Reinforced polyolefin resin composite fiber and preparation method thereof

Abstract

The invention relates to the field of polyolefin fibers, and discloses a reinforced polyolefin resin composite fiber and a preparation method thereof.The composite fiber is prepared from high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano silicon dioxide, modified multi-walled carbon nanotubes, a polyethylene grafted maleic anhydride compatilizer, an antioxidant phosphorous acid tri (2, 2, 6-trimethyl-1, 3-pentanediol-2-yl)-2, 3, 6-trimethyl-1, 3-pentanediol-2-yl)-2, 3, 6- the antioxidant is prepared from 2, 4-di-tert-butylbenzene) ester and an antioxidant tetra [beta-(3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester; the modified multi-walled carbon nanotube is prepared from a multi-walled carbon nanotube, a concentrated nitric acid solution and a cetyl trimethyl ammonium bromide aqueous solution; the modified nano silicon dioxide is prepared from nano silicon dioxide, gamma-(methacryloyloxy) propyl trimethoxy silane, acetic acid and an ethanol water solution. The composite fiber provided by the invention has good wear resistance, antistatic property and mechanical property.

Description

Technical Field

[0001] This invention relates to the field of polyolefin fibers, and more specifically to a reinforced polyolefin resin composite fiber and its preparation method. Background Technology

[0002] Polyolefin resins are a general term for thermoplastic plastics polymerized from simple olefin monomers (such as ethylene and propylene). They are the most produced and widely used synthetic polymer materials globally. Their family mainly includes polyethylene (PE) and polypropylene (PP), boasting a vast product system. These materials are favored due to their abundant raw materials, low cost, and excellent overall performance. Common characteristics include excellent chemical stability, superior electrical insulation, low density, and good processability. By adjusting catalysts, comonomers, and process conditions, their molecular structure can be precisely controlled, thereby producing products in various forms, from highly crystalline rigid plastics to elastic rubbers, to meet diverse needs. Polyolefins are ubiquitous in daily life. From common plastic bags, cling film, and beverage bottles to household appliances, automotive parts, industrial pipes, and fiber products, their applications cover almost all industrial sectors, including packaging, agriculture, automotive, medical, and electronics.

[0003] Patent CN109487365B discloses a dyeable polyolefin fiber, which is mainly composed of polyolefin, modified polyester, compatibilizer, and antioxidant. However, the existing technology has some shortcomings: polyolefin is an excellent insulator, but during use, it is prone to generating electrostatic sparks due to charge accumulation, posing a safety hazard. Summary of the Invention

[0004] The purpose of this invention is to provide a reinforced polyolefin resin composite fiber and its preparation method, so as to solve the problems existing in the prior art.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a reinforced polyolefin resin composite fiber, wherein the composite fiber is prepared from high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; the modified multi-walled carbon nanotubes are prepared from multi-walled carbon nanotubes, concentrated nitric acid solution and hexadecyltrimethylammonium bromide aqueous solution; the modified nano-silica is prepared from nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane, acetic acid and ethanol aqueous solution.

[0006] Furthermore, the mass ratio of nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane and aqueous ethanol solution is 1:(0.15-0.25):(8-12).

[0007] Furthermore, the mass ratio of multi-walled carbon nanotubes, concentrated nitric acid solution, and hexadecyltrimethylammonium bromide aqueous solution is 1:(8-12):(15-25).

[0008] Furthermore, the mass ratio of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite, and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] is (60-70):(15-20):(2-3):(3-5):(4-6):(0.1-0.3):(0.2-0.4).

[0009] Furthermore, a method for preparing reinforced polyolefin resin composite fibers includes the following steps: (1) Preheat and dry high-density polyethylene resin at 80℃±5℃ for 2-2.2 hours; preheat and dry nano-silica with a particle size of 20-40nm and multi-walled carbon nanotubes with an outer diameter of 8-15nm and a length of 30-50μm under vacuum at 80℃±5℃ for 2-3 hours. (2) Mix γ-(methacryloyloxy)propyltrimethoxysilane with an ethanol aqueous solution of 50-60% by mass, adjust the pH value to 5.5-6.0 with acetic acid, stir at 50-60℃ and 200-300rpm for 30-40 minutes, then add nano-silica, sonicate at 300-400W for 30-40 minutes, filter, wash with anhydrous ethanol 2-4 times, and then vacuum dry at 70-80℃ for 4-6 hours to obtain modified nano-silica; (3) Add multi-walled carbon nanotubes to a concentrated nitric acid solution with a mass fraction of 55-65%, and sonicate at 65-75℃ for 2-4 hours. The ultrasonic power is 300-500W and the frequency is 35-45kHz. After treatment, wash with deionized water until neutral, and then vacuum dry at 85-95℃ for 6-8 hours to obtain acidified multi-walled carbon nanotubes. Add the acidified multi-walled carbon nanotubes to a hexadecyltrimethylammonium bromide aqueous solution with a mass fraction of 3-5%, stir at 60-70℃ at 400-600rpm for 3-5 hours, filter, wash with ethanol 3-5 times, and vacuum dry at 75-85℃ for 4-6 hours to obtain modified multi-walled carbon nanotubes. (4) Place half of the total mass of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted maleic anhydride compatibilizer with a grafting rate of 0.8-1.2%, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] in a mixer and mix at a speed of 600-800 rpm for 5-10 minutes to obtain a premix. (5) The premixed material is added to a twin-screw extruder for co-extrusion, and then water-cooled and pelletized to obtain composite masterbatch; (6) Mix the composite masterbatch and the remaining high-density polyethylene, then melt spin and cool to obtain nascent fibers; (7) The nascent fibers are stretched in two stages, and then heat-set in a heat-setting box at 100-120℃ in a relaxed state for 1-2 minutes. After oiling, the composite fibers are obtained by winding.

[0010] Furthermore, the molecular weight of high-density polyethylene resin is 120,000-150,000.

[0011] Furthermore, the ultra-high molecular weight polyethylene powder has a particle size of 20-30 μm and a molecular weight of 2-3 million.

[0012] Furthermore, in step (5), the temperature zones of the twin-screw extruder are: zone 1 165-175℃, zone 2 185-195℃, zone 3 195-205℃, zone 4 200-210℃, and die head 205-220℃. The screw speed is controlled at 200-400 rpm, and the length-to-diameter ratio is 39-41:1.

[0013] Furthermore, the conditions for melt spinning in step (6) are: spinneret orifice diameter 0.24-0.26 mm, spinning rate 60-100 m / min, and spinning temperature 200-230 ℃.

[0014] Furthermore, in step (7), the two-stage stretching is as follows: the first stage uses hot water stretching at 90-99℃ with a stretching ratio of 3-5 times; the second stage uses hot roller stretching at 100-120℃ with a stretching ratio of 2-3 times.

[0015] Compared with the prior art, the beneficial effects achieved by the present invention are: 1. This invention employs γ-(methacryloyloxy)propyltrimethoxysilane to perform surface grafting modification on nano-silica. The methoxy group at one end of this silane coupling agent molecule hydrolyzes to generate silanol groups, which then undergo a condensation reaction with the silanol groups on the surface of nano-silica to form Si-O-Si covalent bonds. This reduces the surface energy of the nano-silica and improves its interfacial compatibility with organic matrices. Secondly, multi-walled carbon nanotubes are acidified and modified with surfactants. Treatment with concentrated nitric acid introduces oxygen-containing functional groups such as carboxyl groups into the tube walls. These functional groups subsequently bind with the quaternary ammonium cations in hexadecyltrimethylammonium bromide through ionic bonds. The introduction of long alkyl chains significantly improves the nonpolar properties of multi-walled carbon nanotubes. The dispersibility of the modified polyolefin matrix; the anhydride groups in the polyethylene grafted maleic anhydride compatibilizer molecules can strongly interact with the active groups (methacryloyloxy groups of silanes or quaternary ammonium salt cationic polar head groups on the surface of carbon nanotubes) on the surface of the modified filler, while its polyethylene segments are entangled with the resin matrix, thereby constructing an interfacial bridge between the filler and the matrix; ultra-high molecular weight polyethylene powder serves as a reinforcing phase to improve the strength of the fiber; nano-silica, as a hard dispersed phase, acts as a stress-bearing point and a friction resistance point, improving the stiffness and wear resistance of the fiber, while the uniformly dispersed modified multi-walled carbon nanotubes form conductive pathways in the matrix through mutual overlap, giving the fiber antistatic ability. Detailed Implementation

[0016] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0017] A reinforced polyolefin resin composite fiber is provided, comprising high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite, and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; the modified multi-walled carbon nanotubes are prepared by multi-walled carbon nanotubes, concentrated nitric acid solution, and hexadecyltrimethylammonium bromide aqueous solution; the modified nano-silica is prepared by nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane, acetic acid, and ethanol aqueous solution.

[0018] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products. Example 1

[0019] (1) High-density polyethylene resin with a molecular weight of 120,000 was preheated and dried at 75°C for 2 hours; nano-silica with a particle size of 20 nm and multi-walled carbon nanotubes with an outer diameter of 8 nm and a length of 30 μm were pre-vacuum dried at 75°C for 2 hours. (2) Mix γ-(methacryloyloxy)propyltrimethoxysilane with a 50% ethanol aqueous solution, adjust the pH to 5.5 with acetic acid, stir at 50°C and 200 rpm for 30 minutes, then add nano-silica, sonicate at 300W for 30 minutes, filter, wash twice with anhydrous ethanol, and then vacuum dry at 70°C for 4 hours to obtain modified nano-silica; The mass ratio of nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane, and aqueous ethanol solution is 1:0.15:8.

[0020] (3) Multi-walled carbon nanotubes were added to a 55% concentrated nitric acid solution and ultrasonically treated at 65°C for 2 hours. The ultrasonic power was 300W and the frequency was 35kHz. After treatment, the nanotubes were washed with deionized water until neutral and then vacuum dried at 85°C for 6 hours to obtain acidified multi-walled carbon nanotubes. The acidified multi-walled carbon nanotubes were added to a 3% hexadecyltrimethylammonium bromide aqueous solution and stirred at 400rpm at 60°C for 3 hours. After filtration, the nanotubes were washed three times with ethanol and vacuum dried at 75°C for 4 hours to obtain modified multi-walled carbon nanotubes. The mass ratio of multi-walled carbon nanotubes, concentrated nitric acid solution, and hexadecyltrimethylammonium bromide aqueous solution is 1:8:15.

[0021] (4) Half of the total mass of high-density polyethylene, ultra-high molecular weight polyethylene powder with a particle size of 20 μm and a molecular weight of 2 million, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer with a grafting rate of 0.8%, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] were placed in a mixer and mixed at 600 rpm for 5 minutes to obtain a premix. (5) Add the premixed material into the twin-screw extruder and perform co-extrusion according to the following temperature zones: Zone 1 165℃, Zone 2 185℃, Zone 3 195℃, Zone 4 200℃, and Die head 205℃. The screw speed is controlled at 200 rpm and the length-to-diameter ratio is 39:1. The composite masterbatch is obtained by water cooling and pelletizing. The mass ratio of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite, and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] is 60:15:2:3:4:0.1:0.2.

[0022] (6) The composite masterbatch and the remaining high-density polyethylene are mixed, then melt-spun and cooled to obtain nascent fibers. The melt-spinning conditions are: spinneret orifice diameter 0.24 mm, spinning rate 60 m / min, and spinning temperature 200 °C. (7) The nascent fiber is stretched in two stages. The first stage is stretched with hot water at 90℃, and the stretching ratio is 3 times. The second stage is stretched with hot rollers at 100℃, and the stretching ratio is 2 times. Then, in a relaxed state, it is heat-set in a heat-setting box at 100℃ for 1 minute, oiled, and wound to obtain composite fiber. Example 2

[0023] (1) High-density polyethylene resin with a molecular weight of 135,000 was preheated and dried at 80°C for 2.1 hours; nano-silica with a particle size of 30 nm and multi-walled carbon nanotubes with an outer diameter of 11.5 nm and a length of 40 μm were pre-vacuum dried at 80°C for 2.5 hours. (2) Mix γ-(methacryloyloxy)propyltrimethoxysilane and a 55% ethanol aqueous solution, adjust the pH to 5.75 with acetic acid, stir at 55°C and 250 rpm for 35 minutes, then add nano-silica, sonicate at 350W for 35 minutes, filter, wash three times with anhydrous ethanol, and then vacuum dry at 75°C for 5 hours to obtain modified nano-silica; The mass ratio of nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane, and aqueous ethanol solution is 1:0.2:10.

[0024] (3) Multi-walled carbon nanotubes were added to a 60% concentrated nitric acid solution and ultrasonically treated at 70°C for 3 hours with an ultrasonic power of 400W and a frequency of 40kHz. After treatment, they were washed with deionized water until neutral and then vacuum dried at 90°C for 7 hours to obtain acidified multi-walled carbon nanotubes. The acidified multi-walled carbon nanotubes were added to a 4% hexadecyltrimethylammonium bromide aqueous solution and stirred at 500rpm at 65°C for 4 hours. After filtration, they were washed with ethanol 4 times and vacuum dried at 80°C for 5 hours to obtain modified multi-walled carbon nanotubes. The mass ratio of multi-walled carbon nanotubes, concentrated nitric acid solution, and hexadecyltrimethylammonium bromide aqueous solution is 1:10:20.

[0025] (4) Half of the total mass of high-density polyethylene, ultra-high molecular weight polyethylene powder with a particle size of 30 μm and a molecular weight of 2.5 million, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer with a grafting rate of 1.0%, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] were placed in a mixer and mixed at a speed of 700 rpm for 7.5 minutes to obtain a premix. (5) Add the premixed material to the twin-screw extruder and perform co-extrusion according to the following temperature zones: Zone 1 170℃, Zone 2 190℃, Zone 3 200℃, Zone 4 205℃, and Die head 212.5℃. The screw speed is controlled at 300 rpm and the length-to-diameter ratio is 40:1. The composite masterbatch is obtained by water cooling and pelletizing. The mass ratio of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite, and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] was 65:17.5:2.5:4:5:0.2:0.3.

[0026] (6) The composite masterbatch and the remaining high-density polyethylene are mixed, then melt-spun and cooled to obtain nascent fibers; the melt-spinning conditions are: spinneret orifice diameter 0.25 mm, spinning rate 80 m / min, spinning temperature 215 °C. (7) The nascent fiber is stretched in two stages. The first stage is stretched with hot water at 94.5℃, with a stretching ratio of 4 times. The second stage is stretched with hot rollers at 110℃, with a stretching ratio of 2.5 times. Then, in a relaxed state, it is heat-set in a heat-setting box at 110℃ for 1.5 minutes, oiled, and wound to obtain composite fiber. Example

[0027] (1) The high-density polyethylene resin with a molecular weight of 150,000 was preheated and dried at 85°C for 2.2 hours; the nano-silica with a particle size of 40 nm and the multi-walled carbon nanotubes with an outer diameter of 15 nm and a length of 50 μm were pre-vacuum dried at 85°C for 3 hours. (2) Mix γ-(methacryloyloxy)propyltrimethoxysilane with a 60% ethanol aqueous solution, adjust the pH to 6.0 with acetic acid, stir at 60°C and 300 rpm for 40 minutes, then add nano-silica, sonicate at 400W for 40 minutes, filter, wash 4 times with anhydrous ethanol, and then vacuum dry at 80°C for 6 hours to obtain modified nano-silica; The mass ratio of nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane, and aqueous ethanol solution is 1:0.25:12.

[0028] (3) Multi-walled carbon nanotubes were added to a 65% concentrated nitric acid solution and ultrasonically treated at 75°C for 4 hours with an ultrasonic power of 500W and a frequency of 45kHz. After treatment, they were washed with deionized water until neutral and then vacuum dried at 95°C for 8 hours to obtain acidified multi-walled carbon nanotubes. The acidified multi-walled carbon nanotubes were added to a 5% hexadecyltrimethylammonium bromide aqueous solution and stirred at 70°C at 600rpm for 5 hours. After filtration, they were washed with ethanol 5 times and vacuum dried at 85°C for 6 hours to obtain modified multi-walled carbon nanotubes. The mass ratio of multi-walled carbon nanotubes, concentrated nitric acid solution, and hexadecyltrimethylammonium bromide aqueous solution is 1:12:25.

[0029] (4) Half of the total mass of high-density polyethylene, ultra-high molecular weight polyethylene powder with a particle size of 30 μm and a molecular weight of 3 million, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer with a grafting rate of 1.2%, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] were placed in a mixer and mixed at 800 rpm for 10 minutes to obtain a premix. (5) Add the premixed material into the twin-screw extruder and perform co-extrusion according to the following temperature zones: Zone 1 175℃, Zone 2 195℃, Zone 3 205℃, Zone 4 210℃, and Die head 220℃. The screw speed is controlled at 400 rpm and the length-to-diameter ratio is 41:1. The composite masterbatch is obtained by water cooling and pelletizing. The mass ratio of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite, and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] was 70:20:3:5:6:0.3:0.4.

[0030] (6) The composite masterbatch and the remaining high-density polyethylene are mixed, then melt-spun and cooled to obtain nascent fibers. The melt-spinning conditions are: spinneret orifice diameter 0.26 mm, spinning rate 100 m / min, and spinning temperature 230 °C. (7) The nascent fiber is stretched in two stages. The first stage is stretched with hot water at 99℃, and the stretching ratio is 5 times. The second stage is stretched with hot rollers at 120℃, and the stretching ratio is 3 times. Then, in a relaxed state, it is heat-set in a heat-setting box at 120℃ for 2 minutes, oiled, and wound to obtain composite fiber.

[0031] Comparative Example 1 The only difference between Comparative Example 1 and Example 1 is that γ-(methacryloyloxy)propyltrimethoxysilane was not used to treat the surface of the nano-silica; instead, unmodified nano-silica was used directly.

[0032] Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that the multi-walled carbon nanotubes were not surface-treated with concentrated nitric acid and hexadecyltrimethylammonium bromide; instead, unmodified multi-walled carbon nanotubes were used directly.

[0033] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that ultra-high molecular weight polyethylene powder is not added.

[0034] Comparative Example 4 The only difference between Comparative Example 4 and Example 1 is that no polyethylene-grafted maleic anhydride compatibilizer was added.

[0035] Tensile properties were tested according to GB / T14344-2022. The fibers were woven in a plain weave with a fabric density of 120 warp ends / 10cm and 80 weft ends / 10cm. Antistatic properties were tested according to GB / T12703.3-2009, and abrasion resistance was tested according to GB / T21196.2-2007.

[0036] Table 1 below shows the performance analysis results of the embodiments and comparative examples of the present invention.

[0037] Table 1 Sample group Fracture strength (cN / dtex) Number of rubbing cycles when the sample breaks Charge density (μC / m²) Example 1 40.2 128000 1.7 Example 2 43.5 135000 1.4 Example 3 41.8 132000 1.5 Comparative Example 1 31.5 72000 4.8 Comparative Example 2 34.2 78000 4.5 Comparative Example 3 36.8 88000 4.2 Comparative Example 4 33.1 82000 4.0 Experimental data from the examples and comparative examples show that this invention uses γ-(methacryloyloxy)propyltrimethoxysilane to modify nano-silica, concentrated nitric acid and hexadecyltrimethylammonium bromide to modify multi-walled carbon nanotubes, ultra-high molecular weight polyethylene powder as the reinforcing phase, and polyethylene grafted with maleic anhydride as a compatibilizer. After hydrolysis, the silanol groups of γ-(methacryloyloxy)propyltrimethoxysilane condense with the silanol groups on the surface of nano-silica to form Si-O-Si covalent bonds, improving the dispersibility and interfacial bonding of nano-silica in the organic phase. After acidification with concentrated nitric acid, the multi-walled carbon nanotubes exhibit improved dispersion on their walls. The introduction of oxygen-containing functional groups such as carboxyl groups further binds to the quaternary ammonium cations in hexadecyltrimethylammonium bromide through ionic bonds. The introduction of long alkyl chains enhances the compatibility between carbon nanotubes and polyolefin matrices. Ultra-high molecular weight polyethylene powder serves as a reinforcing phase to improve the strength and wear resistance of fibers. The maleic anhydride compatibilizer grafted onto polyethylene has an anhydride group in its molecule that can strongly interact with the active groups on the surface of the modified nanofiller, while its polyethylene segments become entangled with the resin matrix. This creates an interfacial bridge between the inorganic filler and the organic polymer matrix, preventing phase separation and ensuring effective stress transfer.

[0038] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A reinforced polyolefin resin composite fiber, characterized in that, The composite fiber is prepared from high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite, and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]; the modified multi-walled carbon nanotubes are prepared from multi-walled carbon nanotubes, concentrated nitric acid solution, and hexadecyltrimethylammonium bromide aqueous solution; the modified nano-silica is prepared from nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane, acetic acid, and ethanol aqueous solution.

2. The reinforced polyolefin resin composite fiber according to claim 1, characterized in that... The mass ratio of nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane and aqueous ethanol solution is 1:(0.15-0.25):(8-12).

3. The reinforced polyolefin resin composite fiber according to claim 2, characterized in that... The mass ratio of multi-walled carbon nanotubes, concentrated nitric acid solution, and hexadecyltrimethylammonium bromide aqueous solution is 1:(8-12):(15-25).

4. The reinforced polyolefin resin composite fiber according to claim 3, characterized in that... The mass ratio of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted with maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] is (60-70):(15-20):(2-3):(3-5):(4-6):(0.1-0.3):(0.2-0.4).

5. The method for preparing reinforced polyolefin resin composite fiber according to claim 4, characterized in that, Includes the following steps: (1) Preheat and dry high-density polyethylene resin at 80℃±5℃ for 2-2.2 hours; preheat and dry nano-silica with a particle size of 20-40nm and multi-walled carbon nanotubes with an outer diameter of 8-15nm and a length of 30-50μm under vacuum at 80℃±5℃ for 2-3 hours. (2) Mix γ-(methacryloyloxy)propyltrimethoxysilane with an ethanol aqueous solution of 50-60% by mass, adjust the pH value to 5.5-6.0 with acetic acid, stir at 50-60℃ and 200-300rpm for 30-40 minutes, then add nano-silica, sonicate at 300-400W for 30-40 minutes, filter, wash with anhydrous ethanol 2-4 times, and then vacuum dry at 70-80℃ for 4-6 hours to obtain modified nano-silica; (3) Add multi-walled carbon nanotubes to a concentrated nitric acid solution with a mass fraction of 55-65%, and sonicate at 65-75℃ for 2-4 hours. The ultrasonic power is 300-500W and the frequency is 35-45kHz. After treatment, wash with deionized water until neutral, and then vacuum dry at 85-95℃ for 6-8 hours to obtain acidified multi-walled carbon nanotubes. Add the acidified multi-walled carbon nanotubes to a hexadecyltrimethylammonium bromide aqueous solution with a mass fraction of 3-5%, stir at 60-70℃ at 400-600rpm for 3-5 hours, filter, wash with ethanol 3-5 times, and vacuum dry at 75-85℃ for 4-6 hours to obtain modified multi-walled carbon nanotubes. (4) Place half of the total mass of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted maleic anhydride compatibilizer with a grafting rate of 0.8-1.2%, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] in a mixer and mix at a speed of 600-800 rpm for 5-10 minutes to obtain a premix. (5) The premixed material is added to a twin-screw extruder for co-extrusion, and then water-cooled and pelletized to obtain composite masterbatch; (6) Mix the composite masterbatch and the remaining high-density polyethylene, then melt spin and cool to obtain nascent fibers; (7) The nascent fibers are stretched in two stages, and then heat-set in a heat-setting box at 100-120℃ in a relaxed state for 1-2 minutes. After oiling, the composite fibers are obtained by winding.

6. The method for preparing a reinforced polyolefin resin composite fiber according to claim 5, characterized in that... The molecular weight of high-density polyethylene resin is 120,000-150,000.

7. The method for preparing reinforced polyolefin resin composite fiber according to claim 5, characterized in that... The particle size of ultra-high molecular weight polyethylene powder is 20-30μm, and the molecular weight is 2-3 million.

8. The method for preparing a reinforced polyolefin resin composite fiber according to claim 5, characterized in that... In step (5), the temperature zones of the twin-screw extruder are: Zone 1 165-175℃, Zone 2 185-195℃, Zone 3 195-205℃, Zone 4 200-210℃, and the die head 205-220℃. The screw speed is controlled at 200-400 rpm, and the length-to-diameter ratio is 39-41:

1.

9. The method for preparing a reinforced polyolefin resin composite fiber according to claim 5, characterized in that... The conditions for melt spinning in step (6) are: spinneret orifice diameter 0.24-0.26 mm, spinning rate 60-100 m / min, and spinning temperature 200-230 ℃.

10. The method for preparing a reinforced polyolefin resin composite fiber according to claim 5, characterized in that... In step (7), the two-stage stretching is as follows: the first stage uses hot water stretching at 90-99℃ with a stretching ratio of 3-5 times; the second stage uses hot roller stretching at 100-120℃ with a stretching ratio of 2-3 times.