. The preparation method according to claim 1, characterized in that: In the tannic acid mixed solution, the mass concentration of Tris is 0.1-0.2%, the mass concentration of tannic acid is 0.2-0.4%, the mass concentration of barium sulfate is 0.4-0.6%, and the mass concentration of sodium chloride is 1.4-1.7%.

3. The preparation method according to claim 1, characterized in that: In the tannic acid mixed solution, the mass concentration of Tris is 0.1-0.12%, the mass concentration of tannic acid is 0.25-0.35%, the mass concentration of barium sulfate is 0.45-0.55%, and the mass concentration of sodium chloride is 1.5-1.6%.

4. The preparation method according to claim 1, characterized in that: The dried ultra-high molecular weight polyethylene fiber is immersed in a tannic acid mixed solution, the temperature of the solution is 30-40° C. During the immersion, a shaking method is used to increase the immersion degree.

5. The preparation method according to claim 1, characterized in that: When the ultra-high molecular weight polyethylene fiber is cleaned with anhydrous ethanol, ultrasonic vibration is performed, and the drying temperature after cleaning is 80-90°C.

6. The preparation method according to claim 1, characterized in that: The solvent of the cyanuric chloride solution is tetrahydrofuran, the mass concentration of cyanuric chloride is 0.2-0.4%, and the temperature of the cyanuric chloride solution is -5-5°C.

7. The preparation method according to claim 1, characterized in that: The inert gas used in the inert atmosphere is nitrogen, and the drying temperature is 70-90°C.

8. The preparation method according to claim 1, characterized in that: The solvent of the phenyldiammonium solution is isopropanol, the phenyldiammonium is m-phenylenediamine or p-phenylenediamine, and the temperature of the phenyldiammonium solution is 60-70°C.

9. The preparation method according to claim 8, characterized in that: In the phenyldiammonium solution, the concentration of phenyldiammonium is 5-7 mg / mL.

10. A modified ultra-high molecular weight polyethylene fiber, characterized in that: The method is adopted as claimed in any one of claims 1 to 9.