Aerogel heat preservation yarn and preparation method and application thereof

Abstract

The invention relates to the technical field of aerogel heat preservation yarns, and discloses an aerogel heat preservation yarn and a preparation method and application thereof. The preparation method comprises the following steps: preparing a polymer spinning solution and a silicon dioxide aerogel dispersion solution; carrying out electrostatic spinning on the polymer spinning solution to obtain a nanofiber membrane, and cutting the nanofiber membrane into nanofiber bands; the preparation method comprises the following steps: uniformly coating a nanofiber band with a silicon dioxide aerogel dispersion liquid, and twisting to obtain prefabricated aerogel yarns; the prefabricated aerogel yarn is subjected to annealing treatment, and the aerogel heat preservation yarn is obtained. According to the preparation method, the two-step process of spinning and drying is effectively avoided, continuous forming preparation is successfully achieved, the preparation process is simple, and the large-scale preparation prospect is good. The aerogel heat preservation yarn is internally provided with a spiral structure, so that the aerogel heat preservation yarn has excellent tensile strength; and by virtue of high-load silicon dioxide aerogel particles in the composite material, the composite material has low density, high porosity and excellent heat insulation performance.

Description

Technical Field

[0001] The present application relates to the technical field of aerogel thermal insulation yarns, and in particular to an aerogel thermal insulation yarn and a preparation method and application thereof. Background Art

[0002] Fiber materials are inseparable from human society. In order to adapt to the severe cold environment, ancient people discovered that animal fur (velvet, wool, silk, etc.), plant fiber (cotton, kudzu, linen, etc.) and other materials can be made into clothes to wear on the body to resist the severe cold. Today, various chemical fiber cotton, bionic down, etc. have been developed for use as warm clothing, which are widely loved by people. How to make fibers and their fabric materials lighter and warmer has always been the goal pursued by people.

[0003] Aerogel materials are a type of highly porous, lightweight solid material. Due to their low density and high porosity, their heat conduction paths are complex and they have excellent thermal insulation effects. Therefore, they are widely used in the aerospace and industrial thermal insulation fields. At present, aerogel powders, aerogel blocks, and aerogel films have been widely used, but for human thermal insulation, these materials cannot adapt well to the complex contours of various parts of the human body. Aerogel fibers have been widely studied because of their good weavability and excellent thermal insulation properties. Currently, researchers mostly use polymer solutions or dispersions of nanostructured units as spinning solutions, and form fibers by wet spinning or freeze spinning, and then further shape them by drying methods such as freeze drying or supercritical drying. For example, patent CN202211561762.X reports that aromatic polyamide polymers are dissolved in concentrated acid solutions, and aerogel fibers are obtained by wet spinning and subsequent drying processes. Other researchers (Adv. Mater. 2018, 30, 1706807) dissolved silk fibroin and chitosan to obtain spinning solution, and obtained low-density aerogel fibers by freeze spinning and freeze drying.

[0004] However, the current preparation of aerogel fibers is still a two-step process of spinning and drying. The preparation process is long and cannot be continuously formed. In addition, due to the porous characteristics of the fibers, the tensile strength of the material is low. How to break through the integrated molding preparation of thermal insulation fiber yarns is the difficulty of current research. Summary of the invention

[0005] The present application provides an aerogel thermal insulation yarn and a preparation method and application thereof, aiming to solve the problems of long preparation process and low tensile strength of existing aerogel thermal insulation fibers.

[0006] In order to achieve the above objectives, the present application adopts the following technical solutions.

[0007] In a first aspect of the present application, a method for preparing an aerogel thermal insulation yarn is provided, comprising:

[0008] S1, preparing polymer spinning solution and silica aerogel dispersion;

[0009] S2, obtaining a nanofiber membrane by electrospinning a polymer spinning solution, and cutting the nanofiber membrane into nanofiber strips;

[0010] S3, uniformly coating the silica aerogel dispersion on the nanofiber tape, and obtaining a prefabricated aerogel yarn by twisting;

[0011] S4, annealing the prefabricated aerogel yarn to obtain aerogel thermal insulation yarn.

[0012] Preferably, the preparation method further comprises:

[0013] S5, spraying the polymer spinning solution onto the surface of the aerogel thermal insulation yarn by electrostatic spinning to obtain a core-wrapped aerogel thermal insulation yarn.

[0014] Preferably, the solute of the polymer spinning solution is polyacrylonitrile, and the solvent is N,N-dimethylformamide or dimethyl sulfoxide; the concentration of the polymer spinning solution is 8-14 wt%.

[0015] Preferably, the silica aerogel dispersion is obtained by dispersing silica aerogel in an organic solvent, and the concentration thereof is 0.5-2 wt %;

[0016] The organic solvent includes any one of ethanol, isopropanol, n-hexane or n-octane.

[0017] Preferably, the voltage of the electrospinning in S1 is 18-24 kV;

[0018] The cutting width of the nanofiber tape described in S2 is 2 cm;

[0019] The coating method of the silica aerogel dispersion in S3 includes any one of spraying, dripping or dipping.

[0020] Preferably, the twisting parameter is 4.5-9 turns / cm.

[0021] Preferably, the annealing temperature is 120-140° C., and the annealing time is 0.5-2 h.

[0022] Preferably, the voltage of the electrospinning in S5 is 18-24 kV; during spraying, the distance between the aerogel yarn and the needle is 10-20 cm, and the spraying time is 5-20 min.

[0023] In a second aspect of the present application, an aerogel thermal insulation yarn prepared by the above preparation method is provided.

[0024] The third aspect of the present application provides the use of the aerogel thermal insulation yarn prepared by the above preparation method in thermal insulation fabric materials.

[0025] Compared with the prior art, the beneficial effects of this application are:

[0026] The preparation method of the present application effectively avoids the two-step process of spinning and drying, successfully realizes continuous molding preparation, has a simple preparation process, and has good prospects for large-scale preparation.

[0027] The aerogel thermal insulation yarn prepared in this application has a spiral surface-core structure, which makes it have excellent tensile strength, which can reach 35.1MPa. At the same time, the high-loaded silica aerogel particles inside make the aerogel thermal insulation yarn have a low density (0.20-0.35g·cm -3 ), high porosity (72.5-84.4%) and excellent thermal insulation performance, with thermal conductivity as low as 30.9 W·m -1 ·K -1 .

[0028] In addition, the aerogel thermal insulation yarn of the present application has good weavability, and the thermal insulation fabric obtained by weaving can be used for human body thermal insulation. It still has good thermal insulation effect in various complex occasions and has a wide range of application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments recorded in the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0030] Figure 1 Surface SEM images of aerogel thermal insulation yarns of Examples 4, 5, 6, and 7;

[0031] Figure 2 This is a cross-sectional SEM image of the aerogel thermal insulation yarn of Example 5;

[0032] Figure 3 This is the EDS spectrum of the cross section of the aerogel thermal insulation yarn of Example 5;

[0033] Figure 4 This is a graph showing the test results of the thermal insulation performance of the yarns of Example 5, Comparative Example 2 and Comparative Example 3 when placed on the wrist;

[0034] Figure 5 This is a graph showing the thermal insulation performance test results of the yarns of Example 5, Comparative Example 2 and Comparative Example 3 placed on a hot stage. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0036] In the following description of this embodiment, the terms "include", "comprising", "having" and "containing" are all open terms, meaning including but not limited to.

[0037] In the following description of this embodiment, the term "and / or" is used to describe the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, B exists alone, and A and B exist at the same time. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0038] In the following description of this embodiment, the term "at least one" refers to one or more, and "plurality" refers to two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0039] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0040] Those skilled in the art should understand that in the following description of the embodiments of the present application, the order of serial numbers does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0041] Those skilled in the art will appreciate that the numerical ranges in the embodiments of the present application are to be construed as specifically disclosing each intermediate value between the upper and lower limits of the scope. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present application. The upper and lower limits of these smaller ranges may be independently included or excluded in the scope.

[0042] Unless otherwise specified, the technical / scientific terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs. Although this application only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of this application. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0043] In a first aspect, the present application provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0044] S1, preparing polymer spinning solution and silica aerogel dispersion;

[0045] In the present application, the solute of the polymer spinning solution is polyacrylonitrile, the solvent is N,N-dimethylformamide or dimethyl sulfoxide, and the concentration of the polymer spinning solution is preferably 8-14 wt%.

[0046] In the present application, the silica aerogel dispersion is prepared by dispersing silica aerogel in an organic solvent, and the concentration of the silica aerogel dispersion is preferably 0.5-2wt%, such as 0.5wt%, 1wt%, 2wt% or any concentration within the range. Wherein, the organic solvent includes any one of ethanol, isopropanol, n-hexane or n-octane.

[0047] S2, obtaining a nanofiber membrane by electrospinning a polymer spinning solution, and cutting the nanofiber membrane into nanofiber strips;

[0048] In the present application, the preferred electrospinning voltage is 18-24 kV; the cutting width of the nanofiber tape is preferably 2 cm.

[0049] S3, uniformly coating the silica aerogel dispersion on the nanofiber tape, and obtaining a prefabricated aerogel yarn by twisting;

[0050] In the present application, the coating method of the silica aerogel dispersion includes any one of spraying, dripping or dipping. The coated nanofiber tape is quickly twisted by a twisting machine, and the twisting parameter is set to 4.5-9 turns / cm.

[0051] S4, annealing the prefabricated aerogel yarn to obtain aerogel thermal insulation yarn.

[0052] In the present application, the helical structure of the aerogel thermal insulation yarn is fixed by high temperature thermal annealing to prevent untwisting, wherein the annealing temperature is preferably 120-140° C. and the annealing time is 0.5-2 h.

[0053] In the present application, in order to further prevent the aerogel particles inside the aerogel thermal insulation yarn from falling off, it is preferred to spray a layer of nanofiber wrapping layer on its surface. Specifically, the preparation method further includes:

[0054] S5, spraying the polymer spinning solution onto the surface of the aerogel thermal insulation yarn by electrostatic spinning to obtain a core-wrapped aerogel thermal insulation yarn.

[0055] The voltage of the electrospinning is 18-24 kV; the distance between the aerogel yarn and the needle during spraying is 10-20 cm, and the spraying time is 5-20 min.

[0056] The preparation method of the present application effectively avoids the two-step process of spinning and drying, successfully realizes continuous molding preparation, has a simple preparation process, and has good prospects for large-scale preparation.

[0057] The aerogel thermal insulation yarn prepared in this application has a spiral structure inside. The outer shell of the spiral structure is nanofiber. The hydrophobic silica aerogel particles are distributed on the inner surface of the nanofiber outer shell and in the cavity surrounded by the inner surface, which makes it have excellent tensile strength, which can reach 35.1MPa. At the same time, the high load of silica aerogel particles inside makes the aerogel thermal insulation yarn have low density, high porosity and low thermal conductivity. Its density is only 0.20-0.35g·cm -3 , the porosity is 72.5-84.4%; its thermal conductivity can be as low as 30.9W·m -1 ·K -1 , with excellent thermal insulation performance. In addition, the aerogel thermal insulation yarn of the present application has good weavability, and the thermal insulation fabric woven can be used for human body thermal insulation, and still has good thermal insulation effect in various complex occasions, and has a wide range of application scenarios.

[0058] Based on the excellent thermal insulation performance, excellent tensile strength and good weavability of the aerogel thermal insulation yarn of the present application, it can be used alone as a material for thermal insulation fabrics, or mixed with other materials to prepare thermal insulation fabrics. The thermal insulation fabric woven with the aerogel thermal insulation yarn of the present application can be used for human body insulation, and it still has a good thermal insulation effect in various complex occasions, and has a wide range of application scenarios.

[0059] The present application is further described below by way of examples.

[0060] Example 1

[0061] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0062] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0063] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at a high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 0.5 wt %;

[0064] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0065] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0066] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0067] Example 2

[0068] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0069] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0070] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at a high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 1 wt %;

[0071] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0072] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0073] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0074] Example 3

[0075] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0076] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0077] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0078] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0079] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0080] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0081] Example 4

[0082] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0083] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0084] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0085] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0086] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0087] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0088] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 15 cm, and the spraying time is 5 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0089] Example 5

[0090] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0091] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0092] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0093] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0094] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0095] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0096] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 15 cm, and the spraying time is 10 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0097] Example 6

[0098] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0099] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0100] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0101] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0102] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0103] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0104] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 15 cm, and the spraying time is 15 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0105] Example 7

[0106] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0107] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0108] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0109] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0110] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0111] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0112] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 15 cm, and the spraying time is 20 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0113] Example 8

[0114] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0115] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0116] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0117] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0118] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 4.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0119] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0120] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 15 cm, and the spraying time is 10 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0121] Example 9

[0122] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0123] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0124] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0125] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0126] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 6 turns / cm, to obtain a prefabricated aerogel yarn;

[0127] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0128] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 15 cm, and the spraying time is 10 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0129] Example 10

[0130] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0131] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0132] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0133] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0134] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 9 turns / cm, to obtain a prefabricated aerogel yarn;

[0135] S4, annealing the prefabricated aerogel yarn at 120° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0136] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 15 cm, and the spraying time is 10 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0137] Embodiment 11

[0138] This embodiment provides a method for preparing an aerogel thermal insulation yarn, comprising:

[0139] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 14 wt%;

[0140] Dispersing hydrophobic silica aerogel particles in ethanol and stirring at high speed to prepare a silica aerogel dispersion having a hydrophobic silica aerogel particle concentration of 2 wt %;

[0141] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 18 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0142] S3, spraying the silica aerogel dispersion evenly on the nanofiber tape, and quickly twisting it with a twisting machine, with a twisting parameter of 7.5 turns / cm, to obtain a prefabricated aerogel yarn;

[0143] S4, annealing the prefabricated aerogel yarn at 140° C. for 1 hour, and obtaining aerogel thermal insulation yarn after cooling.

[0144] S5, spraying the polyacrylonitrile spinning solution onto the surface of the aerogel thermal insulation yarn by electrospinning, wherein the spinning voltage is 20 kV, the distance between the fiber and the needle is 20 cm, and the spraying time is 10 min, to obtain the core-wrapped aerogel thermal insulation yarn.

[0145] Comparative Example 1

[0146] Comparative Example 1 provides a method for preparing an aerogel thermal insulation yarn, and compared with the other examples 1, there is no silica aerogel. The preparation method comprises:

[0147] S1, dissolving polyacrylonitrile in N,N-dimethylformamide to prepare a polyacrylonitrile spinning solution with a mass concentration of 12 wt%;

[0148] S2, obtaining a nanofiber membrane by electrospinning a polyacrylonitrile spinning solution, wherein the spinning voltage is 20 kV; and cutting the nanofiber membrane into nanofiber strips with a width of 2 cm;

[0149] S3, twisting the nanofiber ribbon with a twisting machine, with a twisting parameter of 4.5 turns / cm, to obtain a spiral yarn;

[0150] S4, annealing the spiral yarn at 120° C. for 1 hour, and then cooling the spiral yarn to obtain the spiral yarn.

[0151] Comparative Example 2

[0152] Commercially available polymer microfiber felt thermostat TM .

[0153] Comparative Example 3

[0154] Comparative Example 3 is a cotton yarn, the thickness of which is the same as that of the aerogel thermal insulation yarn in Example 6.

[0155] The tensile strength of the aerogel thermal insulation yarn prepared in Examples 1-11 and the spiral yarn of Comparative Example 1 was tested by using an electronic universal material testing machine (Instron 5969) to test the static tensile and compressive properties of the yarn. The test speed was 1 mm min -1 , the tensile test gauge length is 10 mm, and the test results are shown in Table 1.

[0156] Table 1 Strength of each yarn

[0157]

[0158]

[0159] As can be seen from Table 1, the aerogel thermal insulation yarns prepared in the present application all have high breaking strength, and Example 1 can reach 35.1 MPa. The yarn without aerogel dispersion in Comparative Example 1 has the highest breaking strength. From the test results of Comparative Example 1, Example 1, Example 2 and Example 3, it can be seen that with the increase of the concentration of aerogel dispersion, the mechanical properties of the yarn continue to decrease. This is because with the addition of aerogel powder, the diameter of the yarn is thickened, and the effective contact friction between nanofibers is reduced, resulting in a decrease in breaking strength.

[0160] From the test results of Example 3, Example 4, Example 5, Example 6 and Example 7, it can be found that the addition of the nanofiber coating layer can increase the mechanical properties of the yarn.

[0161] From the test results of Example 5, Example 8, Example 9, and Example 10, it can be found that as the number of twisting turns increases, the mechanical properties of the yarn first increase and then decrease. This is because the mechanical properties of the yarn are related to the torsion deflection angle (the angle between the nanofiber and the yarn axis) and the friction coefficient of the nanofiber. As the number of twisting turns increases, the torsion deflection angle increases, while the friction coefficient of the fiber increases; the increase in the torsion deflection angle will lead to a decrease in tensile properties, while the increase in the friction coefficient is the opposite.

[0162] The thermal conductivity of the yarns of Examples 1-3, Example 5 and Comparative Examples 1-3 was tested. The specific test method was as follows: the thermal conductivity was measured using a hot wire thermal conductivity meter (XIATECH TC3000E). The test mode was an aerogel measurement mode. The ambient temperature and humidity were controlled at 20°C and 55%, respectively. Two identical samples were placed above and below the sensor, respectively. Five tests were performed in parallel. The test results are shown in Table 2.

[0163] Table 2 Thermal conductivity of each sample

[0164] sample <![CDATA[Thermal conductivity (mWm -1 K -1 )]]> Example 1 41.4 Example 2 35.9 Example 3 30.9 Example 5 32.3 Comparative Example 1 45.1 Comparative Example 2 35.2 Comparative Example 3 46.7

[0165] As shown in Table 2, the thermal conductivity of the yarns of Examples 1-3 decreases with the increase of aerogel content, and the lowest value can reach 30.9 mW m -1 K -1 , which is lower than commercial products, so it has good thermal insulation effect.

[0166] It can be seen from Table 1 and Table 2 that the tensile strength of the aerogel thermal insulation yarn prepared in the present application decreases with the increase of the aerogel dispersion content; its thermal conductivity decreases with the increase of the aerogel dispersion content, that is, the thermal insulation effect increases with the increase of the aerogel dispersion content. In production, according to the requirements of actual use, aerogel thermal insulation yarns with different tensile strengths and thermal insulation effects can be prepared by adjusting the aerogel dispersion content. When tensile strength is preferred, the aerogel dispersion content can be reduced; when thermal insulation effect is more preferred, the aerogel dispersion content can be increased.

[0167] The surface SEM test of the aerogel thermal insulation yarn prepared in Example 4, Example 5, Example 6 and Example 7 was performed, and the results are as follows: Figure 1 As shown. Figure 1 It can be seen that the aerogel particles on the yarn surface can be effectively constrained by coating, thereby reducing the falling of aerogel particles during use and increasing the mechanical properties of the yarn, which is consistent with the conclusions obtained in Table 1.

[0168] The aerogel thermal insulation yarn of Example 5 has high thermal insulation performance and good tensile strength, and its microscopic morphology and thermal conductivity are tested.

[0169] The cross-sectional SEM test results of the aerogel thermal insulation yarn prepared in Example 5 are as follows: Figure 2 As shown. Figure 2 It can be seen that aerogel yarn has a typical surface-core structure, the surface layer is a thin layer of nanofibers, and the core layer is an assembly formed by nanofibers and aerogel particles, and aerogel exists in large quantities.

[0170] The cross-sectional EDS test results of the aerogel thermal insulation yarn prepared in Example 5 are as follows: Figure 3 shown. Figure 3 It reflects the distribution of four elements: Si, O, N, and C. Si and O correspond to the distribution of SiO2, and N and C correspond to the distribution of PAN. Si and O elements are evenly distributed in large quantities on the yarn cross section, indicating that the aerogel particles are highly evenly loaded inside the yarn. N and C elements reflect the distribution of PAN nanofibers. N and C elements have obvious circular boundaries on the cross section, which intuitively proves the surface-core structure of the yarn from another perspective.

[0171] The thermal insulation performance of the aerogel yarn prepared in Example 5, the yarns in Comparative Examples 2 and 3 was tested on the wrist. The specific method is: the sample is attached to the skin surface and an infrared thermal imaging camera is used to take infrared images. The test results are as follows: Figure 4 As shown. Figure 4 It can be seen that the aerogel yarn in Example 5 has the best thermal insulation performance.

[0172] Take two layers of each of the aerogel insulation yarn prepared in Example 5, Comparative Example 2 and Comparative Example 3, and test their thermal insulation performance on a hot stage. The specific method is: place the two layers of samples on the hot stage, attach thermocouples to the hot stage and the surfaces of the three samples, and turn on the hot stage to increase the temperature. The test results are as follows: Figure 5 As shown, from Figure 5 It can be seen that the aerogel yarn of Example 5 has the best thermal insulation performance. When the temperature of the hot plate is 120°C, the aerogel yarn of Example 5 can insulate 51.9°C.

[0173] Although the present application has been described in detail in general terms and in specific embodiments in this specification, it is obvious to those skilled in the art that some modifications or improvements may be made to the present application. Therefore, these modifications or improvements made without departing from the spirit of the present application are within the scope of protection claimed in the present application.

Claims

1. A method for preparing aerogel thermal insulation yarn, characterized in that: include: S1, preparing polymer spinning solution and silica aerogel dispersion; S2, obtaining a nanofiber membrane by electrospinning a polymer spinning solution, and cutting the nanofiber membrane into nanofiber strips; S3, uniformly coating the silica aerogel dispersion on the nanofiber tape, and obtaining a prefabricated aerogel yarn by twisting; S4, annealing the prefabricated aerogel yarn to obtain aerogel thermal insulation yarn.

2. The preparation method according to claim 1, characterized in that: Also includes: S5, spraying the polymer spinning solution onto the surface of the aerogel thermal insulation yarn by electrostatic spinning to obtain a core-wrapped aerogel thermal insulation yarn.

3. The preparation method according to claim 1, characterized in that: The solute of the polymer spinning solution is polyacrylonitrile, and the solvent is N,N-dimethylformamide or dimethyl sulfoxide; the concentration of the polymer spinning solution is 8-14wt%.

4. The preparation method according to claim 1, characterized in that: The silica aerogel dispersion is obtained by dispersing silica aerogel in an organic solvent, and the concentration thereof is 0.5-2wt%; The organic solvent includes any one of ethanol, isopropanol, n-hexane or n-octane.

5. The preparation method according to claim 1, characterized in that: The voltage of the electrospinning in S1 is 18-24 kV; The cutting width of the nanofiber tape described in S2 is 2 cm; The coating method of the silica aerogel dispersion in S3 includes any one of spraying, dripping or dipping.

6. The preparation method according to claim 1, characterized in that: The twisting parameter is 4.5-9 turns / cm.

7. The preparation method according to claim 1, characterized in that: The annealing temperature is 120-140° C., and the annealing time is 0.5-2 h.

8. The preparation method according to claim 2, characterized in that: The voltage of the electrospinning in S5 is 18-24 kV; During spraying, the distance between the aerogel yarn and the needle is 10-20 cm, and the spraying time is 5-20 min.

9. Aerogel thermal insulation yarn prepared by the preparation method according to any one of claims 1 to 8.

10. Use of the aerogel thermal insulation yarn prepared by the preparation method according to any one of claims 1 to 8 in thermal insulation fabric materials.

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