CN101250273A - Preparation method of nanometer ZnO/polyvinyl acetate composite film - Google Patents

Abstract

The invention relates to a method for preparing a nano ZnO/polyvinyl acetate (PVAc) composite film, belonging to the technical field of nano material processing and application. The invention adopts the methods of sol-gel and impregnation-pulling and then calcining. Specifically, the carrier is put into polyvinyl acetate (PVAc)-acetone solution and zinc oxide precursor sol according to this cycle, and then the substrate is pulled vertically at a speed of 6 cm/min, and it is prepared by calcination. The prepared composite film has the characteristics of non-toxic, easy to obtain raw materials, not easy to lose, easy to recycle, and no secondary pollution; it has higher photocatalytic performance than nano-ZnO film under low-power ultraviolet lamps and sunlight light sources, and is expected to be used in sewage Treatment, air purification and other environmental applications.

Description

Preparation method of nanometer ZnO/polyvinyl acetate composite film

technical field

The invention relates to a method for preparing a nano ZnO/polyvinyl acetate (PVAc) composite film, more specifically, relates to a method for preparing a composite film with photocatalytic properties under low-power ultraviolet lamps and sunlight light sources, belonging to nanomaterials Processing and application technology field.

Background technique

Nano-ZnO is a multi-functional new inorganic material, and its particle size is about 1-100 nanometers. Due to the miniaturization of crystal grains, the surface electronic structure and crystal structure change, resulting in surface effects, volume effects, quantum size effects and macroscopic tunnel effects that macroscopic objects do not have, as well as high transparency and high dispersion. As a semiconductor catalyst, nano-ZnO usually has a band structure consisting of a low-energy valence band full of electrons and an empty high-energy conduction band, separated by a forbidden band. When light waves with energy greater than or equal to the semiconductor bandgap energy irradiate the semiconductor photocatalyst, the electrons in the valence band will be excited to the conduction band, and the valence band will generate holes, thus creating highly active holes on the surface of the semiconductor. hole/electron pair. The two are separated and migrate to different positions on the particle surface under the action of self-built electric field. Photogenerated holes have a strong ability to obtain electrons and are strong oxidants, which can capture electrons from adsorbed substances or solvent molecules (electron donors) on the surface of semiconductor particles, so that substances that do not absorb light are activated and oxidized, thereby completing the organic matter. Degrade and kill germs and viruses. Therefore, nano-ZnO, especially nano-ZnO thin films, are widely used in the degradation of organic matter and sterilization due to their non-toxic, readily available raw materials, not easy to lose, easy to recycle, no secondary pollution, and remarkable photocatalytic effect.

In recent years, people's research on photocatalysts is mainly devoted to finding materials with good photoactivity, high photocatalytic activity, and low cost, especially materials that are sensitive to sunlight, so as to expand the application range of photocatalysts.

Contents of the invention

The purpose of the present invention is to provide a preparation method of a nano-ZnO/polyvinyl acetate (PVAc) composite film which has photocatalytic properties and is easy to recycle under low-power ultraviolet lamps and sunlight light sources.

The preparation method of the nanometer ZnO/PVAc composite film provided by the present invention adopts the methods of sol-gel and dipping-lifting and then calcining, and specifically comprises the following steps:

(1) Add zinc acetate dihydrate and complexing agent into the organic solvent, fully stir in 60 DEG C of water baths, namely obtain stable performance, colorless and transparent zinc oxide precursor sol A; Wherein, organic solvent is dehydrated alcohol, Anhydrous isopropanol or ethylene glycol monomethyl ether; the concentration of zinc acetate dihydrate in the organic solvent is 2mol/L～0.2mol/L; the complexing agent is ethanolamine or diethanolamine, and the concentration in the organic solvent 2mol/L～0.2mol/L; the molar ratio range of dihydrate zinc acetate and complexing agent is 3:1～1:3;

(2) preparing the polyvinyl acetate (PVAc)-acetone solution B with a mass percentage of 5.0 to 12.5%;

(3) put the carrier into the solution B of step (2) and the sol A of step (1) in this way to impregnate for 2 minutes respectively, and then pull the substrate vertically at a speed of 6 cm/min; the carrier can be glass Similar substrates, ceramic substrates, metal substrates or other substrates that are resistant to high temperatures and not easy to decompose; the number of repetitions can be 1 to 10 times;

(4) Immediately put the film into a constant temperature drying oven at 80° C. for drying; then put it into a muffle furnace for calcination to obtain a nano-ZnO/PVAc composite film. The calcination temperature is 200° C. to 350° C., and the calcination time is 30 minutes to 120 minutes.

The nano ZnO/PVAc composite film provided by the invention can be used as a photocatalyst.

A kind of nanometer ZnO/PVAc composite thin film that the present invention proposes, its remarkable effect is: described composite thin film has the characteristics of nontoxicity, raw material is easy to get, not easy to lose, easy to recycle, no secondary pollution; under low power ultraviolet lamp and It has higher photocatalytic performance than nano-ZnO film under sunlight light source, and is expected to be applied in environmental fields such as sewage treatment and air purification.

Utilize the nanometer ZnO/PVAc composite thin film that preparation method of the present invention prepares, show by SEM image: compared with the particle agglomeration in the nanometer ZnO thin film obviously, the ZnO particle in the composite thin film is spherical particle, about 20-40nm in diameter; The properties are good and no obvious agglomeration phenomenon is found; the composite film has a uniform and porous nanostructure. XRD analysis showed that the addition of polymer made the crystallization properties of nano-ZnO better.

Detailed ways

Below in conjunction with example the present invention will be further described, but the present invention is not limited to following example:

Example 1

(1) Add zinc acetate dihydrate and diethanolamine at an equimolar concentration of 1.2 mol/L dihydrate and diethanolamine to absolute ethanol, and stir fully in a water bath at 60°C to obtain a colorless and transparent zinc oxide precursor sol A with stable performance.

(2) Prepare a polyvinyl acetate (PVAc)-acetone solution B with a mass percentage of 12.5%.

(3) Put the glass substrate into PVAc-acetone solution B and zinc oxide precursor sol A for 2 minutes and then pull the substrate vertically at a speed of 6 cm/min;

(4) Step (3) is repeated once;

(5) The film is immediately dried in a constant temperature drying oven at 80°C;

(6) Put the thin film into a muffle furnace for calcination at 200° C. for 30 minutes to obtain a nano-ZnO/PVAc composite thin film with excellent photocatalytic performance.

Example 2

(1) Add zinc acetate dihydrate and diethanolamine to anhydrous isopropanol at an equimolar concentration of 0.75 mol/L. Then fully stir in a water bath at 60° C. to obtain a colorless and transparent zinc oxide precursor sol A with stable performance.

(2) Prepare a polyvinyl acetate (PVAc)-acetone solution B with a mass percentage of 7.5%.

(3) Put the glass substrate into PVAc-acetone solution B and zinc oxide precursor sol A for 2 minutes and then pull the substrate vertically at a speed of 6 cm/min;

(4) Step (3) is repeated three times;

(5) The film is immediately dried in a constant temperature drying oven at 80°C;

(6) Put the thin film into a muffle furnace for calcination at 250° C. for 1 hour to obtain a nano-ZnO/PVAc composite thin film with excellent photocatalytic performance.

Example 3

(1) Add zinc acetate dihydrate and ethanolamine at an equimolar concentration of 0.50 mol/L to ethylene glycol monomethyl ether. Then fully stir in a water bath at 60° C. to obtain a colorless and transparent zinc oxide precursor sol A with stable performance.

(2) Prepare polyvinyl acetate (PVAc)-acetone solution B with a mass percentage of 5.0%.

(3) Put the aluminum substrate into PVAc-acetone solution B and zinc oxide sol A for 2 minutes and then pull the substrate vertically at a speed of 6cm/min;

(4) Step (3) is repeated once;

(5) The film is immediately dried in a constant temperature drying oven at 80°C;

(6) Put the film into a muffle furnace for calcination at 300° C. for 120 minutes to obtain a nano-ZnO/PVAc composite film with excellent photocatalytic performance.

Claims (3)

1. a preparation method of nanometer ZnO//polyvinyl acetate composite film, is characterized in that comprising the steps: (1) Add zinc acetate dihydrate and a complexing agent into the organic solvent, and fully stir in a 60°C water bath to obtain the zinc oxide precursor sol A; wherein, the organic solvent is absolute ethanol, anhydrous isopropanol or ethanol Glycol monomethyl ether; the concentration of zinc acetate dihydrate in the organic solvent is 2mol/L～0.2mol/L; the complexing agent is ethanolamine or diethanolamine, and the concentration in the organic solvent is 2mol/L～0.2mol /L; the molar ratio range of dihydrate zinc acetate and complexing agent is 3:1～1:3; (2) the preparation mass percent is 5.0～12.5% polyvinyl acetate (PVAc)-acetone solution B; (3) The carrier is put into the polyvinyl acetate (PVAc)-acetone solution B of step (2) and the zinc oxide precursor sol A of step (1) according to this cycle and impregnated for 2 minutes respectively, and then with a speed of 6cm/min Lift the substrate vertically, the number of repetitions is 1 to 10 times; (4) Dry the film in a constant temperature drying oven at 80°C; then put it into a muffle furnace for calcination to obtain a nano-ZnO/PVAc composite film; the calcination temperature is 200°C-350°C, and the calcination time is 30-120 minutes. 2. the preparation method of nanometer ZnO//polyvinyl acetate composite film as claimed in claim 1 is characterized in that the carrier in the step (3) is a glass substrate, ceramic substrate, metal substrate or resistant Substrates that are not easily decomposed at high temperatures. 3. nanometer ZnO// polyvinyl acetate composite film as claimed in claim 1 is as the application of photocatalyst.