CN114602395B

CN114602395B - Organic aerogel sheet having surface wrinkles and method for preparing the same

Info

Publication number: CN114602395B
Application number: CN202210174530.2A
Authority: CN
Inventors: 沈洋; 成凤娇; 马德明; 崔真; 袁志浩; 李恩玲
Original assignee: Xian University of Technology
Current assignee: Xian University of Technology
Priority date: 2022-02-24
Filing date: 2022-02-24
Publication date: 2022-11-08
Anticipated expiration: 2042-02-24
Also published as: CN114602395A

Abstract

The invention discloses a preparation method of an organic aerogel sheet with surface wrinkles, which comprises the following steps: step 1, uniformly mixing resorcinol, formalin, sodium carbonate and water; step 2, transferring the mixed solution obtained in the step 1 to a thermostat and standing for 1-2d to obtain sol; step 3, washing and soaking the glass mold with hexamethyldisilazane, and drying to obtain a hydrophobic glass mold; step 4, pouring the obtained sol into a glass mold, and standing in a thermostat; step 5, soaking the obtained wet gel and the mold in deionized water to obtain expanded and deformed wet gel; step 6, soaking and washing the swelling deformation wet gel obtained in the step 5 by using absolute ethyl alcohol to obtain alcohol gel; step 7, carrying out carbon dioxide supercritical drying on the alcogel obtained in the step 6 to obtain an organic aerogel sheet with surface wrinkles; the invention also discloses the organic aerogel sheet with the wrinkled surface, which is prepared by the method.

Description

Organic aerogel sheet having surface wrinkles and method for preparing the same

Technical Field

The invention belongs to the technical field of material preparation, and particularly relates to an organic aerogel sheet with surface wrinkles, and a preparation method of the organic aerogel sheet with the surface wrinkles.

Background

The introduction of some concave-convex fluctuant folds on the surface of the aerogel has important significance for engineering practice applications such as inertial confinement nuclear fusion, low-temperature and high-pressure state equation experiments, fluid mechanics instability experiments and the like. The rough and uneven saw teeth can be formed on the surface of the aerogel by using diamond lathe machining and femtosecond laser for precise micromachining, however, the machining means is very high in cost, time-consuming and inconvenient for large-area machining and manufacturing.

Zhang Xitian et al (national patent publication No. CN 113571841A) discloses a lithium-sulfur battery composite diaphragm, which is characterized in that the lithium-sulfur battery composite diaphragm is a titanium carbide nanosheet/carbon nanotube composite aerogel modified polypropylene film; the titanium carbide nanosheet/carbon nanotube composite aerogel is of a three-dimensional fluffy porous aerogel structure, has a large specific surface area, a multi-level hierarchical pore structure and a large porosity, and meanwhile, the titanium carbide nanosheets form a plurality of folded structures.

Gabo et al (national patent publication No. CN 113371698A) discloses a preparation method of pine sawdust modified graphene aerogel, and the whole prepared pine sawdust modified graphene aerogel presents a complete transparent gauze-like folded structure, which can cause the whole free energy of graphene to be lower and exist stably, so that a feasible way is provided for the mass production of graphene-based adsorbents.

Zhang Yi et al (national patent publication No. CN 113083295A) disclose a high quality active three-dimensional hierarchical porous composite material, a preparation method and an application thereof, wherein the high quality active three-dimensional hierarchical porous composite material uses a biomass hydrogel to form a carbon aerogel after carbonization and a stable monatomic/nitrogen co-doped material formed by coordination of a nitrogen doping source and monatomic metal ions; in the monatomic/nitrogen co-doped material, the carbon aerogel rich micropores and nano folds can easily capture monatomic, so that the metal active sites with atomic-level dispersion are obtained.

Zhang-winged and other people (national invention patent publication No. CN 113078327A) disclose a preparation method of a carbon aerogel containing double metal sites and application of an aluminum air battery, wherein the aerogel takes gelatin as a monomer, silicon dioxide as a hard template, an iron/copper-o-diazaphenanthrene complex as a hydrogel precursor synthesized by a nitrogen source and a metal source, and the uniformly loaded iron and copper double-site doped carbon aerogel is obtained through freeze drying, high-temperature pyrolysis and acid washing.

Cone et al (national patent publication No. CN 112791697A) discloses an elastic super-hydrophobic graphene gel ball and a preparation method and application thereof, belonging to the field of organic matter and oil spill cleaning. The method comprises the following steps: and dripping the graphene oxide aqueous dispersion liquid into a coagulating bath containing a hydrophobic gelling agent to obtain a hydrophobically modified graphene oxide gel sphere, and drying and annealing at a proper temperature to obtain the super-hydrophobic graphene aerogel sphere with good elasticity. The method provided by the invention obtains the elastic super-hydrophobic graphene gel spheres through a one-step crosslinking gel method. The method has the advantages of simple preparation process, excellent performance, capability of realizing continuous large-scale production, wrinkle and porous structure in the gel spheres, and wide application prospect in the field of organic pollutant adsorption.

Li Feng et al (national patent publication No. CN 108298523A) discloses a wide-temperature stable isotropic high-elasticity graphene-based composite porous foam and a preparation method thereof, and belongs to the technical field of functional graphene porous foams. Liquid phase self-assembly and freeze drying are utilized to form micron-sized interconnected macroporous aerogel, and in-situ thermal polymerization is carried out in the process of reducing the graphene oxide framework by heat treatment to generate carbon nitride nanosheets, so that the graphene-based composite porous foam rich in micro-nano-scale wrinkles is obtained. The composite material has the characteristics of isotropic superelasticity (both radial and axial reversible strains are more than 99%), excellent fatigue resistance stability, wide temperature range mechanical stability (-100 to 600 ℃), good electrical conductivity, no change along with strain and the like. The invention has the characteristics of simple preparation process, adjustable microcosmic folds, easy large-area preparation and the like, and provides a material basis for the research and application of the assembled graphene macro material in the fields of flexible conductors, sensors, micro-mechanical electronics, flexible energy storage devices and the like.

Miao Zhongzheng et al (national invention patent publication No. CN 110371954A) discloses a high-temperature expansion preparation method of iron-doped folded graphene aerogel. Firstly, preparing an oxygen-containing group layer and ferric trichloride alternate intercalation graphite material, putting the oxygen-containing group layer and ferric trichloride alternate intercalation graphite material into a water solution, performing ultrasonic stripping to obtain ferric trichloride intercalation graphene oxide which can be dispersed in water, performing freeze drying to obtain ferric trichloride intercalation graphene oxide aerogel, and performing high-temperature treatment to obtain iron-doped folded graphene aerogel. The method effectively reduces the damage of the graphene lamellar structure, efficiently removes oxygen-containing groups at high temperature, decomposes ferric trichloride to generate gas, enables the nanosheets to be wrinkled, increases the specific surface area of the aerogel, enhances the mechanical elasticity of the aerogel, uniformly distributes iron ions among the graphene lamellar layers, effectively improves the conductivity of the graphene nanosheets and further improves the conductivity of the aerogel.

The aerogel is very easy to shrink and crack in the preparation process, which is mainly caused by the delicate and fragile gel framework, the surface tension in the gel framework or local stress imbalance due to the too high fluid flow rate easily causes the framework collapse along with the loss of the solvent in the drying process, and thus, the shrinkage and the cracking are caused. In 2016, shen et al repeatedly searched to obtain a proper ratio, the matching between layers can reach a relatively good level, the obtained sample has good smoothness, and CO is adopted ₂ The supercritical fluid drying technology can further improve the quality of the sample, and the micro deformation of the sample in the drying process can be further reduced by clamping the sample by adopting a mould in the supercritical drying process.

However, the research on expanding the aerogel and generating wrinkles on the surface has not been reported. It remains a challenge to prepare organic aerogel flakes having surface corrugations by simple means.

Disclosure of Invention

The invention aims to provide an organic aerogel sheet with surface wrinkles, which is used for engineering practice research of inertial confinement nuclear fusion, low-temperature high-pressure equation of state experiments and hydrodynamic instability experiments.

Another object of the present invention is to provide a method for preparing an organic aerogel sheet having surface wrinkles, which is simple and easy to implement.

The first technical scheme adopted by the invention is a preparation method of an organic aerogel sheet with surface wrinkles, which is characterized by comprising the following steps:

step 1, uniformly mixing resorcinol, formalin, sodium carbonate and water, and magnetically stirring for 1-2 hours to form a mixed solution;

step 2, transferring the mixed solution obtained in the step 1 to a thermostat and standing for 1-2d to obtain sol;

step 3, washing and soaking the glass mold with hexamethyldisilazane, and drying to obtain a hydrophobic glass mold;

step 4, pouring the sol obtained in the step 2 into the hydrophobic glass mold obtained in the step 3, filling the container with the sol, covering a hydrophobic glass cover, sealing, and placing the container in a thermostat for standing to obtain wet gel;

step 5, soaking the wet gel obtained in the step 4 and the mould in deionized water to swell the wet gel and obtain an expanded wet gel;

step 6, soaking and washing the swelling deformation wet gel obtained in the step 5 by using absolute ethyl alcohol to obtain alcohol gel;

and 7, performing carbon dioxide supercritical drying on the alcogel obtained in the step 6 to obtain the organic aerogel sheet with surface wrinkles.

The present invention is also characterized in that,

in the step 1, the formaldehyde aqueous solution is a formaldehyde aqueous solution with the mass fraction of 38%, and the mass ratio of the resorcinol, the formaldehyde aqueous solution, the sodium carbonate and the water is (1.5).

In step 2, the temperature of the incubator is 45-50 ℃.

In the step 3, the soaking time is 12-24h.

In step 4, the temperature of the incubator is 45-50 ℃.

And step 5, soaking the mixture in deionized water for 1-10 days.

In step 6, soaking and washing the mixture for 3-4 days by using absolute ethyl alcohol, and replacing the solvent once every 1 day.

In step 7, the temperature of supercritical drying is set to be 40-42 ℃, the air pressure is set to be 10-11MPa, the heating rate is set to be 0.5-1 ℃/min, the constant temperature time is 3-4h, and the decompression rate is 1-3MPa/h.

The second technical scheme adopted by the invention is that the organic aerogel sheet with surface wrinkles is characterized by being prepared by the preparation method.

The beneficial effects of the invention are:

(1) The method is simple and easy to implement, the preparation equipment is cheap and easy to obtain, a plurality of concave-convex fluctuant folds are introduced on the surface of the aerogel, the method has important significance for engineering practice applications such as inertial confinement nuclear fusion, low-temperature and high-pressure state equation experiments, hydromechanics instability experiments and the like, in the hydromechanics instability experiments, when shock waves compress the surface of a material, the folds on the surface of the aerogel can cause micro disturbance, so that the research on the instability growth process of the shock waves is facilitated, and in the state equation experiment research, the folds on the surface of the aerogel flyer can introduce gradient change of density, so that the compression time of the shock waves is prolonged.

(2) The surface of the organic aerogel sheet with surface wrinkles prepared by the invention is covered with wrinkles, and the part which is soaked by water and swells is obviously different from the part which is not swelled.

Drawings

FIG. 1 is a flow chart of the production process of the present invention;

FIG. 2 is an SEM image (10 μm scale) of organic aerogel flakes having surface wrinkles, prepared according to example 1 of the present invention;

FIG. 3 is an SEM image (scale: 2 μm) of organic aerogel flakes having surface wrinkles, prepared according to example 1 of the present invention;

FIG. 4 is an SEM image (scale bar is 1 μm) of the organic aerogel sheet having surface wrinkles, prepared according to example 1 of the present invention;

FIG. 5 is an SEM image (scale: 500 nm) of the organic aerogel sheet having surface wrinkles, prepared according to example 1 of the present invention;

FIG. 6 is an SEM image (10 μm scale) of organic aerogel flakes having surface wrinkles, prepared according to example 5 of the present invention;

FIG. 7 is an SEM image (scale bar is 1 μm) of the organic aerogel sheet having surface wrinkles, prepared in example 5 of the present invention;

FIG. 8 is an SEM image (500 nm on the scale) of organic aerogel flakes having surface wrinkles, prepared according to example 5 of the present invention;

FIG. 9 is an SEM image (10 μm scale) of an organic aerogel sheet having no surface wrinkles, prepared according to example 6 of the present invention;

FIG. 10 is an SEM image (scale bar: 2 μm) of an organic aerogel sheet having no surface wrinkles, prepared according to example 6 of the present invention;

fig. 11 is an SEM image (scale: 500 nm) of organic aerogel flakes having no surface wrinkles, prepared in example 6 of the present invention.

Detailed Description

The invention is described in detail below with reference to the drawings and the detailed description.

The invention provides a preparation method of an organic aerogel sheet with surface wrinkles, which specifically comprises the following steps as shown in figure 1:

step 4, pouring the sol obtained in the step 2 into the hydrophobic glass mold obtained in the step 3, filling the container with the sol, covering the hydrophobic glass mold with a hydrophobic glass cover, sealing, and standing in a thermostat to obtain wet gel;

step 7, carrying out carbon dioxide supercritical drying on the alcogel obtained in the step 6 to obtain an organic aerogel sheet with surface wrinkles;

in the step 1, the formaldehyde aqueous solution is a 38% formaldehyde aqueous solution, and the mass ratio of the resorcinol to the formaldehyde aqueous solution to the sodium carbonate to the water is 1.5;

in step 2, the temperature of the incubator is 45-50 ℃.

In the step 3, the soaking time is 12-24h.

In step 4, the temperature of the incubator is 45-50 ℃.

In step 5, soaking the mixture in deionized water for 1-10 days.

The invention also provides an organic aerogel sheet with surface wrinkles, which is prepared by adopting the preparation method.

Example 1

Organic aerogel flakes having surface corrugations with corrugations ranging from about 50%.

Firstly, uniformly mixing resorcinol, a formaldehyde water solution with the mass fraction of 38%, sodium carbonate and water according to the mass ratio of 1.5;

secondly, transferring the mixed solution into a thermostat with the temperature of 50 ℃ and standing for 1d to obtain sol;

thirdly, soaking the glass mold in hexamethyldisilazane for 24 hours, and drying to obtain a hydrophobic glass mold;

fourthly, pouring the sol into a hydrophobic glass mold, filling the container with the sol, covering a hydrophobic glass cover, sealing, and standing in a thermostat at 50 ℃ for 2d to obtain hydrogel;

fifthly, soaking the wet gel together with the glass mold in deionized water for 3d to swell the wet gel to obtain the wet gel with expansion deformation;

sixthly, soaking and washing the wet gel subjected to swelling deformation by using absolute ethyl alcohol for 3 days, and replacing the solvent once every 1 day to obtain alcogel;

and finally, carrying out carbon dioxide supercritical drying on the alcogel, setting the temperature of the supercritical drying to be 40 ℃, setting the air pressure to be 10MPa, setting the heating rate to be 1 ℃/min, setting the constant temperature time to be 4h, and setting the decompression rate to be 3MPa/h, and drying to obtain the organic aerogel slice with surface wrinkles. Fig. 2 to 5 are SEM images of the organic aerogel sheet having surface wrinkles prepared in example 1 of the present invention, and it can be seen from the images that the surface of the prepared organic aerogel sheet covers wrinkles, and the portions swollen by water immersion are clearly distinguished from the portions not swollen.

Example 2

Organic aerogel flakes having surface corrugations with corrugations ranging from about 10%.

secondly, transferring the mixed solution into a thermostat with the temperature of 48 ℃ and standing for 1.5d to obtain sol;

thirdly, soaking the glass mold in hexamethyldisilazane for 22h, and drying to obtain a hydrophobic glass mold;

fourthly, pouring the sol into a hydrophobic glass mold, filling the container with the sol, covering a hydrophobic glass cover, sealing, and standing in a thermostat at 48 ℃ for 2d to obtain hydrogel;

fifthly, soaking the wet gel and the glass mold in deionized water for 1d to swell the wet gel and obtain the wet gel which is expanded and deformed;

sixthly, soaking and washing the wet gel subjected to swelling deformation by using absolute ethyl alcohol for 4 days, and replacing the solvent once every 1 day to obtain alcogel;

and finally, carrying out carbon dioxide supercritical drying on the alcogel, setting the temperature of the supercritical drying to be 41 ℃, setting the air pressure to be 10.5MPa, setting the heating rate to be 0.6 ℃/min, setting the constant temperature time to be 3.5h and the decompression rate to be 2MPa/h, and drying to obtain the organic aerogel slice with surface wrinkles.

Example 3

Organic aerogel flakes having surface corrugations with corrugations ranging from about 30%.

secondly, transferring the mixed solution into a thermostat at 45 ℃ and standing for 2d to obtain sol;

thirdly, soaking the glass mold in hexamethyldisilazane for 12 hours, and drying to obtain a hydrophobic glass mold;

fourthly, pouring the sol into a hydrophobic glass mold, filling the container with the sol, covering a hydrophobic glass cover, sealing, and standing in a thermostat at 45 ℃ for 2d to obtain hydrogel;

fifthly, soaking the wet gel and the glass mold in deionized water for 2d to swell the wet gel and obtain the expanded and deformed wet gel;

sixthly, soaking and washing the wet gel subjected to swelling deformation by absolute ethyl alcohol for 3 days, and replacing the solvent once every 1 day to obtain alcogel;

and finally, carrying out carbon dioxide supercritical drying on the alcogel, setting the temperature of the supercritical drying to be 42 ℃, setting the air pressure to be 11MPa, setting the heating rate to be 0.5 ℃/min, setting the constant temperature time to be 3h, and setting the decompression rate to be 1MPa/h, and drying to obtain the organic aerogel slice with surface wrinkles.

Example 4

Organic aerogel flakes having surface corrugations with corrugations ranging from about 70%.

secondly, transferring the mixed solution into a thermostat at 50 ℃ and standing for 1d to obtain sol;

fifthly, soaking the wet gel together with the glass mold in deionized water for 5 days to swell the wet gel to obtain an expanded wet gel;

and finally, carrying out carbon dioxide supercritical drying on the alcogel, setting the temperature of the supercritical drying to be 40 ℃, setting the air pressure to be 10MPa, setting the heating rate to be 1 ℃/min, setting the constant temperature time to be 4h, and setting the decompression rate to be 3MPa/h, and drying to obtain the organic aerogel slice with surface wrinkles.

Example 5

Organic aerogel flakes having surface corrugations with corrugations ranging from about 100%.

fifthly, soaking the wet gel and the glass mold in deionized water for 10 days to swell the wet gel and obtain the wet gel which is expanded and deformed;

and finally, carrying out carbon dioxide supercritical drying on the alcogel, setting the temperature of the supercritical drying to be 40 ℃, setting the air pressure to be 10MPa, setting the heating rate to be 1 ℃/min, setting the constant temperature time to be 4h, and setting the decompression rate to be 3MPa/h, and drying to obtain the organic aerogel slice with surface wrinkles. Fig. 6 to 8 are SEM images of the organic aerogel flakes having surface wrinkles prepared in example 5 of the present invention, and it can be seen from the images that the surface of the prepared organic aerogel flakes covers wrinkles, and the portions swollen by water immersion are clearly different from the portions not swollen.

Example 6

Organic aerogel flakes having no surface wrinkles, as shown in fig. 9-11, had no wrinkles without soaking the surface of the organic aerogel flakes.

Firstly, uniformly mixing resorcinol, a formaldehyde aqueous solution with the mass fraction of 38%, sodium carbonate and water according to the mass ratio of 1.5;

fifthly, soaking and washing the hydrogel with absolute ethyl alcohol for 3d, and replacing the solvent once every 1d to obtain alcogel;

and finally, carrying out carbon dioxide supercritical drying on the alcogel, setting the temperature of the supercritical drying to be 40 ℃, setting the air pressure to be 10MPa, setting the heating rate to be 1 ℃/min, setting the constant temperature time to be 4h, and setting the decompression rate to be 3MPa/h, and drying to obtain the organic aerogel slice without surface wrinkles.

The structure of the glass mold of examples 1 to 6 was a glass slide-glass gasket-glass slide laminate structure.

Claims

1. The preparation method of the organic aerogel sheet with surface wrinkles is characterized by comprising the following steps:

step 1, uniformly mixing resorcinol, formalin, sodium carbonate and water, and stirring for 1-2 hours by magnetic force to form a mixed solution;

step 6, soaking and washing the wet gel which is subjected to swelling deformation and obtained in the step 5 by using absolute ethyl alcohol to obtain alcohol gel;

2. The method for preparing the organic aerogel sheet with surface wrinkles as claimed in claim 1, wherein in step 1, the aqueous formaldehyde solution is a 38% aqueous formaldehyde solution, and the mass ratio of the resorcinol, the aqueous formaldehyde solution, the sodium carbonate and the water is 1.001-0.01.

3. The method for preparing organic aerogel sheet having surface wrinkles as claimed in claim 1, wherein the temperature of the oven in step 2 is 45-50 ℃.

4. The method for preparing organic aerogel flakes having surface wrinkles as claimed in claim 1, wherein in step 3, the soaking time is 12-24h.

5. The method for preparing organic aerogel sheet having surface wrinkles as claimed in claim 1, wherein the temperature of the oven in step 4 is 45-50 ℃.

6. The method for preparing organic aerogel flakes having surface folds according to claim 1, wherein in step 5, deionized water is used for soaking for 1-10 days.

7. The method for preparing organic aerogel flakes having surface wrinkles as claimed in claim 1, wherein in step 6, the solvent is replaced every 1d by soaking and washing with absolute ethanol for 3-4 d.

8. The method for preparing organic aerogel flakes having surface wrinkles as claimed in claim 1, wherein in step 7, the temperature of supercritical drying is set to 40-42 ℃, the air pressure is set to 10-11MPa, the temperature rise rate is set to 0.5-1 ℃/min, the constant temperature time is 3-4h, and the pressure reduction rate is 1-3MPa/h.

9. Organic aerogel flakes having surface corrugations, characterised in that they are obtained by the preparation process according to any of claims 1 to 8.