阅读说明：本技术 一种气凝胶纤维的制备方法及其在保暖面料加工中的应用 (Preparation method of aerogel fiber and application of aerogel fiber in thermal fabric processing ) 是由 张丽 马晓飞 张志成 于 2021-08-16 设计创作，主要内容包括：本发明公开了一种气凝胶纤维的制备方法及其在保暖面料加工中的应用,涉及功能纤维技术领域,本发明先通过缩聚反应制备有机硅聚脲,再经凝胶纺丝法形成有机硅聚脲凝胶纤维,然后经溶剂置换、干燥制成有机硅聚脲气凝胶纤维；并且本发明制备的有机硅聚脲气凝胶纤维具有比表面积大、孔隙率高、密度低等特性,尤其导热系数小,能够作为保暖纤维应用于保暖面料的加工,提高面料的保暖效果。(The invention discloses a preparation method of aerogel fiber and application of the aerogel fiber in the processing of warm-keeping fabric, and relates to the technical field of functional fiber, wherein organic silicon polyurea is prepared through polycondensation reaction, then organic silicon polyurea gel fiber is formed through a gel spinning method, and then organic silicon polyurea aerogel fiber is prepared through solvent replacement and drying; the organic silicon polyurea aerogel fiber prepared by the invention has the characteristics of large specific surface area, high porosity, low density and the like, particularly has small heat conductivity coefficient, and can be used as a thermal fiber for processing thermal fabrics to improve the thermal effect of the fabrics.)

1. A preparation method of aerogel fiber is characterized by comprising the following steps: the preparation method comprises the following preparation steps:

(1) dissolving diphenylmethane diisocyanate in an organic solvent, heating to dehydrate, adding 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane, heating to react under the protection of nitrogen, and after the reaction is finished, carrying out reduced pressure distillation to recover the organic solvent to obtain organic silicon polyurea;

(2) dissolving the organic silicon polyurea prepared in the step (1) in dimethyl sulfoxide, and defoaming to obtain spinning solution;

(3) extruding the spinning solution prepared in the step (2) through a spinneret orifice of a spinneret assembly, feeding the obtained spinning trickle into a gel bath to form nascent fiber, and ageing the nascent fiber in an ageing liquid after hot drawing to obtain organic silicon polyurea gel fiber;

(4) and (4) washing the organic silicon polyurea gel fiber prepared in the step (3) with deionized water, then carrying out solvent replacement by adopting a replacement solvent, and carrying out vacuum freeze drying to obtain the organic silicon polyurea aerogel fiber.

2. The method for preparing aerogel fibers according to claim 1, characterized in that: the molar ratio of the diphenylmethane diisocyanate to the 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane is 1 (1.05-1.1).

3. The method for preparing aerogel fibers according to claim 1, characterized in that: the organic solvent is a mixed solvent of toluene and tetrahydrofuran.

4. The method for preparing aerogel fibers according to claim 1, characterized in that: the defoaming time is 24-48 h.

5. The method for preparing aerogel fibers according to claim 1, characterized in that: the gel bath is dimethyl sulfoxide water solution.

6. The method for preparing aerogel fibers according to claim 1, characterized in that: the temperature of the hot drawing is 100-150 ℃, and the drawing multiplying power is 1-2 times.

7. The method for preparing aerogel fibers according to claim 1, characterized in that: the aging liquid is ethanol water solution.

8. The method for preparing aerogel fibers according to claim 1, characterized in that: the aging time is 0.5-2 h.

9. The method for preparing aerogel fibers according to claim 1, characterized in that: the replacement solvent is at least one of acetone, ethanol, isopropanol and methanol.

10. Use of aerogel fibers prepared according to any of claims 1-9 in the processing of thermal fabrics.

The technical field is as follows:

the invention relates to the technical field of functional fibers, in particular to a preparation method of aerogel fibers and application of the aerogel fibers in the processing of thermal fabrics.

Background art:

the aerogel is an ultra-light solid material, has a continuous three-dimensional network structure, and is divided into three categories, namely inorganic aerogel, organic aerogel and carbon aerogel, according to the component difference of the structure. The aerogel has the characteristics of high porosity, high specific surface area, low density, low thermal conductivity, low elastic modulus, strong adsorbability, low refractive index, low acoustic impedance and the like, so that the aerogel has wide application prospects in multiple fields of mechanics, thermal, optics, acoustics and the like.

In the seventies of the last century, researchers developed superfine fibers, and artificial leathers and other bionic materials made of the superfine fibers enabled the heat retention performance of chemical fibers to be equal to that of natural materials. Through researches on hollow fibers and superfine fibers, the heat retention property of the fiber material is found to be in direct proportion to the content of still air in the fiber material, in inverse proportion to the diameter of the fiber and in inverse proportion to the density of the whole material. The aerogel fiber has the remarkable characteristics of extremely high porosity, ultralow density and the like, has good heat insulation and preservation effects, and is the most important development direction of the existing thermal fiber.

Currently, most of aerogel fibers are prepared by using synthetic fibers as raw materials and performing spinning, gel forming, solvent replacement and drying. Patent CN201911221326.6 discloses a preparation method of polyimide aerogel fiber, which comprises the steps of carrying out polymerization reaction on diamine containing a tea ketone structure and other diamine compounds and dianhydride compounds, then carrying out extrusion by a spinneret plate, photocuring, gel bath drafting and winding, then carrying out solvent exchange, and carrying out freeze drying to obtain the polyimide aerogel fiber with light weight, heat resistance and hydrophobic characteristics. Based on the inspiration of the patent, the inventor prepares a polymer by adopting diphenylmethane diisocyanate and 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane as raw materials through a polycondensation reaction, and prepares aerogel fibers through spinning, gel forming, solvent replacement and drying, wherein the thermal conductivity coefficient of the aerogel fibers is lower than 0.020W/(m.K), and the aerogel fibers are suitable for processing of thermal fabrics.

The invention content is as follows:

the invention aims to solve the technical problem of providing a preparation method of aerogel fibers, wherein the organic silicon polyurea aerogel fibers are prepared by utilizing synthesized organic silicon polyurea, and the organic silicon polyurea aerogel fibers are applied to the processing of thermal fabrics, so that the fabrics have excellent thermal effect.

The technical problem to be solved by the invention is realized by adopting the following technical scheme:

a preparation method of aerogel fibers comprises the following preparation steps:

(1) dissolving diphenylmethane diisocyanate in an organic solvent, heating to dehydrate, adding 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane, heating to react under the protection of nitrogen, and after the reaction is finished, carrying out reduced pressure distillation to recover the organic solvent to obtain organic silicon polyurea;

(2) dissolving the organic silicon polyurea prepared in the step (1) in dimethyl sulfoxide, and defoaming to obtain spinning solution;

(3) extruding the spinning solution prepared in the step (2) through a spinneret orifice of a spinneret assembly, feeding the obtained spinning trickle into a gel bath to form nascent fiber, and ageing the nascent fiber in an ageing liquid after hot drawing to obtain organic silicon polyurea gel fiber;

(4) and (4) washing the organic silicon polyurea gel fiber prepared in the step (3) with deionized water, then carrying out solvent replacement by adopting a replacement solvent, and carrying out vacuum freeze drying to obtain the organic silicon polyurea aerogel fiber.

The reaction mechanism of silicone polyureas: the molecular structure of diphenylmethane diisocyanate contains two isocyanate groups, the molecular structure of 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyl disiloxane contains two amino groups, polyurea is generated through polycondensation, and the polyurea molecular structure contains Si-C bonds, so the polyurea is also called organosilicon polyurea. Because the reactivity of the isocyanate group and the amino group is higher, the invention adopts a mode of properly raising the temperature to accelerate the reaction rate and improve the conversion rate of the raw materials without adding a catalyst.

The molar ratio of the diphenylmethane diisocyanate to the 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane is 1 (1.05-1.1). The excessive 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane can ensure the complete reaction of diphenylmethane diisocyanate and avoid the existence of free isocyanate group, because the isocyanate group is very easy to react with moisture in the air.

The organic solvent is a mixed solvent of toluene and tetrahydrofuran. The mixed solvent can be used for dissolving diphenylmethane diisocyanate, and the energy consumption cost in the recovery of the organic solvent can be reduced.

The defoaming time is 24-48 h. Because bubbles are generated in the dissolving process of the organic silicon polyurea, the invention removes the bubbles contained in the spinning solution through defoaming treatment to ensure that the subsequent spinning process can be smoothly carried out.

The gel bath is dimethyl sulfoxide water solution. The dimethyl sulfoxide aqueous solution is used as a gel bath to form three-dimensional network-shaped pores, and the porosity is high and the pore diameter is moderate.

The gel spinning has two processes of gelation and phase separation, wherein the gelation is a process that a polymer solution is gradually changed into a single-phase elastic gel; phase separation refers to the separation between the polymer phase and the solvent phase. The gelled polymer crystallite structure forms chain-to-chain physical entanglements. Thus when the gel undergoes phase separation to form a solid filament, the polymer chains become entangled with each other, increasing the intrinsic bonding force, thereby allowing the fibers to be successfully pulled out of the coagulation. During spinning, flexible chain molecules with ultrahigh molecular weight are utilized to be disentangled in a semi-dilute solution, and then spinning and crystallization are carried out, and then the stretched chain is obtained through high-power stretching. The spinning solution basically has no solvent diffusion in the process of solidification and formation, and only heat exchange is carried out, so that the nascent fiber contains a large amount of solvent and is in a gel state.

The temperature of the hot drawing is 100-150 ℃, and the drawing multiplying power is 1-2 times.

The aging liquid is ethanol water solution. The microscopic morphology of the gel can be stabilized through aging treatment, and the strength of the network framework is improved.

The aging time is 0.5-2 h.

The replacement solvent is at least one of acetone, ethanol, isopropanol and methanol.

The washing process can be carried out under the action of ultrasonic waves, so that the washing time is shortened, and the washing efficiency is improved.

The transformation from wet gel to aerogel is completed by vacuum freeze drying on the premise of maintaining the skeleton structure, the aerogel can keep a good network structure, and the aerogel fiber with light weight and excellent pore structure is obtained.

The invention has the beneficial effects that: the invention firstly prepares organic silicon polyurea through polycondensation reaction, then forms organic silicon polyurea gel fiber through gel spinning method, and then prepares organic silicon polyurea aerogel fiber through solvent replacement and drying; the organic silicon polyurea aerogel fiber prepared by the invention has the characteristics of large specific surface area, high porosity, low density and the like, particularly has small heat conductivity coefficient, and can be used as a thermal fiber for processing thermal fabrics to improve the thermal effect of the fabrics.

The specific implementation mode is as follows:

in order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

Example 1

(1) Dissolving diphenylmethane diisocyanate in an organic solvent, wherein the organic solvent is toluene and tetrahydrofuran in a volume ratio of 1:1, heating to dehydrate, adding 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane in a molar ratio of 1:1, heating to react under the protection of nitrogen until the diphenylmethane diisocyanate completely reacts, and recovering the organic solvent by reduced pressure distillation after the reaction is finished to obtain the organic silicon polyurea.

(2) And (2) dissolving the organic silicon polyurea prepared in the step (1) in dimethyl sulfoxide, and defoaming for 24 hours to obtain a spinning solution.

(3) Extruding the spinning solution prepared in the step (2) through a spinneret orifice of a spinneret assembly, feeding the obtained spinning trickle into a gel bath to form nascent fibers, wherein the gel bath is a dimethyl sulfoxide water solution with the volume concentration of 70%, performing hot drawing, and then feeding the spinning trickle into an aging solution for aging for 1h, wherein the hot drawing temperature is 110 ℃, the drawing ratio is 1.5 times, and the aging solution is an ethanol water solution with the volume concentration of 40%, so that the organic silicon polyurea gel fibers are obtained.

(4) And (4) washing the organic silicon polyurea gel fiber prepared in the step (3) with deionized water, then carrying out solvent replacement by using acetone, and carrying out vacuum freeze drying to obtain the organic silicon polyurea aerogel fiber.

Example 2

(1) Dissolving diphenylmethane diisocyanate in an organic solvent, wherein the volume ratio of the organic solvent is toluene and tetrahydrofuran is 2:1, heating to dehydrate, adding 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane, the molar ratio of the diphenylmethane diisocyanate to the 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane is 1:1.1, heating to react under the protection of nitrogen until the diphenylmethane diisocyanate completely reacts, and after the reaction is finished, recovering the organic solvent by reduced pressure distillation to obtain the organic silicon polyurea.

(2) And (2) dissolving the organic silicon polyurea prepared in the step (1) in dimethyl sulfoxide, and defoaming for 36 hours to obtain a spinning solution.

(3) Extruding the spinning solution prepared in the step (2) through a spinneret orifice of a spinneret assembly, feeding the obtained spinning trickle into a gel bath to form nascent fibers, wherein the gel bath is a dimethyl sulfoxide water solution with the volume concentration of 75%, performing hot drawing, and then feeding the spinning trickle into an aging solution for aging for 0.5h, wherein the hot drawing temperature is 120 ℃, the drawing ratio is 2 times, and the aging solution is an ethanol water solution with the volume concentration of 50%, so as to obtain the organic silicon polyurea gel fibers.

(4) And (4) washing the organic silicon polyurea gel fiber prepared in the step (3) with deionized water, then carrying out solvent replacement by using acetone, and carrying out vacuum freeze drying to obtain the organic silicon polyurea aerogel fiber.

Example 3

(1) Dissolving diphenylmethane diisocyanate in an organic solvent, heating the organic solvent to dehydrate the toluene and tetrahydrofuran in a volume ratio of 1:1, adding 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane in a molar ratio of 1:1.08, heating the mixture under the protection of nitrogen to react until the diphenylmethane diisocyanate completely reacts, and recovering the organic solvent by reduced pressure distillation to obtain the organic silicon polyurea.

(2) And (2) dissolving the organic silicon polyurea prepared in the step (1) in dimethyl sulfoxide, and defoaming for 48 hours to obtain a spinning solution.

(3) Extruding the spinning solution prepared in the step (2) through a spinneret orifice of a spinneret assembly, feeding the obtained spinning trickle into a gel bath to form nascent fibers, wherein the gel bath is a dimethyl sulfoxide water solution with the volume concentration of 80%, performing hot drawing, and then feeding the spinning trickle into an aging solution for aging for 2 hours, wherein the hot drawing temperature is 130 ℃, the drawing ratio is 1.8 times, and the aging solution is an ethanol water solution with the volume concentration of 45%, so that the organic silicon polyurea gel fibers are obtained.

(4) And (4) washing the organic silicon polyurea gel fiber prepared in the step (3) with deionized water, then carrying out solvent replacement by using isopropanol, and carrying out vacuum freeze drying to obtain the organic silicon polyurea aerogel fiber.

Comparative example 1

Comparative example 1 was obtained by replacing 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane in example 1 with hexamethylenediamine, and the rest of the procedure was exactly the same as in example 1.

Comparative example 2

Comparative example 2 was prepared by replacing 1, 3-bis (3-aminopropyl) -1,1,3, 3-tetramethyldisiloxane from example 1 with polyether diol 210 and adding a catalytic amount of dibutyltin dilaurate, and the remaining steps were exactly the same as example 1.

Specific surface areas, porosities, and thermal conductivities of the aerogel fibers prepared in examples 1 to 3 and comparative examples 1 to 2 were measured, and the measurement results are shown in table 1.

Adopting NOVAtouch analyzer of full-automatic specific surface area and aperture of Antopa-Kangta company^TMMeasuring the specific surface area and the porosity of the aerogel fibers; the heat conductivity coefficient is measured according to GB/T10294-.

TABLE 1

As can be seen from table 1, the silicone polyurea aerogel fibers prepared in examples 1 to 3 of the present invention have larger specific surface area, higher porosity, and smaller thermal conductivity than the aerogel fibers prepared in comparative examples 1 and 2, and thus are more suitable for processing of thermal insulation fabrics.

The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.