Silica aerogel fiber with adjustable transparency and hydrophobicity as well as preparation method and application

A technology of airgel fiber and silica, applied in the direction of fiber chemical characteristics, textiles and papermaking, can solve the problems of uneven nanostructure, low thermal conductivity, weak mechanical properties, etc., and achieve weavability and easy processing and use Excellent, mild reaction conditions, simple preparation process

Active Publication Date: 2020-04-10
SUZHOU INST OF NANO TECH & NANO BIONICS CHINESE ACEDEMY OF SCI
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  • Application Information

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Problems solved by technology

2. The pore size of airgel is generally below 40nm, which is smaller than the molecular free path of air, so it will prevent the heat conduction of gas molecules inside the aerogel
3. The air inside the airgel is still, and the existence of still air will prevent the heat convection of the air inside the airgel
However, since the sol-gel process of airgel is a dynamic and slow process, and is also affected by weak mechanical properties during the drying process, the preparation of airgel fibers of various components, especially silica airgel fibers has been a huge challenge
Due to its combination of visible transparency and low thermal conductivity, silica airgel fibers are suitable for transparent thermal insulation buildings and other fields, however, the brittleness of silica is still inevitable for the continuous spinning of airgel fibers. obstacles
The most promising method to overcome this shortcoming is to form organic-inorganic hybrid aerogels, or to coat the surface with other materials to strengthen the gel network, but increasing the organic content will lead to the inhomogeneity of the nanostructure and reduce the Slow gel speed, these solutions will have a great impact on the transparency and thermal insulation performance of airgel, and cannot meet the requirements of fiber preparation
[0005] Furthermore, the existing aerogels are mainly three-dimensional blocks and powders. Due to the slow gelation process of airgel, an external container must be used as a shape support, and its three-dimensional shape is limited by the shape of the container.
Moreover, due to the brittleness of aerogels, especially silica aerogels, the processability and cuttability of three-dimensional blocks are limited.
Powder aerogels can only be used as coatings or fillers, and the scope of use is very limited

Method used

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  • Silica aerogel fiber with adjustable transparency and hydrophobicity as well as preparation method and application
  • Silica aerogel fiber with adjustable transparency and hydrophobicity as well as preparation method and application
  • Silica aerogel fiber with adjustable transparency and hydrophobicity as well as preparation method and application

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preparation example Construction

[0046] Another aspect of the embodiments of the present invention also provides a method for preparing silica airgel fibers with adjustable transparency and hydrophobicity, which includes:

[0047] providing a spinning solution comprising a linear organosiloxane polymer having a multifunctional group;

[0048] Using a wet spinning method, injecting the spinning solution into an alkaline coagulation bath to obtain continuous silica gel fibers;

[0049] The silica gel fiber is dried to obtain the silica airgel fiber with adjustable transparency and hydrophobicity.

[0050] Wherein, in a more specific typical implementation case, the preparation method includes:

[0051] (1) Design and synthesize linear organosiloxane polymers with multifunctional groups, and then prepare spinning dope;

[0052] (2) Prepare an alkaline coagulation bath, and carry out a wet spinning method to obtain continuous silica gel fibers;

[0053] (3) The silica gel fiber obtained in step (2) is subjecte...

Embodiment 1

[0096] (1) Preparation of spinning dope: Using PMDS and TEOS as monomers at a molar ratio of 1:1, polycondensate in THF to prepare a multifunctional group linear organosiloxane with a number average molecular weight of 800. After testing, the polymer chain contains 5 ethoxy groups, 8 siloxane groups and 3 silanol groups; and then dispersing the obtained polymer in an ethanol solution to prepare a spinning stock solution with a mass fraction of an organosiloxane polymer of 10%;

[0097] (2) Wet spinning: prepare an aqueous solution of NaOH, the mass fraction is 0.1%, the diameter of the spinneret hole is 300 μm, the temperature difference between the spinneret hole and the coagulation bath is 10 ° C, and the temperature difference between the spinning solution and the alkaline coagulation bath is The solvent concentration difference is 80%, and the extrusion speed is 10 μl / min to obtain silica hydrogel fibers;

[0098] (3) Preparation of airgel fibers: the above-mentioned silic...

Embodiment 2

[0100] (1) Preparation of spinning dope: Use PMDS and TEOS as monomers with a molar ratio of 2:1, polycondensate in DMF to prepare a multifunctional group linear organosiloxane with a number average molecular weight of 5000. After testing, the polymer chain contains 16 ethoxy groups, 18 siloxane groups and 11 silanol groups; then the obtained polymer is dispersed in an ethanol solution to prepare a spinning dope with a mass fraction of an organosiloxane polymer of 40%;

[0101] (2) Wet spinning: prepare an aqueous solution of KOH, the mass fraction is 3%, the diameter of the spinneret hole is 300 μm, the temperature difference between the spinneret hole and the coagulation bath is 50 ° C, and the temperature difference between the spinning solution and the alkaline coagulation bath is The solvent concentration difference is 75%, and the extrusion speed is 150 μl / min to obtain silica hydrogel fibers;

[0102] (3) Preparation of airgel fiber: the above-mentioned silica gel fiber...

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Abstract

The invention discloses a silica aerogel fiber with adjustable transparency and hydrophobicity, as well as a preparation method and an application. The silica aerogel fiber has a communicated three-dimensional porous network structure, wherein the transparency of the silica aerogel fiber is 20-95%, the contact angle with water is 0-158 degrees, the porosity is 80-99.9%, the specific surface area is 100-2000 m2 / g, the thermal conductivity is 0.010-0.030W / (m*K), the diameter is 10[mu]m to 3mm and the length-diameter ratio is greater than 10. The preparation method comprises the following steps of providing a spinning solution containing a linear organosiloxane polymer with a multifunctional group; and adopting a wet spinning method, injecting the spinning solution into an alkaline coagulation bath, obtaining silica gel fiber, and carrying out drying treatment to obtain the silica aerogel fiber. The silica aerogel fiber disclosed by the invention is low in thermal conductivity, has a spinnability, is adjustable in transparency, is controllable in hydrophobicity, and has a huge application prospect.

Description

technical field [0001] The invention relates to a novel functional fiber, in particular to a silica airgel fiber with adjustable transparency and hydrophobicity and its preparation method and application, belonging to the technical field of nanoporous materials and functional fibers. Background technique [0002] The airgel material is a material obtained by replacing the liquid component in the gel with gas while keeping the gel network from collapsing. Airgel was first born in the 1830s and was invented by chemist Sterven.S.Kistler of California Pacific University. It uses supercritical drying technology for the first time to replace the liquid component in the wet gel with gas and keep the gel skeleton structure intact, thus obtaining aerogel. Airgel has a very low apparent density (0.003~0.3g / cm 3 ), large specific surface area (100~2400m 2 / g), high porosity (80-99.8%) and low thermal conductivity [10-40mW / (m·K)]. There are three main reasons for the low thermal con...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): D01F9/10
CPCD01F9/10
Inventor 张学同杜煜王锦
Owner SUZHOU INST OF NANO TECH & NANO BIONICS CHINESE ACEDEMY OF SCI
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