Reinforced polyolefin resin composite fiber and method for producing the same

Abstract

The application relates to the field of polyolefin fibers, and discloses a reinforced polyolefin resin composite fiber and a preparation method thereof, wherein the composite fiber is prepared from high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano silicon dioxide, modified multi-walled carbon nanotubes, polyethylene grafted maleic anhydride compatilizer, antioxidant tris(2,4-di-t-butylphenyl) phosphite and antioxidant tetra[beta-(3,5-di-t-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester; the modified multi-walled carbon nanotubes are prepared from multi-walled carbon nanotubes, concentrated nitric acid solution and hexadecyl trimethyl ammonium bromide aqueous solution; and the modified nano silicon dioxide is prepared from nano silicon dioxide, gamma-(methacryloyloxy) propyl trimethoxysilane, acetic acid and ethanol aqueous solution. The composite fiber has good wear resistance, antistatic property and mechanical property.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of polyolefin fibers, in particular to a reinforced polyolefin resin composite fiber and a preparation method thereof. BACKGROUND

[0002] Polyolefin resin is a general term for a class of thermoplastics that are polymerized from simple olefin monomers such as ethylene and propylene. It is the largest and most widely used synthetic polymer material in the world. Its family mainly includes polyethylene (PE), polypropylene (PP), etc., with a huge product system. This kind of material is favored because of its abundant raw materials, low cost and excellent comprehensive performance. Its common characteristics include excellent chemical stability, excellent electrical insulation, low density and good processing performance. By adjusting the catalyst, comonomer and process conditions, the molecular structure can be precisely controlled, so as to produce different forms of products from high crystallinity rigid plastics to elastic rubbers, to meet the diversified needs. In daily life, polyolefins are everywhere. From common plastic bags, preservative films, beverage bottles, to household appliances, automobile parts, industrial pipes and fiber products, their applications cover packaging, agriculture, automobiles, medical care, electronics and almost all industrial fields.

[0003] The patent with publication number CN109487365B discloses a dyeable polyolefin fiber, which mainly consists of polyolefin, modified polyester, compatibilizer and antioxidant. The existing technology still has some deficiencies: polyolefin is an excellent insulator, which is easy to produce static sparks due to charge accumulation during use, causing safety hazards. SUMMARY

[0004] The purpose of the present application is to provide a reinforced polyolefin resin composite fiber and a preparation method thereof to solve the problems in the prior art.

[0005] In order to solve the above technical problems, the present application provides the following technical scheme: a reinforced polyolefin resin composite fiber, which is prepared from high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silicon dioxide, modified multi-walled carbon nanotubes, polyethylene grafted maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester; the modified multi-walled carbon nanotubes are prepared from multi-walled carbon nanotubes, concentrated nitric acid solution and hexadecyl trimethyl ammonium bromide aqueous solution; and the modified nano-silicon dioxide is prepared from nano-silicon dioxide, γ-(methacryloyloxy) propyl trimethoxysilane and ethanol aqueous solution.

[0006] Further, the mass ratio of nano-silicon dioxide, γ-(methacryloyloxy) propyl trimethoxysilane and ethanol aqueous solution is 1:(0.15-0.25):(8-12).

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

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

[0009] Further, a method for preparing a reinforced polyolefin resin composite fiber comprises the following steps:

[0010] (1) The high-density polyethylene resin is preheated and dried at 80℃±5℃ for 2-2.2 hours; the nano-silica with a particle size of 20-40 nm and the multi-walled carbon nanotube with an outer diameter of 8-15 nm and a length of 30-50 μm are pre-dried in vacuum at 80℃±5℃ for 2-3 hours;

[0011] (2) The γ-(methacryloyloxy) propyl trimethoxysilane is mixed with the aqueous solution of ethanol with a mass fraction of 50-60%, the pH value is adjusted to 5.5-6.0 with acetic acid, and the mixture is stirred at 50-60℃ and a rotation speed of 200-300 rpm for 30-40 minutes, then the nano-silica is added, and the mixture is ultrasonically treated at a power of 300-400 W for 30-40 minutes, and then filtered, washed with anhydrous ethanol for 2-4 times, and dried in vacuum at 70-80℃ for 4-6 hours to obtain the modified nano-silica;

[0012] (3) The multi-walled carbon nanotube is added to the concentrated nitric acid solution with a mass fraction of 55-65%, and ultrasonically treated at 65-75℃ for 2-4 hours at an ultrasonic power of 300-500 W and a frequency of 35-45 kHz, then washed with deionized water until neutral, and dried in vacuum at 85-95℃ for 6-8 hours to obtain the acidified multi-walled carbon nanotube; the acidified multi-walled carbon nanotube is added to the aqueous solution of cetyltrimethylammonium bromide with a mass fraction of 3-5%, and stirred at 400-600 rpm at 60-70℃ for 3-5 hours, then filtered, washed with ethanol for 3-5 times, and dried in vacuum at 75-85℃ for 4-6 hours to obtain the modified multi-walled carbon nanotube;

[0013] (4) 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 tetra [beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester are placed in a mixer and mixed at a speed of 600-800 rpm for 5-10 minutes to obtain a premix;

[0014] (5) the premix is added to a twin-screw extruder for blending and extrusion, and then granulated by water cooling to obtain a composite master batch;

[0015] (6) the composite master batch and the remaining high-density polyethylene are mixed, and then melt spinning is carried out to obtain a nascent fiber after cooling;

[0016] (7) the nascent fiber is subjected to two-stage drawing, and then heat setting is carried out in a heat setting box at 100-120℃ in a relaxed state, the treatment time is 1-2 minutes, oiling is carried out, and winding is carried out to obtain a composite fiber.

[0017] Further, the molecular weight of the high-density polyethylene resin is 120-150 million.

[0018] Further, the particle size of the ultra-high molecular weight polyethylene powder is 20-30 μm, and the molecular weight is 2-3 million.

[0019] Further, in step (5), the temperature partition of the twin-screw extruder is: zone 1 165-175℃, zone 2 185-195℃, zone 3 195-205℃, zone 4 200-210℃, and the die 205-220℃, and the screw rotation speed is controlled at 200-400 rpm, and the length-diameter ratio is 39-41:1.

[0020] Further, in step (6), the conditions of melt spinning are: spinneret hole diameter 0.24-0.26 mm, spinning rate 60-100 m / min, and spinning temperature 200-230℃.

[0021] Further, in step (7), the two-stage drawing is: the first stage uses hot water drawing at 90-99℃, and the drawing multiple is 3-5 times; the second stage uses hot roller drawing at 100-120℃, and the drawing multiple is 2-3 times.

[0022] Compared with the prior art, the beneficial effects achieved by the present application are:

[0023] 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

[0024] 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.

[0025] 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.

[0026] 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

[0027] (1) The high-density polyethylene resin with a molecular weight of 120,000 was preheated and dried at 75°C for 2 hours; the nano-silica with a particle size of 20 nm and the multi-walled carbon nanotube with an outer diameter of 8 nm and a length of 30 μm were pre-dried in vacuum at 75°C for 2 hours;

[0028] (2) The γ-(methacryloyloxy)propyl trimethoxysilane and the 50% mass fraction ethanol aqueous solution were mixed, the pH value was adjusted to 5.5 with acetic acid, and then stirred at 50°C and 200 rpm for 30 minutes, and then the nano-silica was added, and ultrasonic treatment was carried out at a power of 300 W for 30 minutes, and then filtered and washed with anhydrous ethanol for 2 times, and then dried in vacuum at 70°C for 4 hours to obtain the modified nano-silica;

[0029] The mass ratio of the nano-silica, the γ-(methacryloyloxy)propyl trimethoxysilane and the ethanol aqueous solution is 1:0.15:8.

[0030] (3) The multi-walled carbon nanotube was added into the concentrated nitric acid solution with a mass fraction of 55%, and ultrasonic treatment was carried out at 65°C for 2 hours, the ultrasonic power was 300 W, and the frequency was 35 kHz, and then the treated product was washed with deionized water until neutral, and then dried in vacuum at 85°C for 6 hours to obtain the acidified multi-walled carbon nanotube; the acidified multi-walled carbon nanotube was added into the cetyltrimethylammonium bromide aqueous solution with a mass fraction of 3%, and stirred at 400 rpm at 60°C for 3 hours, and then filtered and washed with ethanol for 3 times, and then dried in vacuum at 75°C for 4 hours to obtain the modified multi-walled carbon nanotube;

[0031] The mass ratio of the multi-walled carbon nanotube, the concentrated nitric acid solution and the cetyltrimethylammonium bromide aqueous solution is 1:8:15.

[0032] (4) Half of the total mass of the high-density polyethylene, the ultra-high molecular weight polyethylene powder with a particle size of 20 μm and a molecular weight of 2,000,000, the modified nano-silica, the modified multi-walled carbon nanotube, the polyethylene grafted maleic anhydride compatibilizer with a grafting rate of 0.8%, the antioxidant tris(2,4-di-tert-butylphenyl) phosphite and the antioxidant tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester were placed in a mixer, and mixed at a rotation speed of 600 rpm for 5 minutes to obtain a premix;

[0033] (5) The premix was added into a twin-screw extruder, and blended and extruded according to the following temperature zoning: the first zone was 165°C, the second zone was 185°C, the third zone was 195°C, the fourth zone was 200°C, and the die head was 205°C, the screw rotation speed was controlled at 200 rpm, and the length-diameter ratio was 39:1, and then the composite master batch was obtained by water cooling and pelletizing;

[0034] 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.

[0035] (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.

[0036] (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

[0037] (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.

[0038] (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;

[0039] The mass ratio of nano-silica, γ-(methacryloyloxy)propyltrimethoxysilane, and aqueous ethanol solution is 1:0.2:10.

[0040] (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.

[0041] The mass ratio of the multi-walled carbon nanotube, the concentrated nitric acid solution and the aqueous solution of cetyltrimethylammonium bromide is 1:10:20.

[0042] (4) Half of the total mass of the high-density polyethylene, an 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, a polyethylene grafted maleic anhydride compatibilizer with a grafting rate of 1.0%, the antioxidant tris(2,4-di-tert-butylphenyl) phosphite and the antioxidant tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester are placed in a mixer and mixed at a rotation speed of 700 rpm for 7.5 minutes to obtain a premix;

[0043] (5) The premix is added to a twin-screw extruder and blended and extruded in the following temperature zones: 170℃ in the first zone, 190℃ in the second zone, 200℃ in the third zone, 205℃ in the fourth zone and 212.5℃ in the die head, with the screw rotation speed controlled at 300 rpm and the length-diameter ratio at 40:1, and the composite master batch is obtained by water cooling and pelletizing;

[0044] The mass ratio of the high-density polyethylene, the ultra-high molecular weight polyethylene powder, the modified nano-silica, the modified multi-walled carbon nanotubes, the polyethylene grafted maleic anhydride compatibilizer, the antioxidant tris(2,4-di-tert-butylphenyl) phosphite and the antioxidant tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester is 65:17.5:2.5:4:5:0.2:0.3.

[0045] (6) The composite master batch and the remaining high-density polyethylene are mixed, and then melt spinning is performed to obtain a nascent fiber; the melt spinning conditions are: spinneret hole diameter 0.25 mm, spinning rate 80 m / min and spinning temperature 215℃,

[0046] (7) The nascent fiber is subjected to two-stage drawing, the first stage being drawing with hot water at 94.5℃ with a draw ratio of 4 times, and the second stage being drawing with hot rollers at 110℃ with a draw ratio of 2.5 times; then, heat setting is performed in a heat setting oven at 110℃ in a relaxed state for 1.5 minutes, oiling is performed and the composite fiber is obtained by winding. Example

[0047] (1) The high-density polyethylene resin with a molecular weight of 150,000 is preheated and dried at 85℃ for 2.2 hours; the nano-silica with a particle size of 40 nm and the multi-walled carbon nanotube with an outer diameter of 15 nm and a length of 50 μm are pre-dried in a vacuum at 85℃ for 3 hours;

[0048] (2) mixed γ-(methacryloyloxy)propyl trimethoxysilane and 60% ethanol aqueous solution, adjusted pH value to 6.0 with acetic acid, stirred at 60℃ and 300 rpm for 40 min, then added nano-silica, ultrasonic treated for 40 min with 400 W, filtered, washed with anhydrous ethanol for 4 times, and then dried at 80℃ for 6 h under vacuum to obtain modified nano-silica;

[0049] wherein the mass ratio of nano-silica, γ-(methacryloyloxy)propyl trimethoxysilane and ethanol aqueous solution is 1:0.25:12.

[0050] (3) added multi-walled carbon nanotubes into 65% concentrated nitric acid solution, ultrasonic treated for 4 h at 75℃ with 500 W and 45 kHz, washed with deionized water to neutral after treatment, and then dried at 95℃ for 8 h under vacuum to obtain acidified multi-walled carbon nanotubes; added the acidified multi-walled carbon nanotubes into 5% cetyltrimethylammonium bromide aqueous solution, stirred at 70℃ for 5 h with 600 rpm, washed with ethanol for 5 times after filtration, and then dried at 85℃ for 6 h under vacuum to obtain modified multi-walled carbon nanotubes;

[0051] The mass ratio of multi-walled carbon nanotubes, concentrated nitric acid solution and cetyltrimethylammonium bromide aqueous solution is 1:12:25.

[0052] (4) mixed half of the total mass of high-density polyethylene, 30 μm particle size, 3 million molecular weight of ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, 1.2% grafting rate of polyethylene grafted maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester in a mixer at 800 rpm for 10 min to obtain a premix;

[0053] (5) added the premix into a twin-screw extruder, and blended and extruded according to the following temperature zoning: 175℃ for zone 1, 195℃ for zone 2, 205℃ for zone 3, 210℃ for zone 4, and 220℃ for the die head, with screw rotation speed controlled at 400 rpm and length-diameter ratio of 41:1, and then water-cooled and pelletized to obtain a composite master batch;

[0054] The mass ratio of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotubes, polyethylene grafted maleic anhydride compatibilizer, antioxidant tris(2,4-di-tert-butylphenyl) phosphite and antioxidant tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester is 70:20:3:5:6:0.3:0.4.

[0055] (6) mixing the composite master batch and the remaining high density polyethylene, and then melt spinning, cooling to obtain the as-spun fiber; the melt spinning conditions are: spinneret aperture 0.26 mm, spinning rate 100 m / min, spinning temperature 230℃,

[0056] (7) the as-spun fiber is subjected to two-stage drawing, the first stage uses 99℃ hot water drawing with a draw ratio of 5 times; the second stage uses 120℃ hot roller drawing with a draw ratio of 3 times; then in a relaxed state, heat setting is carried out in a heat setting oven at 120℃ for 2 minutes, oiling, and winding to obtain the composite fiber.

[0057] Comparative Example 1

[0058] The difference between Comparative Example 1 and Example 1 is only that the nano-silica is not surface treated with γ-(methacryloyloxy)propyl trimethoxysilane, but directly used as unmodified.

[0059] Comparative Example 2

[0060] The difference between Comparative Example 2 and Example 1 is only that the multi-walled carbon nanotube is not surface treated with concentrated nitric acid and cetyltrimethylammonium bromide, but directly used as unmodified.

[0061] Comparative Example 3

[0062] The difference between Comparative Example 3 and Example 1 is only that the ultra-high molecular weight polyethylene powder is not added.

[0063] Comparative Example 4

[0064] The difference between Comparative Example 4 and Example 1 is only that the polyethylene grafted maleic anhydride compatibilizer is not added.

[0065] The tensile property test is carried out according to GB / T14344-2022. The fiber is woven with plain weave, the fabric density is 120 ends / 10 cm in the warp direction and 80 ends / 10 cm in the weft direction, the antistatic property is tested according to GB / T12703.3-2009, and the wear resistance test is referenced to GB / T21196.2-2007.

[0066] The performance analysis results of the examples and comparative examples of the application are given in the following Table 1.

[0067] Table 1

[0068] Sample group Breaking strength (cN / dtex) Friction count at breakage (times) 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

[0069] From the experimental data of the examples and comparative examples, it can be found that the present application uses γ-(methacryloyloxy) propyl trimethoxysilane to modify nano-silica, concentrated nitric acid and cetyl trimethyl ammonium bromide to modify multi-walled carbon nanotubes, and uses ultra-high molecular weight polyethylene powder as a reinforcing phase, and polyethylene grafted maleic anhydride as a compatibilizer. After hydrolysis of γ-(methacryloyloxy) propyl trimethoxysilane, the silicon hydroxyl groups thereof condense with the silicon hydroxyl groups on the surface of nano-silica to form Si-O-Si covalent bonds, which improves the dispersibility and interfacial bonding force of nano-silica in the organic phase. After acidification treatment of multi-walled carbon nanotubes with concentrated nitric acid, carboxyl groups and other oxygen-containing functional groups are introduced into the walls of the carbon nanotubes. These functional groups further combine with the quaternary ammonium cations in cetyl trimethyl ammonium bromide through ionic bonds. The introduction of long alkyl chains enhances the compatibility of carbon nanotubes with the polyolefin matrix. The ultra-high molecular weight polyethylene powder as a reinforcing phase improves the strength and wear resistance of the fibers. The acid anhydride groups in the polyethylene grafted maleic anhydride compatibilizer can produce strong interactions with the active groups on the surface of the modified nano-filler, and the polyethylene segments thereof can undergo segment entanglement with the resin matrix, thereby building an interface bridge between the inorganic filler and the organic polymer matrix, preventing phase separation and ensuring effective stress transmission.

[0070] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and can be implemented in other concrete forms without departing from the spirit or essential characteristics of the application. Therefore, the embodiments should be considered in all respects as illustrative and not restrictive, the scope of the application being defined by the appended claims rather than the above description, and it is intended that all changes which come within the meaning and range of equivalency of the claims are embraced therein. Any reference signs in the claims should not be construed as limiting the claims to the figures in which the reference signs are used.

Claims

1. An enhanced polyolefin resin composite fiber, characterized by, The composite fiber is prepared from high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotube, polyethylene grafted maleic anhydride compatibilizer, antioxidant tris (2, 4-di-tert-butylphenyl) phosphite and antioxidant tetra [beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester; the modified multi-walled carbon nanotube is prepared from multi-walled carbon nanotube, concentrated nitric acid solution and hexadecyl trimethyl ammonium bromide aqueous solution; the modified nano-silica is prepared from nano-silica, gamma- (methacryloyloxy) propyl trimethoxysilane, acetic acid and ethanol aqueous solution; The preparation method of the reinforced polyolefin resin composite fiber comprises the following preparation steps: (1) high-density polyethylene resin is preheated and dried at 80℃±5℃ for 2-2.2 hours; nano-silica with a particle size of 20-40nm and multi-walled carbon nanotube with an outer diameter of 8-15nm and a length of 30-50μm are pre-dried in vacuum at 80℃±5℃ for 2-3 hours; (2) gamma- (methacryloyloxy) propyl trimethoxysilane and ethanol aqueous solution with a mass fraction of 50-60% are mixed, acetic acid is used to adjust the pH value to 5.5-6.0, stirring is carried out at 50-60℃ and a rotating speed of 200-300rpm for 30-40 minutes, then nano-silica is added, ultrasonic treatment is carried out at a power of 300-400W for 30-40 minutes, suction filtration is carried out, the product is washed with anhydrous ethanol for 2-4 times, and then vacuum drying is carried out at 70-80℃ for 4-6 hours to obtain modified nano-silica; (3) the multi-walled carbon nanotube is added into concentrated nitric acid solution with a mass fraction of 55-65%, ultrasonic treatment is carried out at 65-75℃ for 2-4 hours, the ultrasonic power is 300-500W, the frequency is 35-45kHz, after treatment, the product is washed with deionized water until neutral, and then vacuum drying is carried out at 85-95℃ for 6-8 hours to obtain acidified multi-walled carbon nanotube; the acidified multi-walled carbon nanotube is added into hexadecyl trimethyl ammonium bromide aqueous solution with a mass fraction of 3-5%, stirring is carried out at 400-600rpm at 60-70℃ for 3-5 hours, the product is filtered and washed with ethanol for 3-5 times, and then vacuum drying is carried out at 75-85℃ for 4-6 hours to obtain modified multi-walled carbon nanotube; (4) half of the total mass of high-density polyethylene, ultra-high molecular weight polyethylene powder, modified nano-silica, modified multi-walled carbon nanotube, polyethylene grafted maleic anhydride compatibilizer with a grafting rate of 0.8-1.2%, antioxidant tris (2, 4-di-tert-butylphenyl) phosphite and antioxidant tetra [beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid] pentaerythritol ester are placed in a mixing machine, mixing is carried out at a rotating speed of 600-800rpm for 5-10 minutes to obtain a premix; (5) the premix is added into a double-screw extruder for blending and extrusion, water cooling and pelletizing are carried out to obtain a composite master batch; (6) the composite master batch and the remaining high-density polyethylene are mixed, and then melt spinning is carried out to obtain a primary fiber. (7) the primary fibers are drawn in two stages, and then heat set in a heat setting oven at 100-120 DEG C in a relaxed state for 1-2 minutes, oiled, and wound to obtain the composite fibers.

2. The reinforced polyolefin resin composite fiber according to claim 1, characterized by The mass ratio of the nano-silica, gamma-(methacryloyloxy)propyl trimethoxysilane and the ethanol aqueous solution is 1:(0.15-0.25):(8-12).

3. The reinforced polyolefin resin composite fiber according to claim 2, characterized by The mass ratio of the multi-walled carbon nanotube, concentrated nitric acid solution and hexadecyl trimethyl ammonium bromide aqueous solution is 1:(8-12):(15-25).

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

5. The reinforced polyolefin resin composite fiber according to claim 1, wherein The molecular weight of the high-density polyethylene resin is 120-150 million.

6. The reinforced polyolefin resin composite fiber according to claim 1, wherein The particle size of the ultra-high molecular weight polyethylene powder is 20-30 microns, and the molecular weight is 200-300 million.

7. The reinforced polyolefin resin composite fiber according to claim 1, wherein The temperature zoning of the double-screw extruder in step (5) is: zone 1 165-175 DEG C, zone 2 185-195 DEG C, zone 3 195-205 DEG C, zone 4 200-210 DEG C, and the head 205-220 DEG C, the screw rotation speed is controlled at 200-400 rpm, and the length-diameter ratio is 39-41:

1.

8. The reinforced polyolefin resin composite fiber according to claim 1, wherein The conditions of melt spinning in step (6) are: spinneret hole diameter 0.24-0.26 mm, spinning rate 60-100 m / min, and spinning temperature 200-230 DEG C.

9. The reinforced polyolefin resin composite fiber according to claim 1, wherein The two-stage drawing in step (7) is: the first stage uses hot water drawing at 90-99 DEG C, and the drawing ratio is 3-5 times; the second stage uses hot roller drawing at 100-120 DEG C, and the drawing ratio is 2-3 times.