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

Abstract

The invention discloses a modified ultra-high molecular weight polyethylene fiber as well as a preparation method and application thereof. The modified ultra-high molecular weight polyethylene fiber is prepared from 100 parts by mass of ultra-high molecular weight polyethylene resin, 3-10 parts by mass of modified nano composite ceramic particles, 2-8 parts by mass of modified aramid fiber, 1-5 parts by mass of modified carbon nanotubes and 1-3 parts by mass of an auxiliary agent through the processes of a two-stage blending method, dry-wet spinning, gradient hot stretching, pulse heat setting and the like. The tensile strength of the prepared modified ultra-high molecular weight polyethylene fiber is greater than 4.5 GPa, the elongation at break is kept at 5.0-5.5%, the cutting resistance is as high as 310N, the puncture resistance is as high as 465N, and the modified ultra-high molecular weight polyethylene fiber can be applied to protective products.

Description

Technical Field

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

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fibers have excellent properties such as high strength, high modulus, low density, and wear resistance, and are widely used in aerospace, military equipment, sporting goods, and other fields. However, in some fields with high protection requirements, such as personal protective equipment (bulletproof vests, cut-resistant gloves, etc.), the cut and puncture resistance of ordinary UHMWPE fibers still needs to be improved.

[0003] Currently, existing technologies for improving the cut and puncture resistance of UHMWPE fibers primarily utilize methods such as blending, surface modification, and compounding. However, these methods present several challenges, such as uneven dispersion of additives during the blending process, resulting in unstable fiber properties and a short-lived surface modification effect. Therefore, developing a modified UHMWPE fiber with both cut and puncture resistance that offers superior performance and stability, with a simple preparation process, is of great practical significance. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a modified ultra-high molecular weight polyethylene fiber and a preparation method thereof. By modifying the polyethylene fiber with ceramic particles, aramid fibers and carbon nanotubes, the shortcomings of the existing technology are overcome, the protective performance of the fiber is significantly improved, and the modified fiber is used in protective products with good cut resistance and puncture resistance.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] First, the present invention provides a modified ultra-high molecular weight polyethylene fiber, which includes the following raw materials in parts by mass: 100 parts of ultra-high molecular weight polyethylene resin, 3-10 parts of modified nano-composite ceramic particles, 2-8 parts of modified aramid fiber, 1-5 parts of modified carbon nanotubes, and 1-3 parts of additives.

[0007] Furthermore, the average molecular weight of the ultra-high molecular weight polyethylene resin is 1-5 million;

[0008] The particle size of the modified nanocomposite ceramic particles is 50-200 nm;

[0009] The modified aramid fiber has a diameter of 5-50 nm and a length of 0.5-5 μm;

[0010] The modified carbon nanotubes have a diameter of 1-20 nm and a length of 1-10 μm;

[0011] The auxiliary agent comprises 0.5-1.5 parts by mass of a hindered amine light stabilizer, 0.3-1 parts by mass of an antioxidant, and 0.2-0.5 parts by mass of nano-scale titanium dioxide.

[0012] Furthermore, the modified nanocomposite ceramic particles are prepared by the following steps:

[0013] 40-60 wt.% of nano-alumina, 30-50 wt.% of nano-silicon carbide, and 10-20 wt.% of nano-zirconium oxide are uniformly mixed to form nano-composite ceramic particles;

[0014] The nanocomposite ceramic particles are first subjected to ultrasonic treatment at 60-70° C. for 1-2 hours in a 3-5% by mass silane coupling agent KH-560 solution, and then a 1-2% by mass graphene solution is added, and the ultrasonic treatment is continued for 0.5-1 hour. The particles are filtered, washed, and dried at 80-100° C. to obtain modified nanocomposite ceramic particles.

[0015] The mass ratio of the nanocomposite ceramic particles, graphene and silane coupling agent is (10-50): (0.1-1): (0.01-0.1).

[0016] In the modification of nanocomposite ceramic particles, silane coupling agents can form an organic coating on the surface of the ceramic particles, enhancing their bonding with graphene and resin. Graphene quantum dots can further improve the interfacial bonding between the ceramic particles and the matrix, while also imparting certain self-healing properties to the fibers. In the event of minor damage, graphene quantum dots can promote the rearrangement and bonding of molecular chains.

[0017] Furthermore, the modified aramid fiber is prepared by the following steps:

[0018] The aramid nanofibers are placed in a Tris-HCl buffer solution (pH = 8.5-9.0) containing 0.5-1% dopamine hydrochloride, stirred at room temperature for 6-8 hours, and then filtered, washed with deionized water, and dried at 60-80° C. to obtain modified aramid fibers;

[0019] The mass ratio of the aramid nanofiber to the Tris-HCl buffer solution is 1:(5-20).

[0020] In the modification of aramid nanofibers, the polydopamine coating formed by dopamine self-polymerization can significantly improve the bonding strength between aramid nanofibers and ultra-high molecular weight polyethylene matrix.

[0021] Furthermore, the modified carbon nanotubes are prepared by the following steps:

[0022] The carbon nanotubes are first acidified by reflux treatment in mixed acid (concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 3:1) at 50-60°C for 2-3 hours. The acidified carbon nanotubes are then filtered and washed, and then added to an ethanol solution containing 2-3% polyethyleneimine, stirred at room temperature for 12-16 hours, filtered, and dried to obtain modified carbon nanotubes.

[0023] In this process, the mass ratio of carbon nanotubes to mixed acid is 1:(10-20), and the mass ratio of acidified carbon nanotubes to polyethyleneimine is 1:(1-3).

[0024] In the modification of carbon nanotubes, this treatment grafts amino groups onto the surface of carbon nanotubes, thereby enhancing their compatibility and dispersibility with the ultra-high molecular weight polyethylene matrix.

[0025] Secondly, the present invention also provides a method for preparing the modified ultra-high molecular weight polyethylene fiber, which comprises the following steps:

[0026] Weigh the following raw materials: 100 parts by mass of ultra-high molecular weight polyethylene resin, 3-10 parts by mass of modified nanocomposite ceramic particles, 2-8 parts by mass of modified aramid fiber, 1-5 parts by mass of modified carbon nanotubes, and 1-3 parts by mass of additives;

[0027] The ultra-high molecular weight polyethylene resin is melted at 100-120°C, and then modified carbon nanotubes are added and mixed for 10-15 minutes under high-speed stirring (800-1000 r / min) to form a base material; then modified nano-composite ceramic particles, modified aramid fibers and additives are added to the above base material and mixed at a relatively low speed (300-500 r / min) for 20-30 minutes to uniformly disperse the components. The mixed material is transferred to a twin-screw extruder for extrusion. The temperature of the twin-screw extruder is set to 180-220°C and the screw speed is set to 100-300 r / min to obtain modified UHMWPE pellets. This blending method allows the carbon nanotubes to form a well-dispersed network in the resin before introducing other reinforcements to avoid agglomeration. The uniform mixture is conveyed to the twin-screw extruder for melt extrusion to ensure that the mixture is fully melted and uniformly extruded.

[0028] The modified UHMWPE pellets are dissolved in a mixed solvent of decalin and paraffin oil (volume ratio of 7:3) to prepare a solution with a mass fraction of 12-15%, and stirred and dissolved at 130-140°C for 3-4 hours to form a spinning solution;

[0029] The spinning solution is delivered to a spinneret via a metering pump. The spinneret has an aperture of 0.1-0.5 mm and a spinning speed of 5-10 m / min. The filaments are extruded at the spinneret to form filaments. The filaments first pass through an air layer of 10-20 cm in length, at a temperature of 120-130° C. and a humidity of 30-40%. The filaments then enter a coagulation bath having an ethanol to water volume ratio of 8:2 for coagulation molding. The coagulation temperature is 25-30° C., and the filaments remain in the coagulation bath for 1-3 minutes to form nascent fibers. The dry-wet spinning process employed by the present invention can better control the fiber molding process and make the internal structure of the fibers more compact.

[0030] The solidified fiber is subjected to multi-stage stretching, and the specific stretching process adopts "gradient thermal stretching". The nascent fiber is first pre-stretched at 80-90°C with a stretching ratio of 2-3 times, and then the main stretching is carried out at 110-120°C with a stretching ratio of 4-5 times; thereafter, it is heat-set at 180-200°C in a pulsed manner (heating for 10-20 seconds, cooling for 5-10 seconds, and cycling 3-5 times) to obtain modified ultra-high molecular weight polyethylene fiber; in this step, the orientation and crystallinity of the fiber are improved by "gradient thermal stretching", thereby improving the mechanical properties of the fiber, and the use of "pulse thermal setting" can effectively eliminate the internal stress of the fiber and further improve the crystallinity and orientation of the fiber.

[0031] Furthermore, the modified ultra-high molecular weight polyethylene fiber can also undergo surface treatment. The specific process is: immersing the prepared modified ultra-high molecular weight polyethylene fiber in a polyurethane solution or a polytetrafluoroethylene solution, and then drying and curing at 80-120°C for 1-2 hours. After surface treatment, a uniform protective film can be formed on the fiber surface, improving the fiber's wear resistance and corrosion resistance.

[0032] Thirdly, the present invention also provides the application of modified ultra-high molecular weight polyethylene fiber in protective products, such as bulletproof vests, cut-resistant gloves, and stab-resistant clothing. It can also be applied to high-end fields such as structural reinforcement materials for aerospace and cable materials for deep-sea exploration.

[0033] The beneficial effects of the present invention are:

[0034] The present invention utilizes a variety of surface treatment methods during raw material pretreatment, such as graphene quantum dots co-processing ceramic particles, dopamine-treated aramid nanofibers, and other processes, as well as two-stage blending, dry-wet spinning, gradient thermal stretching, and pulse heat setting. This unique preparation process system is formed. The synergistic effect of these processes is the key to achieving high-performance fibers. Furthermore, due to the introduction of a self-healing component (graphene quantum dots (GQDs)) into the system, the mechanical properties of the fibers can be restored to a certain extent after minor damage.

[0035] The modified ultra-high molecular weight polyethylene fiber produced by the present invention forms a "three-dimensional interpenetrating network structure" within it. Nano-ceramic particles are evenly embedded in the ultra-high molecular weight polyethylene matrix. Aramid nanofibers and carbon nanotubes interweave and intersperse, forming a strong interfacial bond with the ultra-high molecular weight polyethylene molecular chains. This structure enables the fiber to more effectively disperse stress when subjected to external forces, avoiding damage caused by localized stress concentration. The synergistic effect of the nano-scale composite ceramic particles, combined with the hardness of aluminum oxide, the wear resistance of silicon carbide, and the toughness of zirconium oxide, significantly improves the fiber's cut and puncture resistance. The high aspect ratio of the aramid nanofibers and carbon nanotubes acts as "nano-rebar" within the fiber, enhancing the fiber's mechanical properties.

[0036] Ceramic particles themselves have high hardness and good wear resistance. Adding them to the matrix material can effectively improve the hardness and wear resistance of the overall material. By selecting modified composite ceramic particles of different types, particle sizes and surface properties, the friction coefficient of the material can be adjusted to meet the friction performance requirements of different application scenarios. The high hardness of ceramic particles makes it more difficult for cutting tools to cut into the surface of the fiber material, and during the cutting process, ceramic particles can disperse the cutting force to avoid stress concentration in one place, causing the fiber to be easily cut. In terms of puncture resistance, ceramic particles can resist the invasion of puncturing objects when subjected to puncture force, and by dispersing stress, prevent large-scale damage to the fiber material around the puncture point, thereby enhancing the material's puncture resistance.

[0037] Aramid fibers possess excellent mechanical properties, such as high strength and high modulus. After modification, they can better bond with other materials and serve as a skeletal support in composite materials, effectively improving the material's overall strength, toughness, and tensile strength. This allows them to withstand greater external forces and loads, allowing them to absorb more energy through deformation when subjected to cutting or puncture forces. The active groups on the aramid fiber surface form a good interface with the ultra-high molecular weight polyethylene fibers and ceramic particles, enabling the various components of the material to work synergistically when subjected to force. This synergistic effect allows the material to more effectively disperse external forces throughout the structure when cut or punctured, thereby improving its cut and puncture resistance.

[0038] Carbon nanotubes have extremely high strength and modulus. By modifying the carbon nanotubes and grafting amino groups on their surface, the compatibility and dispersibility with the matrix are enhanced. Adding them to ultra-high molecular weight polyethylene fibers can play a reinforcing role. During the preparation process, the ultra-high molecular weight polyethylene resin is first melted, and the modified carbon nanotubes are added and stirred at high speed to help the carbon nanotubes better disperse in the ultra-high molecular weight polyethylene matrix and mix evenly with other components to give full play to their reinforcing effect, making the performance of the fiber more stable and uniform, thereby effectively improving the tensile strength and other mechanical properties of the fiber. High rigidity and strength mean that the material is less likely to deform and damage when subjected to cutting or puncture forces. In terms of puncture resistance, carbon fiber can enhance the material's ability to resist extrusion and deformation of the puncturing object, allowing the material to better maintain structural integrity during the puncture process.

[0039] During the dry-wet spinning process, the solution streams in the air layer primarily undergo solvent volatilization and partial macromolecular chain orientation. On the one hand, in a high-temperature, low-humidity air environment, the solvents (decalin and paraffin oil) evaporate rapidly, causing the solution stream's concentration and viscosity to rapidly increase, initially forming a filament structure with a certain strength and shape stability. On the other hand, during the extrusion process, the streams are subjected to tensile forces and air flow, causing the ultra-high molecular weight polyethylene macromolecular chains to begin to orient along the fiber axis. This orientation is crucial for improving the mechanical properties of the final fiber. Furthermore, excessively high temperatures can cause the solvent to evaporate too quickly, prematurely solidifying the filament surface to form a cortex, hindering further solvent volatilization within the filament and resulting in an uneven skin-core structure. Excessively low temperatures can lead to insufficient solvent volatilization, compromising filament formation and subsequent coagulation. Improper humidity control can lead to moisture absorption or condensation on the filament surface, compromising fiber quality. Therefore, the temperature and humidity of the air layer are controlled. After passing through the air layer, the filaments enter the coagulation bath, where a rapid double diffusion process occurs between the solvent in the spinning solution and the non-solvent (ethanol and water) in the coagulation bath. Since UHMWPE is insoluble in ethanol and water, as the solvent continues to diffuse into the coagulation bath, the non-solvent diffuses into the filaments, increasing the concentration of the solution until it reaches supersaturation, causing the UHMWPE macromolecular chains to phase separate and precipitate, forming solid fibers. During the coagulation process, the filaments have already formed a certain structure and orientation in the air layer. This structure and orientation are further fixed and strengthened after entering the coagulation bath.

[0040] In the gradient heat-setting process, increasing the stretching temperature and multiple can better orient the fiber molecular chains. Optimizing the heat-setting process can more effectively eliminate internal fiber stress, further increasing the fiber's crystallinity and orientation, thereby improving the fiber's mechanical properties. Using "pulse heat setting" can effectively eliminate internal fiber stress and further improve the fiber's crystallinity and orientation.

[0041] Compared with the prior art, the modified ultra-high molecular weight polyethylene fiber prepared by the present invention has a tensile strength greater than 4.5 GPa, an elongation at break maintained at 5.0-5.5%, a cutting resistance of up to 310 N, and a puncture resistance of up to 465 N. DETAILED DESCRIPTION

[0042] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0043] The reagents and instruments used in the present invention without manufacturer indication are all conventional products that can be purchased from the market.

[0044] Example 1

[0045] 1. Raw material pretreatment

[0046] Preparation of modified nanocomposite ceramic particles:

[0047] Mixed raw materials: 50wt.% nano-alumina (particle size 100nm), 40wt.% nano-silicon carbide (particle size 150nm), and 10wt.% nano-zirconium oxide (particle size 80nm) are weighed in proportion, added to a high-speed mixer, and stirred at 600r / min for 15min to form nano-composite ceramic particles.

[0048] Surface Treatment: The composite ceramic particles and a 4% (mass fraction) silane coupling agent KH-560 solution were added to a reaction vessel in a 30:2 mass ratio and ultrasonically treated at 65°C for 1.5 hours. Subsequently, a 1.5% (mass fraction) graphene solution (mass ratio of graphene to composite ceramic particles: 0.5:30) was added and ultrasonically treated for another 0.8 hour. After treatment, the particles were filtered, washed three times with deionized water, and dried in a vacuum oven at 90°C for 8 hours to obtain modified nanocomposite ceramic particles.

[0049] The solution in the silane coupling agent KH-560 solution and the graphene solution is DMSO.

[0050] Preparation of modified aramid fiber:

[0051] Aramid nanofibers (20 nm in diameter, 2 μm in length) were mixed with a Tris-HCl buffer solution (pH 8.8) containing 0.8% dopamine hydrochloride at a mass ratio of 1:12 and stirred at room temperature for 7 hours. After the reaction, the fibers were separated by filtration, washed five times with deionized water to remove unreacted dopamine, and finally dried in a 70°C air drying oven for 10 hours to obtain the modified aramid fibers.

[0052] Preparation of modified carbon nanotubes:

[0053] Acidification: Carbon nanotubes (10 nm diameter, 3 μm length) and concentrated sulfuric acid-nitric acid (3:1 volume ratio) were added to a three-necked flask at a mass ratio of 1:15 and refluxed at 55°C for 2.5 hours. After the reaction, the carbon nanotubes were separated by filtration and washed with deionized water until the filtrate reached a neutral pH.

[0054] Amino grafting: The acidified carbon nanotubes were added to an ethanol solution containing 2.5% polyethyleneimine (the mass ratio of carbon nanotubes to polyethyleneimine was 1:2), stirred at room temperature for 14 hours, and filtered and dried after the reaction to obtain modified carbon nanotubes.

[0055] Preparation of additives:

[0056] Accurately weigh 1 part by mass of hindered amine light stabilizer (GW-540), 0.6 part by mass of antioxidant 1010, and 0.4 part by mass of nano-sized titanium dioxide (particle size 50 nm), mix them evenly and set aside.

[0057] 2. Blending and extrusion

[0058] In the first stage of blending, 100 parts by mass of ultra-high molecular weight polyethylene resin with an average molecular weight of 3 million was melted at 110°C; then 3 parts by mass of modified carbon nanotubes were added and stirred at 900 rpm for 12 minutes to form a carbon nanotube-reinforced base material;

[0059] The second stage of blending: 6 parts by mass of modified nanocomposite ceramic particles, 5 parts by mass of modified aramid fibers and 2 parts by mass of the prepared additives were added to the base material in sequence, and stirred at a low speed of 400 r / min for 25 minutes;

[0060] Melt extrusion: The mixed material was passed through a twin-screw extruder (temperature setting: zone 1 185°C, zone 2 195°C, zone 3 205°C, zone 4 210°C; screw speed 200 r / min), and after extrusion, water-cooled and pelletized to obtain modified UHMWPE pellets.

[0061] 3. Solution spinning

[0062] Solution preparation: The modified UHMWPE pellets were dissolved in a mixed solvent of decalin and paraffin oil (volume ratio 7:3) to prepare a solution with a mass fraction of 13%. The solution was stirred and dissolved at 135°C for 3.5 hours to ensure complete dissolution and uniform dispersion to form a spinning solution.

[0063] Dry-wet spinning: The spinning solution is pumped to a spinneret (pore size 0.3 mm) via a metering pump and extruded at 8 m / min to form filaments. The filaments first pass through a 15 cm long air layer at 125°C and 35% humidity before entering a coagulation bath (temperature 28°C) of ethanol and water (volume ratio 8:2) for 2 minutes to complete coagulation and form the spun fibers.

[0064] 4. Post-processing

[0065] Gradient thermal stretching: The as-spun fiber was pre-stretched 2.5 times at 85°C, and then stretched 4.5 times at 115°C.

[0066] Pulse heat setting: Pulse treatment is performed at 190°C (heating for 15 seconds, cooling for 8 seconds, and 4 cycles) to eliminate internal stress and increase crystallinity, ultimately producing modified ultra-high molecular weight polyethylene fibers.

[0067] Example 2

[0068] 1. Raw material pretreatment: The process is the same as that in Example 1, except that:

[0069] Modified nanocomposite ceramic particles: 60 wt.% nano-alumina, 30 wt.% nano-silicon carbide, and 10 wt.% nano-zirconium oxide were used, and the mass ratio of the silane coupling agent and graphene was adjusted to 50:0.8:0.1. The treatment temperature was increased to 70° C., and the ultrasonic time was 2 hours.

[0070] Modified aramid fiber: The mass ratio of aramid nanofiber to Tris-HCl buffer solution was adjusted to 1:15, the concentration of dopamine hydrochloride was increased to 1%, and the reaction time was 8 hours.

[0071] Modified carbon nanotubes: The mass ratio of carbon nanotubes to mixed acid was adjusted to 1:18, and after acidification, the mass ratio of carbon nanotubes to polyethyleneimine was adjusted to 1:3, and the stirring time was extended to 16 hours.

[0072] Additives: 1.2 parts by mass of hindered amine light stabilizer, 0.8 parts by mass of antioxidant, and 0.3 parts by mass of nano-sized titanium dioxide.

[0073] 2. Preparation process

[0074] Blending and extrusion: The process is the same as that of Example 1, except that the temperature of the twin-screw extruder is set to 190°C in zone 1, 200°C in zone 2, 210°C in zone 3, and 215°C in zone 4.

[0075] Solution spinning: The process is the same as that of Example 1, except that the mass fraction of the solution is adjusted to 14%, the spinning speed is increased to 9 m / min, the air layer temperature is raised to 130°C, and the coagulation bath temperature is maintained at 28°C.

[0076] Post-treatment: The process is the same as that of Example 1, except that: pre-stretching temperature is 90°C, stretching is 3 times, main stretching temperature is 120°C, stretching is 5 times; pulse heat setting temperature is 200°C (heating for 20 seconds, cooling for 10 seconds, and cycle 5 times).

[0077] Example 3

[0078] 1. Raw material pretreatment: The process is the same as that in Example 1, except that:

[0079] Modified nano-composite ceramic particles: 40wt.% nano-alumina, 50wt.% nano-silicon carbide, and 10wt.% nano-zirconium oxide are used, and the mass ratio of the modified nano-composite ceramic particles to the silane coupling agent and graphene is 30:1:0.1.

[0080] Modified aramid fiber: mass ratio 1:5, dopamine hydrochloride concentration 0.5%, reaction time 6 hours.

[0081] Modified carbon nanotubes: the mass ratio of carbon nanotubes to mixed acid is 1:10, and after acidification, the mass ratio of carbon nanotubes to polyethyleneimine is 1:1.

[0082] Additives: 0.5 parts by mass of hindered amine light stabilizer, 0.3 parts by mass of antioxidant, and 0.2 parts by mass of nano-sized titanium dioxide.

[0083] 2. Preparation process

[0084] Blending and extrusion: The process is the same as that of Example 1, except that the temperature of the twin-screw extruder is reduced to 180°C in zone 1, 190°C in zone 2, 200°C in zone 3, and 205°C in zone 4.

[0085] Solution spinning: The process is the same as that of Example 1, except that the mass fraction of the solution is 12%, the spinning speed is 5 m / min, and the air layer length is shortened to 10 cm.

[0086] Post-treatment: The process is the same as that of Example 1, except that: pre-stretching at 80°C, stretching 2 times, main stretching at 110°C, stretching 4 times; pulse heat setting at 180°C (heating for 10 seconds, cooling for 5 seconds, and 3 cycles).

[0087] Comparative Example 1

[0088] 1. Raw material preparation

[0089] Weigh 100 parts of ultra-high molecular weight polyethylene resin with an average molecular weight of 3,000,000.

[0090] Prepare 6 parts by mass of unmodified nano-composite ceramic particles, weigh 50 wt.% nano-alumina (particle size 100 nm), 40 wt.% nano-silicon carbide (particle size 150 nm), and 10 wt.% nano-zirconium oxide (particle size 80 nm) in proportion, add them to a high-speed mixer, and stir at 600 r / min for 15 minutes to form nano-composite ceramic particles. The nano-composite ceramic particles are not subjected to any surface treatment.

[0091] Five portions of aramid short fibers (diameter 20 nm, length 2 μm) were prepared. The fiber surface was smooth and no special treatment was performed.

[0092] 3 parts by mass of carbon nanotubes (diameter 10 nm, length 3 μm) were prepared, and the surface of the carbon nanotubes was not modified.

[0093] Preparation of additives: Accurately weigh 1 part by mass of hindered amine light stabilizer (GW-540), 0.6 part by mass of antioxidant 1010, and 0.4 part by mass of nano-sized titanium dioxide (particle size 50 nm), mix well and set aside.

[0094] 2. Preparation process: The preparation process is the same as that in Example 1.

[0095] Comparative Example 2

[0096] 1. Raw material pretreatment: The process is the same as that of Example 1, except that the modified carbon nanotubes are not prepared.

[0097] 2. Preparation process: The process is the same as that of Example 1, except that:

[0098] Melt extrusion: 100 parts by mass of ultra-high molecular weight polyethylene resin with an average molecular weight of 3 million was melted at 110°C; then 6 parts by mass of modified nano-composite ceramic particles, 5 parts by mass of modified aramid fiber and 2 parts by mass of the prepared additive were added, and stirred at a low speed of 400 r / min for 25 minutes;

[0099] The mixed material was passed through a twin-screw extruder (temperature setting: zone 1 185°C, zone 2 195°C, zone 3 205°C, zone 4 210°C; screw speed 200 r / min), extruded and water-cooled and pelletized to obtain modified UHMWPE pellets.

[0100] Comparative Example 3

[0101] 1. Raw material pretreatment: The process is the same as that of Example 1, except that the modified aramid fiber is not included.

[0102] 2. Preparation process: The process is the same as that of Example 1, except that no modified aramid fiber is added to the preparation raw materials.

[0103] Comparative Example 4

[0104] 1. Raw material pretreatment: The process is the same as that of Example 1, except that the modified nanocomposite ceramic particles are not included.

[0105] 2. Preparation process: The process is the same as that of Example 1, except that the modified nanocomposite ceramic particles are not added to the raw materials.

[0106] Comparative Example 5

[0107] 1. Raw material pretreatment: the same preparation process as in Example 1.

[0108] 2. Preparation process:

[0109] Blending and extrusion: The preparation process is the same as that in Example 1.

[0110] Solution spinning: The modified UHMWPE pellets were dissolved in a mixed solvent of decalin and paraffin oil (volume ratio of 7:3) to prepare a solution with a mass fraction of 13%, and the solution was stirred and dissolved at 135°C for 3.5 hours to ensure complete dissolution and uniform dispersion. The solution was transported to a spinneret (pore size 0.3 mm) through a metering pump and extruded at a speed of 8 m / min to form filaments. The extruded filaments entered a coagulation bath (temperature 28°C) of ethanol and water (volume ratio 8:2) and stayed for 2 minutes to complete coagulation and forming to obtain nascent fibers.

[0111] Post-processing: the same as the preparation process in Example 1.

[0112] Comparative Example 6

[0113] 1. Raw material pretreatment: the same preparation process as in Example 1.

[0114] 2. Preparation process:

[0115] Blending and extrusion: The preparation process is the same as that in Example 1.

[0116] Solution spinning: The preparation process is the same as that in Example 1.

[0117] Post-treatment: The as-spun fibers were heat-stretched at 100°C with a stretching ratio of 7 times, and then heat-treated in an oven at 180°C for 15 minutes to obtain modified ultra-high molecular weight polyethylene fibers.

[0118] Performance Testing

[0119] The modified ultra-high molecular weight polyethylene fibers prepared in Examples 1 to 3 and Comparative Examples 1 to 6 were subjected to the following tests:

[0120] Self-repair efficiency test method: Inflict 20% of the initial tensile strength on the fiber, and then test the recovery strength after standing at room temperature for 24 hours. The recovery strength is calculated as (recovery strength / initial strength) × 100%.

[0121] Mechanical properties test: The tensile strength and elongation at break of the modified ultra-high molecular weight polyethylene fibers prepared in Examples 1-3 and Comparative Examples 1-6 were tested using the method specified in GBT 19975-2005.

[0122] Cut resistance test: The modified ultra-high molecular weight polyethylene fibers prepared in Examples 1-3 and Comparative Examples 1-4 were spun, coated, and woven to produce industrial gloves. The gloves were then tested for cut resistance in accordance with EN388, the European standard for protective industrial gloves.

[0123] Puncture resistance test: The modified ultra-high molecular weight polyethylene fibers prepared in Examples 1-3 and Comparative Examples 1-4 were spun, woven and post-finished to produce a surface density of 5 kg / m 2 According to the GA68-2019 standard for police stab-resistant clothing, a puncture test is carried out on the fabric using a puncture testing machine with the specified puncture head shape and puncture speed to measure the maximum puncture force that the fiber can withstand and evaluate the puncture-resistant performance of the fiber.

[0124]

[0125]

[0126] Test data description:

[0127] 1. Mechanical properties

[0128] Examples 1-3: Through the synergistic modification of nanomaterials (carbon nanotubes, aramid nanofibers, modified ceramic particles) and innovative processes (two-stage blending, dry-wet spinning, gradient thermal stretching), the tensile strength, cut resistance and puncture resistance are all improved compared to the control example.

[0129] Comparative Example 1: The unmodified nanomaterial has poor dispersion and weak interface bonding, resulting in mechanical properties significantly lower than those in the example.

[0130] Comparative Examples 2-3: lack modified carbon nanotubes and modified aramid nanofibers respectively, the reinforcement system is incomplete, and the mechanical properties are lower than those of the embodiment, but are still better than those of Comparative Example 1.

[0131] Comparative Example 4: The modified nanocomposite ceramic particles are missing, the reinforcing effect is lost, and the mechanical properties are affected.

[0132] Comparative Example 5: Wet spinning was used without passing through an air layer, the internal structure of the fiber was not dense enough, and the mechanical properties were reduced.

[0133] Comparative Example 6: The conventional heat stretching and heat setting process failed to effectively eliminate the internal stress and improve the crystallinity, resulting in a lower elongation at break and mechanical properties inferior to those of the examples.

[0134] 2. Self-repair efficiency:

[0135] Example 1-3: Contains multiple functional components such as modified nano-composite ceramic particles, modified carbon nanotubes and modified aramid nanofibers, and the preparation process is conducive to the synergistic effect of these components, and the self-repair efficiency is high.

[0136] Comparative Example 2-3: Although some modified components are missing, it still contains modified nano-composite ceramic particles, which contributes to the self-repairing performance to a certain extent, and the self-repairing efficiency is 3%-4%.

[0137] Comparative Example 4: Due to the lack of modified nanocomposite ceramic particles, there is no self-repairing ability.

[0138] Comparative Example 5: The difference in process may have affected the self-repairing performance of the modified nanocomposite ceramic particles, but there is still a certain self-repairing efficiency of 5%.

[0139] Comparative Example 6: The post-treatment process is not conducive to the formation of the self-repair mechanism, and the self-repair efficiency is low, at 2%.

[0140] 3. Dispersion uniformity:

[0141] Examples 1-3: Nanomaterials are evenly dispersed in the matrix through two-stage blending and raw material modification.

[0142] Comparative Example 1: The unmodified raw material is easy to agglomerate and has the worst dispersibility.

[0143] Comparative Example 2-3: Due to the lack of some modified components, local uneven dispersion occurred.

[0144] Comparative Examples 4-6: The overall dispersibility is relatively good, but still not as good as the examples.

[0145] 4. Process impact:

[0146] Comparative Example 5: Wet spinning (without air layer) was used, the fiber structure was loose, and the performance was lower than that of the embodiment.

[0147] Comparative Example 6: Conventional heat stretching and setting resulted in residual internal stress, decreased elongation at break, and no pulse heat setting to improve crystallinity.

[0148] The test results show that the fiber of the embodiment of the present invention is significantly better than the control example in various performance indicators, which proves the synergistic effectiveness of the raw material formula innovation, surface treatment technology and preparation process.

[0149] It should be noted that the modified ultra-high molecular weight polyethylene fibers obtained in Examples 1 and 3 can also be surface treated. The specific process is as follows: the modified ultra-high molecular weight polyethylene fibers are immersed in polyurethane (5% by mass) or polytetrafluoroethylene solution (5% by mass), and dried and cured at 100°C for 1.5 hours. A uniform protective film can be formed on the fiber surface, thereby improving the wear resistance and corrosion resistance of the fiber.

[0150] Based on the disclosure of the above description, those skilled in the art may also make appropriate changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and any modifications and variations of the present invention should also fall within the scope of protection of the claims of the present invention. In addition, although certain specific terms are used in this description, these terms are merely for convenience of description and do not constitute any limitation to the present invention.

Claims

1. A modified ultra-high molecular weight polyethylene fiber, characterized in that: The ultra-high molecular weight polyethylene fiber comprises the following raw materials in parts by mass: 100 parts of ultra-high molecular weight polyethylene resin, 3-10 parts of modified nano-composite ceramic particles, 2-8 parts of modified aramid fiber, 1-5 parts of modified carbon nanotubes, and 1-3 parts of additives.

2. The modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: The average molecular weight of the ultra-high molecular weight polyethylene resin is 1-5 million; The particle size of the modified nanocomposite ceramic particles is 50-200 nm; The modified aramid fiber has a diameter of 5-50 nm and a length of 0.5-5 μm; The modified carbon nanotubes have a diameter of 1-20 nm and a length of 1-10 μm; The auxiliary agent comprises 0.5-1.5 parts by mass of a hindered amine light stabilizer, 0.3-1 parts by mass of an antioxidant, and 0.2-0.5 parts by mass of nano-scale titanium dioxide.

3. The modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: The modified nanocomposite ceramic particles are prepared by the following steps: firstly dispersing the nanocomposite ceramic particles in a silane coupling agent solution by ultrasonic treatment at 60-70° C., then adding a graphene solution, continuing ultrasonic treatment and dispersion, and then filtering, washing, and drying to obtain the modified nanocomposite ceramic particles.

4. The modified ultra-high molecular weight polyethylene fiber according to claim 3, characterized in that: The nanocomposite ceramic particles include 40-60 wt.% nano-aluminum oxide, 30-50 wt.% nano-silicon carbide, and 10-20 wt.% nano-zirconium oxide; The mass fraction of the silane coupling agent in the silane coupling agent solution is 3-5%; The mass fraction of graphene in the graphene solution is 1-2%; The mass ratio of the nanocomposite ceramic particles, graphene and silane coupling agent is (10-50): (0.1-1): (0.01-1).

5. The modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: The modified aramid fiber is prepared by the following steps: placing aramid nanofibers in a Tris-HCl buffer solution containing 0.5-1% dopamine hydrochloride, stirring and reacting for 6-8 hours, and then filtering, washing, and drying to obtain the modified aramid fiber; The mass ratio of the aramid nanofiber to the Tris-HCl buffer solution is 1:(5-20).

6. The modified ultra-high molecular weight polyethylene fiber according to claim 1, characterized in that: The modified carbon nanotubes are prepared by the following steps: first, acidifying the carbon nanotubes in a mixed acid, then adding the acidified carbon nanotubes to a polyethyleneimine solution, stirring and reacting at room temperature for 12-16 hours, filtering, and drying to obtain the modified carbon nanotubes; The mass ratio of the carbon nanotubes to the mixed acid is 1:(10-20), and the mass ratio of the acidified carbon nanotubes to the polyethyleneimine is 1:(1-3).

7. A method for preparing the modified ultra-high molecular weight polyethylene fiber according to any one of claims 1 to 6, characterized in that: The steps include: Weigh the following raw materials: 100 parts by mass of ultra-high molecular weight polyethylene resin, 3-10 parts by mass of modified nanocomposite ceramic particles, 2-8 parts by mass of modified aramid fiber, 1-5 parts by mass of modified carbon nanotubes, and 1-3 parts by mass of additives; The ultra-high molecular weight polyethylene resin is melted at 100-120°C, and then the modified carbon nanotubes are added, and the mixture is stirred and mixed at a speed of 800-1000 r / min for 10-15 minutes to form a base material; then the modified nano-composite ceramic particles, modified aramid fibers and additives are added to the base material, and the mixture is stirred and mixed at a speed of 300-500 r / min for 20-30 minutes. The mixed material is transferred to a twin-screw extruder for extrusion, and the temperature of the twin-screw extruder is set at 180-220°C and the screw speed is 100-300 r / min to obtain modified UHMWPE pellets; Dissolving the modified UHMWPE pellets in a mixed solvent of decalin and paraffin oil to prepare a solution with a mass fraction of 12-15%, stirring at 130-140°C for 3-4 hours to form a spinning solution; The spinning solution is delivered to the spinneret by a metering pump and extruded at the spinneret to form filaments. The filaments first pass through an air layer with a length of 10-20 cm, a temperature of 120-130°C, and a humidity of 30-40%, and then enter the coagulation bath for coagulation and forming to form primary fibers; The as-spun fiber is first pre-stretched at 80-90°C with a stretching ratio of 2-3 times, then subjected to main stretching at 110-120°C with a stretching ratio of 4-5 times, and then heat-set at 180-200°C in a pulsed manner to obtain modified ultra-high molecular weight polyethylene fiber.

8. The preparation method according to claim 7, characterized in that: The spinneret has an aperture of 0.1-0.5 mm and a spinning speed of 5-10 m / min; The specific process of the coagulation molding is as follows: the extruded filaments enter a coagulation bath with a volume ratio of ethanol to water of 8:2 for coagulation molding, the coagulation temperature is 25-30° C., and the residence time of the filaments in the coagulation bath is 1-3 minutes; The specific process of the pulse heating is: heating for 10-20 seconds, cooling for 5-10 seconds, and cycling for 3-5 times.

9. The preparation method according to claim 1, wherein: The modified ultra-high molecular weight polyethylene fiber is also surface treated. The specific process is: immersing the prepared modified ultra-high molecular weight polyethylene fiber in a polyurethane solution or a polytetrafluoroethylene solution, and then drying and curing at 80-120° C. for 1-2 hours.

10. Application of modified ultra-high molecular weight polyethylene fiber in protective products.

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