阅读说明：本技术 聚合单宁酸包覆高活性铝粉/硅粉的制备方法 (Preparation method of high-activity aluminum powder/silicon powder coated by polymeric tannic acid ) 是由 张文超 陈亚杰 吴刚刚 俞春培 王嘉鑫 陈俊宏 刘琦 于 2019-08-28 设计创作，主要内容包括：本发明公开了一种聚合单宁酸包覆高活性铝粉/硅粉的制备方法。所述方法先将缓冲试剂溶解在有机溶液中,加入单宁酸,搅拌溶解得到单宁酸-缓冲溶液,再将铝粉或硅粉分散至单宁酸-缓冲溶液中,搅拌进行自聚合反应,得到聚合单宁酸包覆的铝或硅粉。本发明的原料来源广泛、绿色环保安全,简单便捷,适合工业化生产。本发明制备的铝或硅@聚合单宁酸核壳结构复合材料可有效阻止铝/硅颗粒表面的迅速氧化,保护铝粉或硅粉的活性。将铝或硅@聚合单宁酸核壳结构复合材料加入固体推进剂进行高温燃烧时,因包覆的聚合单宁酸含碳丰富,可提供额外的燃烧热,促进铝粉或硅粉的快速燃烧反应,从而提高固体推进剂的燃烧性能。(The invention discloses a preparation method of high-activity aluminum powder/silicon powder coated by polymeric tannic acid. The method comprises the steps of dissolving a buffering reagent in an organic solution, adding tannic acid, stirring and dissolving to obtain a tannic acid-buffering solution, dispersing aluminum powder or silicon powder into the tannic acid-buffering solution, stirring to perform self-polymerization reaction, and obtaining the aluminum or silicon powder coated by the polymeric tannic acid. The raw materials of the invention have wide sources, are green, environment-friendly, safe, simple and convenient, and are suitable for industrial production. The aluminum or silicon @ polymeric tannic acid core-shell structure composite material prepared by the invention can effectively prevent the surface of aluminum/silicon particles from being rapidly oxidized and protect the activity of aluminum powder or silicon powder. When the aluminum or silicon @ polymeric tannic acid core-shell structure composite material is added into a solid propellant for high-temperature combustion, the coated polymeric tannic acid contains abundant carbon, so that extra combustion heat can be provided, and the rapid combustion reaction of aluminum powder or silicon powder is promoted, thereby improving the combustion performance of the solid propellant.)

1. The preparation method of the high-activity aluminum powder/silicon powder coated by the polymeric tannic acid is characterized by comprising the following steps:

(1) Preparation of tannin-buffer solution:

Uniformly dissolving a buffer reagent in an organic solution, adding tannic acid, and stirring and dissolving to obtain a tannic acid-buffer solution;

(2) the tannin is oxidized and self-polymerized to coat the high-activity aluminum powder/silicon powder:

And dispersing aluminum powder or silicon powder into the tannin-buffer solution, stirring for self-polymerization reaction, filtering and washing to obtain the aluminum or silicon powder coated by the polymeric tannin.

2. the preparation method according to claim 1, wherein in the step (1), the organic solution is a mixed solution prepared by mixing any one of methanol, ethanol, isopropanol, N-propanol and acetone with N, N-dimethylformamide or N, N-dimethylacetamide in a volume ratio of 10-0.5: 1.

3. The method according to claim 1, wherein in the step (1), the buffer reagent is selected from tris (hydroxymethyl) aminomethane, tris (hydroxymethyl) aminomethane hydrochloride, bis (2-hydroxyethylamino) tris (hydroxymethyl) methane or bis (2-hydroxyethylamino) tris (hydroxymethyl) methane hydrochloride.

4. the preparation method according to claim 1 or 3, wherein in the step (1), the buffer reagent is dissolved in an organic solvent to form a buffer solution with a concentration of 1-30 mmol/L.

5. The preparation method of claim 1, wherein in the step (1), the mass concentration of the tannic acid is 0.1-100 mg/mL.

6. The preparation method according to claim 1, wherein in the step (2), the size of the aluminum powder or the silicon powder is micro-nano.

7. The preparation method according to claim 1, wherein in the step (2), the self-polymerization reaction time is 0.5-60 h.

Technical Field

The invention belongs to the technical field of energetic materials, and relates to a preparation method of high-activity aluminum powder/silicon powder coated by polymeric tannic acid.

Background

Tannic acid is a plant polyphenol compound which is present in natural plants (tea, wood, oak, etc.) and contains five dimethylol ester groups per se (Pan L, Wang H, Wu C, et al. tannic-acid-coated polypropylene membrane as a separator for substrates [ J ]. ACS applied materials & interfaces,2015,7(29): 16003-. Similar to polydopamine coatings, tannic acid coatings can also undergo oxidative autopolymerization at room temperature to form polymeric tannic acid, and the thickness of the resulting polymeric tannic acid coating can be precisely controlled to one to tens of nanometers, a polymeric coating material that is stable at low temperatures (SileikaT S, Barrett D G, Zhang R, et al. multicolor coatings absorbed by solvents found in foot, chlorolate, and wire [ J ]. Angewandte Chemie International Edition,2013,52(41): 10766-10770.).

With the increasing comprehensive requirements of modern high-performance weapon ammunition on energetic materials, the energetic materials have higher energy density and energy release rate, more excellent combustion characteristics and higher safety, and become the main development direction in the field of energetic materials. The metal powder is used as an important additive in the application of the solid rocket propellant, has a special effect on improving the performance of the energetic materials, and compared with the common metal powder, the micro-nano metal powder has higher surface chemical activity and reaction capability of the metal powder particles due to smaller particle size and obvious surface-interface effect and small-size effect of the particles. The micro-nano aluminum powder/silicon powder becomes the most common metal additive in energetic material application (the latest progress of the research on the surface coating modification of nano aluminum powder, Yao Ergang, Zhao Feng Ji, Anting.) due to the advantages of high energy density, high combustion heat, high activity, rich raw materials and the like, 2011,8(2): 81-90.).

₄The micro-nano aluminum powder/silicon powder has great application potential in the application of the solid propellant, but micro-nano particles have high surface energy, so that the surface of the aluminum powder/silicon powder is easily oxidized to form an inert oxidation shell layer in practical application, thereby reducing the activity of the aluminum powder/silicon powder and seriously influencing the use efficiency of the aluminum powder/silicon powder in the solid propellant.

Disclosure of Invention

The invention aims to provide a simple, feasible, economic and environment-friendly preparation method of high-activity aluminum powder/silicon powder coated with polymeric tannic acid. The method adopts plant polyphenol tannin to perform self-polymerization reaction on the surface of micro/nano-scale aluminum powder or silicon powder to form a uniform coating layer, and prevents the self oxidation of high-activity aluminum powder/silicon powder, thereby maintaining the activity of particles.

The technical scheme for realizing the purpose of the invention is as follows:

The preparation method of the high-activity aluminum powder/silicon powder coated by the polymeric tannic acid comprises the following steps:

(1) Preparation of tannin-buffer solution:

Uniformly dissolving a buffer reagent in an organic solution, adding Tannic Acid (TA), and stirring and dissolving to obtain a tannic acid-buffer solution;

(2) the tannin is oxidized and self-polymerized to coat the high-activity aluminum powder/silicon powder:

And dispersing aluminum powder or silicon powder into the tannin-buffer solution, stirring for self-polymerization reaction, filtering and washing to obtain the aluminum or silicon powder coated by the polymeric tannin.

Preferably, in the step (1), the organic solution is a mixed solution prepared by mixing any one of methanol, ethanol, isopropanol, N-propanol and acetone with N, N-dimethylformamide or N, N-dimethylacetamide in a volume ratio of 10-0.5: 1.

Preferably, in the step (1), the buffer reagent is selected from Tris (hydroxymethyl) aminomethane (Tris), Tris (hydroxymethyl) aminomethane hydrochloride (Tris-HCl), Bis (2-hydroxyethylamino) Tris (hydroxymethyl) methane (Bis-Tris) or Bis (2-hydroxyethylamino) Tris (hydroxymethyl) methane hydrochloride (Bis-Tris-HCl), and the buffer reagent is dissolved in an organic solvent to form a buffer solution with a concentration of 1 to 30 mmol/L.

Preferably, in the step (1), the mass concentration of the tannic acid is 0.1-100 mg/mL.

Preferably, in the step (2), the size of the aluminum powder or the silicon powder is micro-nano.

preferably, in the step (2), the self-polymerization reaction time is 0.5-60 h.

Compared with the prior art, the invention has the following advantages:

(1) The polymerized tannic acid has stable property at low temperature, can effectively protect the activity of aluminum powder and silicon powder, can improve the surface electrical property and the surface activity of particles, and is favorable for preventing agglomeration among the particles; (2) the polymeric tannic acid is adopted to form uniform coating on the surface of the high-activity aluminum powder or silicon powder, so that the oxidation inactivation of the polymeric tannic acid can be effectively prevented; (3) the coated polymeric tannic acid contains abundant carbon, and when the formed composite material is added into a solid propellant for high-temperature combustion, additional combustion heat can be provided to promote the rapid combustion reaction of aluminum powder and silicon powder, so that the combustion performance of the solid propellant is improved; (4) compared with the preparation methods of vapor deposition, electric arc, laser and the like, the method has low requirement on equipment, simple reaction and easy operation, and can prepare the micro/nano aluminum or silicon @ polymeric tannin core-shell structure composite material in batches.

Drawings

Fig. 1 is a schematic diagram of the preparation process of tannic acid polymer coated micro/nano particles.

FIG. 2 is an SEM image of the nano-aluminum powder coated by the nano-aluminum powder and tannic acid in example 1.

FIG. 3 is an SEM image of silica fume and tannin coated silica fume in example 2.

FIG. 4 is a TEM image of the nano-aluminum powder coated by the polymerization of nano-aluminum powder and tannic acid in example 1.

FIG. 5 is a TEM image of silica fume coated with polymerization of silica fume and tannic acid in example 2.

Fig. 6 is an XRD (X-ray diffraction) pattern of the nano-aluminum powder coated by the nano-aluminum powder and the tannic acid in example 1.

FIG. 7 is an XRD pattern of silica nanopowder coated with tannin polymerization in example 2.

Detailed Description

the invention is further illustrated by the following examples and figures.