CN106317714A - Method of modifying nano-aluminium oxide using cold plasma - Google Patents

Abstract

The invention provides a nano-aluminum oxide low-temperature plasma modification treatment method, which comprises the following steps: (1) according to the loading rate of the monomer to be grafted on the surface of the nano-alumina particle, select different Monomer loading method, that is: direct loading or solvent-assisted loading; and (2) low-temperature plasma treatment of nano-alumina particles loaded with monomers to be grafted on the surface, wherein the processing power is 10W-150W, and the time The temperature is 0.1s to 3600s, and the temperature is 10-400°C. Low-temperature plasma induces monomer polymerization on the surface of nano-alumina particles to realize surface modification of nano-alumina.

Description

Low-temperature plasma modification treatment method of nano-aluminum oxide

technical field

The invention belongs to the modification field of nano-alumina materials, and in particular relates to a low-temperature plasma modification treatment method of nano-alumina.

Background technique

Nanoparticles have broad application prospects in many fields such as medicine, biology and environment. Organic materials doped with nanoparticles are a new class of composite materials with special mechanical properties, thermal stability, optical properties, rheological properties, electrochemical properties and catalytic properties. In the development of such composite materials, nano-alumina has attracted much attention due to its excellent mechanical, adsorption, and catalytic properties. However, the specific surface area and surface energy of nano-alumina particles are large, and they are very easy to agglomerate, and their dispersion in composite materials is poor; The material matrix is peeled off, resulting in the weakening of the performance of the composite material. Surface modification of nano-alumina is an important method to solve the above two problems.

The traditional modification method utilizes the adsorption properties of aluminum oxide or the hydroxyl groups on its surface to graft specific monomers through chemical action to achieve the modification of nanoparticles. This method involves the use of chemical solvents. The use of these solvents will cause harm to human health on the one hand, and on the other hand, the exposure of solvents to the environment will cause damage to water bodies and soil. In addition, the method of chemical grafting has poor adaptability, and the types of monomers that can be selected are limited.

Low temperature plasma technology is an environmentally friendly powder surface treatment technology. After the grafted monomers are introduced into the reactor, molecular fragments are formed in the plasma atmosphere, and these molecular fragments repolymerize on the surface of the powder, thereby realizing the coating of the powder. Under the action of low-temperature plasma, alkanes, alkenes, alkynes and vinyl monomers can all undergo the above reactions, thus greatly expanding the range of graftable monomers. However, in the traditional plasma treatment process, the polymerization of monomers on the powder surface is random, so the uniformity of grafting is difficult to guarantee.

Therefore, there is an urgent need in the art to develop a method for modifying nano-alumina materials that can overcome the above-mentioned defects of the prior art.

Contents of the invention

The invention provides a novel nano-aluminum oxide low-temperature plasma modification treatment method, thereby solving the problems in the prior art.

The invention provides a nano-aluminum oxide low-temperature plasma modification treatment method, which comprises the following steps:

(1) According to the loading rate of the monomer to be grafted on the surface of the nano-alumina particle, select different monomer loading methods, namely: direct loading or solvent-assisted loading; and

(2) Low-temperature plasma treatment is carried out on the nano-alumina particles loaded with monomers to be grafted on the surface, wherein the treatment power is 10W-150W, the time is 0.1s-3600s, the temperature is 10-400°C, and the low-temperature plasma The body induces monomer polymerization on the surface of nano-alumina particles to realize surface modification of nano-alumina particles.

In a preferred embodiment, in step (1), the direct loading refers to directly mixing nano-alumina with the monomer to be grafted when the loading rate of the monomer to be grafted is greater than 10%. , so as to realize the uniform loading of the monomer on the surface of the nanoparticle; the solvent-assisted loading refers to dispersing the monomer to be grafted into the solvent when the loading rate of the monomer to be grafted is less than 10%, and then mixing with the nanometer three Alumina is mixed and the solvent is removed, resulting in uniform loading of monomers on the nanoparticle surface.

In another preferred embodiment, the monomer to be grafted is methyl methacrylate, hydroxyethyl methacrylate, ethylene glycol, polyethylene glycol, vinylpyrrolidone, polyvinylpyrrolidone, vinyl alcohol, poly Vinyl alcohol, dopamine, polymerized dopamine, or mixtures thereof.

In another preferred embodiment, the solvent in the solvent auxiliary load is water, methanol, ethanol, acetone, N-N dimethylacetamide, N-N dimethylformamide, N-methylpyrrolidone, triethyl phosphate , dimethyl sulfoxide or their mixed liquid.

In another preferred embodiment, the particle size of the nano-alumina particles is 10 nm-100 nm.

In another preferred embodiment, in the case of direct loading, the weight ratio of the monomer to be grafted to the nano-alumina particles is 5:1 to 1:100.

In another preferred embodiment, in the case of solvent-assisted loading, the weight ratio of the monomer to be grafted to the solvent dispersed is 1:10000 to 1:10.

In another preferred embodiment, argon, nitrogen, helium or a combination thereof with a purity of 99.99% is used to generate a plasma atmosphere.

In another preferred embodiment, in the case of direct loading, after directly mixing the nano-alumina oxide with the monomer to be grafted, it is sufficiently ground to achieve uniform loading of the monomer on the surface of the nanoparticle.

In another preferred embodiment, in the case of solvent-assisted loading, the solvent is removed by centrifugation and drying.

Description of drawings

FIG. 1 shows a transmission electron microscope image of nanoparticles modified by low-temperature plasma according to Example 1 of the present application.

Fig. 2 shows before and after modification according to Example 2 of the present application, the nanoparticles are dispersed in N,N-dimethylacetamide, and the photos after standing for 24h, (a) in the figure means before modification, (b) Indicates after modification.

Fig. 3 shows the loss of nanoparticles over time in the PVDF (polyvinylidene fluoride) composite membrane prepared according to the modified sample of Example 3 of the present application as an additive under the action of acid solution.

Fig. 4 shows the loss of nanoparticles over time in the PVDF composite membrane prepared according to the modified sample of Example 4 of the present application as an additive under the action of alkaline solution.

Fig. 5 shows the particle size distribution of the modified sample according to Example 5 of the present application after being dispersed in water.

detailed description

After extensive and in-depth research, the inventors of the present application have proposed to combine monomers and nanoparticles with a certain amount of The modification method is a modification method of fully mixing the ratio and then performing plasma treatment, and aiming at the application of nanoparticles commonly used in water treatment membrane modification, a series of organic additives for ultrafiltration membranes are used as surface modification materials for nanoparticles. The method of the present invention performs simple pretreatment before the action of the low-temperature plasma, reduces the number of related modules introduced into the monomer during the action process, has strong process controllability, and is environmentally friendly; in organic solvents, the dispersibility of the modified particles is significantly improved ; The chemical stability of the modified particles in the composite PVDF membrane is significantly improved.

The invention provides a method for modifying the surface of nano-alumina with low-temperature plasma. The method comprises the following steps:

The first step: directly mix the monomer to be grafted with the nano-alumina particles at a certain volume/weight ratio (when the monomer loading rate is greater than 10%); or mix the monomer to be grafted Disperse in water or organic solvent, then mix nano-dispersant with nanoparticles, and remove water or organic solvent by centrifugation and drying (in the case of monomer loading rate less than 10%), so as to realize nano-three Pretreatment of alumina;

The second step: placing the pretreated nano-alumina particles in a low-temperature plasma reactor, setting certain plasma parameters to treat the particles; and

Step 3: Collect samples after low-temperature plasma treatment.

In the present invention, in the first step, the monomer to be grafted is methyl methacrylate, hydroxyethyl methacrylate, ethylene glycol, polyethylene glycol, vinylpyrrolidone, polyvinylpyrrolidone, vinyl alcohol , polyvinyl alcohol, dopamine, polymerized dopamine, or mixtures thereof.

In the present invention, in the first step, the organic solvent of the dispersing monomer is methanol, ethanol, acetone, N-N dimethylacetamide, N-N dimethylformamide, N-methylpyrrolidone, triethyl phosphate , dimethyl sulfoxide or their mixed liquid.

In the present invention, in the first step, the particle size of the aluminum oxide nanoparticles is 10nm-100nm.

In the present invention, in the first step, the (volume/weight) ratio of the monomer to the nanoparticles (mL monomer solution/g nanoparticles) is 5:1˜1:100.

In the present invention, in the first step, the weight ratio of the monomer dispersed in the solvent (monomer weight/solvent weight) is 1:10000 to 1:10.

In the present invention, in the second step, argon, helium, nitrogen or their combination gases with a purity of 99.99% are used to generate a plasma atmosphere.

In the present invention, in the second step, the plasma discharge power used is 10W-150W, the treatment time is 0.1s-3600s, and the temperature is 10-400°C.

The main advantages of the present invention are:

Compared with traditional grafting methods, the present invention has the following advantages:

1. The process is simple, highly controllable and environmentally friendly;

2. The agglomeration of nanoparticles is reduced, and the functional groups coated on the surface improve their chemical resistance;

3. The pre-mixing treatment of monomers and aluminum oxide nanoparticles significantly improves the uniformity of grafting.

Example

The present invention is further described below in conjunction with specific examples. However, it should be understood that these examples are only used to illustrate the present invention and not to limit the scope of the present invention. The test methods for which specific conditions are not indicated in the following examples are generally in accordance with conventional conditions, or in accordance with the conditions suggested by the manufacturer. All percentages and parts are by weight unless otherwise indicated.

Example 1:

Process steps:

Mix methyl methacrylate and aluminum oxide with a particle size of 10 nm uniformly at a volume/weight ratio of 0.6 mL/1.0 g to obtain pretreated nano aluminum oxide particles. The above-mentioned particles were placed in a low-temperature plasma reactor (model: PDC-32G-2, manufacturer: Harrick Plasma), under the conditions of a low-temperature plasma atmosphere with a temperature of 380°C, a discharge power of 15W, and a treatment time of 30min. Surface treatment of aluminum oxide.

Experimental results:

A transmission electron micrograph of the resulting treated sample is shown in FIG. 1 . It can be seen from Figure 1 that there is an irregular covering on the surface of the treated nanoparticles, indicating that the polymer is wrapped on the surface of the nanoparticles.

Example 2:

Process steps:

Mix methyl methacrylate and aluminum oxide with a particle size of 20 nm uniformly at a volume/weight ratio of 0.1 mL/1.0 g to obtain pretreated nano aluminum oxide particles. The above-mentioned particles were placed in a low-temperature plasma reactor, and the surface treatment of nano-alumina was carried out under the conditions of a low-temperature plasma atmosphere with a temperature of 320° C., a discharge power of 50 W, and a treatment time of 10 minutes.

Experimental results:

The resulting treated sample was dispersed in the organic solvent N,N-dimethylacetamide (mass concentration: 1%), and the comparison experiment diagram after standing for 24 hours is shown in FIG. 2 . It can be seen from Figure 2 that the surface-modified nanoparticles maintain good stability in the solvent and can be stably suspended in the solvent for a long time, while the untreated nanoparticles quickly precipitate to the bottom of the container.

Example 3:

Process steps:

Mix methyl methacrylate and aluminum oxide with a particle size of 10 nm uniformly at a volume/weight ratio of 0.6 mL/1.0 g to obtain pretreated nano aluminum oxide particles. The above-mentioned particles are placed in a low-temperature plasma reactor, and the surface treatment of nano-alumina is carried out under the conditions of a low-temperature plasma atmosphere of 280°C, a discharge power of 15W and a treatment time of 30min.

Experimental results:

The resulting treated sample was used as an additive, and the prepared PVDF composite membrane was immersed in an acid solution with a pH of 1.65. The loss of aluminum oxide over time is shown in Figure 3. Aluminum oxide PVDF composite membrane. It can be seen from Figure 3 that the loss rate of surface-modified nanoparticles is significantly lower than that of unmodified particles under acid immersion, and the modification enhances the ability of nanoparticles to resist acid erosion.

Example 4:

Process steps:

Mix methyl methacrylate and aluminum oxide with a particle size of 10 nm uniformly at a volume/weight ratio of 0.6 mL/1.0 g to obtain pretreated nano aluminum oxide particles. The above-mentioned particles are placed in a low-temperature plasma reactor, and the surface treatment of nano-alumina is carried out under the conditions of a low-temperature plasma atmosphere of 240°C, a discharge power of 15W and a treatment time of 30min.

Experimental results:

The resulting treated sample was used as an additive, and the prepared PVDF composite membrane was soaked in an alkali solution with a pH of 12.23. The loss of aluminum oxide over time was shown in Figure 4. Aluminum PVDF composite membrane. It can be seen from Figure 4 that the loss rate of the surface-modified nanoparticles is significantly lower than that of the unmodified particles under the immersion of alkaline solution, and the modification enhances the ability of the nanoparticles to resist the erosion of alkaline solution.

Example 5:

Process steps:

Hydroxyethyl methacrylate and aluminum oxide with a particle size of 10 nm are uniformly mixed at a volume/weight ratio of 0.6 mL/1.0 g to obtain pretreated nano aluminum oxide particles. The above-mentioned particles are placed in a low-temperature plasma reactor, and the surface treatment of nano-alumina is carried out under the conditions of a low-temperature plasma atmosphere at 200°C, a discharge power of 15W, and a treatment time of 30min.

Experimental results:

The particle size distribution of the resulting treated samples dispersed in water is shown in Figure 5, where 0min is the untreated Al2O3 particles. It can be seen from Figure 5 that the particle size distribution curve of the modified nanoparticles shifts to the left, and the particle size decreases significantly, indicating that the agglomeration effect of the modified nanoparticles is reduced. .

The embodiments listed above are only preferred embodiments of the present invention, and are not intended to limit the implementation scope of the present invention. That is, all equivalent changes and modifications made according to the content of the patent scope of the present invention shall be within the technical scope of the present invention.

All documents mentioned in this application are incorporated by reference in this application as if each were individually incorporated by reference. In addition, it should be understood that after reading the above teaching content of the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

Claims (10)

1. the low-temperature plasma modified processing method of nano-aluminium oxide, the method comprises the following steps:

(1) according to treating the grafted monomers load factor size at nano-aluminium oxide particle surface, different monomer charge is selected Mode, it may be assumed that directly load or solvent assistant load；And

(2) area load being treated, the nano-aluminium oxide granule of grafted monomers carries out Low Temperature Plasma Treating, wherein, place Reason power is 10W～150W, and the time is 0.1s～3600s, and temperature is 10-400 DEG C, and low temperature plasma induction nanometer three aoxidizes The monomer polymerization on two alumina particles surfaces, it is achieved the surface modification of nano-aluminium oxide.

2. the method for claim 1, it is characterised in that in step (1), described direct load refers to treating that grafting is single Body load factor more than in the case of 10%, directly by nano-aluminium oxide with treat that grafted monomers mixes, thus realize monomer and exist The uniform load of nano grain surface；Described solvent assistant load refers to be less than the situation of 10% in monomer charge rate to be grafted Under, will monomer dispersion be grafted in solvent, then mix and get rid of solvent with nano-aluminium oxide, thus realize monomer and exist The uniform load of nano grain surface.

3. method as claimed in claim 1 or 2, it is characterised in that described in treat that grafted monomers is methyl methacrylate, methyl 2-(Acryloyloxy)ethanol, ethylene glycol, Polyethylene Glycol, vinylpyrrolidone, polyvinylpyrrolidone, vinyl alcohol, polyvinyl alcohol, DOPA Amine, polymerization dopamine or their mixture.

4. method as claimed in claim 1 or 2, it is characterised in that the solvent in described solvent assistant load be water, methanol, Ethanol, acetone, N-N dimethyl acetylamide, N-N dimethylformamide, N-Methyl pyrrolidone, triethyl phosphate, dimethyl are sub- Sulfone or their mixing liquid.

5. method as claimed in claim 1 or 2, it is characterised in that the particle diameter of described nano-aluminium oxide granule is 10nm ～100nm.

6. method as claimed in claim 2, it is characterised in that in the case of directly loading, described in treat grafted monomers and receive The weight ratio of rice aluminium sesquioxide granule is 5:1 to 1:100.

7. method as claimed in claim 2, it is characterised in that in the case of solvent assistant load, described in treat grafted monomers The weight ratio being distributed in solvent is 1:10000 to 1:10.

8. method as claimed in claim 1 or 2, it is characterised in that the argon that uses purity to be 99.99%, nitrogen, helium or Person's combinations thereof gas produces plasma atmosphere.

9. method as claimed in claim 2, it is characterised in that in the case of directly load, directly nanometer three is being aoxidized Two aluminum, with after grafted monomers mixes, are fully ground the uniform load realizing monomer at nano grain surface.

10. method as claimed in claim 2, it is characterised in that in the case of solvent assistant load, by centrifugation and The mode dried gets rid of solvent.