阅读说明：本技术 一种3d打印氮化硅纤维气凝胶及其制备方法与应用 (3D printing silicon nitride fiber aerogel and preparation method and application thereof ) 是由 朱光达 侯仪 赵宁 徐坚 于 2020-06-02 设计创作，主要内容包括：本发明公开一种3D打印氮化硅纤维气凝胶及其制备方法与应用。所述方法包括如下步骤：(1)含有硅源、碳源和高分子粘结剂的打印墨水,在氮气气氛下高温烧结,得到所述氮化硅纤维气凝胶；或者(1’)含有硅源、碳源和高分子粘结剂的打印墨水经3D打印,得到打印制件；所述打印制件在氮气气氛下高温烧结,得到所述氮化硅纤维气凝胶。所用原料简单廉价,制备过程简单,首次以打印墨水或直接墨水书写方式得到氮化硅纤维气凝胶,制备的氮化硅纤维气凝胶结构完整,可通过所述3D打印方法赋予复杂结构,并可以应用于阻燃、保温、隔热、吸附、传感器等诸多领域。(The invention discloses a 3D printing silicon nitride fiber aerogel and a preparation method and application thereof. The method comprises the following steps: (1) the printing ink containing a silicon source, a carbon source and a high-molecular binder is sintered at high temperature in a nitrogen atmosphere to obtain the silicon nitride fiber aerogel; or (1') printing ink containing a silicon source, a carbon source and a high-molecular binder is subjected to 3D printing to obtain a printing part; and sintering the printed part at a high temperature in a nitrogen atmosphere to obtain the silicon nitride fiber aerogel. The used raw materials are simple and cheap, the preparation process is simple, the silicon nitride fiber aerogel is obtained in a printing ink or direct ink writing mode for the first time, the prepared silicon nitride fiber aerogel has a complete structure, a complex structure can be endowed by the 3D printing method, and the silicon nitride fiber aerogel can be applied to the fields of flame retardance, heat preservation, heat insulation, adsorption, sensors and the like.)

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

(1) the printing ink containing a silicon source, a carbon source and a high-molecular binder is sintered at high temperature in a nitrogen atmosphere to obtain the silicon nitride fiber aerogel;

or (1') printing ink containing a silicon source, a carbon source and a high-molecular binder is subjected to 3D printing to obtain a printing part; and sintering the printed part at a high temperature in a nitrogen atmosphere to obtain the silicon nitride fiber aerogel.

2. The method of claim 1, wherein the silicon source is selected from at least one of the following materials: fumed silica, nano silica, micro silica, glass powder and polysiloxane; preferably, the silicon source is fumed silica and/or glass frit.

3. The method according to claim 1 or 2, wherein the carbon source is selected from at least one of the following materials: graphene, carbon black, carbon nanotubes, fullerenes and graphdiynes; preferably, the carbon source is at least one of graphene, carbon black and carbon nanotubes.

4. The production method according to any one of claims 1 to 3, wherein the polymer binder comprises a polymer material and a solvent;

preferably, the polymer material is selected from thermoplastic polymer materials, preferably from at least one of the following materials: polyethylene, silicone, polypropylene, polyvinyl alcohol, polystyrene, polybutadiene, polymethyl methacrylate; more preferably polyvinyl alcohol, polymethyl methacrylate and/or polystyrene;

preferably, the solvent is selected from at least one of the following materials: water, ethanol, ethyl acetate, dichloromethane, N-hexane, petroleum ether, toluene, xylene, acetone, tetrahydrofuran, chloroform and N, N-dimethylformamide; preferably water and/or acetone;

preferably, in the polymer binder, the mass ratio of the solvent to the polymer material is 100 (0.1-30);

preferably, the mass ratio of the high molecular material to the sum of the masses of the silicon source and the carbon source is (0.1-5): 100.

5. The method according to any one of claims 1 to 4, wherein the mass ratio of the carbon source to the silicon source is (1-10): (1-10), preferably (1-5): (1-5).

6. The production method according to any one of claims 1 to 5, wherein in step (1'), the 3D printing is direct writing 3D printing.

7. The method according to any one of claims 1-6, wherein in step (1'), the temperature for the high-temperature sintering is 1300-1800 ℃, preferably 1400-1600 ℃.

Preferably, the time for high-temperature sintering is 1-12h, preferably 3-8 h.

Preferably, the heating rate of the high-temperature sintering is 1-20 ℃/min, and preferably 3-10 ℃/min.

Preferably, the heating rate or the cooling rate of the high-temperature sintering is the same, and the high-temperature sintering is preferably cooled along with the furnace at 1-10 ℃/min or during cooling.

8. A silicon nitride fiber aerogel obtained by the method of any one of claims 1 to 7.

9. The silicon nitride fiber aerogel according to claim 8, wherein the density of the silicon nitride fiber aerogel is 0.01-300 mg/cm³Preferably 0.1～50mg/cm³；

Preferably, the silicon nitride fibers have a diameter of 10 to 500nm, preferably 20 to 300 nm;

preferably, a small amount of the silicon source in claim 2 and/or the carbon source in claim 3 is attached to the surface of the silicon nitride fiber;

preferably, the silicon nitride aerogel has a morphology substantially as shown in fig. 2 or fig. 4.

10. Use of the silicon nitride fiber aerogel according to claim 8 or 9 in the fields of flame retardancy, thermal insulation, adsorption or sensors.

Technical Field

The invention belongs to the technical field of 3D printing, and particularly relates to a 3D printing silicon nitride fiber aerogel and a preparation method and application thereof.

Background

Aerogel materials have the advantages of low density, large specific surface area, excellent heat insulation performance and the like, and are widely applied to the fields of heat preservation and insulation, pollutant adsorption, sensors and the like. Aerogels built with fibers as basic cells exhibit lower density and greater specific surface area than aerogels built with particles or sheets as cells. Among them, polymer fiber is a material commonly used to construct fiber aerogel, however, polymer itself has poor heat resistance, which limits the use of fiber aerogel. Although a series of aerogel materials based on inorganic ceramic fibers have been developed in the prior art, the preparation method is complex, the reaction atmosphere and the precursor components need to be strictly controlled, and the aerogel materials are difficult to be applied in a large scale.

The silicon nitride ceramic has the properties of high strength, low density, high temperature resistance and the like, and is a ceramic material with wide application. 3D printing is a new rapid forming technology, a complex structure can be obtained through one-step forming, and in the prior art, a compact silicon nitride ceramic material is mainly prepared through laser sintering or photocuring. At present, no report for preparing silicon nitride fiber aerogel by 3D printing exists.

Disclosure of Invention

The invention provides a preparation method of silicon nitride fiber aerogel, which comprises the following steps:

(1) the printing ink containing a silicon source, a carbon source and a high-molecular binder is sintered at high temperature in a nitrogen atmosphere to obtain the silicon nitride fiber aerogel;

or (1') printing ink containing a silicon source, a carbon source and a high-molecular binder is subjected to 3D printing to obtain a printing part; and sintering the printed part at a high temperature in a nitrogen atmosphere to obtain the silicon nitride fiber aerogel.

According to an embodiment of the present invention, the silicon source may be selected from at least one of the following materials: fumed silica, nano-silica, micro-silica, glass powder, polysiloxane and the like; preferably, the silicon source is fumed silica and/or glass frit.

According to an embodiment of the present invention, the carbon source may be selected from at least one of the following materials: graphene, carbon black, carbon nanotubes, fullerenes, graphdiynes, and the like; preferably, the carbon source is at least one of graphene, carbon black and carbon nanotubes.

According to an embodiment of the present invention, the polymeric binder includes a polymeric material and a solvent.

According to an embodiment of the invention, the polymeric material is selected from thermoplastic polymeric materials, preferably from at least one of the following materials: polyethylene, silicone, polypropylene, polyvinyl alcohol, polystyrene, polybutadiene, polymethyl methacrylate, and the like; exemplary are polyvinyl alcohol, polymethyl methacrylate and/or polystyrene.

According to an embodiment of the present invention, the solvent may be selected from at least one of the following materials: water, ethanol, ethyl acetate, dichloromethane, N-hexane, petroleum ether, toluene, xylene, acetone, tetrahydrofuran, chloroform, N-dimethylformamide, etc.; preferably water and/or acetone.

According to an embodiment of the invention, the mass ratio of the solvent to the polymer material in the polymer binder is 100 (0.1-30), preferably 100 (5-25), and exemplarily 100:10, 100:20, 100: 30.

According to an embodiment of the invention, the mass ratio of the polymeric material to the sum of the masses of the silicon source and the carbon source is (0.1-5):100, preferably (0.5-3):100, exemplarily 0.5:100, 1:100, 2:100, 3:100, 4:100, 5: 100.

According to an embodiment of the invention, the mass ratio of the carbon source to the silicon source is (1-10): (1-10), preferably (1-5): (1-5), exemplary 1:1, 4:5, 5: 4.

According to an embodiment of the present invention, the nitrogen atmosphere may be selected from the group consisting of dinitrogen or high purity nitrogen.

According to an embodiment of the present invention, in step (1'), the 3D printing is direct writing 3D printing.

According to an embodiment of the present invention, the temperature of the high temperature sintering is 1300-.

According to an embodiment of the invention, the high temperature sintering time is 1 to 12h, such as 3 to 8h, exemplary 4h, 5h, 6h, 7 h.

According to an embodiment of the invention, the temperature rise rate of the high temperature sintering is 1-20 ℃/min, such as 3-10 ℃/min, exemplary 3 ℃/min, 4 ℃/min, 5 ℃/min.

According to an embodiment of the invention, the heating rate or cooling rate of the high temperature sintering is the same, for example 1-10 ℃/min, such as 2-8 ℃/min; or cooling along with the furnace when cooling.

The above preparation process is based on the following reaction:

SiO₂(solid) + C (solid) + SiO (gas) + CO (gas) (a)

3SiO (gas) + C (solid) +2N₂(gas) ═ Si₃N₄(solid) +3CO (gas) (b)

6SiO (gas) +4N₂(gas) ═ 2Si₃N₄(solid) +3O₂(gas) (c)

The invention also provides the silicon nitride fiber aerogel prepared by the method.

According to the embodiment of the invention, the density of the silicon nitride fiber aerogel is 0.01-300 mg/cm³Preferably 0.1 to 50mg/cm³。

According to an embodiment of the invention, the silicon nitride fibres have a diameter of 10-500nm, such as 20-300nm, such as 50-100 nm.

According to an embodiment of the present invention, a small amount of the silicon source and/or carbon source is attached to the surface of the silicon nitride fiber.

According to an embodiment of the present invention, the silicon nitride aerogel has a morphology substantially as shown in fig. 2 or fig. 4.

The invention also provides application of the silicon nitride fiber aerogel in the fields of flame retardance, heat preservation, heat insulation, adsorption or sensors and the like.

The invention has the beneficial effects that:

the invention provides a silicon nitride fiber aerogel and a preparation method and application thereof, the used raw materials are simple and cheap, the preparation process is simple, the silicon nitride fiber aerogel is obtained by printing ink or directly writing the ink for the first time, the prepared silicon nitride fiber aerogel has a complete structure, the 3D printing method can endow the structure with a complex structure, and the silicon nitride fiber aerogel can be applied to the fields of flame retardance, heat preservation, heat insulation, adsorption, sensors and the like.

Drawings

FIG. 1 is a photograph of the aerogel of silicon nitride fiber according to example 1.

FIG. 2 is a scanning electron micrograph of the silicon nitride fiber aerogel in example 1.

FIG. 3 is a photograph of the silicon nitride fiber aerogel of example 1 before and after burning by an alcohol lamp.

FIG. 4 shows the procedure of directly writing a printed article and a photograph of the article in example 2.

FIG. 5 is a scanning electron micrograph of the silicon nitride fiber aerogel in example 2.

FIG. 6 is a thermogravimetric plot of the silicon nitride fiber aerogel of example 2.

Detailed Description

The technical solution of the present invention will be further described in detail with reference to specific embodiments. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.

Unless otherwise indicated, the starting materials and reagents used in the following examples are all commercially available products.

Example 1

1) Grinding and dispersing 5g of water, 1g of polyvinyl alcohol, 50g of graphene and 50g of fumed silica to obtain printing ink;

2) placing the printing ink obtained in the step 1) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1500 ℃ at 3 ℃ per minute, preserving heat for 4 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

Fig. 1 is a photograph of the silicon nitride fiber aerogel material in example 1, which shows that the silicon nitride fiber aerogel is white as a whole and has good flexibility.

FIG. 2 is a scanning electron microscope image of the aerogel material of silicon nitride fiber in example 1, which shows that the aerogel material has a fiber structure as a unit and the fiber diameter is about tens of nanometers.

FIG. 3 is a photograph of the silicon nitride fiber aerogel in example 1 burned by an alcohol lamp, and it can be seen that the silicon nitride fiber aerogel does not burn in the outer flame of the alcohol lamp (burning time is 3 minutes), and the morphology of the silicon nitride fiber aerogel does not change before and after burning, which illustrates the excellent flame retardancy and heat resistance.

Example 2

1) Grinding and dispersing 5g of water, 1g of polyvinyl alcohol, 40g of graphene and 50g of fumed silica to obtain printing ink;

2) putting the ink obtained in the step 1) into an injector of a direct writing printer, setting a program, and then printing a designed workpiece;

3) and (3) placing the printed part obtained in the step 2) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1500 ℃ at 4 ℃ per minute, preserving heat for 4 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

Fig. 4 shows the printing process of the direct writing printed article and the photo of the resulting article in example 2, and it can be seen that the printed article is black and a variety of different printed structures can be obtained.

Fig. 5 is a scanning electron microscope image of the silicon nitride fiber aerogel material in example 2, which shows that the aerogel material has a fiber structure as a unit, the fiber diameter is about tens of nanometers, and a small amount of fumed silica nanoparticles are attached to the surface of the fiber.

Fig. 6 is a thermal weight loss curve of the silicon nitride fiber aerogel in example 2, and it can be found that the quality of the silicon nitride fiber aerogel is substantially maintained during the whole heating process, which shows that the aerogel material has good heat resistance.

Example 3

1) Grinding and dispersing 5g of acetone, 0.5g of polymethyl methacrylate, 50g of graphene and 50g of fumed silica to obtain printing ink;

2) putting the ink obtained in the step 1) into an injector of a direct writing printer, setting a program, and then printing a designed workpiece;

3) and (3) placing the printed part obtained in the step 2) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1600 ℃ at 4 ℃ per minute, preserving heat for 5 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

Example 4

1) Grinding and dispersing 5g of acetone, 0.5g of polymethyl methacrylate, 50g of graphene and 40g of fumed silica to obtain printing ink;

2) putting the ink obtained in the step 1) into an injector of a direct writing printer, setting a program, and then printing a designed workpiece;

3) and (3) placing the printed part obtained in the step 2) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1400 ℃ at the temperature of 5 ℃ per minute, preserving heat for 5 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

Example 5

1) Grinding and dispersing 5g of acetone, 0.5g of polystyrene, 50g of graphene and 40g of fumed silica to obtain printing ink;

2) putting the ink obtained in the step 1) into an injector of a direct writing printer, setting a program, and then printing a designed workpiece;

3) and (3) placing the printed part obtained in the step 2) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1400 ℃ at the temperature of 5 ℃ per minute, preserving heat for 5 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

Example 6

1) Grinding and dispersing 5g of acetone, 0.5g of polystyrene, 50g of carbon black and 50g of fumed silica to obtain printing ink;

2) putting the ink obtained in the step 1) into an injector of a direct writing printer, setting a program, and then printing a designed workpiece;

3) and (3) placing the printed part obtained in the step 2) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1400 ℃ at the temperature of 5 ℃ per minute, preserving heat for 6 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

Example 7

1) Grinding and dispersing 5g of acetone, 0.5g of polystyrene, 50g of carbon nanotubes and 50g of fumed silica to obtain printing ink;

2) putting the ink obtained in the step 1) into an injector of a direct writing printer, setting a program, and then printing a designed workpiece;

3) and (3) placing the printed part obtained in the step 2) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1400 ℃ at the temperature of 5 ℃ per minute, preserving heat for 6 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

Example 8

1) Grinding and dispersing 5g of water, 1g of polyvinyl alcohol, 40g of carbon nano tube and 50g of glass powder to obtain printing ink;

2) putting the ink obtained in the step 1) into an injector of a direct writing printer, setting a program, and then printing a designed workpiece;

3) and (3) placing the printed part obtained in the step 2) into a crucible, placing the crucible into a tubular furnace protected by a high-purity nitrogen atmosphere, heating to 1500 ℃ at 4 ℃ per minute, preserving heat for 4 hours, cooling along with the furnace, and taking out the crucible to obtain the silicon nitride fiber aerogel material.

The silicon nitride fiber aerogel materials obtained in examples 3-8 have the same structure, morphology, flame retardancy and heat resistance as those of examples 1 and 2.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.