Graphene-polyester composite thermal insulation fiber and preparation method thereof

Abstract

The invention relates to a block copolymer dispersing agent, a preparation method of the block copolymer dispersing agent, a graphene-silicon dioxide aqueous dispersion, a graphene modified silicon dioxide composite material, a graphene-polyester composite thermal insulation fiber and application of the graphene-silicon dioxide aqueous dispersion, the graphene modified silicon dioxide composite material and the graphene-polyester composite thermal insulation fiber. And a good combination effect is achieved on hydrophilic vapor-phase silicon dioxide and graphene oxide, so that effective dispersion of silicon dioxide and graphene is achieved. The graphene oxide and the hydrophilic vapor-phase silicon dioxide are dispersed by the block copolymer dispersing agent and then are melt-blended with the polyester fiber, so that the graphene-polyester composite thermal insulation fiber which is better in flexibility, high in antistatic effect and better in hygroscopicity is obtained.

Description

Technical Field

[0001] This invention belongs to the field of graphene composite material technology, and specifically relates to a block copolymer dispersant and its preparation method, as well as graphene-silica aqueous dispersion, graphene-modified silica composite material and graphene-polyester composite thermal insulation fiber and their applications. Background Technology

[0002] Currently, widely used fibers in the clothing fabric industry include polyester fibers, commonly known as polyester fiber. Polyester fiber is a synthetic fiber obtained by spinning polyester, which is formed by the condensation polymerization of organic diacids and diols. It possesses good mechanical strength, high strength, high modulus, good resilience, good insulation, and good abrasion resistance. However, polyester fibers are prone to static electricity during processing or when used in fabrics. Furthermore, polyester fibers have poor moisture absorption, making them unsuitable for wicking away moisture and perspiration, and their thermal insulation performance needs improvement.

[0003] Graphene is a two-dimensional sheet-like nanomaterial composed of carbon atoms, characterized by high specific surface area, high thermal conductivity, and high electrical conductivity. Due to its high thermal conductivity, when graphene is dispersed in a polyester matrix, the two form a disordered thermally conductive network, which actually reduces the overall thermal conductivity of the composite fiber. Simultaneously, it enhances the mechanical properties of the composite fiber, promotes the formation of micropores within the fiber, thereby improving the thermal insulation effect. Graphene also enhances electrical conductivity and improves the antistatic effect of the composite fiber.

[0004] Given the significant improvements in various properties that can be achieved when graphene is combined with polyester fibers, research on graphene / polyester composites has become a hot topic. The main composite modification scheme involves first preparing graphene-silica aerogel, and then melt-blending it with polyester fibers. However, the preparation of graphene-silica aerogel involves many steps, high cost, long time, and low efficiency. Therefore, a simpler method for preparing graphene-silica composite polyester fibers is needed. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention proposes the preparation of a special hydrophobic-hydrophilic-hydrophobic block copolymer dispersant. Graphene / silica is dispersed using the block copolymer dispersant and then melt-blended with polyester fibers, thereby obtaining graphene-polyester composite thermal insulation fibers with better flexibility, higher antistatic effect, and better moisture absorption.

[0006] In a first aspect, there is a block copolymer dispersant, the molecular structure of which is star-shaped, consisting of at least three branches sequentially connected to the central core of a polysiloxane, wherein the branches include hydrophilic segments and hydrophobic segments, and the hydrophilic segments and hydrophobic segments are respectively concentrated on the branches to form different segments.

[0007] The general molecular structural formula of block copolymer dispersants is: or ;

[0008] Where n is a positive integer greater than or equal to 1, and R base is selected from straight-chain aliphatic hydrocarbons, branched aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons, or mixed structures of aliphatic hydrocarbons and aromatic hydrocarbons with 1 to 60 carbon atoms.

[0009] Preferably, n is a positive integer greater than or equal to 5, and the R base is selected from straight-chain aliphatic hydrocarbons, branched aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons, or a mixture of aliphatic and aromatic hydrocarbons with 10 to 60 carbon atoms.

[0010] Further optimization, n=5~25;

[0011] Further optimization, the R basis is selected from: , or .

[0012] Secondly, the preparation method of the block copolymer dispersant mentioned above includes: a hydrosilylation reaction of a hydrogen-containing silane with at least three functionalities with 3-isopropyl-dimethylbenzyl isocyanate (TMI) to obtain an intermediate product, and then reacting the intermediate product with a hydroxyl-containing polyoxyethylene ether compound to obtain the block copolymer dispersant.

[0013] Wherein, the at least trifunctional hydrogen-containing silane is selected from any one of: methyltris(dimethylsiloxy)-silane or 2,4,6,8-tetramethylcyclotetrasiloxane;

[0014] The hydrosilylation reaction requires a hydrosilylation catalyst, which is selected from one or more of the following platinum complex catalysts: platinum-isopropanol complex catalyst, platinum-ene complex catalyst, platinum-phosphine amine complex catalyst, or platinum-(N-heterocyclic carbene) complex. Preferably, the hydrosilylation catalyst is selected from platinum-ene complex catalyst; more preferably, the hydrosilylation catalyst is selected from platinum-divinyltetramethyldisiloxane complex.

[0015] And / or, the reaction formulas for hydrosilylation reactions are shown below:

[0016] , ;

[0017] Preferably, the structural formula of the intermediate product includes: or ;

[0018] Preferably, the hydroxyl-containing polyoxyethylene ether compound is selected from one of polystyrene phenol polyoxyethylene ether, polyethylene glycol o-phenyl phenyl ether acrylate, alkylphenol polyoxyethylene ether, or cashew phenol polyoxyethylene ether;

[0019] Preferably, a catalyst is used in the reaction process of the intermediate product with the hydroxyl-containing polyoxyethylene ether compound, and the catalyst is preferably dibutyltin dilaurate.

[0020] And / or, the reaction formula for the reaction of the intermediate product with a hydroxyl-containing polyoxyethylene ether compound is shown below: , ;

[0022] And / or, the block copolymer dispersant has the following structural formula: , ;

[0023] Preferably, the R base is selected from: , or .

[0024] Thirdly, a graphene-silica aqueous dispersion is obtained by dispersing graphene, silica, and the block copolymer dispersant described above in water.

[0025] Wherein, the graphene is graphene oxide; the silicon dioxide is fumed silicon dioxide;

[0026] Preferably, the silicon dioxide is hydrophilic fumed silicon dioxide.

[0027] Preferably, the water is deionized water with a conductivity of less than 10 μS / cm at room temperature.

[0028] Preferably, the specific steps of the dispersion include: pre-dissolving the block copolymer dispersant described above in water, pre-dispersing for 10-60 min, and then adding graphene oxide and fumed silica to continue dispersion for 10-60 min.

[0029] Fourthly, a graphene-modified silica composite material is obtained by drying the graphene-silica aqueous dispersion described above.

[0030] Preferably, the drying is vacuum drying.

[0031] Fifthly, the application of the graphene-modified silica composite material described above in the modification of polyester fibers.

[0032] Sixthly, a graphene-polyester composite thermal insulation fiber is prepared by premixing, melt blending, melt spinning, cooling, hot roller stretching and winding of the graphene-modified silica composite material and polyester as described above.

[0033] Preferably, the premixing involves mechanically mixing the graphene-modified silica composite material with the polyester at 80-120°C for 10-60 minutes.

[0034] Preferably, the melt blending temperature is 230-280℃;

[0035] Further preferred, the melt blending temperature is 230-260℃;

[0036] Preferably, the specific steps of melt spinning are to extrude, draw, and pelletize the blended melt, and then feed the blended particles into a spinning screw extruder and extrude them into melt fibers through the spinneret.

[0037] Preferably, the temperature of the hot roller stretching is 60-90℃, and the stretching ratio is 1.5-2.3.

[0038] Seventhly, one application is the use of the graphene-polyester composite thermal insulation fiber described above in human body thermal management.

[0039] Eighthly, an application of the graphene-polyester composite insulating fiber described above in fabrics and wearable devices.

[0040] The beneficial effects of this invention are as follows: A special hydrophobic-hydrophilic-hydrophobic block copolymer dispersant is designed. This dispersant has a star-shaped structure, with a core of linear or cyclic polysiloxane-Si-O-structure, exhibiting high-temperature stability and preventing thermal decomposition during melt processing. Simultaneously, this dispersant possesses polyoxyethylene side chains and aromatic or aromatic-alkene side chain structures. The polyoxyethylene segments are hygroscopic and have a good binding effect on hydrophilic fumed silica. The aromatic or alkene groups possess π electrons, which can bind with sp2-hybridized carbon in graphene through π-π interactions, thereby achieving effective dispersion of silica and graphene. Furthermore, the block copolymer dispersant can introduce polyoxyethylene segments with better hygroscopicity into graphene-polyester composite insulation fibers, which is beneficial for improving the flexibility and bendability of the composite fibers, enhancing the absorption of sweat, and improving antistatic properties. Attached Figure Description

[0041] Figure 1 The 1H NMR spectrum of the block copolymer dispersant prepared in Example 1 ( 1 H-NMR).

[0042] Figure 2The TG and DTG curves are shown for the block copolymer dispersant prepared in Example 1.

[0043] Figure 3 Torque-time curves of graphene-modified silica composite materials and polyester in Examples 5, 7, 9, and 11, and comparative examples of graphene, silica, and polyester. Detailed Implementation

[0044] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] Unless otherwise specified, the experimental conditions used in the examples are generally in accordance with conventional conditions in the art or the conditions recommended by the reagent company. Unless otherwise specified, the materials and reagents used in the examples can be purchased commercially.

[0047] Example 1:

[0048] Preparation of block copolymer dispersant: 53.72 g (0.2 mol) of methyltris(dimethylsiloxane)silane was dissolved in 100 mL of toluene in a three-necked flask. 0.8 g of Karstedt catalyst, 124.66 g of 3-isopropyl-α,α-dimethylbenzyl isocyanate (TMI, 0.62 mol) and 100 mL of toluene solvent were added dropwise with stirring. The reaction temperature was controlled at 90 °C. The addition was completed within 1 hour, and the reaction was maintained at this temperature for 2 hours.

[0049] The corresponding reaction formula is: .

[0050] 377.58 g (0.62 mol) of cashew phenol polyoxyethylene ether NX-7507 (Cardley, containing 7 polyoxyethylene ether EO segments) was vacuum dried at 100 °C for 2 hours to remove residual water. Then the vacuum was removed, and nitrogen gas was continuously introduced for protection. The temperature was raised to 90 °C, and 2.5 g of dibutyltin dilaurate was added as a catalyst. The product was added dropwise under stirring to react. After 6 hours of reaction, the temperature was lowered, and the solvent and unreacted monomers were removed by vacuum distillation at 0.01 MPa and 60 °C to obtain the final block copolymer.

[0051] The corresponding reaction formula is:

[0052] in, .

[0053] The chemical structural formula of the block copolymer dispersant prepared in Example 1 is as follows: ;

[0054] The structural characterization of the block copolymer dispersant prepared in Example 1 is as follows: Figure 1 As shown, the nuclear magnetic resonance spectrometer is 600MHz and the nuclear magnetic solvent is CDCl3.

[0055] Thermogravimetric analysis of the block copolymer dispersant prepared in Example 1 is as follows: Figure 2 As shown, the heating range is from room temperature to 800℃, the heating rate is 20℃ / min, the atmosphere is air, and thermogravimetric analysis shows that its initial thermal decomposition temperature starts from about 250℃.

[0056] Example 2:

[0057] Preparation of block copolymer dispersant: 48.10 g (0.2 mol) of tetramethylcyclotetrasiloxane was dissolved in 100 mL of toluene and placed in a three-necked flask. 1.0 g of Karstedt catalyst, 169.06 g of 3-isopropyl-α,α-dimethylbenzyl isocyanate (TMI, 0.84 mol) and 50 mL of toluene solvent were added dropwise to the flask. The reaction temperature was controlled at 95 °C and the addition was completed within 1 hour. The reaction was then maintained at this temperature for 2 hours.

[0058] The corresponding reaction formula is: .

[0059] 511.56 g (0.84 mol) of cashew phenol polyoxyethylene ether NX-7507 (Cardley, containing 7 polyoxyethylene ether EO segments) was vacuum dried at 100 °C for 1 hour to remove residual water. The product was then added dropwise with stirring, the temperature was raised to 90 °C, and 3.5 g of dibutyltin dilaurate was added as a catalyst. After reacting for 8 hours, the temperature was lowered, and the solvent and unreacted monomers were removed by vacuum distillation at 0.01 MPa and 60 °C to obtain the final block copolymer.

[0060] The corresponding reaction formula is:

[0061] in, .

[0062] The chemical structural formula of the block copolymer dispersant prepared in Example 2 is as follows: .

[0063] Example 3:

[0064] Preparation of the block copolymer dispersant: SIPOMER SEM-25 triphenylethylphenol polyoxyethylene ether methacrylate monomer (containing 25 polyoxyethylene ether EO segments, Solvay) was dried under vacuum at 105℃ for 8 hours to remove water. 488g (0.31mol) of SEM-25 monomer and 3.2g of hydroquinone monomethyl ether (hydroquinone) inhibitor were weighed and added to a three-necked flask. 250mL of toluene was added for dissolution. The mixture was heated to 105℃ with stirring, and a mixture of 26.86g (0.1mol) methyltris(dimethylsiloxane)silane, 2.4g of Karstedt catalyst, and 20mL of toluene was added dropwise. The reaction temperature was controlled at 105℃, and the addition was completed within 2 hours. The reaction was maintained at this temperature for another 3 hours. The reaction was then stopped, the temperature was lowered, and the solvent and unreacted monomers were removed by vacuum distillation at 0.01MPa and 60℃ to obtain the final block copolymer.

[0065] The corresponding reaction formula is:

[0066] in, ;

[0067] The chemical structural formula of the block copolymer dispersant prepared in Example 3 is as follows: .

[0068] Example 4:

[0069] Preparation of the block copolymer dispersant: Polyethylene glycol o-phenyl ether acrylate (OPPEA) monomer (containing 5 polyoxyethylene ether EO segments, Guangzhou Sanwang) was dried under vacuum at 105℃ for 8 hours to remove water. 364.3 g (0.82 mol) of OPPEA monomer and 3.6 g of hydroquinone monomethyl ether (hydroquinone monomethyl ether) were weighed and added to a three-necked flask, followed by the addition of 160 mL of toluene for dissolution. The mixture was heated to 105℃ with stirring, and 48.10 g (0.2 mol) of tetramethylcyclotetrasiloxane, 2.0 g of Karstedt catalyst, and 10 mL of toluene solvent were added dropwise. The reaction temperature was controlled at 105℃, and the addition was completed within 2 hours. The reaction was then maintained at this temperature for 3 hours. The reaction was then stopped, the temperature was lowered, and the solvent and unreacted monomers were removed by vacuum distillation at 0.01 MPa and 60℃ to obtain the final block copolymer.

[0070] The corresponding reaction formula is: ;

[0071] The chemical structural formula of the block copolymer dispersant prepared in Example 4 is as follows: .

[0072] Example 5:

[0073] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 1, 144 parts of single-layer graphene oxide XF002-1 (Xianfeng Nano, graphene oxide sheet diameter 0.5-5μm, thickness 0.8-1.2nm, the same below), 270 parts of deionized water, and 96 parts of hydrophilic fumed silica HL-380 (Hubei Huifu, specific surface area of ​​380m2 / g, the same below).

[0074] The preparation method of the above composite material is as follows: The block copolymer dispersant prepared in Example 1 is dissolved in deionized water and dispersed at 800 rpm for 15 min using a disperser. Then, monolayer graphene oxide and hydrophilic fumed silica are added sequentially while maintaining a speed of 800 rpm. After the addition is completed, the speed of the disperser is increased to 1000 rpm and dispersed at this speed for 30 min. The resulting graphene-modified silica aqueous dispersion is vacuum dried at 80℃ and -0.08 MPa vacuum to finally obtain the graphene-modified silica composite material.

[0075] Example 6:

[0076] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 1, 120 parts of monolayer graphene oxide, 270 parts of deionized water, and 120 parts of hydrophilic fumed silica.

[0077] Preparation method of composite material: same as in Example 5.

[0078] Example 7:

[0079] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 2, 144 parts of monolayer graphene oxide, 270 parts of deionized water, and 96 parts of hydrophilic fumed silica.

[0080] Preparation method of composite material: same as in Example 5.

[0081] Example 8:

[0082] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 2, 120 parts of monolayer graphene oxide, 270 parts of deionized water, and 120 parts of hydrophilic fumed silica.

[0083] Preparation method of composite material: same as in Example 5.

[0084] Example 9:

[0085] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 3, 144 parts of monolayer graphene oxide, 270 parts of deionized water, and 96 parts of hydrophilic fumed silica.

[0086] Preparation method of composite material: same as in Example 5.

[0087] Example 10:

[0088] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 3, 120 parts of monolayer graphene oxide, 270 parts of deionized water, and 120 parts of hydrophilic fumed silica.

[0089] Preparation method of composite material: same as in Example 5.

[0090] Example 11:

[0091] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 4, 144 parts of monolayer graphene oxide, 270 parts of deionized water, and 96 parts of hydrophilic fumed silica.

[0092] Preparation method of composite material: same as in Example 5.

[0093] Example 12:

[0094] A graphene-modified silica composite material, by weight, comprises the following materials: 30 parts of the block copolymer dispersant prepared in Example 4, 120 parts of monolayer graphene oxide, 270 parts of deionized water, and 120 parts of hydrophilic fumed silica.

[0095] Preparation method of composite material: same as in Example 5.

[0096] Molding process of graphene-polyester composite thermal insulation fiber: The graphene-modified silica composite material prepared in Example 5-12 is processed into PET polyester chips by melt spinning, wherein the mass ratio of PET polyester chips to graphene-modified silica composite material is 100:1.5.

[0097] The specific steps of the molding process are as follows: graphene-modified silica composite material and polyester chips are mechanically mixed in a mixer for 30 minutes, with the mixing temperature controlled at 90℃ and the stirring speed at 800 rpm. Then, the mixture is melt-blended in a twin-screw extruder at 250℃ to obtain a blended melt. The blended melt is then extruded, drawn into strands, and pelletized. The blended particles are then fed into a spinning screw extruder and extruded into melt fibers through a 0.2 mm spinneret. The fibers are then cooled by a cooling air blower, stretched by a hot roller at 70℃ with a stretch ratio of 1.8, and finally wound on a winding machine at a winding speed of 2500 m / min to obtain graphene-polyester composite thermal insulation fiber.

[0098] The molding process of the comparative graphene-polyester composite thermal insulation fiber: the mass ratio of PET polyester chips to graphene oxide and hydrophilic fumed silica is 100:0.9:0.6.

[0099] The specific steps of the molding process are as follows: monolayer graphene oxide XF002-1, hydrophilic fumed silica HL-380 and polyester chips are mechanically mixed in a mixer for 30 minutes, with the mixing temperature controlled at 90℃ and the stirring speed at 800rpm. Then, the mixture is melt-blended in a twin-screw extruder at 245℃ to obtain a blended melt. The blended melt is then extruded, drawn into strands, and pelletized. The blended particles are then fed into a spinning screw extruder and extruded into melt fibers through a 0.2mm spinneret. The fibers are then cooled by a cooling air blower, stretched by a hot roller at 70℃ with a stretch ratio of 1.8, and finally wound on a winding machine at a winding speed of 2500m / min to obtain graphene-polyester composite thermal insulation fiber.

[0100] Performance testing section:

[0101] Torque-time curve testing: The torque-time curves of the graphene-modified silica composites in Examples 5, 7, 9, and 11, and the graphene oxide and hydrophilic fumed silica in Comparative Example 1, were tested using a torque rheometer during the premixing process with polyester chips at 90°C. The results are as follows: Figure 3 As shown.

[0102] The tensile strength of the fabric was tested in accordance with the standard GB / T 3923.1. The tensile strength of the graphene-polyester composite thermal insulation fiber sample was tested using a constant rate of elongation tester at a tensile rate of 20 mm / min.

[0103] The bending stiffness of the fabric was tested according to Part 1 of GB / T 18318.1, the inclined plane method, using a bending length meter to test the bending stiffness of the graphene-polyester composite thermal insulation fiber samples.

[0104] The antistatic properties of the fabric were tested in accordance with the standard GB / T 12703.4, and the surface resistivity of the graphene-polyester composite thermal insulation fiber sample was tested using a fabric resistivity tester.

[0105] The moisture permeability of fabrics is tested in accordance with the standard GB / T 12704.1. The mass of water vapor passing vertically through a unit area sample using a moisture permeability cup is used to determine the moisture permeability of the fabric.

[0106] The test results of the graphene-polyester composite thermal insulation fibers prepared in Examples 5-12 and the comparative examples are summarized in Table 1.

[0107] pass Figure 3 Torque-time curve analysis shows that, in the comparative examples, the block copolymer dispersant of Examples 1-4 was not used to disperse graphene oxide and fumed silica. Instead, graphene oxide, fumed silica, and polyester chips were directly mixed. During the premixing process, the torque increased sharply after about 15 minutes. This is related to the lack of dispersion and lubrication, which led to the agglomeration of graphene oxide or fumed silica. In contrast, Examples 5, 7, 9, and 11 introduced a block copolymer dispersant to pre-prepare graphene-modified silica composite materials, thus avoiding the rapid agglomeration of graphene oxide or fumed silica during the premixing process.

[0108] Table 1 Test sample Fracture strength (cN / dtex) Bending stiffness (mN·cm) Surface resistivity (Ω) Moisture permeability (g / (m2·h)) Example 5 113.3 1.89 4.3×109 288.9 Example 6 112.3 1.85 3.9×109 293.2 Example 7 112.0 1.86 4.4×109 284.0 Example 8 111.6 1.82 4.2×109 289.5 Example 9 108.4 1.77 1.6×109 323.8 Example 10 109.2 1.75 1.5×109 321.4 Example 11 114.1 1.97 5.7×109 258.7 Example 12 114.6 1.93 6.2×109 262.3 Comparative Example 103.5 2.10 1.3×1010 125.6

[0109] Analysis of the data in Table 1 shows that the graphene-modified silica composite material uses a block copolymer dispersant with a special structure. The polyoxyethylene segments of this dispersant can bind to the hydroxyl groups in the fumed silica via hydrogen bonds. Furthermore, the π-electron cloud of the phenyl group and the sp² carbon atom conjugated system of graphene can form a stable adsorption through van der Waals forces. During aqueous dispersion, the block copolymer dispersant can simultaneously adsorb onto the surfaces of both fumed silica and graphene, ensuring uniform and stable dispersion in the aqueous solution. In the subsequent processing of the graphene-polyester composite insulation fiber, the polyoxyethylene segments of the block copolymer dispersant also provide hygroscopicity, improving the poor hygroscopicity and antistatic properties caused by the lack of hydrophilic groups in the polyester fiber macromolecular chain. This avoids the problems of static electricity generation and dust adsorption during friction in dry environments.

[0110] In addition, the addition of block copolymer dispersants helps polyester fibers to adsorb silica and graphene, thereby forming a coating on the fiber surface. This helps to reduce internal friction of the fiber, making the composite fiber smoother when bending and stretching, thus improving the flexibility of the composite fiber, reducing the bending stiffness of the fiber, preventing the nylon material from becoming more rigid at low temperatures, and improving the wearing experience.

[0111] Finally, improving the moisture absorption of composite fibers can also enhance the fabric's perspiration wicking ability. Timely perspiration wicking can prevent sweating from lowering the perceived temperature and affecting the insulation performance. Therefore, introducing polyoxyethylene segments into graphene-polyester composite insulating fibers through block copolymer dispersants can improve both antistatic properties and the insulation effect of the composite fiber fabric itself.

[0112] In the comparative example, the block copolymer dispersant of Examples 1-4 was not used to disperse graphene oxide and fumed silica. Instead, graphene oxide, fumed silica and polyester chips were directly mixed and melt-processed. The graphene oxide and fumed silica had poor compatibility with the polyester resin matrix, resulting in uneven distribution, which affected the mechanical properties of the composite fiber. At the same time, the lack of highly hygroscopic polyoxyethylene segments resulted in low hygroscopicity and poor antistatic properties of the composite fiber.

[0113] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of them. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention. Although the specific embodiments of the present invention have been described above, they are not intended to limit the protection scope of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the protection scope of the present invention.

Claims

1. A block copolymer dispersant, characterized in that, The molecular structure of the block copolymer dispersant is star-shaped, consisting of at least three branches sequentially connected to the central core of the polysiloxane; Among them, the side chain contains hydrophilic segments and hydrophobic segments, and the hydrophilic segments and hydrophobic segments are respectively concentrated on the side chain to form different segments; The general molecular structural formula of the block copolymer dispersant is: or ; Where n is a positive integer greater than or equal to 1, and R base is selected from straight-chain aliphatic hydrocarbons, branched aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons, or a mixture of aliphatic and aromatic hydrocarbons with 1 to 60 carbon atoms.

2. The method for preparing the block copolymer dispersant as described in claim 1, characterized in that, An intermediate product is obtained by hydrosilylation reaction of a hydrogen-containing silane with at least three functionalities with 3-isopropyl-dimethylbenzyl isocyanate. The intermediate product is then reacted with a hydroxyl-containing polyoxyethylene ether compound to obtain a block copolymer dispersant. The at least trifunctional hydrogen-containing silane is selected from any one of methyltris(dimethylsiloxy)-silane or 2,4,6,8-tetramethylcyclotetrasiloxane.

3. The method for preparing the block copolymer dispersant according to claim 2, characterized in that, The hydrosilylation reaction requires a hydrosilylation catalyst, which is selected from one or more of the following platinum complex catalysts: platinum-isopropanol complex catalyst, platinum-ene complex catalyst, platinum-phosphine amine complex catalyst, or platinum-(N-heterocyclic carbene) complex catalyst; And / or, the reaction formulas for hydrosilylation reactions are shown below: 、 ； And / or, the structural formula of the intermediate product includes: or ; And / or, the hydroxyl-containing polyoxyethylene ether compound is selected from one of polystyrene phenol polyoxyethylene ether, polyethylene glycol o-phenyl phenyl ether acrylate, alkylphenol polyoxyethylene ether, or cashew phenol polyoxyethylene ether; And / or, the reaction of the intermediate with the hydroxyl-containing polyoxyethylene ether compound uses a catalyst, preferably dibutyltin dilaurate; And / or, the reaction formula for the reaction of the intermediate product with a hydroxyl-containing polyoxyethylene ether compound is shown below: 、 ； And / or, the block copolymer dispersant has the following structural formula: 、 。 4. A graphene-silica aqueous dispersion, characterized in that, It is obtained by dispersing graphene, silicon dioxide and the block copolymer dispersant described above in water; The graphene in question is graphene oxide. The silicon dioxide is fumed silicon dioxide.

5. The graphene-silica aqueous dispersion according to claim 4, characterized in that, The silica is hydrophilic fumed silica; And / or, the water is deionized water with a conductivity of less than 10 μS / cm at room temperature; And / or, the specific steps of the dispersion include: pre-dissolving the block copolymer dispersant described above in water, pre-dispersing for 10-60 min, and then adding graphene oxide and fumed silica to continue dispersion for 10-60 min.

6. A graphene-modified silica composite material, characterized in that, The graphene-silica aqueous dispersion according to any one of claims 4-5 is obtained by drying.

7. An application characterized in that, The application of the graphene-modified silica composite material as described in claim 6 in the modification of polyester fibers.

8. A graphene-polyester composite thermal insulation fiber, characterized in that, The graphene-modified silica composite material described in claim 6 is prepared by premixing, melt blending, melt spinning, cooling, hot rolling stretching, and winding molding with polyester.

9. An application characterized in that, The application of the graphene-polyester composite thermal insulation fiber as described in claim 8 in human body thermal management.

10. An application characterized in that, The application of the graphene-polyester composite thermal insulation fiber as described in claim 8 in fabrics and wearable devices.

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