Preparation and regulation method of olefinic carbon reinforced phase change aramid fiber

Abstract

The invention relates to the technical field of phase change fibers, in particular to a preparation and regulation method of an olefinic carbon reinforced phase change aramid fiber, which comprises the following steps: adding an olefinic carbon material into dimethyl sulfoxide to prepare an olefinic carbon dispersion liquid; adding the aramid fiber III into an olefinic carbon dispersion liquid containing an alkaline substance, stirring, carrying out a deprotonation reaction to prepare a nanofiber spinning solution, extruding the nanofiber spinning solution through spinneret orifices, solidifying the nanofiber spinning solution through a first coagulating bath, carrying out a second coagulating bath, winding and collecting to obtain wet gel fibers; replacing the obtained wet gel fibers with a solvent, and drying to obtain porous aramid fibers; the porous aramid fibers are placed in the phase change material, and the phase change material is prepared through vacuum impregnation and drying. According to the invention, accurate control of fiber diameter and pore is realized, enthalpy value regulation and control requirements of phase change fibers in different aramid III fiber systems are met, and the product has high tensile strength, wide adjustable range of phase change temperature and high phase change enthalpy or latent heat; the material has very wide application prospects in the fields of thermal interface materials, energy storage materials and high-temperature protection materials.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of phase change fibers, and in particular to a preparation and regulation method of olefin-carbon reinforced phase change aramid fibers. BACKGROUND

[0002] Clothing as the "second skin" of the human body has played an important role in keeping warm since ancient times. In the face of harsh climate environments such as high altitudes, the North and South Poles, and other areas, thermal protective equipment in extremely cold environments has received widespread attention. The batting is an important component of thermal equipment, which usually uses the low thermal conductivity of still air to suppress the loss of human body heat to achieve the effect of keeping warm, so the thermal insulation effect of the batting is proportional to the thickness of the batting. The single still air thermal insulation mechanism inevitably leads to heavy equipment, which is difficult to meet the equipment requirements in extremely cold environments. Phase change fibers can reversibly store and release latent heat at a constant temperature by introducing phase change materials, and can be used as thermal control media to regulate the local temperature of the human body surface. It has the advantages of low cost, environmental protection, and reusability, so it is expected to realize the preparation of light and ultra-thin thermal insulation batting by introducing phase change materials with heat storage function into the thermal insulation batting and utilizing the additional temperature regulation function of phase change fibers.

[0003] In recent years, researchers have used alkali in the KOH / DMSO system to break the hydrogen bonds between aramid molecular chains, allowing aramid fibers to be decomposed from top to bottom into aramid nanofibers with a diameter of 5-10 nm. Aramid porous fibers are then obtained through spinning and other processes. Subsequently, researchers load phase change materials into porous aramid fibers through vacuum impregnation to obtain aramid phase change fibers. In the currently published related materials on the preparation of phase change fibers from aramid fibers from top to bottom, the main focus is on how to improve the preparation efficiency and strength of aramid phase change fibers, while there is little research on the enthalpy regulation of phase change fibers suitable for different scenarios. In addition, current research mainly focuses on para-aramid fibers, and there is no reported research on the preparation of phase change fibers from aramid III fibers in a heterocyclic system from top to bottom. Therefore, it is crucial to regulate the enthalpy of phase change fibers in aramid III fiber systems to better meet the needs of different application scenarios. SUMMARY

[0004] To solve the above problems, the present application provides a regulation method of olefin-carbon reinforced phase change aramid fibers, which introduces olefin-carbon materials into the wet spinning process of aramid III nanofibers and adjusts the draw ratio of the first and second coagulation baths to regulate the enthalpy of phase change fibers in aramid III fiber systems.

[0005] To achieve the above-mentioned purposes, the present application provides the following technical solutions: On the one hand, the present application provides a regulation method of olefin-carbon reinforced phase change aramid fibers, which includes the following steps: S1. Adding olefin-carbon material into dimethyl sulfoxide, ultrasonic dispersion, preparing olefin-carbon dispersion liquid with mass fraction of 0.01-0.5%; S2. Adding aramid fiber III into olefin-carbon dispersion liquid containing alkaline substance, stirring, carrying out deprotonation reaction, preparing nanofiber spinning solution with aramid concentration of 0.5-15%; S3. Extruding nanofiber spinning solution through spinneret, coagulating through first coagulation bath and second coagulation bath, winding and collecting to obtain wet gel fiber; S4. Replacing solvent of obtained wet gel fiber, drying to prepare aramid porous fiber; S5. Placing aramid porous fiber into phase change material, vacuum impregnating and drying to obtain olefin-carbon reinforced phase change aramid fiber.

[0006] Further, in S1, the olefin-carbon material is selected from one of graphene oxide, graphene, and reduced graphene oxide.

[0007] Further, in S2, the aramid fiber III is in one of chopped, filament, precipitated, or pulp form; Further, the alkaline substance is selected from one or more of potassium hydroxide, sodium hydroxide, sodium ethoxide, potassium ethoxide, sodium tert butyl alcohol, or potassium tert butyl alcohol; In some preferred embodiments, the alkaline substance is selected from potassium hydroxide and sodium hydroxide.

[0008] Further, in S2, the mass ratio of aramid fiber, alkaline substance, and olefin-carbon dispersion liquid is (1-10):(1-10):(90-110).

[0009] Further, in S3, the first coagulation bath is water with / without auxiliary component; The auxiliary component is selected from one or more of sulfuric acid, hydrochloric acid, formic acid, acetic acid, oxalic acid, citric acid, phosphoric acid, tartaric acid, ethanol, tert butyl alcohol, n-hexane, hexafluoroisopropyl alcohol, cyclohexane, and acetone.

[0010] In some specific embodiments, the first coagulation bath is water; Further, in S3, the second coagulation bath is water with / without auxiliary component; The auxiliary component is selected from one or more of sulfuric acid, hydrochloric acid, formic acid, acetic acid, oxalic acid, citric acid, phosphoric acid, tartaric acid, ethanol, tert butyl alcohol, n-hexane, hexafluoroisopropyl alcohol, cyclohexane, and acetone.

[0011] In some specific embodiments, the second coagulation bath is water; Further, in the S3, the ratio of the first coagulation bath collection line speed to the second coagulation bath collection line speed is the draw ratio, and the draw ratio is 1-2. In some embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1-1.8; in some embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1.2-1.8; in some embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1.2-1.6; and in some preferred embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1.5.

[0012] Further, in the S4, the solvent replacement is to immerse the wet gel fiber into a replacement solvent for replacement; the replacement solvent is one or a combination of two or more of water, ethanol, tert-butyl alcohol, n-hexane, hexafluoroisopropanol, cyclohexane, and acetone; and / or, the number of times of solvent replacement is 1-3 times; and / or, the drying treatment is selected from CO2 supercritical drying; and / or, the supercritical pressure is 8.5-11.5 MPa.

[0013] In some embodiments, the replacement solvent is ethanol or tert-butyl alcohol; the number of times of solvent replacement is 1-2 times; and / or, the number of times of solvent replacement is 2-3 times. In some embodiments, the drying treatment is selected from CO2 supercritical drying, and the supercritical pressure can be selected to be 8.5 MPa, 9.5 MPa, 10.5 MPa, or 11.5 MPa. Further, in the S5, the vacuum impregnation temperature is 60-80℃; and / or, the vacuum impregnation pressure is 0.5-50 mbar.

[0014] In some embodiments, the vacuum impregnation temperature can be selected to be 60℃, 70℃, or 80℃. In some embodiments, the vacuum impregnation pressure can be selected to be 0.5 mbar, 1 mbar, 5 mbar, 10 mbar, 20 mbar, 30 mbar, 40 mbar, or 50 mbar. In a second aspect, the present application provides a phase change aramid fiber, characterized in that the fiber strength is 140-350 MPa, the elongation at break is 16-25%, and the phase change latent heat is 48-115 J / g.

[0015] Compared with the prior art, the present application has the following beneficial effects: (1) This invention introduces olefinic carbon material into dimethyl sulfoxide before deprotonation of aramid III fiber to enhance fiber strength. Then, by adjusting the draw ratio of the first and second coagulation baths, the fiber diameter and porosity can be precisely controlled to meet the enthalpy control requirements of phase change fibers in different aramid III fiber systems. (2) The phase change aramid fiber obtained by the present invention has high tensile strength, wide adjustable range of phase change temperature, and high phase change enthalpy or latent heat; it has a very broad application prospect in the fields of thermal interface materials, energy storage materials and high temperature protection materials. Attached Figure Description

[0016] Figure 1 This is a scanning electron microscope image of the phase change aramid fiber of the present invention. Detailed Implementation

[0017] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be described in detail below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally performed under conventional conditions or as recommended by the manufacturer. Unless otherwise specified, the test materials used in the following embodiments were purchased from conventional biochemical reagent stores. Unless otherwise stated, percentages and parts are by weight. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar with the art. Furthermore, any methods and materials similar to or equivalent to those described herein can be applied to the present invention. The preferred embodiments and materials described herein are for illustrative purposes only.

[0018] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0019] Based on this invention, aramid fiber III is obtained by copolymerization of three monomers: p-phenylenediamine, terephthaloyl chloride, and a diamine with a heterocyclic structure containing elements such as N, O, and S. It has superior mechanical strength, modulus, electrical insulation, corrosion resistance, and high temperature resistance. Aramid fiber III is selected as the raw material, and olefinic carbon materials are introduced into DMSO before its deprotonation to enhance the fiber strength. By adjusting the draw ratio of the first and second coagulation baths, the fiber diameter and porosity can be precisely controlled to meet the enthalpy control requirements of phase change fibers in different aramid III fiber systems.

[0020] Based on the present invention, the phase change aramid fiber has a fiber strength of 90-350, a breaking elongation of 15-30%, and a phase change latent heat of 25-150 J / g.

[0021] Based on this invention, olefin-carbon reinforced phase change aramid fibers are prepared by the following method: olefin-carbon material is added to dimethyl sulfoxide and ultrasonically dispersed to obtain an olefin-carbon dispersion with a mass fraction of 0.01-0.5%; aramid fiber III is added to the olefin-carbon dispersion containing an alkaline substance and stirred to undergo a deprotonation reaction, resulting in a nanofiber spinning solution with an aramid concentration of 0.5-15%; the nanofiber spinning solution is extruded through a spinneret and then coagulated in a first coagulation bath and a second coagulation bath, and collected by winding to obtain wet gel fibers; the obtained wet gel fibers are solvent-displaced and dried to obtain porous aramid fibers; the porous aramid fibers are placed in a phase change material, vacuum impregnated, and dried to obtain olefin-carbon reinforced phase change aramid fibers (e.g., ...). Figure 1 (As shown).

[0022] Based on this invention, the graphene-carbon material is selected from one of graphene oxide, graphene, and reduced graphene oxide.

[0023] Based on the present invention, the aramid fiber III is in the form of one of chopped strands, filaments, precipitate, or pulp; Based on the present invention, the alkaline substance is selected from one or more of potassium hydroxide, sodium hydroxide, sodium ethoxide, potassium ethoxide, sodium tert-butoxide, or potassium tert-butoxide. In some preferred embodiments, the alkaline substance is selected from potassium hydroxide and sodium hydroxide.

[0024] Based on the present invention, the mass ratio of the aramid fiber, the alkaline substance and the olefinic carbon dispersion is (1-10):(1-10):(90-110).

[0025] Based on the present invention, the first coagulation bath is water with or without added auxiliary components; the second coagulation bath is water with or without added auxiliary components; the auxiliary components are selected from one or more of sulfuric acid, hydrochloric acid, formic acid, acetic acid, oxalic acid, citric acid, phosphoric acid, tartaric acid, ethanol, tert-butanol, n-hexane, hexafluoroisopropanol, cyclohexane, and acetone.

[0026] In some preferred embodiments, the first coagulation bath is water; the second coagulation bath is water; Based on the present invention, the ratio of the linear velocity of the first coagulation bath collection to the linear velocity of the second coagulation bath collection is the draw ratio, and the draw ratio is 1-2; In some specific embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1-1.8; in some specific embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1.2-1.8; in some specific embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1.2-1.6; in some preferred embodiments, the draw ratio of the first coagulation bath to the second coagulation bath is 1.5.

[0027] Based on the present invention, the solvent replacement involves immersing the wet gel fiber in a replacement solvent for replacement; the replacement solvent is one or a combination of two or more of water, ethanol, tert-butanol, n-hexane, hexafluoroisopropanol, cyclohexane, and acetone; and / or, the number of solvent replacements is 1-3 times; and / or, the drying treatment is selected from supercritical CO2 drying; and / or, the supercritical pressure is 8.5-11.5 MPa.

[0028] In some specific embodiments, the replacement solvent is ethanol or tert-butanol; the number of solvent replacements is 1-2 times; and / or, the number of solvent replacements is 2-3 times; In some specific embodiments, the drying process is selected from CO2 supercritical drying, and the supercritical pressure can be selected as 8.5 MPa, 9.5 MPa, 10.5 MPa, or 11.5 MPa; Based on the present invention, the vacuum impregnation temperature is 60 ~ 80°C; and / or, the vacuum impregnation pressure is 0.5 ~ 50 mbar.

[0029] In some specific embodiments, the vacuum impregnation temperature can be selected as 60°C, 70°C, or 80°C; In some specific embodiments, the vacuum impregnation pressure can be selected as 0.5 mbar, 1 mbar, 5 mbar, 10 mbar, 20 mbar, 30 mbar, 40 mbar, or 50 mbar; The technical solution of the present invention will be further described in detail below with reference to several preferred embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be understood that the following embodiments are only used to explain the present invention and are not intended to limit the present invention.

[0030] Example 1 Preparation of graphene-carbon material dispersion: Small-sized graphene is added to DMSO and stirred to obtain a 0.05% (w / w) graphene-carbon dispersion; Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.02:0.02:100; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. Both the first and second coagulation baths were composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the linear velocity collected in the first coagulation bath to the linear velocity collected in the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.5 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer and the system pressure was set to 9.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer, and then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0031] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 244 MPa, the elongation at break was 23.7%, and the latent heat of phase change could reach 79.4 J / g.

[0032] Example 2 Preparation of graphene-carbon material dispersion: Small-sized graphene, large-sized graphene oxide, small-sized graphene oxide, and reduced graphene oxide are added to DMSO and stirred to obtain a 0.1% (by mass) graphene-carbon dispersion. Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.02:0.02:100; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. Both the first and second coagulation baths were composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the linear velocity collected in the first coagulation bath to the linear velocity collected in the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.5 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer and the system pressure was set to 9.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer, and then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0033] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 336 MPa, the elongation at break was 19.1%, and the latent heat of phase change could reach 51.7 J / g.

[0034] Example 3 Preparation of graphene-carbon material dispersion: Small-sized graphene, large-sized graphene oxide, small-sized graphene oxide, and reduced graphene oxide are added to DMSO and stirred to obtain a 0.2% (by mass) graphene-carbon dispersion. Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.02:0.02:100; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. Both the first and second coagulation baths were composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the linear velocity collected in the first coagulation bath to the linear velocity collected in the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.5 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer and the system pressure was set to 9.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer, and then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0035] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 276 MPa, the elongation at break was 17.9%, and the latent heat of phase change could reach 66.1 J / g.

[0036] Example 4 Preparation of graphene-carbon material dispersion: Small-sized graphene, large-sized graphene oxide, small-sized graphene oxide, and reduced graphene oxide are added to DMSO and stirred to obtain a 0.5% (by mass) graphene-carbon dispersion. Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.02:0.02:100; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. Both the first and second coagulation baths were composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the linear velocity collected in the first coagulation bath to the linear velocity collected in the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.5 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer and the system pressure was set to 9.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer, and then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0037] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 145 MPa, the elongation at break was 20.8%, and the latent heat of phase change could reach 79.3 J / g.

[0038] Example 5 Preparation of graphene-carbon material dispersion: Large-sized graphene oxide is added to DMSO and stirred to obtain a 0.1% (by mass) graphene-carbon dispersion; Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.01:0.02:90; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. The first and second coagulation baths were both composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the collection linear velocity of the first coagulation bath to the collection linear velocity of the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.1 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer. The system pressure was set to 8.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer. Then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0039] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 128.6 MPa, the elongation at break was 20%, and the latent heat of phase change could reach 114.2 J / g.

[0040] Example 6 Preparation of graphene-carbon material dispersion: Small-sized graphene oxide is added to DMSO and stirred to obtain a 0.2% (by mass) graphene-carbon dispersion; Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.05:0.1:100; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. The first and second coagulation baths were both composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the collection linear velocity of the first coagulation bath to the collection linear velocity of the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.8 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer and the system pressure was set to 10.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer, and then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0041] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 336 MPa, the elongation at break was 19.1%, and the latent heat of phase change could reach 48.5 J / g.

[0042] Example 7 Preparation of graphene-carbon material dispersion: Small-sized graphene is added to DMSO and stirred to obtain a 0.4% (by mass) graphene-carbon dispersion; Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.08:0.1:110; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. Both the first and second coagulation baths were composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the collection linear velocity of the first coagulation bath to the collection linear velocity of the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.0 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer. The system pressure was set to 11.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer. Then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0043] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 276 MPa, the elongation at break was 17.9%, and the latent heat of phase change could reach 67.7 J / g.

[0044] Example 8 Preparation of olefin-carbon material dispersion: Reduced graphene oxide is added to DMSO and stirred to obtain an olefin-carbon dispersion with a mass fraction of 0.5%. Preparation of nanofiber spinning solution: Add olefin carbon dispersion to 0.4wt% KOH aqueous solution, ultrasonically disperse to obtain aramid dissolution system, then add aramid fiber III and let stand for 24h, then stir for 24h to obtain nanofiber dispersion, wherein the mass ratio of aramid fiber III, KOH and olefin carbon dispersion is 0.1:0.1:90; Preparation of olefin-carbon composite aramid gel fibers: A aramid nanofiber dispersion was extruded into a coagulation bath using a high-pressure injection pump. The first and second coagulation baths were both composed of deionized aqueous solutions. The first coagulation bath was a negative drawing bath, and the second coagulation bath was a drawing water washing bath. The ratio of the collection linear velocity of the first coagulation bath to the collection linear velocity of the second coagulation bath was the drawing ratio. The drawing ratio was fixed at 1.8 to obtain olefin-carbon aramid gel fibers. Preparation of olefin-carbon composite aramid porous fiber: The gel fiber was placed in 10 times its mass of deionized water and allowed to stand to ensure that the solvent DMSO was completely washed away. The deionized water was replaced with an equal volume of ethanol. The solution was changed every 8 hours for a total of two changes. After the above solvent replacement was completed, the gel fiber was placed in a CO2 supercritical dryer and the system pressure was set to 9.5 MPa. After 10 hours of CO2 supercritical drying, no ethanol was generated in the separation vessel of the dryer, and then the olefin-carbon composite aramid porous fiber was obtained. Preparation of olefin-carbon composite phase change aramid fiber: olefin-carbon porous fiber is immersed in molten octadecane liquid and vacuum impregnated for 8 hours at 60-100℃ and 0.5-50 mbar pressure. Then the fiber is wrapped with filter paper and placed in a 100℃ oven for 20 min to remove residual octadecane on the fiber surface. Finally, olefin-carbon phase change aramid fiber is obtained.

[0045] The performance of the olefin-carbon phase change aramid fiber in this embodiment was characterized. The fiber strength was 305.1 MPa, the elongation at break was 18.7%, and the latent heat of phase change could reach 58.6 J / g.

[0046] Comparative Example 1 Same as Example 1, except that no olefinic carbon material is added.

[0047] The phase change aramid fiber of this embodiment was characterized for performance. The fiber strength was 99 MPa, the elongation at break was 30%, and the latent heat of phase change was 150 J / g.

[0048] Comparative Example 2 Similar to Example 1, except that no olefinic carbon material is added and the draw ratio is fixed at 1.

[0049] The phase change aramid fiber of this embodiment was characterized for performance. The fiber strength was 99 MPa, the elongation at break was 20%, and the latent heat of phase change was 148 J / g.

[0050] Comparative Example 3 Similar to Example 1, except that no olefinic material is added and the draw ratio is fixed at 3.

[0051] The phase change aramid fiber of this embodiment was characterized for performance. The fiber strength was 99 MPa, the elongation at break was 18%, and the latent heat of phase change was 140 J / g.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of the present invention. Those skilled in the art, under the guidance of the present invention, can make various similar representations without departing from the spirit and claims of the present invention, and such modifications all fall within the protection scope of the present invention.

Claims

1. A method for controlling the phase change aramid fiber reinforced with olefin carbon, characterized in that, Includes the following steps: S1. Add the olefin carbon material to dimethyl sulfoxide and disperse it ultrasonically to obtain an olefin carbon dispersion with a mass fraction of 0.01-0.5%; S2. Aramid fiber III is added to an olefin carbon dispersion containing alkaline substances and stirred to carry out a deprotonation reaction, thereby obtaining a nanofiber spinning solution with an aramid concentration of 0.5-15%. S3. After the nanofiber spinning solution is extruded through the spinneret, it is coagulated in the first coagulation bath and the second coagulation bath, and then wound and collected to obtain wet gel fibers. S4. The obtained wet gel fiber is replaced with solvent and dried to obtain aramid porous fiber; S5. Aramid porous fibers are placed in a phase change material, and then vacuum impregnated and dried to obtain olefin-carbon reinforced phase change aramid fibers.

2. The method for controlling the phase change aramid fiber reinforced with olefin carbon according to claim 1, characterized in that, In S1, the olefinic material is selected from one of graphene oxide, graphene, and reduced graphene oxide.

3. The method for controlling the phase change of aramid fiber reinforced with olefin carbon according to claim 1, characterized in that, In S2, the aramid fiber III is in the form of chopped strands, filaments, precipitate, or pulp; and / or, the alkaline substance is selected from one or more of potassium hydroxide, sodium hydroxide, sodium ethoxide, potassium ethoxide, sodium tert-butoxide, or potassium tert-butoxide.

4. The method for controlling the phase change aramid fiber reinforced with olefin carbon according to claim 1, characterized in that... In S2, the mass ratio of the aramid fiber, the alkaline substance and the olefinic carbon dispersion is (0.01-0.1):(0.01-0.1):(90-110).

5. The method for controlling the phase change aramid fiber reinforced with olefin carbon according to claim 1, characterized in that... In S3, the first coagulation bath is water with or without added auxiliary components; The auxiliary components are selected from one or more of sulfuric acid, hydrochloric acid, formic acid, acetic acid, oxalic acid, citric acid, phosphoric acid, tartaric acid, ethanol, tert-butanol, n-hexane, hexafluoroisopropanol, cyclohexane, and acetone.

6. The method for controlling the phase change of aramid fiber reinforced with olefin carbon according to claim 1, characterized in that... In S3, the second coagulation bath is water with or without added auxiliary components; The auxiliary components are selected from one or more of sulfuric acid, hydrochloric acid, formic acid, acetic acid, oxalic acid, citric acid, phosphoric acid, tartaric acid, ethanol, tert-butanol, n-hexane, hexafluoroisopropanol, cyclohexane, and acetone.

7. The method for controlling the phase change of aramid fiber reinforced with olefin carbon according to claim 1, characterized in that... In S3, the ratio of the linear velocity of the first coagulation bath collection to the linear velocity of the second coagulation bath collection is the draw ratio, which is 1-2; or 1-1.8; or 1.2-1.8; or 1.2-1.6; or 1.

5.

8. The method for controlling the phase change of aramid fiber reinforced with olefin carbon according to claim 1, characterized in that... In S4, the solvent replacement involves immersing the wet gel fiber in a replacement solvent for replacement; the replacement solvent is one or a combination of two or more of water, ethanol, tert-butanol, n-hexane, hexafluoroisopropanol, cyclohexane, and acetone; and / or, the number of solvent replacements is 1-3 times; and / or, the drying treatment is selected from CO2 supercritical drying; and / or, the supercritical pressure is 8.5-11.5 MPa.

9. The method for controlling the phase change aramid fiber reinforced with olefin carbon according to claim 1, characterized in that... In S5, the vacuum impregnation temperature is 60 ~ 80°C; and / or, the vacuum impregnation pressure is 0.5 ~ 50 mbar.

10. A phase change aramid fiber prepared by any one of claims 1-9, characterized in that, The fiber has a strength of 140-350 MPa, an elongation at break of 16-25%, and a latent heat of phase change of 48-115 J / g.

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