阅读说明：本技术 一种改性铝/含氟高分子复合物及其制备方法 (Modified aluminum/fluorine-containing polymer compound and preparation method thereof ) 是由 曾诚成 巩飞艳 潘丽萍 王军 张建虎 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种改性铝/含氟高分子复合物,它是由改性铝粉、含氟聚合物组成。其中铝粉尺寸为50nm～5μm,重量占比为90％～70％,含氟聚合物重量占比为10％～30％。本发明可以作为一种铝粉改性层与高分子聚合物相容性的简单有效判据,作为炸药造粒工艺适配的一种评判参考。同时为铝粉反应性材料的设计提供参考。工艺简单,容易操作。(The invention discloses a modified aluminum/fluorine-containing polymer compound, which consists of modified aluminum powder and fluorine-containing polymer. Wherein the aluminum powder has a size of 50 nm-5 μm, a weight ratio of 90-70%, and a fluorine-containing polymer weight ratio of 10-30%. The invention can be used as a simple and effective criterion for the compatibility of the aluminum powder modified layer and the high molecular polymer and as a criterion for the adaptation of the explosive granulation process. And meanwhile, reference is provided for the design of the aluminum powder reactive material. Simple process and easy operation.)

1. A modified aluminum/fluorine-containing polymer compound is characterized in that: comprises surface modified aluminum powder and fluorine-containing polymer, wherein the selected spherical particle aluminum powder with the surface modified aluminum powder size average particle diameter of 50 nm-5 mu m; the selected fluorine-containing polymer is a copolymer of vinylidene fluoride and chlorotrifluoroethylene; wherein the weight ratio of the aluminum powder is 90-70%, and the weight ratio of the fluorine-containing polymer is 10-30%.

2. A preparation method of a modified aluminum/fluorine-containing polymer compound is characterized by comprising the following steps: the method comprises the following steps: dispersing 90-70 wt% of modified aluminum powder in an organic solvent A, and performing ultrasonic treatment to form a suspension; dispersing 10-30 wt% of fluorine-containing polymer in another part of organic solvent A, and magnetically stirring; mixing the above two materials, and stirring; and (3) dropwise adding the mixed solution on the surface of deionized water at a certain temperature, simultaneously carrying out vacuum treatment until the solvent is completely volatilized, forming a film by using the liquid drops, taking out and drying to obtain the modified aluminum/fluorine-containing polymer compound.

3. The method for preparing a modified aluminum/fluoropolymer composite according to claim 2, wherein: the aluminum powder surface modification layer is one of poly nitrogen glycidyl ether (GAP) and polyvinylidene fluoride (PVDF).

4. The method for preparing a modified aluminum/fluoropolymer composite according to claim 2, wherein: the organic solvent A is one of ethyl acetate and butyl acetate.

5. The method for preparing a modified aluminum/fluoropolymer composite according to claim 2, wherein: the ultrasonic frequency is 30 kHz-100 kHz.

6. The method for preparing a modified aluminum/fluoropolymer composite according to claim 2, wherein: the temperature is 50-70 ℃.

7. The method for preparing a modified aluminum/fluoropolymer composite according to claim 2, wherein: the magnetic stirring speed is 200 rpm-600 rpm, and the vacuum degree is 40 mbar-100 mbar.

Technical Field

The invention belongs to the field of energetic material composites, and particularly relates to a modified aluminum/fluorine-containing polymer composite for simply judging the compatibility of an aluminum powder surface modification layer and a fluorine-containing polymer and a preparation method thereof.

Background

The aluminum powder is added into the high-energy explosive due to high density and high combustion enthalpy, so that the reaction rate, detonation heat and other detonation properties of the mixed explosive are improved. The aluminum powder is coated by inorganic matters or organic matters, so that the dispersion and storage of the aluminum powder can be effectively improved, and the surface is prevented from being further oxidized. However, the coating layers are at the cost of sacrificing the energy density of the system, and no energy contribution is caused in the combustion and explosion process of the system, and researches show that fluorine is used as an oxidizing agent to replace oxygen to react with aluminum to generate AlF₃The reaction can give off 13.31kcal/g of heat to generate Al₂O₃The exothermic heat of reaction was only 7.4 kcal/g. The mixture of fluoride and aluminum powder has been widely used as a high energy density material in nano thermite and reactive materials (mat. sci.2007,25, 95). Therefore, the aluminum powder is subjected to surface modification by using GAP or PVDF, so that the nano aluminum powder can be effectively passivated, and meanwhile, the coating layer can contribute energy to an energy-containing system and improve the reaction and energy release rate.

The aluminum-containing explosive is a multi-phase mixed material and comprises components such as a main explosive, aluminum powder, a binding agent and the like, so that in such a complex multi-interface system, the interface compatibility among the components has an important influence on the interface property of the composite material, and further the mechanical strength of the formed explosive column is changed. The interface work is calculated by utilizing the test contact angle, and the method is a common method for judging the interface compatibility of the components of the composite material. He et al performed Polydopamine (PDA) coating on the surface of main explosive TATB, and the compatibility of the explosive and fluoropolymer was characterized by measuring the contact angle between fluoropolymer solution and the grain and calculating the interfacial energy (j. mater. chem. a,2017, 5, 13499). Zeng et al tabletted fluoropolymers, tested the contact angles of water and diiodomethane on their surfaces, and calculated the corresponding interfacial work; the comparison of the values of the interfacial work shows that the TATB surface is subjected to grafting modification and then has the strongest interfacial action with the fluoropolymer, and a criterion is provided for mechanical enhancement (Polymers,2019,11, 1308). However, in testing the contact angle of compressed tablets, the surface properties are different from those of the granules before compression due to the crushing of the granules by pressure, the obtained interfacial contact angle is not accurate, and it is difficult to fully reflect the interfacial properties of the granules of the composite material. For direct testing of the contact angle of powders, there are currently two major types, Column picking or Washburn capitllary rise (Powder Technology 2016,287,201). The two methods can only test the surface wetting condition of different solutions to the powder, and cannot reflect the interfacial action condition of the polymer component and the polymer component, and even if the high polymer is dissolved to prepare a solution, the existence of the solvent causes errors.

Bear liber et al disclose a method of chemical plating of a surface on a chemical polymer film to improve the surface energy of the polymer, but this approach is difficult to extend into the binder of energetic materials (CN 109576683A). Sclerite et al invented a method for the chemical modification of the surface of aluminum powder by which a mixed explosive can be prepared in water, which provides support for the preparation of fluorine-containing composites (ZL 201610478426.7).

Disclosure of Invention

The invention discloses a modified aluminum/fluorine-containing polymer compound and a preparation method thereof, aiming at the problem that the interface compatibility of components in an aluminum-containing explosive and a binding agent is difficult to visually represent. The solvent is volatilized under the action of hot water and vacuum to form a film, the modified aluminum/fluorine-containing polymer compound is obtained, and the result of interfacial compatibility between the two is visually observed through an electron microscope. The method is expected to be widened to the range between other modified fine particles and high polymers, and provides a preliminary judgment basis for the interface matching of the components in the mixed material; the film prepared at the same time may provide a reference for the design of the aluminum powder reactive material.

In order to realize the purpose of the invention, the invention provides the following technical scheme:

a modified aluminum/fluorine-containing polymer compound comprises surface modified aluminum powder and fluorine-containing polymer, wherein the selected surface modified aluminum powder is spherical particle aluminum powder with the average size of 50 nm-5 mu m; the selected fluorine-containing polymer is a copolymer of vinylidene fluoride and chlorotrifluoroethylene; wherein the weight ratio of the aluminum powder is 90-70%, and the weight ratio of the fluorine-containing polymer is 10-30%.

The invention also discloses a preparation method of the modified aluminum/fluorine-containing polymer compound, which comprises the following steps: dispersing 90-70 wt% of modified aluminum powder in an organic solvent A, and performing ultrasonic treatment to form a suspension; dispersing 10-30 wt% of fluorine-containing polymer in another part of organic solvent A, and magnetically stirring; mixing the above two materials, and stirring; and (3) dropwise adding the mixed solution on the surface of deionized water at a certain temperature, simultaneously carrying out vacuum treatment until the solvent is completely volatilized, forming a film by using the liquid drops, taking out and drying to obtain the modified aluminum/fluorine-containing polymer compound.

To successfully prepare the modified aluminum/fluorine-containing polymer composite, the following points are required:

the ultrasonic time of the modified aluminum powder is controlled within 3min, so that the modified aluminum powder is fully dispersed, and a modified layer is not damaged as much as possible; preparing a binder mixed solution with a certain concentration by the fluorine-containing polymer before taking the fluorine-containing polymer, wherein the selected solvent is required to be consistent with a subsequent dispersion solvent A; the mixed solution is kept in a stirring state all the time during liquid taking, so that the aluminum powder is prevented from settling; controlling the liquid taking to be once for two drops as far as possible, and simultaneously paying attention to the fact that the vacuum is not too close to the water surface to prevent the liquid surface from being damaged; after the solvent is completely volatilized, the filter paper is cut into a certain angle or the film is taken by using a silicon wafer, and after the film is dried in vacuum, the film can be separated from the filter paper.

In some embodiments, the aluminum powder surface modification layer is one of polyaziridinyl glycidyl ether (GAP), polyvinylidene fluoride (PVDF).

In some embodiments, the organic solvent a is one of ethyl acetate and butyl acetate.

In some embodiments, the ultrasonic frequency is between 30kHz and 100 kHz.

In some embodiments, the temperature is 50 to 70 ℃.

In some embodiments, the magnetic stirring speed is 200rpm to 600rpm and the vacuum is 40mbar to 100 mbar.

Compared with the prior art, the invention has the beneficial effects that:

the modified aluminum/fluorine-containing polymer composite obtained by the invention is used as a means for preliminarily judging the interface compatibility of the two. The direct observation can be carried out through an electron microscope photo, and if the interface interaction of the two is strong, each aluminum powder particle is uniformly dispersed in the fluoropolymer film, so that the contact area of the two is increased; if the interface compatibility of the two is poor, the aluminum powder is agglomerated, and the aluminum powder on the surface of the fluoropolymer can be less.

Drawings

For a clearer explanation of the embodiments or technical solutions in the prior art of the present application, the drawings used in the description of the embodiments or prior art will be briefly described below, it is obvious that the drawings in the following description are only references to some embodiments in the present application, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a flow diagram illustrating the preparation of a modified aluminum/fluoropolymer composite according to the present invention;

FIG. 2 is an electron microscope image of a modified aluminum/fluoropolymer composite according to example 1 of the present invention;

FIG. 3 is an electron microscope image of a modified aluminum/fluoropolymer composite according to example 3 of the present invention;

FIG. 4 is an electron micrograph of a modified aluminum/fluoropolymer composite according to example 5 of the present invention.

Detailed Description

The present invention will be further described with reference to the following examples, which are intended to illustrate only some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, other embodiments used by those skilled in the art without any creative effort belong to the protection scope of the present invention.

Example 1

As shown in figure 1, 0.18g of modified aluminum powder with the average diameter of 50nm (the modified layer is GAP) is ultrasonically dispersed in 10ml of butyl acetate for 3 min; 0.5g of fluoropolymer adhesive A (the concentration is 4 percent, actually 0.02g) is added into 10ml of butyl acetate, and the mixture is magnetically stirred at the rotating speed of 200 rpm; pouring the aluminum powder suspension into the fluoropolymer solution, and keeping magnetic stirring at the rotating speed of 300 rpm; and (3) dropwise adding about 1ml of mixed solution on the surface of deionized water at 70 ℃, carrying out vacuum treatment at 40mbar until the solvent is completely volatilized, taking out the film by using clean filter paper, and drying at 60 ℃ in vacuum to obtain the modified aluminum/fluorine-containing polymer compound with the weight ratio of 9: 1.

Example 2

As shown in figure 1, 0.16g of modified aluminum powder with the average diameter of 200nm (the modified layer is GAP) is ultrasonically dispersed in 10ml of butyl acetate for 2 min; 1g of fluoropolymer adhesive A (the concentration is 4 percent, actually 0.04g) is added into 10ml of butyl acetate, and the mixture is magnetically stirred at the rotating speed of 300 rpm; pouring the aluminum powder suspension into the fluoropolymer solution, and keeping magnetic stirring at the rotating speed of 500 rpm; and (3) dropwise adding about 1ml of mixed solution on the surface of deionized water at 70 ℃, carrying out vacuum treatment at 60mbar until the solvent is completely volatilized, taking out the film by using clean filter paper, and drying at 60 ℃ in vacuum to obtain the modified aluminum/fluorine-containing polymer compound with the weight ratio of 8: 2.

Example 3

As shown in fig. 1, 0.14g of modified aluminum powder with an average diameter of 3 μm (the modified layer is GAP) is ultrasonically dispersed in 10ml of butyl acetate for 1 min; adding 1.5g of fluoropolymer adhesive A (the concentration is 4 percent, actually 0.04g) into 10ml of butyl acetate, and magnetically stirring at the rotating speed of 300 rpm; pouring the aluminum powder suspension into the fluoropolymer solution, and keeping magnetic stirring at the rotating speed of 600 rpm; and (3) dropwise adding about 1ml of mixed solution on the surface of deionized water at 70 ℃, carrying out vacuum treatment at 100mbar until the solvent is completely volatilized, taking out the film by using clean filter paper, and drying at 60 ℃ in vacuum to obtain the modified aluminum/fluorine-containing polymer compound with the weight ratio of 7: 1.

Example 4

As shown in FIG. 1, 0.18g of modified aluminum powder with an average diameter of 50nm (modified layer GAP) is ultrasonically dispersed in 10ml of ethyl acetate for 3 min; adding 0.5g of fluoropolymer binder B (the concentration is 4 percent, and the actual concentration is 0.02g) into 10ml of ethyl acetate, and magnetically stirring at the rotating speed of 200 rpm; pouring the aluminum powder suspension into the fluoropolymer solution, and keeping magnetic stirring at the rotating speed of 400 rpm; and (3) dropwise adding about 1ml of mixed solution on the surface of deionized water at 60 ℃, carrying out vacuum treatment at 40mbar until the solvent is completely volatilized, taking out the film by using clean filter paper, and drying at 60 ℃ in vacuum to obtain the modified aluminum/fluorine-containing polymer compound with the weight ratio of 9: 1.

Example 5

Example 5 is a blank control with aluminum powder as the raw material without surface modification.

Taking 0.16g of raw material aluminum powder with the average diameter of 50nm to be ultrasonically dispersed in 10ml of butyl acetate for 1 min; 1g of fluoropolymer adhesive A (the concentration is 4 percent, actually 0.04g) is added into 10ml of butyl acetate, and the mixture is magnetically stirred at the rotating speed of 200 rpm; pouring the aluminum powder suspension into the fluoropolymer solution, and keeping magnetic stirring at the rotating speed of 350 rpm; and (3) dropwise adding about 1ml of mixed solution on the surface of deionized water at 70 ℃, carrying out vacuum treatment at 70mbar until the solvent is completely volatilized, taking out the film by using clean filter paper, and drying at 60 ℃ in vacuum to obtain the modified aluminum/fluorine-containing polymer compound with the weight ratio of 8: 2.

As can be seen from comparison of electron microscope photographs, in examples 1 to 4, the aluminum powder subjected to surface modification treatment can be well dispersed on the surface of the fluoropolymer film, and the size of the aluminum powder has little influence on the uniformity of the composite, as shown in FIGS. 2 to 3; in example 5, the mixed solution is difficult to volatilize to form a complete film without surface modification during the preparation process, and the film has many holes mainly due to poor interface compatibility between the raw aluminum powder and the fluoropolymer, as shown in fig. 4. Therefore, the modified aluminum/fluorine polymer film prepared by the method has reference significance for preliminarily judging the interfacial compatibility of the aluminum powder and the high-molecular binder in the aluminum-containing explosive.

Although the present invention has been described herein with reference to the illustrated embodiments thereof, which are intended to be preferred embodiments of the present invention, it is to be understood that the invention is not limited thereto, and that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure.