阅读说明：本技术 具有可回弹纳米纤维构架的陶瓷海绵材料及制备方法 (Ceramic sponge material with resilient nanofiber framework and preparation method thereof ) 是由 张笑妍 张深根 丁云集 刘波 *** 于 2020-06-03 设计创作，主要内容包括：本发明涉及新型多级孔材料、纳米纤维材料技术领域,提供了一种具有可回弹纳米纤维构架的陶瓷海绵材料及制备方法,所述制备方法以硅溶胶、水溶性炭黑及单质硅颗粒作为初始原料配制均匀稳定分散的悬浮体,利用经过预处理的有机泡沫作为模板,浸渍上述悬浮体并挤压或甩浆、干燥得到有机泡沫预制体,通过在不同气氛下进行反应烧结,最终得到具有可回弹特性的纳米纤维编织而成的多级孔结构陶瓷新材料。本发明具有低成本、无需高昂设备、工艺简单、高效合成、易于工业化生产的特点,所得纳米纤维编织陶瓷海绵综合性能优越：高气孔率、良好渗透性、高比表面积、可回弹、隔热、有机物吸附等特性。(The invention relates to the technical field of novel hierarchical porous materials and nanofiber materials, and provides a ceramic sponge material with a resilient nanofiber framework and a preparation method thereof. The invention has the characteristics of low cost, no need of expensive equipment, simple process, high-efficiency synthesis and easy industrial production, and the obtained nano-fiber woven ceramic sponge has excellent comprehensive performance: high porosity, good permeability, high specific surface area, resilience, heat insulation, organic matter adsorption and the like.)

1. A preparation method of a ceramic sponge material with a reboundable nanofiber framework is characterized in that silica sol, water-soluble carbon black and simple substance silicon are used as raw materials to prepare uniformly dispersed mixed slurry; dipping the pretreated organic foam into the mixed slurry to obtain a foam prefabricated blank body with a net structure; and sintering the foam prefabricated blank to obtain the ceramic sponge material with the reboundable nanofiber framework.

2. A method of making a ceramic sponge material having a resilient nanofiber framework as claimed in claim 1, wherein said method of making comprises:

s1, adding one or more of silica sol, water-soluble carbon black and simple substance silicon particles serving as raw materials into an aqueous solution containing a binder with a certain concentration, and preparing uniformly dispersed mixed slurry through ultrasonic dispersion or ball milling; water-soluble carbon black is excluded when the feedstock is a single feedstock;

s2, soaking the organic foam in NaOH solution for alkali treatment, taking out and drying the organic foam, then putting the organic foam into surfactant aqueous solution for surface modification, taking out and drying the organic foam to obtain pretreated organic foam;

s3, soaking the organic foam processed in the step S2 in the mixed slurry obtained in the step S1 for slurry hanging treatment, extruding to remove redundant slurry, and drying to obtain a foam prefabricated blank;

and S4, reacting and sintering the foam prefabricated blank body in a protective atmosphere to obtain the ceramic sponge material woven by the nano fibers.

3. The method for preparing a ceramic sponge material with a resilient nanofiber framework as claimed in claim 2, wherein in step S1, the silica sol content is 0-100 wt.% of the total mass of the raw material powder, and the particle size is 10-100 nm;

the addition amount of the water-soluble carbon black accounts for 0-20 wt% of the total mass of the raw material powder, and the particle size is 10nm

-1.0μm；

The addition amount of the simple substance silicon particles accounts for 0-100 wt% of the total mass of the raw material powder, and the particle size is 10nm-1.0 μm;

the solid content of the mixed slurry is 10-70 wt.%.

4. The method for preparing a ceramic sponge material with a resilient nanofiber framework as claimed in claim 2, wherein in step S1, the binder is one or two of sodium carboxymethylcellulose and polyvinyl alcohol, and the amount of the binder added is 0.1-3.0 wt.% of the mass of the mixed slurry.

5. The method of making a ceramic sponge material having a resilient nanofiber framework as claimed in claim 2 wherein in step S2, the organic foam has a specification of 15-90 PPI;

in the alkali treatment process, the concentration of NaOH solution is 5-30 wt.%, the treatment temperature is 50-80 ℃, and the treatment time is 0.5-10 h;

in the surface modification process, the surface modifier is one or more of sodium carboxymethylcellulose, sodium dodecyl sulfate and polyvinyl alcohol, the concentration is 0.5-10 wt.%, the treatment temperature is 50-80 ℃, and the treatment time is 0.5-10 h.

6. The method for preparing a ceramic sponge material having a resilient nanofiber framework as set forth in claim 2, wherein the drying temperature in step S2 is 25-80 ℃ and the processing time is 3-48 hours.

7. The method for preparing a ceramic sponge material with a resilient nanofiber framework as claimed in claim 2, wherein the sizing process is repeated 1-7 times, followed by drying process in step S3.

8. The method for preparing the ceramic sponge material with the resilient nanofiber framework as claimed in claim 2, wherein in step S4, the protective atmosphere is one of nitrogen or argon, the ceramic sponge material is heated to 1200-1700 ℃ at a heating rate of 0.5-10 ℃/min during sintering, and the temperature is maintained for 0.5-6 h.

9. Method for the preparation of a ceramic sponge material with a resilient nanofibrous framework according to any of claims 1 to 8, characterised in that the nanofibres are Si₃N₄、SiC、Si₂N₂And one or more of O, the nano fibers are tightly woven by taking the foam prefabricated blank as a template to form the novel porous material.

10. A ceramic sponge material having a framework of resilient nanofibres, obtainable using the preparation method according to any of claims 1 to 9; the ceramic sponge material is a porous material and is formed by weaving nano fibers with the diameter of 5-300nm and the length of 0.1-100 mu m; the primary pore structure of the porous material is an organic foam green body net structure, and the pore diameter is 10 mu m-3.0 mm; the secondary pore structure of the porous material is a microporous structure formed by overlapping nano fibers, and the pore diameter is 10nm-5.0 mu m; the porous material has the characteristics of resilience, heat insulation and organic matter adsorption.

Technical Field

The invention relates to the technical field of novel hierarchical pore materials and nanofiber materials, in particular to a ceramic sponge material with a reboundable nanofiber framework and a preparation method thereof.

Background

In recent years, porous materials having high porosity, high specific surface area, ultra-low bulk density, and reliable mechanical properties have received much attention due to their excellent performance in the fields of thermal insulation, catalysis, tissue engineering, energy storage, filtration, and environmental protection. At present, part of catalytic reaction in the treatment process for smoke emission or catalytic combustion is higher than 1000 ℃, and the working temperature of supersonic automobile heat insulation materials reaches 1200 ℃ or even higher, so that the application of the porous materials in high-temperature environment is urgent.

The ceramic material has the characteristics of high strength, excellent high-temperature mechanical/chemical stability and the like, but the development of the ceramic material in the field of ultralight and high-elasticity materials is limited by the brittleness and defect sensitivity of the ceramic material. At present, researchers prepare the coating TiO by means of efficient solution blow molding, chemical vapor deposition and the like₂、ZrO₂、BaTiO₃、Al₂O₃、Si₃N₄The structure of the light high-temperature resistant three-dimensional ceramic sponge of various systems such as SiC and the like is composed of a large number of mutually-arrangedThe results of the compositions of the staggered ceramic fibers show that the material has the characteristics of ultralow density, high energy absorption and resilience, can still keep good restoring force when being compressed in a high-temperature environment of 1300 ℃, has excellent comprehensive properties of high temperature resistance, low thermal conductivity and the like, and is expected to be applied to the fields of elastic resistance, photocatalysis, heat insulation and the like. However, the research on the novel ceramic sponge material is in the beginning, and most of the research is focused on the metal oxide system, and the Si has excellent room temperature and high temperature mechanical, thermal and chemical stability₃N₄、SiC、Si₂N₂O-ceramic systems have been reported to be less limited by high-end equipment, harsh reaction conditions, and the like. In addition, the ceramic sponge material obtained in the above manner is basically formed by interweaving a large number of nanowires, and the disorder directly limits the realization of the performance stability of the ceramic sponge material. Therefore, a novel foam ceramic material with ultralow density, ultrahigh specific surface area, rebound property and ordered microstructure is prepared by a simple technology, and a new idea is provided for the development of the fields of heat insulation, filtration, catalysis, wave transmission and the like.

The organic foam impregnation method has the characteristics of simple and convenient process, low cost, no need of complex equipment and the like, can be used for preparing porous ceramics with a porosity of 70-90% and a communicating pore structure, has high automation level, is beneficial to industrial production, and has multiple purposes in the fields of filtration, catalyst carriers and the like. The three-dimensional reticular skeleton structure constructed by the organic foam impregnation process can provide sufficient space foundation and atmosphere environment for the growth of the nano fibers, and provides conditions for the construction of the nano fibers in a three-dimensional space and the realization of the subsequent springback characteristic.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provides a ceramic sponge material with a reboundable nanofiber framework and a preparation method thereof.

The invention adopts the following technical scheme:

a preparation method of a ceramic sponge material with a resilient nanofiber framework comprises the steps of preparing uniformly dispersed mixed slurry by taking silica sol, water-soluble carbon black and simple substance silicon as raw materials; dipping the pretreated organic foam into the mixed slurry to obtain a foam prefabricated blank body with a net structure; and sintering the foam prefabricated blank to obtain the ceramic sponge material with the reboundable nanofiber framework.

Further, the preparation method comprises the following steps:

s1, adding one or more of silica sol, water-soluble carbon black and simple substance silicon particles (excluding single water-soluble carbon black) serving as raw material powder into an aqueous solution containing a binder with a certain concentration, and preparing uniformly dispersed mixed slurry through ultrasonic dispersion or ball milling; the binder has the function of increasing the viscosity of the slurry and facilitating slurry hanging on the organic foam template;

s2, soaking the organic foam in NaOH solution for alkali treatment, taking out and drying the organic foam, then putting the organic foam into surfactant aqueous solution for surface modification, taking out and drying the organic foam to obtain pretreated organic foam; the impregnation is used for constructing a communicated porous structure on a three-dimensional space by taking the porous organic foam as a template;

s3, soaking the organic foam processed in the step S2 in the mixed slurry obtained in the step S1 for slurry hanging treatment, extruding to remove redundant slurry, and drying to obtain a foam prefabricated blank;

and S4, reacting and sintering the foam prefabricated blank body in a protective atmosphere to obtain the ceramic sponge material woven by the nano fibers.

Further, in step S1, the silica sol content is 0 to 100 wt.% of the total mass of the raw material powder, and the particle size is 10 to 100 nm; the silica sol is preferably an alkaline silica sol;

the addition amount of the water-soluble carbon black accounts for 0-20 wt% of the total mass of the raw material powder, and the particle size is 10nm-1.0 mu m;

the addition amount of the simple substance silicon particles accounts for 0-100 wt% of the total mass of the raw material powder, and the particle size is 10nm-1.0 μm;

the mixed slurry has a solids content of 10-70 wt.%, wherein a single feedstock does not include a single water-soluble carbon black suspension.

Further, in step S1, the binder is one or two of sodium carboxymethylcellulose and polyvinyl alcohol, and the addition amount of the binder is 0.1 to 3.0 wt.% of the mass of the mixed slurry.

Further, in step S2, the specification of the organic foam is 15 to 90 PPI;

in the alkali treatment process, the concentration of NaOH solution is 5-30 wt.%, the treatment temperature is 50-80 ℃, and the treatment time is 0.5-10 h;

in the surface modification process, the surface modifier is one or more of sodium carboxymethylcellulose, sodium dodecyl sulfate and polyvinyl alcohol, the concentration is 0.5-10 wt.%, the treatment temperature is 50-80 ℃, and the treatment time is 0.5-10 h.

Further, the drying temperature in the step S2 is 25-80 ℃, and the processing time is 3-48 h.

Further, in step S3, the sizing process is repeated 1-7 times, followed by a drying process.

Further, in step S4, the protective atmosphere is nitrogen or argon, and the sintering process is performed by heating to 1200 ℃ and 1700 ℃ at a heating rate of 0.5-10 ℃/min, and maintaining the temperature for 0.5-6 h.

Further, the nanofiber is Si₃N₄、SiC、Si₂N₂And one or more of O, the nano fibers are tightly woven by taking the foam prefabricated blank as a template to form the novel porous material.

The Si can be obtained from single silica sol or single silicon particles₃N₄The Si can be obtained by the reaction of nano-fiber (in nitrogen environment) or SiC (in argon or vacuum environment), silica sol and carbon black or silica sol and simple substance silicon particles₃N₄/Si₂N₂One or two of O composite nano-fiber (in nitrogen environment) or SiC (in argon or vacuum environment), simple substance silicon particles and carbon black react to obtain Si₃N₄The Si can be obtained from the nano-fiber (in nitrogen environment) or SiC (in argon or vacuum environment) and the three raw material powders₃N₄/Si₂N₂O one or two composite nanofibers (in a nitrogen environment) or SiC (in an argon or vacuum environment).

The organic foam is pyrolyzed into carbon during heat treatment, and the sintering function is to react the three raw materials to grow the nano-fiber.

The invention also provides a ceramic sponge material with a reboundable nanofiber framework, which is obtained by using the preparation method; the ceramic sponge material is a porous material and is formed by weaving nano fibers with the diameter of 5-300nm and the length of 0.1-100 mu m; the primary pore structure of the porous material is an organic foam green body net structure, and the pore diameter is 10 mu m-3.0 mm; the secondary pore structure of the porous material is a microporous structure formed by overlapping nano fibers, and the pore diameter is 10nm-5.0 mu m; the porous material has the characteristics of resilience, heat insulation and organic matter adsorption.

The invention has the beneficial effects that: the preparation method comprises the steps of taking silica sol, water-soluble carbon black and simple substance silicon particles as initial raw materials to prepare uniformly and stably dispersed suspension for the first time, taking pretreated organic foam as a template, impregnating the suspension, extruding or throwing slurry, drying to obtain an organic foam preform, and performing reactive sintering in different atmospheres to finally obtain a new hierarchical pore structure ceramic material woven by nanofibers with rebound characteristics. The invention has the characteristics of low cost, no need of expensive equipment, simple process, high-efficiency synthesis and easy industrial production, and the obtained nano-fiber woven ceramic sponge has excellent comprehensive performance: high porosity, good permeability, high specific surface area, resilience, heat insulation, organic matter adsorption and the like.

Drawings

FIG. 1 is an SEM image of a reticulated foam preform body prepared in example 1.

FIG. 2a is an SEM image of the resilient ceramic sponge of example 1.

FIG. 2b shows an SEM image of the nanofibers of example 1.

Fig. 3 is a photograph showing the reboundable characteristics of the ceramic sponge prepared in example 1.

Detailed Description

Specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that technical features or combinations of technical features described in the following embodiments should not be considered as being isolated, and they may be combined with each other to achieve better technical effects.