KR20090021739A - Preparation method of nanocomposites in supercritical carbon dioxide - Google Patents

Abstract

A manufacturing method of nanocomposite is provided to improve dispersibility within supercritical carbon dioxide and zygosity with the other materials by reforming surface of the magnetic property nano particle using a silane coupling agent. A manufacturing method of nanocomposite comprises a step of including uniformly magnetic property inorganic oxide in conductivity polymer at a step of polymerizing magnetic property inorganic oxide particle surface-modified with conductivity monomer using a silane coupling agent in supercritical carbon dioxide. A nanocomposite including the magnetic property inorganic oxide in the conductivity polymer includes one or more magnetic property inorganic oxide particles in a conductivity polymer particle.

Description

Manufacturing method of nanocomposite using supercritical carbon dioxide {PREPARATION METHOD OF NANOCOMPOSITES IN SUPERCRITICAL CARBON DIOXIDE}

The present invention relates to a method for producing a nanocomposite using supercritical carbon dioxide, and more particularly, to surface-modify a magnetic inorganic oxide, and then polymerize the surface-modified magnetic inorganic oxide and a conductive polymer in the supercritical carbon dioxide. The present invention relates to a method of manufacturing a nanocomposite in which an inorganic oxide is uniformly contained in a conductive polymer.

Recently, researches on making nano composite materials by inserting inorganic particles into polymers have been actively conducted. Nanocomposites manufactured through this method are new materials that have both physical advantages of inorganic materials and processability and elasticity of polymers.

In addition, due to the wide range of applications of nanocomposites, numerous researches on their preparation have been conducted. Various methods have been used to prepare nanocomposites, and one of the best known methods is emulsion polymerization with inorganic oxide particles.

However, in general, conductive polymers are not soluble in common solvents, and magnetic nanoparticles tend to aggregate easily due to high surface energy and strong attractive force between nanoparticles, so that they are mixed or dissolved in a solvent to form a composite of conductive polymer / magnetic inorganic material. It is difficult to manufacture.

In Korean Patent No. 0606324, a nanometer-sized conductive polymer nanocapsule was manufactured using ultrasonic polymerization, and according to Guihua Qiu's research published in Macromolecular, 2006, vol. Using polypyrrole polymer / triiron tetraoxide (Fe ₃ O ₄ ) magnetic nanocomposite was synthesized in an aqueous solution.

In Korean Patent 0528688, a conductive polymer nanocomposite material having evenly dispersed iron oxide nanoparticles in a soluble conductive polymer was prepared in a basic solution.

However, such a manufacturing method has problems such as low purification efficiency, high separation process operation cost, and increase of environmental pollution treatment cost due to the use of excessive solvents in the process.

The nanocomposite manufacturing method of the present invention uses supercritical carbon dioxide as a polymerization solvent to provide excellent diffusivity and easy material transfer to increase the yield, and to easily separate the product by removing the solvent by simple decompression operation after the completion of the reaction. There is an advantage. In addition, the nanocomposite in which the magnetic characteristic inorganic oxide is uniformly distributed in the conductive polymer may be prepared by surface-treating the magnetic characteristic inorganic oxide and effectively dispersing it in the supercritical carbon dioxide and the conductive monomer reaction solution.

Supercritical carbon dioxide is a low-cost, nonflammable, non-toxic solvent, and has been used as an environmentally friendly solvent in fields such as extraction. In particular, it has the same density as the liquid and the same viscosity as the gas has excellent characteristics of diffusing and easy material transfer to increase the conversion rate in the chemical reaction.

In addition, the nanocomposite having both electrical conductivity and magnetic properties of the present invention can be used as a conductive material because of its electrical conductivity, and on the other hand, it can be used as a magnetic material. Furthermore, it is expected to be useful as a material for controlling electromagnetic waves in magnetic media, device fields, and electromagnetic wave related fields that require both electrical conductivity and magnetic properties.

The present invention is to solve the above problems, an object of the present invention is to modify the surface of the magnetic nanoparticles using a silane coupling agent to improve the adhesion with other materials and at the same time dispersibility in supercritical carbon dioxide Then, it is to provide a method for producing a nanocomposite containing a residual solvent-free, environmentally friendly and magnetic properties inorganic oxide uniformly contained in the conductive polymer prepared by polymerization reaction with a conductive monomer in supercritical carbon dioxide.

In order to achieve the above object, the present invention comprises the step of polymerizing the surface-modified magnetic nanoparticles using a silane coupling agent in a supercritical carbon dioxide with a conductive monomer, homogeneous magnetic inorganic oxide to the conductive polymer It provides a method for producing a nanocomposite including.

Hereinafter, the present invention will be described in more detail.

The most important issue at present in a variety of applications of magnetic nanoparticles with magnetic properties is the ease of making more uniform nanocomposites.

In the present invention, the nanocomposite refers to a composite including nanoparticles having an average particle diameter of several hundred nanometers or less. The emergence of uniform nanocomposites has been a major influence in the technical field. Nanoparticles have a very large surface area to volume ratio and a large surface defect ratio than conventional bulk materials, so the surface properties of the material are very important.

The nanocomposite containing magnetic inorganic oxide in the conductive polymer of the present invention includes one or more magnetic inorganic oxide nanoparticles in one conductive polymer particle, and the surface-modified magnetic nanoparticle and the conductive monomer are supercritical. Obtained by reaction using a catalyst in carbon dioxide.

The magnetic material of the present invention is ferric trioxide (Fe ₂ O ₃ ), triiron tetraoxide (Fe ₃ O ₄ ), ferric cobalt tetraoxide (CoFe ₂ O ₄ ), magnesium ferric tetraoxide (MgFe ₃ O ₄ ), copper tetraoxide (CuFe ₃ O ₄ ), chromium dioxide (CrO ₂ ), manganese oxide (MnO), nickel oxide (NiO) may be one or more selected from. However, the magnetic material of the present invention is not limited only to the above examples.

The magnetic material may be used by purchasing a nano-sized one, or may be used by synthesizing an inorganic oxide of various sizes.

The conductive material of the present invention can be prepared by using a compound X and / or a compound Y represented by the following formulas (1) and (2) as monomers, either by single or co-polymerization thereof;

[Formula 1]

또는

or

[Formula 2]

또는

or

Wherein Z is an imine group or a vinyl group, Q is S, Se or NR 7, and R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are, independently from each other, hydrogen, a hydroxyl group, a halogen atom, a halide Alkyl groups, alkoxy groups, alkyl carboxyl groups, ylalkyl ester groups, alkylhydroxy groups, nitroalkyl groups, cyanoalkyl groups, haloalkyl groups, oxyhaloalkyl groups, nitroalkyl groups, cyanohaloalkyl groups, aryl groups, It is selected from the group consisting of an oxyaryl group, haloaryl group, nitroaryl group, cyanoaryl group, oxyhaloalkylaryl group, haloalkylaryl group, nitrohaloalkylaryl group, and cyanohaloalkylaryl group, Average molecular weight of the prepared polymer is 1,000 to 10,000,000.

The conductive polymer may be prepared by the following three methods:

1) a method of synthesizing a homopolymer of X by homopolymerizing the X monomer of Formula 1;

2) a method of synthesizing the homopolymer of Y by homopolymerizing the Y monomer of Formula 2; And

3) A method of synthesizing a copolymer polymer of X and Y by copolymerizing monomer X of Formula 1 and monomer Y of Formula 2 in a molar ratio of 0.01: 99.99 to 99.99: 0.01.

The copolymer of monomers X and Y prepared by the method of 3) may be represented by the following formula (3);

 [Formula 3]

In the above formula,

또는

이고,

or

ego,

또는

이며,

or

Is,

Z is an imine group or a vinyl group, Q is S, Se or NR 7, and R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are, independently from each other, hydrogen, a hydroxyl group, a halogen atom, a halide, 50 carbon atoms. Within an alkyl group, an alkoxy group, an alkyl carboxyl group, an alkyl group, an alkylhydroxy group, a nitroalkyl group, a cyanoalkyl group, a haloalkyl group, an oxyhaloalkyl group, a nitroalkyl group, a cyanohaloylalkyl group, an aryl group, an oxyaryl group , Haloaryl group, nitroaryl group, cyanoaryl group, oxyhaloalkylaryl group, haloalkylaryl group, nitrohaloalkylaryl group, and cyanohaloalkylaryl group, m is the mole fraction For example, 0 ≦ m ≦ 1.0, n is a polymer degree of polymerization, 5 ≦ n ≦ 500,000, and the weight average molecular weight of the prepared polymer is 1,000 to 10,000,000.

These polymerization reactions require a catalyst, and any oxidizing agent can be used as the polymerization reaction catalyst. At this time, the oxidizing agent is preferably selected from the group consisting of ammonium persulfate, ferric chloride, cupric chloride, copper fluoride (II), copper (II) chloride and potassium dichromate.

The surface modification is performed by reaction with a hydroxyl group (OH) group present in the magnetic material in a solvent and a silane coupling agent having a double bond at the end. The surface-modified inorganic oxide serves to make a form that can be included in the conductive polymer.

The solvent used in the surface modification may be at least one selected from supercritical carbon dioxide, toluene, water, ethanol and methanol. However, when water, ethanol and methanol are used, use of a catalyst such as acetic acid is required, and toluene is preferable.

As the silane coupling agent having a double bond at the terminal, 3- (acryloxypropyl) trimethoxysilane, 3- (trimethoxysilyl) propyl methacrylate, N- (3-acryloxy-2-hydroxypropyl) -3-amino propyltriethoxysilane, O- (methacryloxyetyl) -N- (triethoxy-silylpropyl) urethane, N- (3-methacryloxy-2-hydroxypropyl) -3-aminopropyltriethoxysilane, methacryloxypropyltriethoxysilane, methacryloxymethyltriethoxysilane, methacryloxymethltrimethoxysilane, 3- (acryloxypropyl) methyldimethoxysilane, (methacryloxymethyl) methyldiethoxysilane, (methacoxyoxyoxymethyl) Diethoxysilane, methacryloxypropylmethyl dimethoxysilane, methacryloxypropyl dimethylethoxysilane, methacryloxypropyl dimethylmethoxysilane can be used. However, the silane coupling agent having a double bond at the terminal of the present invention is not limited only to the above examples.

In the method for producing a nanocomposite in which magnetic nanoparticles are uniformly dispersed in a conductive polymer comprising the step of polymerizing the surface-modified material together with a conductive monomer in supercritical carbon dioxide, the surface-modified magnetic oxide nanoparticles And a conductive monomer are prepared by reacting with the catalyst in supercritical carbon dioxide for 1 to 2 hours.

The conductive polymer is formed by polymerization of a conductive monomer and a catalyst, wherein the weight average molecular weight of the conductive polymer is 1,000 to 10,000,000.

The supercritical carbon dioxide condition is made at a temperature of 31 to 100 ℃ and a pressure of 137.9 to 500 bar, preferably the temperature is 40 ℃, the pressure is 137.9 bar.

In the dispersed inorganic oxide and the conductive polymer, the inorganic oxide is preferably 5 to 40% by weight of the conductive monomer.

The polymerization in the supercritical carbon dioxide is preferably 1 to 2 hours, in which a yield of generally 95% by weight or more can be obtained.

Hereinafter, preferred embodiments of the present invention will be described. However, the following examples are only preferred embodiments of the present invention, and are not limited by the following embodiments of the present invention.

< Example  1>

Ferric trioxide ( Fe ₂ O ₃ ) Preparation of Particles

A magnetic bar was placed in a three-necked round bottom flask equipped with a condenser, and a dropping funnel on one side and a glass cap on the other side were replaced with nitrogen gas for 30 minutes. The reaction was replaced with nitrogen, and 6.5 g of (NH ₄ ) Fe (SO ₄ ) ₂ 12H ₂ O was dissolved in 150 ml of water, and 125 ml of concentrated hydrochloric acid was added thereto, followed by stirring for 30 minutes. After maintaining the temperature of the flask to which (NH ₄ ) Fe (SO ₄ ) ₂ 12H ₂ O was added at 0 ° C. or below, 6.3 g of Cupferron was dissolved in 150 ml of water and dropped in a dropping funnel to proceed with the reaction. When the reaction was completed to obtain a brown precipitate, it was separated using a funnel. The product was then washed with dilute hydrochloric acid, washed with 5 M ammonia water and recrystallized with heptane.

In order to remove oxygen and water, 7 g of trioctylamine was left at 20 m Torr at 100 ° C. for 1 hour under nitrogen substitution, and 0.3 M Fe (Cup) ₃ octylamine solution was 20 m Torr at 60 ° C. Prepared by standing under nitrogen substitution for hours. When 4 ml of Fe (Cup) ₃ octylamine solution is rapidly injected while stirring trioctylamine at 300 ° C. with nitrogen, the color of the solution changes from dark to dark brown. Thereafter, the reaction was further proceeded at 225 ° C. for 30 minutes and then stopped. Then, 1 ml of toluene was added, and it recrystallized in methanol, and the brown powder was obtained.

< Example  2>

Ferric trioxide  Surface treatment method of the particle

In a 250 ml three-necked flask containing purified toluene, 2.5 g of dried ferric trioxide powder having 20 nm particles was added and dispersed. Then, an excess of silane coupling agent 3- (trimethoxysilyl) propyl methacrylate (γ-MPS) was injected into the reactor by a syringe, followed by stirring at room temperature for 24 hours. All reactions were run under argon gas atmosphere. After the surface modification, the unreacted γ-MPS and γ-MPS dissolved in toluene were separated using a centrifugal separator. This process was performed several times until all of the unreacted γ-MPS were removed. Was done. The separated ferric trioxide particles were dried for 24 hours in a 50 ℃ vacuum oven.

< Example  3>

Supercritical Carbon Dioxide  Method for producing nanocomposites in the interior

In the method for preparing nanocomposites in supercritical carbon dioxide, 0.05 g of surface-modified ferric trioxide and 0.5 g of pyrrole were dispersed in a suspension state, and then charged in a stainless high pressure reactor. Ferric trichloride was dissolved in a small amount of methanol, placed in a high pressure reactor, and a Teflon-coated magnetic bar was simultaneously placed in a high pressure reactor to perform polymerization. The pressure inside the reactor was controlled using an ISCO syringe pump (Model 260D), and the reaction temperature was 40 or 65 ℃, the pressure was 137.9 or 344.8 bar. Various experiments were carried out depending on the pressure, temperature, and the amount of inorganic oxides. All polymerization proceeded for 2 hours and the reaction was terminated by cooling the reactor to room temperature. The obtained polymer particles were easily separated from the reaction mixture by reducing the carbon dioxide into a gaseous state, and the polymerization product was used to remove residual iron chloride. Finally it was dried in an oven at 50 ° C. for 24 hours. Yield measured after drying showed more than 90% by weight, it was confirmed that the pyrrole polymer is a nanocomposite containing inorganic oxide particles uniformly using TGA, XRD, TEM and IR.

<Table 1> Complexity according to Pressure, Temperature and Magnetic Property

< Comparative example  1>

Untreated Ferric trioxide  using Supercritical Carbon Dioxide  Method for producing nanocomposites in the interior

The nanocomposite manufacturing method in supercritical carbon dioxide using the surface-treated ferric trioxide was carried out in the same manner as in Example 3.

First, 0.05 g of ferric trioxide and 0.5 g of pyrrole were dispersed in a suspension state, and then charged in a stainless high pressure reactor. Ferric trichloride was dissolved in a small amount of methanol, placed in a high pressure reactor, and a Teflon-coated magnetic bar was simultaneously placed in a high pressure reactor to perform polymerization. The pressure inside the reactor was controlled using an ISCO syringe pump (Model 260D), and the reaction temperature and pressure were fixed at 40 ℃ and 137.9 bar, respectively. The experiments were carried out according to the amount of magnetic inorganic oxides for the monomers, and the degree of compounding according to each experimental value is shown in Table 2. All polymerization proceeded for 2 hours and the reaction was terminated by cooling the reactor to room temperature. The obtained polymer particles were easily separated from the reaction mixture by reducing the carbon dioxide into a gaseous state, and the polymerization product was used to remove residual iron chloride. Finally it was dried in an oven at 50 ° C. for 24 hours. The yield measured after drying showed more than 90% by weight, and the results showed that the pyrrole polymer contained inorganic oxide particles using TGA, XRD, TEM, and IR. It was.

Table 2 Experiments on the amount of magnetic inorganic oxides for monomers

In the present invention, since the nanocomposite of the conductive polymer and the magnetic material is prepared using supercritical carbon dioxide as a polymerization solvent, the synthesis method is simple, the yield is high, and there is no problem of solubilization in the process of removing the solvent, and easy separation of the product. The fabricated nanocomposites have both electrical conductivity and magnetic properties, allowing them to be used in batteries, electrochemical display devices, electromagnetic interference shielding, electromagneto-rheological fluids, and microwave absorbing materials. It is effective to make practical use in various fields such as (microwave-absorbing materials).

Claims (9)

A method for producing a nanocomposite, characterized in that the conductive polymer uniformly comprises a magnetic inorganic oxide in the step of polymerizing the surface-modified magnetic inorganic oxide particles with the conductive monomer using a silane coupling agent in supercritical carbon dioxide. The method of claim 1, wherein the nanocomposite including the magnetic inorganic oxide in the conductive polymer comprises one or two or more magnetic inorganic oxide particles in one conductive polymer particle. The method of claim 1, wherein the inorganic inorganic oxide is ferric trioxide (Fe ₂ O ₃ ), triiron tetraoxide (Fe ₃ O ₄ ), cobalt tetraoxide (CoFe ₂ O ₄ ), magnesium iron ferric oxide (MgFe ₃ O ₄ ), One or more selected from the group consisting of ferric tetraoxide (CuFe ₃ O ₄ ), chromium dioxide (CrO ₂ ), manganese oxide (MnO), nickel oxide (NiO) or two or more magnetic inorganic oxides Method for producing a nanocomposite characterized in that. The preparation of the nanocomposite according to claim 1, wherein the catalyst is selected from the group consisting of ammonium persulfate, ferric chloride, cupric chloride, cuprous fluoride (II), cuprous chloride (II) chloride and potassium dichromate. Way. The method of claim 1, wherein the supercritical carbon dioxide conditions are maintained at supercritical conditions using a temperature of 31 to 65 ° C. and a pressure of 137.9 to 500 bar. The method of claim 1, wherein the content of the surface-modified magnetic inorganic oxide and the conductive monomer is 5 to 40 weight percent of the conductive monomer. The conductive polymer of claim 1, wherein the conductive polymer has a weight average molecular weight of 1,000 to 10,000,000 obtained by homopolymerizing the monomer X represented by Formula 1 or the monomer Y represented by Formula 2 below: [Formula 1]

or

ego, [Formula 2]

or

Is, Wherein Z is an imine group or a vinyl group, Q is S, Se or NR 7, and R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are, independently from each other, hydrogen, a hydroxyl group, a halogen atom, a halide Alkyl groups, alkoxy groups, alkyl carboxyl groups, ylalkyl ester groups, alkylhydroxy groups, nitroalkyl groups, cyanoalkyl groups, haloalkyl groups, oxyhaloalkyl groups, nitroalkyl groups, cyanohaloalkyl groups, aryl groups, One selected from the group consisting of an oxyaryl group, haloaryl group, nitroaryl group, cyanoaryl group, oxyhaloalkylaryl group, haloalkylaryl group, nitrohaloalkylaryl group, and cyanohaloalkylaryl group or Method for producing a nanocomposite, characterized in that two or more conductive polymers. The conductive polymer according to claim 7, which is obtained by copolymerizing a monomer X represented by Formula 1 and a monomer Y represented by Formula 2, wherein the weight average molecular weight is 1,000 to 10,000,000. [Formula 3]

In the above formula,

or

ego,

or

Is, Z is an imine group or a vinyl group, Q is S, Se or NR 7, and R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are, independently from each other, hydrogen, a hydroxyl group, a halogen atom, a halide, 50 carbon atoms. Within alkyl group, alkoxy group, alkyl carboxyl group, alkyl group, alkylhydroxy group, nitroalkyl group, cyanoalkyl group, haloalkyl group, oxyhaloalkyl group, nitroalkyl group, cyanohaloylalkyl group, aryl group, oxyaryl group , Haloaryl group, nitroaryl group, cyanoaryl group, oxyhaloalkylaryl group, haloalkylaryl group, nitrohaloalkylaryl group, and cyanohaloalkylaryl group, m is mole As a fraction, 0 ≦ m ≦ 1.0 and n is a polymer degree of polymerization, wherein 5 ≦ n ≦ 500,000. The method of manufacturing a nanocomposite according to claim 8, wherein the monomer X and the monomer Y are copolymerized in a molar ratio of 0.01: 99.99 to 99.99: 0.01.