Superhydrophobic polyvinylidene fluoride (PVDF) aerogel material and preparation method thereof

A polyvinylidene fluoride and aerogel technology, which is applied in the field of super-hydrophobic polyvinylidene fluoride (PVDF) aerogel material and its preparation, can solve the problem of removing powder and slag, detrimental to the health of environmental protection construction personnel, and destroying aerogel insulation materials. Pore ​​structure and other problems, to achieve the effect of good flexibility, good hydrophobicity and thermal insulation performance, and safe preparation process

Inactive Publication Date: 2018-06-22
NANJING TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the most researched and commercialized is SiO 2 Airgel insulation, but SiO 2 Airgel has low strength and high brittleness, resulting in SiO 2 Airgel insulation materials generally have the problem of "dropping powder and slag", which not only limits SiO 2 The use of airgel insulation materials is not conducive to environmental protection and the health of production and construction personnel
SiO can be improved to some extent by surface hydrophobic modification 2 The powder and slag problem of airgel, but this problem cannot be fundamentally changed, and the surface modification will destroy SiO 2 Pore ​​Structure of Airgel Thermal Insulation Materials

Method used

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  • Superhydrophobic polyvinylidene fluoride (PVDF) aerogel material and preparation method thereof
  • Superhydrophobic polyvinylidene fluoride (PVDF) aerogel material and preparation method thereof

Examples

Experimental program
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Effect test

example 1

[0025] At 70°C, add sodium chloride with a mass fraction of 1% and PVDF powder with a mass fraction of 5% into N-N dimethylformamide, and stir for 20 minutes to obtain a clear PVDF solution. Deionized water with a mass fraction of 20% was added to the PVDF solution to obtain PVDF sol; PVDF sol was placed at 10°C for sol-gel reaction to obtain PVDF gel; PVDF gel was immersed in deionized water at 20°C for solvent replacement for 8 times (each replacement time is 6 hours) to obtain a hydrogel, and the hydrogel is freeze-dried to obtain a superhydrophobic PVDF airgel material. PVDF airgel sample density 0.075 / g / cm 3 , porosity 95.8%, specific surface area 306m 2 / g, the water contact angle is 153°, the thermal conductivity is 0.04463W / (m·K), the nanopores are distributed in the range of 3-100nm, and the micropores are distributed in the range of 0.5-5μm.

example 2

[0027] At 80°C, add lithium chloride with a mass fraction of 2% and PVDF powder with a mass fraction of 10% into N-N dimethylacetamide, and stir for 40 minutes to obtain a clear PVDF solution. Deionized water with a mass fraction of 15% was added to the PVDF solution to obtain a PVDF sol; the PVDF sol was placed at 20°C for a sol-gel reaction to obtain a PVDF gel; the PVDF gel was immersed in ethanol at 25°C for 6 times of solvent replacement ( Each replacement time is 8 hours) to obtain an alcohol gel, and the alcohol gel is subjected to CO 2 The superhydrophobic PVDF airgel material was obtained by supercritical drying. PVDF airgel sample density 0.143g / cm 3 , porosity 92%, specific surface area 343m 2 / g, water contact angle of 158°, thermal conductivity of 0.03531W / (m·K), nanopores distributed in the range of 5-80nm, and micropores distributed in the range of 0.5-3μm.

[0028] See attached picture, figure 1 Photo of the PVDF airgel made in Example 2. It can be seen th...

example 3

[0031] At 90°C, add polyvinylpyrrolidone with a mass fraction of 3% and PVDF powder with a mass fraction of 15% into dimethyl sulfoxide, and stir for 60 minutes to obtain a clear PVDF solution. 10% deionized water was added to the solution to obtain PVDF sol; the PVDF sol was placed at 10°C for sol-gel reaction to obtain PVDF gel; the PVDF gel was immersed in methanol at 30°C for 4 solvent replacements (each replacement The time is 12 hours) to obtain the alcohol gel, and the alcohol gel is subjected to CO 2 The superhydrophobic PVDF airgel material was obtained by supercritical drying. PVDF airgel sample density 0.198g / cm 3 , porosity 89%, specific surface area 256m 2 / g, the water contact angle is 154°, the thermal conductivity is 0.04152W / (m·K), the nanopores are distributed in the range of 3-100nm, and the micropores are distributed in the range of 0.8-5μm.

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Abstract

The invention relates to a superhydrophobic PVDF aerogel material. The superhydrophobic PVDF aerogel material is characterized in that the material is a white opaque blocky material with a density of0.075-0.198 g / cm<3>, a porosity of 89-95.8%, a specific surface area of 256-343 m<2> / g, a water contact angle of 153-158 degrees and a thermal conductivity of 0.03531-0.04463 W / (m.K); and the materialhas a hierarchical pore structure, wherein the sizes of nanopores are in a range of 3-100 nm, and the sizes of micropores are in a range of 0.5 to 5 [mu]m. A PVDF aerogel is prepared by using a physical sol-gel process based on a phase inversion method. A preparation method for the PVDF aerogel comprises the following steps: subjecting PVDF powder and an additive to dissolving and uniform mixingin an organic solvent at a certain temperature; then adding deionized water and allowing PVDF to undergo phase inversion so as to form a PVDF gel; and subjecting the PVDF gel to solvent replacement and drying successively to prepare the PVDF aerogel. A novel preparation method is adopted in the invention to prepare the novel superhydrophobic PVDF aerogel material, and the method is simple in process and easy to realize industrial production; and the prepared PVDF aerogel material has low thermal conductivity and is a heat insulation material applicable to low-temperature humid environments.

Description

technical field [0001] The invention belongs to the field of preparation of new materials, and relates to a superhydrophobic polyvinylidene fluoride PVDF airgel material and a preparation method thereof. Background technique [0002] As a nanoporous material, airgel has a three-dimensional nanoporous network structure, endowing it with low density, high specific surface area, large porosity and other characteristics, which can effectively limit heat transfer, and is an ideal high-performance thermal insulation material. The thermal conductivity under normal pressure is generally below 0.02W / (m K), which is much better than traditional insulation materials. It is the solid material with the lowest thermal conductivity and can be used in industrial production, building energy saving, aerospace and other fields. At present, the most researched and commercialized is SiO 2 Airgel insulation, but SiO 2 Airgel has low strength and high brittleness, resulting in SiO 2 Airgel insu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08J9/28C08L27/16
CPCC08J9/28C08J2201/0484C08J2205/026C08J2205/044C08J2205/05C08J2327/16
Inventor 孔勇张嘉月沈晓冬
Owner NANJING TECH UNIV
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