Preparation method of zinc oxide whisker

Abstract

The invention discloses a preparation method of zinc oxide whiskers. Comprising the following steps: S1, respectively adding inorganic alkali and zinc oxide powder into a continuous flow reactor I to obtain a mixed solution I; s2, respectively adding a certain amount of deionized water and the mixed solution I into a continuous flow reactor II to obtain a medium saturated suspension II; s3, respectively adding a surfactant, a directional growth agent and the suspension II into a continuous flow reactor III to obtain reaction slurry III; s4, repeatedly washing the reaction slurry III in a continuous flow reactor IV by using water and absolute ethyl alcohol; and S5, drying the washing product in a continuous flow reactor V, and grinding to obtain the zinc oxide whisker. The method is high in reaction speed, high in heat and mass transfer efficiency, high in selectivity, low in cost and simple in process.

Description

Technical Field

[0001] The present invention relates to a method for preparing zinc oxide whiskers. Background Art

[0002] Whiskers are single-crystal fiber materials with a certain aspect ratio and are generally grown under artificially controlled conditions.

[0003] Whiskers mainly include organic whiskers and inorganic whiskers. Zinc oxide whiskers belong to typical inorganic whiskers, which have the advantages of high strength, high reaction safety, high selectivity, good thermal stability, and special spatial structure. At present, they have good industrial application value and are mainly used in ceramic materials and polymer materials. Therefore, adding them to polymer materials can not only improve the mechanical properties of the materials, but also endow the materials with antistatic properties, antibacterial properties, etc., and is a multifunctional filler material.

[0004] The traditional synthesis routes of this series of products generally use a type of reactor, but there is only one device at the center of the top of the cylinder body of most of this type of reactor, which will result in unevenness, poor mixing effect between fluids, and the inability to achieve continuity of the materials. Summary of the Invention

[0005] To achieve the above object, the present invention provides the following technical solution: A process for producing zinc oxide whiskers using a continuous flow reactor. The basic idea of this method is: using inorganic base as a solvent and zinc oxide powder as a raw material, enabling the whiskers to grow directionally through a hydrothermal method, and then performing subsequent treatment on the reaction slurry to obtain zinc oxide whiskers with regular morphology and uniform rod crystals. This process is simple to operate, easy to control the temperature and time, the raw materials are uniform, the reaction is complete, and it is easy to promote industrially.

[0006] Preferably, turn on, add the inorganic base solution to the continuous flow reactor I at a flow rate of 0.1 mL / min to 0.8 mL / min through a metering pump, then add zinc oxide powder, and increase the rotation speed as the amount of zinc oxide powder added increases. After adding, continue for 5 minutes to make it fully mixed to obtain a uniform mixed solution I. The mass ratio of the inorganic base to zinc oxide is 2:0.5 to 1.5, and the reaction temperature is 20°C to 30°C.

[0007] Preferably, the mixed solution is introduced into the continuous flow reactor II at a flow rate of 0.1 mL / min to 1 mL / min, and deionized water is pumped in through a circulating water vacuum pump. After adding, continue to increase the rotation speed and mix for 5 minutes to obtain a metastable suspension II. The volume ratio of deionized water to the mixed solution is 1 to 4:1, and the reaction temperature is 20°C to 30°C.

[0008] Preferably, the suspension is introduced into the continuous flow reactor III at a flow rate of 0.1 mL / min to 1 mL / min, a surfactant and a directional growth agent are added, and a milky white slurry is obtained through a high-temperature reaction. The reaction temperature is 60°C to 150°C, and the residence time is 5 to 60 minutes; the reaction slurry is repeatedly washed in the reactor IV.

[0009] Preferably, the washed product is dried and ground in the reactor V to obtain zinc oxide whiskers. The drying temperature is 150°C to 200°C, and the time is 0.5 h to 8 h.

[0010] Compared with the prior art, the present invention provides a method for producing zinc oxide whiskers using a continuous flow reactor, and has the following beneficial effects:

[0011] 1. The method for producing zinc oxide whiskers using a continuous flow reactor uses a continuous flow reactor from feeding to discharging, realizing continuous production. With the limitation of various parameters in the process, the materials can be effectively mixed, avoiding problems such as the need for additional equipment configuration in conventional reactions and accumulation and leakage during transfer, significantly reducing production costs and improving reaction safety.

[0012] 2. The method for preparing zinc oxide whiskers using a continuous flow reactor uses a continuous flow reactor to produce zinc oxide whiskers, with simple operation, stable process, and high product purity, which is conducive to large-scale industrial production. Description of the Drawings

[0013] Figure 1 is the process flow chart of the present invention;

[0014] Figure 2 is the scanning electron microscope image of the zinc oxide raw material used in Examples 1, 2, 3, and 4 of the present invention;

[0015] Figure 3 is the XRD spectrum of the zinc oxide whiskers of the present invention;

[0016] Figure 4 is the scanning electron microscope image of the present zinc oxide whiskers. Detailed Embodiments

[0017] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0018] Example 1

[0019] Prepare 30 L of 8 mol / L sodium hydroxide solution. Start the operation. Add the sodium hydroxide solution to the continuous flow reactor I through a metering pump at a flow rate of 0.5 mL / min. Uniformly add 4.8 kg of zinc oxide powder. After adding, continue for 5 min. Then increase the rotation speed. Inject the above mixed solution into reactor II. Then pump in 60 L of deionized water through a circulation pump. After adding, continue for 5 min at 25 °C to obtain a suspension; Inject the above suspension into reactor III at a flow rate of 0.8 mL / min. Add 9 g of ammonium carbonate and 9 g of polyethylene glycol to the suspension. Set the reaction temperature at 100 °C and the residence time at 10 min to obtain a white milky slurry. Transfer the above slurry to reactor IV for repeated washing. Dry it at 200 °C for 2 h and then grind it to obtain zinc oxide whiskers. Through several steps, basically all the zinc oxide is transformed from a granular state into a rod-like crystal structure, and the rod crystals are uniform in thickness.

[0020] Example 2

[0021] Prepare 30 L of 8 mol / L sodium hydroxide solution. Start the operation. Add the sodium hydroxide solution to the continuous flow reactor I through a metering pump at a flow rate of 0.5 mL / min. Uniformly add 4.8 kg of zinc oxide powder. After adding, continue for 5 min. Then increase the rotation speed. Inject the above mixed solution into reactor II. Then pump in 90 L of deionized water through a circulation pump. After adding, continue for 5 min at 25 °C to obtain a suspension; Inject the above suspension into reactor III at a flow rate of 0.8 mL / min. Add 9 g of ammonium carbonate and 9 g of polyethylene glycol to the suspension. Set the reaction temperature at 100 °C and the residence time at 10 min to obtain a white milky slurry. Transfer the above slurry to reactor IV for repeated washing. Dry it at 200 °C for 2 h and then grind it to obtain zinc oxide whiskers. Through several steps, basically all the zinc oxide is transformed from a granular state into a rod-like crystal structure.

[0022] Example 3

[0023] Prepare 30 L of 8 mol / L sodium hydroxide solution. Start the operation. Add the sodium hydroxide solution to the continuous flow reactor I through a metering pump at a flow rate of 0.5 mL / min. Uniformly add 4.8 kg of zinc oxide powder. After adding, continue for 5 min. Then increase the rotation speed. Inject the above mixed solution into reactor II. Then pump in 60 L of deionized water through a circulation pump. After adding, continue for 5 min at 25 °C to obtain a suspension; Inject the above suspension into reactor III at a flow rate of 0.8 mL / min. Add 9 g of ammonium carbonate and 9 g of polyethylene glycol to the suspension. Set the reaction temperature at 100 °C and the residence time at 30 min to obtain a white milky slurry. Transfer the above slurry to reactor IV for repeated washing. Dry it at 200 °C for 2 h and then grind it to obtain zinc oxide whiskers. Through several steps, basically all the zinc oxide is transformed from a granular state into a rod-like crystal structure.

[0024] Example 4

[0025] Prepare 30 L of 8 mol / L sodium hydroxide solution, start it, and add the sodium hydroxide solution to the continuous flow reactor I through a metering pump at a flow rate of 0.5 mL / min. Uniformly add 4.8 kg of zinc oxide powder, continue for 5 minutes after adding, then increase the rotation speed, inject the above mixture into reactor II, and then pump 60 L of deionized water through a circulation pump. After adding, continue for 5 minutes under the condition of 25 °C to obtain a suspension; inject the above suspension into reactor III at a flow rate of 0.8 mL / min, add 9 g of ammonium carbonate and 9 g of polyethylene glycol to the suspension, set the reaction temperature at 140 °C, and the residence time at 10 minutes to obtain a white milky slurry. Transfer the above slurry to reactor IV for repeated washing, and dry it at 200 °C for 2 hours to obtain zinc oxide whiskers. Through several steps, basically all the zinc oxide is transformed from a granular state to a rod-like crystal structure.

[0026] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing zinc oxide whiskers, characterized in that: The synthesis route is as follows: It includes the following steps: S1. Add an inorganic base solution and zinc oxide powder into a continuous flow reactor I respectively to fully dissolve them, obtaining a mixed solution I. The inorganic base solution is added to the continuous flow reactor I through a metering pump, and the reaction temperature in the reactor I is 20°C to 30°C; S2. Add a certain amount of deionized water and the mixed solution I into a continuous flow reactor II respectively to obtain a metastable suspension II. Among them, the mixed solution is introduced into the continuous flow reactor II at a flow rate of 0.1 mL / min to 1 mL / min, and the deionized water is pumped into the reactor by a circulating water vacuum pump, and the reaction temperature in the reactor II is 20°C to 30°C; S3. Add a surfactant, a directional growth agent and the suspension II into a continuous flow reactor III respectively to fully obtain a reaction slurry III. Among them, the suspension is introduced into the continuous flow reactor III at a flow rate of 0.1 mL / min to 1 mL / min, the reaction temperature in this reactor III is 60°C to 150°C, and the residence time is 5 to 60 min; S4. The reaction slurry III is washed with water and repeatedly washed with absolute ethanol in a continuous flow reactor IV to remove impurities; S5. The washed product is dried in a continuous flow reactor V and then ground to obtain the zinc oxide whiskers. The drying temperature is 150°C to 200°C, and the time is 0.5 h to 8 h.

2. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The inorganic base is one of sodium hydroxide solution, potassium hydroxide solution or a mixed solution of the two.

3. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The mass ratio of the inorganic base to zinc oxide is 2:0.5 to 1.

5.

4. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The concentration of the inorganic base is 5 to 20 mol / L.

5. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The surfactant is one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, ammonium carbonate, ammonium sulfate, sodium chloride, ethylenediaminetetraacetic acid and acetic acid.

6. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The directional growth agent is one of polyethylene glycol, polyvinyl alcohol, polyvinylpyrrolidone and cetyltrimethylammonium bromide.

7. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The ratio of the surfactant to zinc oxide is 0.005 to 0.02:

1.

8. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The ratio of the directional growth agent to zinc oxide is 0.005 to 0.02:

1.

9. The preparation method of zinc oxide whiskers according to claim 1, characterized in that: The ratio of the surfactant to the directional growth agent is 1:1.

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