A modified ultra-high molecular weight polyethylene fiber, and a method for preparing and using the same

Abstract

The application relates to the field of high polymer materials, and discloses a modified ultrahigh molecular weight polyethylene fiber as well as a preparation method and application thereof. The method comprises the following steps: mixing ultrahigh molecular weight polyethylene powder, an antioxidant and a solvent, mixing the mixed solution with MIL-101, and spinning the obtained mixed material to obtain ultrahigh molecular weight polyethylene fiber filaments; in the presence of an initiator and a catalyst, reacting the ultrahigh molecular weight polyethylene fiber filaments with caprolactam to obtain polymer modified fiber filaments; performing at least one heat drawing on the polymer modified fiber filaments to obtain preliminary modified fiber filaments; and in the presence of peroxide, reacting the preliminary modified fiber filaments with a modifier. The method fills the ultrahigh molecular weight polyethylene fiber with a metal organic framework, and then performs polymer modification and crosslinking modification, so that the anti-creep performance of the fiber material is improved, and the application range of the ultrahigh molecular weight polyethylene fiber is expanded.

Description

TECHNICAL FIELD

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

[0002] Ultra-high molecular weight polyethylene (UHMWPE) is a linear thermoplastic with excellent performance. The plastic is a linear polymer without branches, which is obtained by coordination polymerization of ethylene monomer under the action of a catalyst. Due to its excellent mechanical properties, low density, abrasion resistance, self-lubricating property, high chemical resistance, excellent biocompatibility and high impact toughness, it is widely used in biomedical, textile, military and aerospace fields. As one of the most important products, UHMWPE fiber has high strength-to-weight ratio, good toughness, chemical resistance and abrasion resistance, and is widely used in military equipment and sports equipment fields.

[0003] However, UHMWPE itself is very sensitive to heat and easily deforms under the action of stress, and has low mechanical strength. In the long-term use process, the ultra-high molecular weight polyethylene fiber is prone to deformation under high temperature or stress, which seriously reduces the service life. Moreover, since the UHMWPE macromolecule is a linear flexible macromolecule, the intermolecular force is small, and the UHMWPE fiber has poor creep resistance. In order to improve the creep resistance and plasticity of UHMWPE, it is necessary to modify the performance of UHMWPE. Therefore, it is of great practical significance to develop a method for modifying UHMWPE to improve its creep resistance. SUMMARY

[0004] The purpose of the present application is to overcome the problems of poor creep resistance of ultra-high molecular weight polyethylene fiber in the prior art, and to provide a modified ultra-high molecular weight polyethylene fiber and a preparation method and application thereof. The method uses metal organic framework material to fill the ultra-high molecular weight polyethylene fiber, and then performs polymerization modification and crosslinking modification, thereby improving the creep resistance of the fiber material and further expanding the application range of the ultra-high molecular weight polyethylene fiber, which has very important social significance and significant economic benefits.

[0005] In order to achieve the above-mentioned purpose, the present application provides a method for preparing a modified ultra-high molecular weight polyethylene fiber, which comprises the following steps:

[0006] (1) mixing ultra-high molecular weight polyethylene powder, antioxidant and solvent, mixing the obtained mixture with metal organic framework material MIL-101, and then spinning the obtained mixture to obtain ultra-high molecular weight polyethylene fiber filaments;

[0007] (2) reacting the ultra-high molecular weight polyethylene fiber filament with caprolactam monomers in an aprotic polar solvent in the presence of an initiator and a catalyst to obtain a polymer-modified fiber filament;

[0008] (3) performing at least one heat drawing on the polymer-modified fiber filament to obtain a preliminary modified fiber filament;

[0009] (4) reacting the preliminary modified fiber filament with a modifier in the presence of a peroxide;

[0010] wherein the initiator is an isocyanate compound, the catalyst is sodium caprolactamate and / or magnesium bromide caprolactamate, and the modifier is selected from one or more than two of acrylamide, hydroxyethyl methacrylate, acrylate, and styrene.

[0011] Preferably, the metal-organic framework material MIL-101 is selected from one or more than two of MIL-101(Cr), MIL-101(Fe), and MIL-101(Al).

[0012] Preferably, the ultra-high molecular weight polyethylene powder has a molecular weight of 800,000-1000,000.

[0013] Preferably, the weight ratio of the amount of the ultra-high molecular weight polyethylene powder to the amount of the metal-organic framework material MIL-101 is 1:0.005-0.01.

[0014] Preferably, in step (2), the reaction conditions include a temperature of 120-150℃ and a time of 30-80 min.

[0015] Preferably, the weight ratio of the amount of the initiator to the amount of the catalyst to the amount of the caprolactam monomers to the amount of the MIL-101 is 0.8-3:0.5-1.2:100:5-30.

[0016] Preferably, the antioxidant is antioxidant 1010 and / or antioxidant 1076.

[0017] Preferably, the aprotic polar solvent is selected from one or more than two of acetone, toluene, and xylene.

[0018] Preferably, the initiator is selected from one or more than two of diphenylmethane diisocyanate, isophorone diisocyanate, and toluene diisocyanate.

[0019] Preferably, the peroxide is selected from one or more than two of tert-butyl peroxide, benzoyl peroxide, dicumyl peroxide, and diisopropylbenzene peroxide.

[0020] Preferably, the weight ratio of the peroxide to the amount of the primary modified fiber filament is 0.003-0.008:1.

[0021] Preferably, the weight ratio of the modifier to the amount of the primary modified fiber filament is 1:15-80.

[0022] Preferably, the specific process of step (3) comprises: sequentially performing one-time stretching, one-time heat treatment, two-time stretching, two-time heat treatment, three-time stretching, three-time heat treatment, four-time stretching, four-time heat treatment and five-time stretching on the polymerized modified fiber filament.

[0023] Preferably, the temperature during the one-time heat treatment is 130-150℃, the temperature during the two-time heat treatment is 130-150℃, the temperature during the three-time heat treatment is 135-165℃, and the temperature during the four-time heat treatment is 135-165℃.

[0024] The second aspect of the present application provides a modified ultra-high molecular weight polyethylene fiber prepared by the above method.

[0025] The third aspect of the present application provides an application of the above modified ultra-high molecular weight polyethylene fiber in textiles, biomedicine, military and aerospace.

[0026] The method of the present application first uses organic metal framework material to blend and fill the ultra-high molecular weight polyethylene fiber, then carries out polymerization reaction of the lactam monomer and the filled organic metal framework material, increases the side chain on the molecular chain of the ultra-high molecular weight polyethylene fiber, thereby increasing the steric hindrance between molecules and improving the creep resistance of the fiber material, and further forms a coating layer with a three-dimensional network structure on the surface of the ultra-high molecular weight polyethylene fiber through chemical crosslinking method, further improving the creep resistance of the ultra-high molecular weight polyethylene fiber. DETAILED DESCRIPTION

[0027] The specific embodiments of the present application are described in detail below. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0028] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges or values should be construed to be approximations that allow for significant variation. Various ranges of values that are provided are only meant to serve as examples. Other ranges of values can be easily determined without departing from the scope of the application.

[0029] The method for preparing the modified ultra-high molecular weight polyethylene fiber of the present application comprises the following steps:

[0030] (1) mixing the super high molecular weight polyethylene powder, the antioxidant and the solvent, mixing the obtained mixture with MIL-101, and then spinning the obtained mixture to obtain the super high molecular weight polyethylene fiber filament;

[0031] (2) reacting the super high molecular weight polyethylene fiber filament with the caprolactam monomer in the presence of the initiator and the catalyst in the aprotic polar solvent to obtain the polymerization modified fiber filament;

[0032] (3) performing at least one heat drawing on the polymerization modified fiber filament to obtain the preliminary modified fiber filament;

[0033] (4) reacting the preliminary modified fiber filament with the modifier in the presence of the peroxide.

[0034] In the method of the present application, since the molecular chains of the super high molecular weight polyethylene are highly entangled in the solution and remain in this state after solution spinning and cooling, in step (1), the super high molecular weight polyethylene powder, the antioxidant and the solvent are mixed, the super high molecular weight polyethylene powder is swelled in the solvent, and the antioxidant is used to prevent the oxidation of the super high molecular weight polyethylene powder.

[0035] In the method of the present application, the molecular weight of the modified super high molecular weight polyethylene is not limited, and preferably, the molecular weight of the super high molecular weight polyethylene powder is 800-1000 million.

[0036] In the preferred embodiment, in step (1), the solvent used is selected from one or more than two of liquid paraffin, decalin, mineral oil and white oil.

[0037] In the preferred embodiment, the antioxidant is antioxidant 1010 and / or antioxidant 1076, and preferably, the antioxidant is antioxidant 1010. Specifically, the weight ratio of the antioxidant to the amount of the super high molecular weight polyethylene powder is 0.003-0.005:1.

[0038] In the specific embodiment, the amount of the solvent and the super high molecular weight polyethylene powder can refer to the conventional techniques in the art.

[0039] In the method of the present application, in step (1), the metal organic framework material MIL-101 is used for filling modification, and the doped metal organic framework material can form physical crosslinking points between the molecular chains of the super high molecular weight polyethylene, increase the steric hindrance between the molecules, and thus improve the creep resistance of the super high molecular weight polyethylene fiber.

[0040] In the method of the present application, the metal organic framework material MIL-101 can be selected from one or more of MIL-101(Cr), MIL-101(Fe) and MIL-101(Al). It can be understood that MIL-101(Cr) refers to the metal atom in the metal organic framework material is Cr. In a specific embodiment, the metal organic framework material MIL-101 can be a commercially available product or a product prepared by a method commonly used in the art.

[0041] In a preferred embodiment, in order to further improve the anti-creep performance of the modified ultra-high molecular weight polyethylene fiber, the particle size of the metal organic framework material MIL-101 is 40-80 nm.

[0042] In a preferred embodiment, the weight ratio of the amount of the ultra-high molecular weight polyethylene powder to the amount of the metal organic framework material MIL-101 is 1:0.005-0.01, preferably 1:0.006-0.008. Specifically, the weight ratio of the amount of the ultra-high molecular weight polyethylene powder to the amount of the metal organic framework material MIL-101 can be 1:0.005, 1:0.006, 1:0.007, 1:0.008, 1:0.009 or 1:0.01.

[0043] In a specific embodiment, in step (1), the obtained mixture can be spun into an ultra-high molecular weight polyethylene fiber filament according to the prior art, and the specific operation of spinning is not limited, for example, it can be wet spinning or dry spinning, and the treatment process and drying process after spinning can also refer to the conventional technology in the art.

[0044] In the method of the present application, the metal organic framework material has a regular structure and good thermal stability. By mixing the metal organic framework material with the swollen material of the ultra-high molecular weight polyethylene, and further filling the metal organic framework material into the ultra-high molecular weight polyethylene fiber filament by spinning, the filled metal organic framework material can play a role of physical crosslinking in the molecule, thereby increasing the space resistance between molecules to some extent, thereby improving the anti-creep performance of the fiber material.

[0045] In the method of the present application, the initiator is an isocyanate compound selected from one or more than two of diphenylmethane diisocyanate, isophorone diisocyanate and toluene diisocyanate; and the catalyst is sodium caprolactam and / or magnesium bromide caprolactamate. In step (2), the filled metal-organic framework material MIL-101 in the ultra-high molecular weight polyethylene fiber filament is caused to react with caprolactam monomers by the action of the initiator and the catalyst, the macromolecular polymer chain segment is connected with the metal-organic framework material through the polymerization reaction, the modified monomer is introduced to increase the content of the side chain groups in the ultra-high molecular weight polyethylene fiber filament, the movement resistance of the molecular chain in the ultra-high molecular weight polyethylene fiber filament is further increased, the intermolecular slip is prevented, and the and thermal stability and anti-creep properties of the modified ultra-high molecular weight polyethylene fiber prepared are enhanced.

[0046] In a preferred embodiment, in step (2), the reaction conditions include a temperature of 120-150℃ and a time of 30-80 min, preferably 35-60 min. Specifically, the reaction temperature can be 120℃, 130℃, 140℃ or 150℃; and the reaction time can be 30 min, 50 min, 60 min, 70 min or 80 min.

[0047] In a specific embodiment, in step (2), the reaction is carried out under vacuum.

[0048] In a preferred embodiment, the weight ratio of the amount of the initiator, the catalyst, the caprolactam monomer and the metal framework material MIL-101 is 0.8-3:0.5-1.2:100:5-30, preferably 0.85-2:0.5-1.2:100:10-30.

[0049] In a preferred embodiment, the aprotic polar solvent is selected from one or more than two of acetone, toluene and xylene, preferably acetone.

[0050] In a specific embodiment, the specific process of step (3) is as follows: the polymeric modified fiber filaments are placed on a guide frame, and then the polymeric modified fiber filaments on the guide frame are fed into a first seven-roller drafting machine at a certain speed for primary stretching, and then transported into a first drafting heat box for primary heat treatment; then transported into a second seven-roller drafting machine for secondary stretching, and then transported into a second drafting heat box for secondary heat treatment; then transported into a third seven-roller drafting machine for tertiary stretching, and then transported into a third drafting heat box for tertiary heat treatment; then transported into a fourth seven-roller drafting machine for quaternary stretching, and then transported into a fourth drafting heat box for quaternary heat treatment; then transported into a fifth seven-roller drafting machine for quinary stretching, to obtain the preliminary modified fiber filaments. Through multiple heat-drawing treatments, the polyethylene macromolecules in the polymeric modified fiber filaments can be stretched and straightened along the stretching direction, and the molecular orientation and the degree of crystallinity are significantly improved, so that the fiber is endowed with excellent mechanical properties and creep resistance.

[0051] In a preferred embodiment, the temperature during the primary heat treatment is 130-150°C, preferably 135-140°C; the temperature during the secondary heat treatment is 130-150°C, preferably 135-140°C; the temperature during the tertiary heat treatment is 135-165°C, preferably 140-150°C; and the temperature during the quaternary heat treatment is 135-165°C, preferably 140-150°C.

[0052] In a preferred embodiment, the stretching speed of the first seven-roller drafting machine is 1.0-4.0 m / min; the stretching speed of the second seven-roller drafting machine is 1.0-4.0 m / min; the stretching speed of the third seven-roller drafting machine is 5.0-10.0 m / min; the stretching speed of the fourth seven-roller drafting machine is 5.0-15.0 m / min; and the stretching speed of the fifth seven-roller drafting machine is 10.0-20.0 m / min.

[0053] In the method of the present application, the modifier can be selected from one or more than two of acrylamide, hydroxyethyl methacrylate, acrylate, and styrene.

[0054] In the method of the present application, by using a peroxide as a crosslinking agent, a three-dimensional network structure is generated on the surface of the fiber material through a crosslinking reaction without destroying the structure of the preliminary modified fiber filaments, thereby further improving the thermal stability and high-temperature resistance of the ultra-high molecular weight polyethylene fiber, so that the fiber is not easy to soften, deform or decompose under high-temperature environment, the aging speed of the material is slowed down, the service life of the material is prolonged, and the stability and reliability of the material under harsh environment are improved.

[0055] In a preferred embodiment, the peroxide is selected from one or more of tert-butyl peroxide, benzoyl peroxide, diisopropylbenzene hydroperoxide and dicumyl peroxide.

[0056] In a preferred embodiment, the weight ratio of the peroxide to the amount of the primary modified fiber filament is 0.003-0.008:1, preferably 0.004-0.005:1. Specifically, the weight ratio of the peroxide to the amount of the primary modified fiber filament can be 0.003:1, 0.0035:1, 0.004:1, 0.005:1, 0.006:1, 0.007:1 or 0.008:1.

[0057] In a preferred embodiment, the weight ratio of the modifier to the amount of the primary modified fiber filament is 1:15-80, preferably 1:30-60. Specifically, the weight ratio of the modifier to the amount of the primary modified fiber filament can be 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:50, 1:60, 1:70 or 1:80.

[0058] In a specific embodiment, in step (4), the reaction conditions include a temperature of 160-180°C and a time of 30-60 min.

[0059] In a specific embodiment, in step (4), the primary modified fiber filament is contacted with the modifier and reacted by means of a liquid-on-fiber device. The liquid-on-fiber device is filled with peroxide, modifier and water (as a solvent for dissolving the peroxide and the modifier). The liquid-on-fiber device is rolled by means of a liquid wheel, so that the primary modified fiber filament is fully contacted with the materials in the liquid-on-fiber device, thereby achieving the purpose of fiber modification. Further specifically, the liquid-on-fiber device is further provided with a hydraulic roller inside and a heat preservation jacket, an electric heating tape and a yarn guide outside, and the jacket is filled with heat conducting oil for heating the reaction.

[0060] The present application further provides a modified ultra-high molecular weight polyethylene fiber prepared by the above method. The modified ultra-high molecular weight polyethylene fiber prepared by the present application has excellent creep resistance, effectively improves the performance of the ultra-high molecular weight polyethylene fiber, promotes industrial upgrading, improves product added value, and meets the demand for high-performance composites.

[0061] The application further provides application of the modified ultrahigh molecular weight polyethylene fiber in textiles, biomedicine, military and aerospace. The modified ultrahigh molecular weight polyethylene fiber has excellent anti-creep performance and still has excellent stability and reliability in harsh environments, so that the modified ultrahigh molecular weight polyethylene fiber can be applied in many fields and has wide application prospect and economic value.

[0062] The application will be described in detail through examples below, but the protection scope of the application is not limited thereto.

[0063] In the application, the experimental methods in the following examples are all conventional methods in the field unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0064] Example 1

[0065] (1) The antioxidant 1010 was dissolved in liquid paraffin, then the ultrahigh molecular weight polyethylene powder was added, and the mixture was stirred and swollen at 100℃ for 24h. The obtained mixture was mixed with the metal organic framework material MIL-101(Fe) for 1h, then the obtained mixture was extruded by a double screw extruder, cooled by a water tank, then pre-stretched on a winding machine to obtain the ultrahigh molecular weight polyethylene fiber filament; wherein the weight ratio of the amount of the ultrahigh molecular weight polyethylene powder and the amount of the MIL-101(Fe) was 1:0.006;

[0066] (2) The caprolactam monomer, diphenyl methane diisocyanate and caprolactam sodium were dissolved in acetone under vacuum, then the obtained mixture was mixed with the ultrahigh molecular weight polyethylene fiber filament to react, the reaction temperature was 130℃, and the reaction time was 40min to obtain the polymer modified fiber filament; wherein the weight ratio of the amount of the diphenyl methane diisocyanate, the amount of the caprolactam sodium, the amount of the caprolactam monomer and the amount of the metal framework material MIL-101(Fe) was 1.5:0.8:100:25;

[0067] (3) the polymeric modified fiber filaments are placed on a guide frame, and then the polymeric modified fiber filaments on the guide frame are fed into a first seven-roller drafting machine for primary stretching (at a speed of 1.28 m / min), and then transported into a first drafting heat box for primary heat treatment (at a temperature of 138°C); then transported into a second seven-roller drafting machine for secondary stretching (at a speed of 1.28 m / min), and then transported into a second drafting heat box for secondary heat treatment (at a temperature of 140°C); then transported into a third seven-roller drafting machine for tertiary stretching (at a speed of 7.69 m / min), and then transported into a third drafting heat box for tertiary heat treatment (at a temperature of 145°C); then transported into a fourth seven-roller drafting machine for quaternary stretching (at a speed of 9.76 m / min), and then transported into a fourth drafting heat box for quaternary heat treatment (at a temperature of 148°C); then transported into a fifth seven-roller drafting machine for quinary stretching (at a speed of 11.30 m / min), to obtain preliminary modified fiber filaments;

[0068] (4) the dicumyl peroxide and acrylamide are dissolved in water, and then the preliminary modified fiber filaments are soaked in the mixed solution for reaction at 160°C for 40 min, and then the fiber is taken out, washed and dried to obtain the modified ultra-high molecular weight polyethylene fiber; wherein the weight ratio of the dicumyl peroxide to the preliminary modified fiber filaments is 0.0045:1; and the weight ratio of the acrylamide to the preliminary modified fiber filaments is 1:40.

[0069] Example 2

[0070] (1) the antioxidant 1010 is dissolved in liquid paraffin, and then the ultra-high molecular weight polyethylene powder is added for shearing stirring swelling at 100°C for 24 h, the obtained mixed solution is stirred with MIL-101(Cr) for 1 h, and then the obtained mixture is extruded by using a double-screw extruder, and then cooled by a water tank, and then pre-stretched on a winding machine to obtain the ultra-high molecular weight polyethylene fiber filaments; wherein the weight ratio of the amount of the ultra-high molecular weight polyethylene powder to the amount of MIL-101(Cr) is 1:0.007;

[0071] (2) the caprolactam monomer, isophorone diisocyanate and sodium caprolactamate are dissolved in acetone under vacuum, and then the obtained mixture is mixed with the ultra-high molecular weight polyethylene fiber filaments for reaction, the reaction temperature is 130°C, and the reaction time is 40 min, to obtain the polymeric modified fiber filaments; wherein the weight ratio of the amount of isophorone diisocyanate, the amount of sodium caprolactamate, the amount of caprolactam monomer and the amount of metal framework material MIL-101(Cr) is 1.3:1:100:20;

[0072] (3) the polymeric modified fiber filaments are placed on a guide frame, and then the polymeric modified fiber filaments on the guide frame are fed into a first seven-roller drafting machine for primary stretching (at a speed of 2.12 m / min), and then transported into a first drafting heat box for primary heat treatment (at a temperature of 135 °C); then transported into a second seven-roller drafting machine for secondary stretching (at a speed of 2.12 m / min), and then transported into a second drafting heat box for secondary heat treatment (at a temperature of 140 °C); then transported into a third seven-roller drafting machine for tertiary stretching (at a speed of 8.69 m / min), and then transported into a third drafting heat box for tertiary heat treatment (at a temperature of 148 °C); then transported into a fourth seven-roller drafting machine for quaternary stretching (at a speed of 9.76 m / min), and then transported into a fourth drafting heat box for quaternary heat treatment (at a temperature of 148 °C); then transported into a fifth seven-roller drafting machine for quinary stretching (at a speed of 10.2 m / min), to obtain preliminary modified fiber filaments;

[0073] (4) benzoyl peroxide and acrylamide are dissolved in water, and then the preliminary modified fiber filaments are soaked in the mixed solution for reaction at 160 °C for 40 min, and then the fiber is taken out, washed and dried to obtain modified ultra-high molecular weight polyethylene fiber; wherein the weight ratio of benzoyl peroxide and the preliminary modified fiber filaments is 0.0048:1; the weight ratio of acrylamide and the preliminary modified fiber filaments is 1:30.

[0074] Example 3

[0075] (1) antioxidant 1010 is dissolved in liquid paraffin, and then ultra-high molecular weight polyethylene powder is added for shearing stirring swelling at 100 °C for 24 h, the obtained mixed solution is stirred with MIL-101 (Al) for 1 h, and then the obtained mixture is extruded by a twin-screw extruder, cooled by a water tank, and then pre-stretched on a winding machine to obtain ultra-high molecular weight polyethylene fiber filaments; wherein the weight ratio of the amount of use of ultra-high molecular weight polyethylene powder and MIL-101 (Al) is 1:0.0085;

[0076] (2) under vacuum conditions, caprolactam monomer, toluene diisocyanate and caprolactam magnesium bromide are dissolved in acetone, and then the obtained mixture is mixed with the ultra-high molecular weight polyethylene fiber filaments for reaction, the reaction temperature is 130 °C, and the reaction time is 40 min, to obtain polymeric modified fiber filaments; wherein the weight ratio of the amount of use of toluene diisocyanate, caprolactam magnesium bromide, caprolactam monomer and metal framework material MIL-101 (Cr) is 1.8:0.9:100:15;

[0077] (3) the polymeric modified fiber filaments are placed on a guide frame, and then the polymeric modified fiber filaments on the guide frame are fed into a first seven-roller drafting machine for primary stretching (at a speed of 1.59 m / min), and after the primary stretching, the polymeric modified fiber filaments are transported into a first drafting heat box for primary heat treatment (at a temperature of 136 °C); then the polymeric modified fiber filaments are transported into a second seven-roller drafting machine for secondary stretching (at a speed of 1.59 m / min), and after the secondary stretching, the polymeric modified fiber filaments are transported into a second drafting heat box for secondary heat treatment (at a temperature of 138 °C); then the polymeric modified fiber filaments are transported into a third seven-roller drafting machine for tertiary stretching (at a speed of 8.12 m / min), and after the tertiary stretching, the polymeric modified fiber filaments are transported into a third drafting heat box for tertiary heat treatment (at a temperature of 145 °C); then the polymeric modified fiber filaments are transported into a fourth seven-roller drafting machine for quaternary stretching (at a speed of 9.36 m / min), and after the quaternary stretching, the polymeric modified fiber filaments are transported into a fourth drafting heat box for quaternary heat treatment (at a temperature of 148 °C); then the polymeric modified fiber filaments are transported into a fifth seven-roller drafting machine for quinary stretching (at a speed of 13.2 m / min), and the primary modified fiber filaments are obtained;

[0078] (4) the hydrogen peroxide diisopropylbenzene and acrylamide are dissolved in water, and then the primary modified fiber filaments are soaked in the mixed solution for reaction at 160 °C for 40 min, and after the reaction, the fiber is taken out, washed and dried to obtain the modified ultra-high molecular weight polyethylene fiber; wherein the weight ratio of the hydrogen peroxide diisopropylbenzene to the primary modified fiber filaments is 0.0055:1; and the weight ratio of the acrylamide to the primary modified fiber filaments is 1:45.

[0079] Example 4

[0080] The method of Example 1 is followed, except that in step (4), the weight ratio of the diisopropylbenzene peroxide to the primary modified fiber filaments is 0.002:1.

[0081] Example 5

[0082] The method of Example 1 is followed, except that in step (4), the weight ratio of the diisopropylbenzene peroxide to the primary modified fiber filaments is 0.006:1.

[0083] Comparative Example 1

[0084] The method of Example 1 is followed, except that the metal-organic framework material MIL-101 (Fe) is replaced with an equal weight of SiO2 for preparation.

[0085] Comparative Example 2

[0086] The method of Example 1 is followed, except that the reaction of step (2) is not performed, i.e., the ultra-high molecular weight polyethylene fiber filaments prepared in step (1) are directly subjected to the modification processes of steps (3) and (4).

[0087] Comparative Example 3

[0088] The procedure of Example 1 was followed except that step (3) was not performed and the polymeric modified fiber filaments obtained in step (2) were directly subjected to the modification process of step (4).

[0089] Comparative Example 4

[0090] The procedure of Example 1 was followed except that step (4) was not performed and the preliminary modified fiber filaments were obtained and the subsequent modification process was stopped.

[0091] Comparative Example 5

[0092] The procedure of Example 1 was followed except that step (4) was not performed and the preliminary modified fiber filaments were obtained and the subsequent modification process was stopped.

[0093] Test Example

[0094] The anti-creep properties and tensile strength of the modified ultra-high molecular weight polyethylene fibers prepared in Examples 1-5 and Comparative Examples 1-5 were tested and the results are shown in Table 1.

[0095] The anti-creep property testing method was as follows: the sample was placed in a standard atmosphere for testing for at least 48 h without being twisted, then one end of the sample was clamped in a clamp, and the other end was clamped in another clamp without being untwisted. A pre-tension (initial load) was applied, a mark was made on the sample, and the mark length was at least 200 mm, then the initial mark length, i.e., the initial length L0, of the sample was observed and recorded, then a heavy load was applied, and the length of the sample after a certain period of time or the final breaking length L1 was observed and recorded, and the anti-creep property of the sample was calculated according to the formula shown in Formula 1.

[0096]

[0097] wherein G is the tensile creep elongation (%), L0 is the initial length of the sample (mm), and L1 is the length of the sample after the heavy load is applied or the final breaking length (mm).

[0098] The tensile strength was tested according to the method of GB / T 19975-2005.

[0099] Table 1

[0100] Example No. Tensile strength (cN / dtex) Tensile creep elongation (%) Example 1 35.79 5.34 Example 2 35.23 5.85 Example 3 34.68 6.47 Example 4 33.47 6.88 Example 5 33.56 6.75 Comparative Example 1 30.15 8.32 Comparative Example 2 30.66 8.13 Comparative Example 3 32.47 7.58 Comparative Example 4 31.21 7.96 Comparative Example 5 32.03 7.85

[0101] As can be seen from the results in Table 1, the modified ultra-high molecular weight polyethylene fibers prepared by the method of the present application have excellent tensile strength and anti-creep properties, and the performance is more excellent, and has a more broad application prospect.

[0102] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A method for preparing modified ultra-high molecular weight polyethylene fiber, characterized in that, The method includes the following steps: (1) Mix ultra-high molecular weight polyethylene powder, antioxidant and solvent, mix the resulting mixture with metal-organic framework material MIL-101, and then spin the resulting mixture to obtain ultra-high molecular weight polyethylene fiber filament. (2) In the presence of an initiator and a catalyst, the ultra-high molecular weight polyethylene fiber precursor is reacted with caprolactam monomer in an aprotic polar solvent to obtain polymerized modified fiber precursor. (3) The polymerized modified fiber filament is subjected to at least one hot stretching to obtain a preliminary modified fiber filament; (4) The preliminarily modified fiber filament is reacted with a modifier in the presence of a peroxide; The initiator is an isocyanate compound, the catalyst is sodium caprolactam and / or magnesium caprolactam bromide, and the modifier is selected from one or more of acrylamide, hydroxyethyl methacrylate, acrylate, and styrene.

2. The method according to claim 1, characterized in that, The metal-organic framework material MIL-101 is selected from one or more of MIL-101Cr, MIL-101Fe, and MIL-101Al; and / or The ultra-high molecular weight polyethylene powder has a molecular weight of 800,000 to 10,000,000.

3. The method according to claim 1, characterized in that, The weight ratio of the ultra-high molecular weight polyethylene powder to the metal-organic framework material MIL-101 is 1:0.005-0.

01.

4. The method according to claim 1 or 3, characterized in that, The initiator, the catalyst, the caprolactam monomer, and the metal-organic framework material MIL-101 are used in a weight ratio of 0.8-3:0.5-1.2:100:5-30; and / or In step (2), the reaction conditions include a temperature of 120-150°C and a time of 30-80 min.

5. The method according to claim 1, characterized in that, The antioxidant is antioxidant 1010 and / or antioxidant 1076; and / or The aprotic polar solvent is selected from one or more of acetone, toluene, and xylene; and / or The initiator is selected from one or more of diphenylmethane diisocyanate, isophorone diisocyanate, and toluene diisocyanate.

6. The method according to claim 1, characterized in that, The peroxide is selected from one or more of tert-butyl peroxide, benzoyl peroxide, dicumyl hydroperoxide, and dicumyl peroxide; and / or The weight ratio of the peroxide to the preliminarily modified fiber filament is 0.003-0.008:

1.

7. The method according to claim 1, characterized in that, The weight ratio of the modifier to the pre-modified fiber filament is 1:15-80.

8. The method according to claim 1, characterized in that, The specific process of step (3) includes: stretching the polymerized modified fiber filament in sequence, performing a first stretch, a first heat treatment, a second stretch, a second heat treatment, a third stretch, a third heat treatment, a fourth stretch, a fourth heat treatment, and a fifth stretch.

9. The method according to claim 8, characterized in that, The temperature during the first heat treatment is 130℃~150℃, the temperature during the second heat treatment is 130℃~150℃, the temperature during the third heat treatment is 135℃~165℃, and the temperature during the fourth heat treatment is 135℃~165℃.

10. Modified ultra-high molecular weight polyethylene fiber prepared by any one of claims 1-9.

11. The application of the modified ultra-high molecular weight polyethylene fiber according to claim 10 in textiles, biomedicine, military and aerospace.

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