Aramid fiber composite material and method of making same
By using ethanol cleaning, NaOH hydrolysis, horseradish peroxidase activation, and high-temperature and high-pressure drying, combined with emulsified sizing agent treatment, the problem of strength loss of aramid fibers under ultraviolet light was solved, and the mechanical properties and UV resistance were improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- ZHONGFANG NEW MATERIAL CO LTD
- Filing Date
- 2023-12-22
- Publication Date
- 2026-07-31
AI Technical Summary
Aramid fibers suffer severe strength loss when exposed to ultraviolet light for extended periods, and current technologies struggle to simultaneously improve their mechanical properties and UV resistance.
The process involves ultrasonic cleaning with ethanol solution, hydrolysis with NaOH solution, activation with horseradish peroxidase-phosphate buffer solution, and high-temperature and high-pressure drying in an inert atmosphere. Combined with emulsifying sizing agent treatment, aramid fibers are formed to form covalent bonds, thereby improving interfacial adhesion and uniformity of component loading.
It significantly improves the mechanical properties and UV resistance of aramid fibers, ensures uniform distribution and tight adhesion of component loads on the fibers, and enhances their stability under ultraviolet light.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of fiber materials technology, specifically relating to an aramid fiber composite material and its preparation method. Background Technology
[0002] Aramid fiber is a general term for aromatic polyamide fibers. It is a new type of high-tech synthetic fiber with excellent properties such as ultra-high strength, high modulus, high temperature resistance, acid and alkali resistance, and light weight. Its strength is 5-6 times that of steel wire, its modulus is 2-3 times that of steel wire or glass fiber, its toughness is twice that of steel wire, and its weight is only about 1 / 5 of steel wire. It does not decompose or melt at a temperature of 560 degrees Celsius. Aramid fiber has good insulation and anti-aging properties and a long lifespan. The discovery of aramid is considered a very important historical process in the materials science field. Worldwide, aramid fiber is developing at an annual growth rate of about 20%, and its applications are shifting from solely military to civilian use. Aramid fiber is used in the automotive and protective equipment industry (68%), shipbuilding (21%), and the remainder in aerospace and military applications. Like glass fiber, aramid fiber products include twisted yarn, untwisted roving, various specifications of fabrics, tapes, felts, and chopped strands.
[0003] Aramid fibers exhibit excellent thermal stability, allowing for long-term use at 180℃ and short-term resistance to 300℃ without significant impact on strength. They do not become brittle at -170℃ and retain their properties. The mechanical properties of aramid fibers are outstanding among organic fibers and comparable to inorganic fibers. Except for strong acids and alkalis, aramid fibers are virtually unaffected by organic solvents and oils. However, aramid fibers are sensitive to ultraviolet light; prolonged exposure to sunlight will significantly reduce their strength. Summary of the Invention
[0004] To address the problems existing in the background art, the present invention provides an aramid fiber composite material and its preparation method, which can simultaneously improve the mechanical properties and UV resistance of aramid fibers.
[0005] To achieve the above objectives, in a first aspect, the present invention provides the following technical solution:
[0006] A method for preparing an aramid fiber composite material includes the following steps:
[0007] S1. Immerse the aramid fiber in an ethanol solution and ultrasonically clean it for 1 hour. Then soak it in an 8% NaOH solution at 60°C for 1 hour. Take out the aramid fiber, wash it with deionized water, dry it, and then put it into a 65% strong acid solution. Soak it at room temperature for 0.5-1 hour, filter it out, and dry it naturally to obtain the acid-washed fiber.
[0008] S2. By weight, add 1 part of the acid-washed fiber to 15-18 parts of horseradish peroxidase-phosphate buffer composite solution and soak at room temperature for 4-6 hours to obtain activated fiber.
[0009] S3. Mix the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water in a mass ratio of 1:(0.4-0.6):(0.1-0.2):(0.05-0.2):15 and disperse evenly to obtain an emulsified sizing agent;
[0010] S4. The activated fiber is immersed in the emulsified sizing agent, the mass ratio of the activated fiber to the emulsified sizing agent is 1:15-20, ultrasonically vibrated at room temperature for 24 hours, then filtered out, and dried in an inert atmosphere at 82-90℃ and 6.2-6.8MPa for 1 hour to obtain the aramid fiber composite material.
[0011] Furthermore, in S1, the strong acid is hydrochloric acid or nitric acid.
[0012] Furthermore, in S2, the preparation method of the horseradish peroxidase-phosphate buffer complex solution is as follows: Take 100g of potassium dihydrogen phosphate, add 800ml of water, adjust the pH to 2.5 with hydrochloric acid, and dilute with water to 1000ml to obtain a pH 5.0 phosphate buffer; take 0.5-1.5g of horseradish peroxidase and dissolve it in 1000ml of pH 5.0 phosphate buffer to obtain the horseradish peroxidase-phosphate buffer complex solution.
[0013] Furthermore, in S3, the isocyanate mixture includes norbornene diisocyanate and methylcyclohexyl diisocyanate.
[0014] Furthermore, in S3, the emulsifier mixture includes Tween80 and Span60.
[0015] Furthermore, in S3, the dispersant is PEG400 or PEG600.
[0016] Further, the specific operating steps of S3 are as follows: Add the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester and emulsifier mixture to the emulsifier, stir evenly, add deionized water, and stir at high speed for 30 minutes. Then add the dispersant to the emulsifier, mix evenly, and sonicate at 100W power for 2 hours. Then continue stirring for 10 hours to obtain the emulsified sizing agent.
[0017] Furthermore, in S3, the mass ratio of the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water is 1:0.5:0.15:0.08:15.
[0018] Secondly, the present invention provides the following technical solution:
[0019] An aramid fiber composite material is prepared by the above-described method for preparing aramid fiber composite materials.
[0020] This application has the following beneficial effects:
[0021] 1. First, ultrasonic cleaning with ethanol solution removes adhering substances from the surface of aramid fibers. Then, hydrolysis and cleaning with NaOH solution until the surface is neutral facilitates subsequent acid washing to increase fiber surface roughness and specific surface area, resulting in more active adhesion points on the fiber surface. Horseradish peroxidase-phosphate buffer composite solution weakens the inertness of the fiber surface and improves interfacial adhesion, ensuring the effective transfer and tight adhesion of subsequent component loads from the emulsion sizing agent to the fiber. Ultrasonic oscillation accelerates the adhesion of component loads in the emulsion sizing agent to the activated fiber. Component loads and hydroxyl and amino groups can form covalent bonds, exhibiting excellent and durable UV absorption conversion performance and UV blocking effect. Then, drying in an inert atmosphere at high temperature and high pressure alleviates the stress enrichment of component loads remaining in a free state on the moist fiber, which helps to improve the uniformity of component load distribution, thereby improving its uniformity on the fiber.
[0022] 2. Horseradish peroxidase exhibits superior stability in pH 5.0 phosphate buffer, which facilitates preservation and performance. It ensures that when applied to acid-washed fibers, it can stably weaken the surface inertia of the fibers and improve interfacial adhesion, providing a solid foundation for the effective adhesion of subsequent component loads. Attached Figure Description
[0023] Figure 1 This is a comparison trend chart of the tensile strength of the products in Examples 1-8 and Comparative Examples 1-15 of the present invention;
[0024] Figure 2 This is a comparison trend chart of the tensile modulus of the products in Examples 1-8 and Comparative Examples 1-15 of the present invention;
[0025] Figure 3 This is a comparison trend chart of the elongation rate of the products in Examples 1-8 and Comparative Examples 1-15 of the present invention;
[0026] Figure 4 The graphs show the trend of tensile strength retention rate under simulated sunlight irradiation of the products in Examples 1-8 and Comparative Examples 1-2 of this invention over time.
[0027] Figure 5 This is a graph showing the trend of tensile strength retention rate under simulated sunlight irradiation as a function of time for products of Embodiment 2, Comparative Example 1, and Comparative Examples 3-9 of the present invention.
[0028] Figure 6 This is a graph showing the trend of tensile strength retention rate under simulated sunlight irradiation as a function of time for products of Embodiment 2, Comparative Example 1, and Comparative Examples 10-15 of the present invention.
[0029] Figure 7 The graph shows the trend of elongation retention rate under simulated sunlight irradiation as a function of time for the products of Embodiment 2 and Comparative Examples 1, 4, 7, and 9 of this invention.
[0030] Figure 8 The graphs show the elongation retention rate of the products in Embodiment 2, Comparative Examples 1, 10, 11, 14, and 15 of this invention under simulated sunlight irradiation, as a function of time. Detailed Implementation
[0031] The present application will be further described in detail below with reference to the embodiments.
[0032] Unless otherwise specified, the raw materials and equipment used in the embodiments and comparative examples of this application are all commercially available.
[0033] Example 1
[0034] This embodiment provides an aramid fiber composite material; the preparation method of the aramid fiber composite material includes the following steps:
[0035] S1. Immerse the aramid fiber in an ethanol solution and ultrasonically clean it for 1 hour. Then, soak it in an 8% NaOH solution at 60°C for 1 hour. Take out the aramid fiber, wash it with deionized water, dry it, and then put it into a 65% nitric acid solution. Soak it at room temperature for 0.5 hours, filter it out, and dry it naturally to obtain the acid-washed fiber.
[0036] S2. By weight, 1 part of the acid-washed fiber is added to 16 parts of horseradish peroxidase-phosphate buffer complex solution and soaked at room temperature for 5 hours to obtain activated fiber.
[0037] The preparation method of the horseradish peroxidase-phosphate buffer complex solution is as follows: Take 100g of potassium dihydrogen phosphate, add 800ml of water, adjust the pH to 2.5 with hydrochloric acid, and dilute with water to 1000ml to obtain a pH 5.0 phosphate buffer; take 1g of horseradish peroxidase and dissolve it in 1000ml of pH 5.0 phosphate buffer to obtain the horseradish peroxidase-phosphate buffer complex solution.
[0038] S3. Mix the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water in a mass ratio of 1:0.4:0.1:0.05:15 and disperse evenly to obtain an emulsified sizing agent.
[0039] The isocyanate mixture is prepared by mixing norbornene diisocyanate and methylcyclohexyl diisocyanate in equal mass ratios.
[0040] The emulsifier mixture was prepared by mixing Tween 80 and Span 60 in equal mass ratios.
[0041] The dispersant is PEG400.
[0042] The specific operation of this step is as follows: Add the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester and emulsifier mixture to the emulsifier (specifically, the FA25 high-shear emulsifier produced by Shanghai Fluke Electromechanical Equipment Co., Ltd.), stir evenly, add deionized water, and stir at high speed for 30 minutes. Then add the dispersant to the emulsifier, mix evenly, and sonicate at 100W power for 2 hours. Then continue stirring for 10 hours to obtain the emulsified sizing agent.
[0043] S4. The activated fiber is immersed in the emulsified sizing agent at a mass ratio of 1:18. The mixture is ultrasonically vibrated at room temperature for 24 hours, then filtered out and dried in an inert atmosphere (specifically argon) at 85±1℃ and 6.5±0.2MPa for 1 hour to obtain the aramid fiber composite material.
[0044] Example 2
[0045] The only difference between this embodiment and Example 1 is that in S3, the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water are mixed in a mass ratio of 1:0.5:0.15:0.08:15 and dispersed evenly to obtain an emulsified sizing agent.
[0046] Example 3
[0047] The only difference between this embodiment and Example 1 is that in S3, the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water are mixed in a mass ratio of 1:0.5:0.11:0.15:15 and dispersed evenly to obtain an emulsified sizing agent.
[0048] Example 4
[0049] The only difference between this embodiment and Example 1 is that in S3, the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water are mixed in a mass ratio of 1:0.55:0.15:0.15:15 and dispersed evenly to obtain an emulsified sizing agent.
[0050] Example 5
[0051] The only difference between this embodiment and Example 1 is that in S3, the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water are mixed in a mass ratio of 1:0.6:0.2:0.2:15 and dispersed evenly to obtain an emulsified sizing agent.
[0052] Example 6
[0053] The only difference between this embodiment and Example 1 is that the isocyanate mixture is prepared by mixing norbornene diisocyanate and methylcyclohexyl diisocyanate in a mass ratio of 1:2.
[0054] The emulsifier mixture was prepared by mixing Tween80 and Span60 in a mass ratio of 1.5:1.
[0055] The dispersant is PEG600.
[0056] Example 7
[0057] The difference between this embodiment and Embodiment 1 is only that: in S4, the activated fiber is immersed in the emulsified sizing agent, the mass ratio of the activated fiber to the emulsified sizing agent is 1:15, ultrasonically vibrates at room temperature for 24 hours, then filters out, and dries in an inert atmosphere (specifically argon) at 89±1℃ and 6.6±0.2MPa for 1 hour to obtain the aramid fiber composite material.
[0058] Example 8
[0059] The difference between this embodiment and embodiment 1 is only that in S4, the activated fiber is immersed in the emulsified sizing agent, the mass ratio of the activated fiber to the emulsified sizing agent is 1:20, ultrasonically vibrates at room temperature for 24 hours, then filters out, and dries in an inert atmosphere (specifically argon) at 81±1℃ and 6.4±0.2MPa for 1 hour to obtain the aramid fiber composite material.
[0060] Comparative Example 1
[0061] The comparative example uses commercially available aramid fiber I.
[0062] Comparative Example 2
[0063] The comparison ratio was selected from commercially available aramid fiber II.
[0064] Comparative Example 3
[0065] The only difference between this comparative example and Example 2 is that the acid washing step S1 is missing.
[0066] That is, firstly, by weight, 1 part of aramid fiber is added to 16 parts of horseradish peroxidase-phosphate buffer complex solution and soaked at room temperature for 5 hours to obtain activated fiber.
[0067] The subsequent steps are the same as in Example 2, and will not be repeated here.
[0068] Comparative Example 4
[0069] The only difference between this comparative example and Example 2 is that the activation step S2 is missing.
[0070] That is, the pickled fiber is immersed in the emulsified sizing agent with a mass ratio of pickled fiber to emulsified sizing agent of 1:18, ultrasonically vibrated at room temperature for 24 hours, then filtered out, and dried in an inert atmosphere (specifically argon) at 85±1℃ and 6.5±0.2MPa for 1 hour to obtain the aramid fiber composite material.
[0071] Other operating steps are the same as in Example 2, and will not be repeated here.
[0072] Comparative Example 5
[0073] The only difference between this comparative example and Example 2 is that in S4, after the activated fiber is mixed with the emulsified sizing agent and ultrasonically vibrated at room temperature for 24 hours, the drying process under inert atmosphere, higher temperature and higher pressure conditions is missing.
[0074] That is, the activated fiber is immersed in the emulsified sizing agent with a mass ratio of activated fiber to emulsified sizing agent of 1:18, ultrasonically vibrated at room temperature for 24 hours, then filtered out and dried at room temperature to obtain the aramid fiber composite material.
[0075] Other operating steps are the same as in Example 2, and will not be repeated here.
[0076] Comparative Example 6
[0077] The only difference between this comparative example and Example 2 is that the acid washing step S1 and the activation step S2 are missing.
[0078] That is, aramid fibers are directly immersed in an emulsified sizing agent with a mass ratio of aramid fibers to emulsified sizing agent of 1:18. The mixture is ultrasonically vibrated at room temperature for 24 hours, then filtered out and dried in an inert atmosphere (specifically argon) at 85±1℃ and 6.5±0.2MPa for 1 hour to obtain the aramid fiber composite material.
[0079] The preparation method and other operating steps of the emulsified sizing agent are the same as in Example 2, and will not be repeated here.
[0080] Comparative Example 7
[0081] The only difference between this comparative example and Example 2 is that the acid washing step of S1 is missing, and the drying process under inert atmosphere, higher temperature and higher pressure conditions is missing after the activated fiber is mixed with the emulsified sizing agent and ultrasonically vibrated at room temperature for 24 hours.
[0082] Specifically, firstly, by weight, 1 part of aramid fiber is added to 16 parts of horseradish peroxidase-phosphate buffer composite solution and soaked at room temperature for 5 hours to obtain activated fiber. The activated fiber is then soaked in an emulsified sizing agent at a mass ratio of 1:18, ultrasonically vibrated at room temperature for 24 hours, filtered out, and dried at room temperature to obtain the aramid fiber composite material.
[0083] Other operating steps are the same as in Example 2, and will not be repeated here.
[0084] Comparative Example 8
[0085] The only difference between this comparative example and Example 2 is that the activation step S2 is missing, the pickled fiber is directly immersed in the emulsified sizing agent, and the pickled fiber and the emulsified sizing agent are mixed and ultrasonically vibrated at room temperature for 24 hours. The drying process under inert atmosphere, higher temperature and higher pressure conditions is missing.
[0086] That is, the acid-washed fiber is immersed in an emulsified sizing agent with a mass ratio of acid-washed fiber to emulsified sizing agent of 1:18, ultrasonically vibrated at room temperature for 24 hours, then filtered out and dried at room temperature to obtain the aramid fiber composite material.
[0087] Other operating steps are the same as in Example 2, and will not be repeated here.
[0088] Comparative Example 9
[0089] The only difference between this comparative example and Example 2 is that the pickling step S1 and the activation step S2 are missing, and the aramid fiber is directly immersed in the emulsified sizing agent. After the aramid fiber and the emulsified sizing agent are mixed and ultrasonically vibrated at room temperature for 24 hours, the drying process under inert atmosphere, higher temperature and higher pressure conditions is missing.
[0090] That is, aramid fibers are immersed in an emulsified sizing agent with a mass ratio of aramid fibers to emulsified sizing agent of 1:18, ultrasonically vibrated at room temperature for 24 hours, then filtered out and dried at room temperature to obtain aramid fiber composite material.
[0091] Other operating steps are the same as in Example 2, and will not be repeated here.
[0092] Comparative Example 10
[0093] The only difference between this comparative example and Example 2 is that in S3, the mass ratio of the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water in the raw material composition of the emulsifying sizing agent is 0.5:0.5:0.15:0.08:15.
[0094] Other operating steps are the same as in Example 2, and will not be repeated here.
[0095] Comparative Example 11
[0096] The only difference between this comparative example and Example 2 is that in S3, the mass ratio of the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water in the raw material composition of the emulsifying sizing agent is 1:0.2:0.15:0.08:15.
[0097] Other operating steps are the same as in Example 2, and will not be repeated here.
[0098] Comparative Example 12
[0099] The only difference between this comparative example and Example 2 is that in S3, the mass ratio of the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water in the raw material composition of the emulsifying sizing agent is 1:0.5:0.1:0.08:15.
[0100] Other operating steps are the same as in Example 2, and will not be repeated here.
[0101] Comparative Example 13
[0102] The only difference between this comparative example and Example 2 is that in S3, the mass ratio of the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water in the raw material composition of the emulsifying sizing agent is 1:0.5:0.15:0.04:15.
[0103] Other operating steps are the same as in Example 2, and will not be repeated here.
[0104] Comparative Example 14
[0105] The only difference between this comparative example and Example 2 is that in S3, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester is replaced with 4-benzoyloxy-2,2,6,6-tetramethylpiperidine in the raw material components for preparing the emulsifying sizing agent.
[0106] That is, in S3, the isocyanate mixture, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, emulsifier mixture, dispersant and deionized water are mixed in a mass ratio of 1:0.5:0.15:0.08:15 and dispersed evenly to obtain an emulsified sizing agent.
[0107] Other operating steps are the same as in Example 2, and will not be repeated here.
[0108] Comparative Example 15
[0109] The only difference between this comparative example and Example 2 is that in S3, the isocyanate mixture and 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester were removed from the raw materials used to prepare the emulsifying sizing agent.
[0110] That is, in S3, the raw material composition ratio for preparing the emulsified sizing agent is 1:0.5:0.15:0.04:15 by mass of the emulsifier mixture, dispersant and deionized water.
[0111] Other operating steps are the same as in Example 2, and will not be repeated here.
[0112] Experimental Example 1
[0113] Test subjects: Fiber material products of Examples 1-8 and Comparative Examples 1-15;
[0114] Test items: tensile strength / breaking strength (MPa), tensile modulus (MPa), elongation / elongation at break (%);
[0115] Testing standard: GJB 993-1990;
[0116] Test data: see Table 1 and Figure 1-3 .
[0117] Table 1. Mechanical property test data of products from Examples 1-8 and Comparative Examples 1-15
[0118] Example 1 2875 12910 2.1 Example 2 2897 13090 2.2 Example 3 2821 12886 2 Example 4 2854 12958 2 Example 5 2866 13028 2 Example 6 2858 12990 2.1 Example 7 2842 12947 2.2 Example 8 2833 12923 2.1 Comparative Example 1 2420 11283 1.9 Comparative Example 2 2478 11347 2.0 Comparative Example 3 2714 12375 2.0 Comparative Example 4 2662 12311 2.0 Comparative Example 5 2587 12107 2.0 Comparative Example 6 2337 11214 1.9 Comparative Example 7 2362 11272 1.9 Comparative Example 8 2259 11089 1.9 Comparative Example 9 2438 11545 1.9 Comparative Example 10 2513 11767 1.9 Comparative Example 11 2684 11938 1.9 Comparative Example 12 2678 12177 2.0 Comparative Example 13 2626 12014 1.9 Comparative Example 14 2537 11878 1.9 Comparative Example 15 2287 10748 1.9
[0119] Results Analysis: Based on the data in Table 1... Figure 1-3 It can be seen that: ① after ultrasonic cleaning with ethanol and cleaning with alkaline solution, the aramid fiber is acid-washed; ② the acid-washed aramid fiber is activated with horseradish peroxidase-phosphate buffer composite solution; ③ drying is carried out in an inert atmosphere, at a high temperature and a high pressure environment to alleviate the stress enrichment of free components; under the premise of using an emulsified sizing agent, the mechanical properties of the aramid fiber composite material obtained by performing the above three treatment steps ①②③ are significantly improved.
[0120] The mechanical properties of the aramid fiber composite material are improved when any one of the three treatment steps (①②③) is omitted, that is, when only any two of the three treatment steps (①②③) are performed on the aramid fiber. However, the improvement in mechanical properties is weakened when all three treatment steps (①②③) are performed simultaneously.
[0121] If any two steps are missing, that is, if only one of the processing steps ①②③ is performed on the aramid fiber, the mechanical properties of the final aramid fiber composite material will decrease instead of increase. In other words, if any one of the three steps ①②③ exists alone and is used to treat the aramid fiber, it will weaken the mechanical properties of the aramid fiber.
[0122] All three steps were cancelled, meaning no treatment was done to the aramid fibers. The aramid fibers were simply soaked in an emulsifying sizing agent. As a result, the mechanical properties of the aramid fibers were only slightly improved, and the improvement effect was not ideal.
[0123] In the raw material composition of the emulsifying sizing agent, if the amount of any component such as the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, or dispersant is too low, the effect on improving the mechanical properties of aramid fibers will be weakened. Among them, the cyanate mixture has the greatest influence, followed by 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester.
[0124] Replacing 2-cyano-3,3-diphenyl-2-acrylate with the conventional UV absorber 4-benzoyloxy-2,2,6,6-tetramethylpiperidine significantly weakens the improvement in mechanical properties.
[0125] The isocyanate mixture and 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester were directly removed from the raw material components of the emulsifying sizing agent, while other operation steps remained unchanged. As a result, the mechanical properties of the final aramid fiber composite material decreased instead of increasing. This indicates that the isocyanate mixture and 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester are the core load-bearing components for improving the mechanical properties of aramid fibers. Without these two core load-bearing components to effectively adhere to the aramid fibers, simply performing the above three steps ①②③ on the aramid fibers will not only fail to improve the mechanical properties of the aramid fibers, but will also damage the aramid fibers, leading to a weakening of their mechanical properties.
[0126] Experimental Example 2
[0127] Test subjects: Examples 1-8 and Comparative Examples 1-15;
[0128] Test content: Under simulated sunlight exposure at different times (temperature 35℃, humidity 40%) using a xenon arc lamp (1500w) light source, the change in mechanical property retention rate is measured. The mechanical property retention rate is the ratio of the performance index value after sun exposure to the original value, specifically used for tensile strength, tensile modulus and elongation.
[0129] Irradiation times were set to 2, 6, 20, 60, 100, 140 and 180 hours, respectively. Mechanical properties were tested using an XQ-1 single fiber tensile strength tester. The changes in mechanical properties of the fiber material products under different irradiation times were recorded, and the corresponding mechanical property retention rates were calculated.
[0130] Test data: see Table 2-3 and Figure 4-8 .
[0131] Table 2. Tensile strength retention rate data of products from Examples 1-8 and Comparative Examples 1-15
[0132]
[0133]
[0134] Table 3. Elongation retention rate data of products in Example 2 and Comparative Examples 1, 4, 7, 9, 10, 11, 14, and 15
[0135] Example 2 99.8 99.2 96.4 93.5 90.1 87.6 85.1 Comparative Example 1 99.1 97.2 94.7 90.8 85.0 80.2 75.9 Comparative Example 4 99.3 98.6 95.7 92.0 88.5 84.9 80.8 Comparative Example 7 98.9 96.8 94.0 90.1 84.3 79.4 75.1 Comparative Example 9 99.3 97.8 95.0 91.2 86.4 82.2 77.8 Comparative Example 10 99.5 98.6 95.4 92.3 88.7 85.0 81.6 Comparative Example 11 99.3 98.2 95.9 92.3 88.9 84.6 81.3 Comparative Example 14 99.1 98.0 95.2 91.7 87.8 82.3 76.2 Comparative Example 15 98.7 96.3 93.1 89.0 83.5 78.1 72.3
[0136] Results Analysis: Combining the data from Tables 2 and 3 Figure 4-8 It can be seen that: ① after ultrasonic cleaning with ethanol and alkaline cleaning, the aramid fibers are acid-washed; ② the acid-washed aramid fibers are activated with a horseradish peroxidase-phosphate buffer composite solution; ③ drying is carried out in an inert atmosphere, at a high temperature and a high pressure environment to alleviate the stress enrichment of free components. Under the premise of using an emulsified sizing agent, the aramid fibers are subjected to the above three treatment steps ①②③. The resulting aramid fiber composite material not only has significantly improved mechanical properties, but also significantly improved UV resistance. Furthermore, the combination and synergy between the three steps ①②③ have a certain degree of synchronicity and consistency in the effect of changing the mechanical properties and UV resistance of the aramid fibers.
[0137] Changes in the raw material composition and ratio of emulsifying sizing agents will not only alter the direction or intensity of changes in the mechanical properties of aramid fibers, but also the direction or intensity of changes in the UV resistance of aramid fibers. Furthermore, there is a clear consistency and synchronicity between the two types of trends.
[0138] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.
[0139] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.
Claims
1. A method of making an aramid fiber composite material, characterized by, Includes the following steps: S1. Immerse the aramid fiber in an ethanol solution and ultrasonically clean it for 1 hour. Then soak it in an 8% NaOH solution at 60°C for 1 hour. Take out the aramid fiber, wash it with deionized water, dry it, and then put it into a 65% strong acid solution. Soak it at room temperature for 0.5-1 hour, filter it out, and dry it naturally to obtain the acid-washed fiber. S2. By weight, add 1 part of the acid-washed fiber to 15-18 parts of horseradish peroxidase-phosphate buffer composite solution and soak at room temperature for 4-6 hours to obtain activated fiber. S3. Mix the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water in a mass ratio of 1:(0.4-0.6):(0.11-0.2):(0.05-0.2):15 and disperse evenly to obtain an emulsified sizing agent; S4. The activated fiber is immersed in the emulsified sizing agent, the mass ratio of the activated fiber to the emulsified sizing agent is 1:15-20, ultrasonically vibrated at room temperature for 24 hours, then filtered out, and dried in an inert atmosphere at 82-90℃ and 6.2-6.8MPa for 1 hour to obtain the aramid fiber composite material. In S3, the isocyanate mixture includes norbornene diisocyanate and methylcyclohexyl diisocyanate; In S3, the emulsifier mixture includes Tween80 and Span60; In S3, the dispersant is PEG400 or PEG600.
2. The method of claim 1, wherein the aramid fiber composite is prepared by the steps of: In S1, the strong acid is hydrochloric acid or nitric acid.
3. The method for preparing aramid fiber composite material according to claim 1, characterized in that, In S2, the preparation method of the horseradish peroxidase-phosphate buffer complex solution is as follows: Take 100g of potassium dihydrogen phosphate, add 800ml of water, adjust the pH to 2.5 with hydrochloric acid, and dilute with water to 1000ml to obtain a pH 5.0 phosphate buffer; take 0.5-1.5g of horseradish peroxidase and dissolve it in 1000ml of pH 5.0 phosphate buffer to obtain the horseradish peroxidase-phosphate buffer complex solution.
4. The method for preparing aramid fiber composite material according to claim 1, characterized in that, The specific operating steps of S3 are as follows: Add the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester and emulsifier mixture to the emulsifier, stir evenly, add deionized water, and stir at high speed for 30 minutes. Then add the dispersant to the emulsifier, mix evenly, and sonicate at 100W power for 2 hours. Then continue stirring for 10 hours to obtain the emulsified sizing agent.
5. The method for preparing aramid fiber composite material according to claim 1, characterized in that, In S3, the mass ratio of the isocyanate mixture, 2-cyano-3,3-diphenyl-2-acrylate-2-ethylhexyl ester, emulsifier mixture, dispersant and deionized water is 1:0.5:0.15:0.08:
15.
6. An aramid fiber composite material, characterized in that, The aramid fiber composite material was prepared using the preparation method described in any one of claims 1-5.