Ultrahigh molecular weight polyethylene fiber surface modification method
By treating UHMWPE fibers with borosilicate chitosan modified liquid, the problem of poor interfacial bonding strength between fibers and resin matrix was solved, resulting in a significant improvement in interfacial shear strength and environmentally friendly industrial production.
Patent Information
- Application Number
- CN202511910800.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-17
- Publication Date
- 2026-02-10
AI Technical Summary
Existing ultra-high molecular weight polyethylene fibers (UHMWPE) have poor interfacial bonding strength with the resin matrix. Commonly used modification methods suffer from problems such as significant fiber damage, serious environmental pollution, complex processes, or limited improvement effects.
UHMWPE fibers are treated with borate-modified chitosan solution. A strong interface layer is built on the fiber surface through an impregnation-heat treatment process. The borate ester bonds form covalent bonds with the fiber surface and waterborne polyurethane, thereby improving the interfacial adhesion.
It significantly improves the interfacial shear strength between UHMWPE fiber and waterborne polyurethane, increasing it from 0.5MPa to 4.5-6.0MPa. The modified liquid is environmentally friendly with no toxic emissions, and the process is simple and easy to industrialize.
Smart Images
Figure CN121496744A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of high-performance fiber composite materials technology, and specifically relates to a method for surface modification of ultra-high molecular weight polyethylene fibers. Background Technology
[0002] Ultra-high molecular weight polyethylene (UHMWPE) fiber has broad application prospects in protective equipment, aerospace, and marine engineering due to its excellent properties such as high strength, high modulus, low density, and resistance to chemical corrosion. However, the surface of UHMWPE fiber is composed of non-polar methylene groups, resulting in low surface energy and strong chemical inertness. This leads to poor interfacial bonding strength between the fiber and the resin matrix, limiting its application in composite materials.
[0003] Currently, commonly used surface modification methods include: chemical reagent treatment (such as strong oxidants like chromic acid and potassium permanganate): although it can introduce polar groups, it will damage the mechanical properties of fibers and pollute the environment; plasma treatment: high equipment requirements, unstable treatment effect, and difficult to industrialize; irradiation grafting treatment: complex process, which may lead to fiber degradation.
[0004] In recent years, some studies have also used physical coating methods such as EVA / TPU blend solutions to improve the adhesion between fibers and waterborne polyurethane, but the improvement is limited (interfacial shear strength is usually below 4 MPa). Chitosan, as a natural biopolymer, has been used for surface modification due to its good film-forming properties and biocompatibility, but its adhesion to UHMWPE fibers is weak when used alone.
[0005] Therefore, it is of great significance to develop an environmentally friendly, efficient surface modification technology that can significantly improve interface performance. Summary of the Invention
[0006] The technical problem to be solved by the present invention is to provide a surface modification method for ultra-high molecular weight polyethylene fibers, which significantly improves their interfacial adhesion with waterborne polyurethane, is environmentally friendly, has a simple process, and is suitable for industrial applications.
[0007] This invention provides a method for surface modification of ultra-high molecular weight polyethylene (UHMWPE) fibers. The UHMWPE fibers are cleaned, dried, immersed in a modification solution, and then heat-treated to obtain modified UHMWPE fibers. The modified liquid comprises the following components in parts by weight: 1-5 parts chitosan, 0.5-3 parts phenylboronic acid or its derivatives, and 92-98.5 parts acetic acid solution, wherein the mass concentration of the acetic acid solution is 1-3%.
[0008] Preferably, derivatives of phenylboronic acid include 3-aminophenylboronic acid.
[0009] Preferably, the degree of deacetylation of chitosan is ≥85%.
[0010] Preferably, the modified liquid comprises the following components in parts by weight: 2-3 parts chitosan, 1-1.5 parts phenylboronic acid or its derivatives, and 94-96 parts acetic acid solution.
[0011] Preferably, the modified solution is prepared by dissolving chitosan in acetic acid solution and stirring until completely dissolved; then adding phenylboronic acid or its derivatives and reacting at 50-70°C to obtain a borate-esterified chitosan solution; finally adjusting the pH to 5-6 with alkali solution to obtain the modified solution.
[0012] Preferably, the reaction is carried out at 50-70℃ for 2-4 hours.
[0013] Preferably, the ultra-high molecular weight polyethylene fiber is ultrasonically cleaned in acetone and anhydrous ethanol in sequence.
[0014] Preferably, the drying temperature is 60°C and the drying time is 2 hours.
[0015] Preferably, the immersion time in the modified solution is 5-30 minutes.
[0016] Preferably, the heat treatment temperature is 100-130℃ and the time is 10-30min.
[0017] The beneficial effects of this invention are that existing UHMWPE fiber surface modification technologies suffer from problems such as large fiber damage, serious environmental pollution, complex processes, or limited interface improvement effects. This invention provides a method for treating UHMWPE fibers with borosilicate chitosan modification liquid, and constructs a strong interface layer on the surface of UHMWPE fibers through an impregnation-heat treatment process, which significantly improves its interfacial adhesion with waterborne polyurethane.
[0018] The interfacial bonding strength of the present invention is significantly improved. The borate ester bond can simultaneously form covalent bonds with the fiber surface and the hydroxyl groups of the waterborne polyurethane, thereby increasing the interfacial shear strength from about 0.5 MPa of the original fiber to 4.5-6.0 MPa.
[0019] This invention boasts excellent environmental friendliness. The modified liquid uses water as a solvent, and chitosan is a renewable resource, resulting in no toxic emissions.
[0020] The process of this invention is simple and controllable. The impregnation-heat treatment process is easy to implement for continuous production and is suitable for industrial applications. Attached Figure Description
[0021] Figure 1 This is a scanning electron microscope image of the unmodified fiber in Example 1 of the present invention.
[0022] Figure 2 This is a scanning electron microscope image of the surface of the modified ultra-high molecular weight polyethylene fiber in Example 1 of the present invention. Detailed Implementation
[0023] Example 1 A method for surface modification of ultra-high molecular weight polyethylene fibers includes the following steps: 1) Preparation of modified solution: Take 2 parts by weight of chitosan with a degree of deacetylation of 85% and dissolve it in 95 parts by weight of 2% acetic acid solution, stirring until completely dissolved. Add 1.5 parts by weight of 3-aminophenylboronic acid and react at 60℃ for 3 hours. Adjust the pH to 5.5 with dilute sodium hydroxide solution to obtain the borate-esterified chitosan modified solution.
[0024] 2) Fiber surface modification: UHMWPE fibers (whose microscopic images are shown in Figure 1) are modified to remove surface impregnation. Figure 1 (As shown) The fiber was placed in acetone and anhydrous ethanol in sequence and ultrasonically cleaned for 20 minutes each to remove surface impurities. Then it was dried at 60°C for 2 hours to obtain surface-modified fiber.
[0025] 3) The surface-modified fibers are immersed in the modification solution obtained in step 1) for 20 minutes, then removed and heat-treated at 120°C for 20 minutes to obtain the surface of the modified ultra-high molecular weight polyethylene fibers (microscopic image of which is shown below). Figure 2 (As shown).
[0026] Composite material preparation and performance testing: Prepare an aluminum alloy U-shaped groove with a depth of 5mm, a width of 10mm, and a length of 30mm. Seal both ends of the groove with silicone. Control the gap between the silicone fibers (i.e., the length of the embedded fiber, denoted by L (mm)) within 5mm. Separate a single fiber from the modified ultra-high molecular weight polyethylene fiber obtained in Example 1 and pass the single fiber through the silicone. Fix it with silicone. Then slowly pour waterborne polyurethane with a solid content of 40% into the gap between the silicone fibers. Dry it in an oven at 70°C for 2 hours. After drying, cut off the silicone with a knife and accurately measure the length of the embedded fiber.
[0027] The prepared sample was fixed on a high-strength tensile testing machine, and the fiber was fixed on the clamp of the tensile testing machine. The clamp descended at a speed of 10 mm / min. The bonding performance between the fiber and the adhesive was measured, and the maximum shear strength (MPa) of the fiber was calculated according to formula (1): τ max =F max / πdL(1) Among them, F max d is the maximum pull-out shear force of the fiber (N); d is the diameter of the fiber (mm); L is the embedding length of the adhesive (mm).
[0028] Test results show that the interfacial shear strength reaches 5.2 MPa.
[0029] Example 2 The difference between Example 2 and Example 1 lies in the preparation of the modified liquid in step 1), specifically: Take 3 parts by weight of chitosan with a degree of deacetylation of 85% and dissolve it in 95 parts by weight of a 2% acetic acid solution, stirring until completely dissolved. Add 1 part by weight of 3-aminophenylboronic acid and react at 60°C for 3 hours. Adjust the pH to 5.5 with dilute sodium hydroxide solution to obtain the borate-modified chitosan solution.
[0030] The rest is the same as in Example 1.
[0031] The interfacial shear strength of the resulting composite material is 4.8 MPa.
[0032] Example 3 The difference between Example 3 and Example 1 lies in step 3), which is specifically as follows: The surface-modified fiber is immersed in the modification solution obtained in step 1) for 10 minutes, and then taken out and heat-treated at 110°C for 20 minutes to obtain the modified ultra-high molecular weight polyethylene fiber surface.
[0033] The rest is the same as in Example 1.
[0034] The interfacial shear strength of the resulting composite material is 4.9 MPa.
[0035] Example 4 Compared with Example 1, Example 4 differs in that 3-aminophenylboronic acid in step 1) is replaced with phenylboronic acid.
[0036] The rest is the same as in Example 1.
[0037] The interfacial shear strength of the resulting composite material is 4.7 MPa.
[0038] Comparative Example 1 Untreated UHMWPE fibers were used directly. The measured interfacial shear strength was only 0.45 MPa.
[0039] Comparative Example 2 UHMWPE fibers were treated with a chromic acid solution (potassium dichromate:water:concentrated sulfuric acid = 7:12:150, treated at 35°C for 5 minutes). The difference between Comparative Example 2 and Example 1 lies in step 1), which is as follows: Preparation of modified solution: Dissolve 7 parts by weight of potassium dichromate in 12 parts by weight of water, then slowly add 150 parts by weight of concentrated sulfuric acid and stir until completely dissolved. Treat at 35℃ for 5 minutes to obtain the modified solution.
[0040] Everything else is the same as in Example 1.
[0041] The measured interfacial shear strength was 2.3 MPa.
[0042] Comparative Example 3 The fibers were treated with an EVA / TPU blend solution (EVA / TPU=4:1).
[0043] The difference between Comparative Example 3 and Example 1 lies in step 1), which is different. Specifically, step 1) is as follows: Preparation of modified solution: Mix 4 parts by weight of EVA and 1 part by weight of TPU, add to 95 parts by weight of tetrahydrofuran, and stir at 70°C until completely dissolved. The modified solution is obtained.
[0044] Everything else is the same as in Example 1.
[0045] The measured interfacial shear strength was 3.8 MPa.
[0046] Comparative Example 4 The modification solution was changed to take 2 parts by weight of chitosan with a degree of deacetylation of 85%, dissolve it in 95 parts by weight of 2% acetic acid solution, and stir until completely dissolved to obtain chitosan acetic acid solution.
[0047] The difference between Comparative Example 4 and Example 1 lies in step 1), which is different. Specifically, step 1) is as follows: Preparation of modified solution: Take 2 parts by weight of chitosan with a degree of deacetylation of 85%, dissolve it in 95 parts by weight of 2% acetic acid solution, stir until completely dissolved, and obtain borate-esterified chitosan modified solution.
[0048] The rest is the same as in Example 1.
[0049] The measured interfacial shear strength was 1.8 MPa.
[0050] Comparative Example 5 The difference between Comparative Example 5 and Example 1 lies in step 1), which is different. Specifically, step 1) is as follows: Preparation of modified solution: 0.5 parts by weight of chitosan with a degree of deacetylation of 85% were dissolved in 97 parts by weight of a 2% acetic acid solution and stirred until completely dissolved. 0.2 parts by weight of 3-aminophenylboronic acid were added, and the mixture was reacted at 60°C for 3 hours. The pH was adjusted to 5.5 with dilute sodium hydroxide solution to obtain the borate-modified chitosan solution.
[0051] The rest is the same as in Example 1.
[0052] The measured interfacial shear strength was 2.5 MPa.
[0053] Comparative Example 6 The difference between Comparative Example 6 and Example 1 lies in step 1). Specifically, step 1) is different. Preparation of modified solution: Take 6 parts by weight of chitosan with a degree of deacetylation of 85% and dissolve it in 90 parts by weight of 2% acetic acid solution (stirring should be extended until completely dissolved). Add 4 parts by weight of 3-aminophenylboronic acid and react at 60℃ for 3 hours. Adjust the pH to 5.5 with dilute sodium hydroxide solution to obtain the borate-esterified chitosan modified solution.
[0054] The rest is the same as in Example 1.
[0055] The measured interfacial shear strength was 3.6 MPa.
[0056] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of protection of this application is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of this application as described above, which are not provided in detail for the sake of brevity.
[0057] One or more embodiments in this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of this application. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments in this application should be included within the protection scope of this application.
Claims
1. A method for surface modification of ultra-high molecular weight polyethylene fibers, characterized in that, After cleaning and drying, ultra-high molecular weight polyethylene fibers are immersed in a modification solution and then subjected to heat treatment to obtain modified ultra-high molecular weight polyethylene fibers. The modified liquid comprises the following components in parts by weight: 1-5 parts chitosan, 0.5-3 parts phenylboronic acid or its derivatives, and 92-98.5 parts acetic acid solution, wherein the mass concentration of the acetic acid solution is 1-3%.
2. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in claim 1, characterized in that, Derivatives of phenylboronic acid include 3-aminophenylboronic acid.
3. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in claim 1, characterized in that, The degree of deacetylation of chitosan is ≥85%.
4. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in claim 1, characterized in that, The modified liquid comprises the following components in parts by weight: 2-3 parts chitosan, 1-1.5 parts phenylboronic acid or its derivatives, and 94-96 parts acetic acid solution.
5. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in claim 1, characterized in that, The modified solution is prepared by dissolving chitosan in acetic acid solution and stirring until completely dissolved; then adding phenylboronic acid or its derivatives and reacting at 50-70°C to obtain a borate-treated chitosan solution; finally adjusting the pH to 5-6 with alkali solution to obtain the modified solution.
6. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in claim 5, characterized in that, React at 50-70℃ for 2-4 hours.
7. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in any one of claims 1-6, characterized in that, Ultra-high molecular weight polyethylene fibers were sequentially placed in acetone and anhydrous ethanol for ultrasonic cleaning.
8. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in any one of claims 1-6, characterized in that, The drying temperature is 60℃.
9. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in any one of claims 1-6, characterized in that, The immersion time in the modified solution is 5-30 minutes.
10. The method for surface modification of ultra-high molecular weight polyethylene fibers as described in any one of claims 1-6, characterized in that, The heat treatment temperature is 100-130℃ and the time is 10-30 minutes.