JP2010222228A - Surface hyperbranched or dendrimer modified inorganic nanoparticles and gas separation membranes - Google Patents

Abstract

An object of the present invention is to improve the dispersibility of inorganic nanoparticles and improve the gas permeation characteristics of a polymer membrane.
A surface hyperbranched or dendrimer-modified inorganic nanoparticle obtained by adding a hyperbranched polymer or a dendrimer polymer to the surface of an inorganic nanoparticle such as a silica nanoparticle having a nano-order particle size. A gas separation membrane is produced by dispersing in resin and forming a membrane. Surface hyperbranched modified silica nanoparticles can be obtained, for example, by treating silica nanoparticles with an amino group-containing trialkoxysilane and then reacting the particles with a compound having one carboxyl group and two or more amino groups or halogen atoms. The surface dendrimer-modified silica nanoparticles can be prepared, for example, by treating the silica nanoparticles with an amino group-containing trialkoxysilane and then treating and reacting the particles with a compound having three or more carboxyl groups. It can be prepared by treating and reacting with a compound having one amino group and repeating this.
[Selection figure] None

Description

  The present invention relates to surface hyperbranched or dendrimer modified inorganic nanoparticles and gas separation membranes containing the surface hyperbranched or dendrimer modified inorganic nanoparticles.

  In recent years, as a rebirth of nanotechnology research, research on fine particles (nanoparticles) having an average particle diameter of about 1 nm to several hundreds nm is on the order of nanometer order. Nano-sized materials are known to be capable of expressing and imparting various modes and characteristics, unlike conventional bulk materials, and are expected to be applied in a wide range of industrial fields. Nanoparticles can be produced as primary particles, but they are highly cohesive due to their fineness, and if left untreated, they form aggregates with micro-order particle sizes. For example, when inorganic nanoparticles as described above are added to an organic component, improvement in heat resistance and mechanical strength can be expected, while inorganic particles are in an organic solvent as they are due to their cohesive strength. In addition, micro-order aggregates may be formed in the polymer matrix, and as a result, the characteristics and performance of the organic-inorganic composite material as expected may not be obtained. For this reason, in order to maintain the dispersibility as primary particles, it has been proposed to perform uniform chemical modification on the particle surface (see, for example, Patent Document 1).

  In addition, organic-inorganic composite materials that are capable of synergistically enhancing the merits of both inorganic and organic components at the nano-level or molecular level are currently attracting attention. This concept is also applied to polymer gas separation membranes that are attracting attention for their usefulness in solving energy and environmental problems. Organic-inorganic composite materials with inorganic nanoparticles added to a polymer matrix Therefore, it is desired to achieve high mechanical strength, thermal stability, and gas permeation characteristics that cannot be achieved by existing methods.

  The gas separation method using the gas permeation characteristics of the polymer membrane allows gas separation and recovery without gas phase change, and is simpler to operate and smaller in size than other gas separation methods. In addition, since gas separation can be performed continuously, it has a characteristic of low environmental load. Such energy-saving polymer gas separation membrane methods have attracted attention in recent years, especially as greenhouse gas separation / recovery, production of oxygen-enriched air, and purification of natural gas. Furthermore, further improvements in gas separation performance and gas permeation amount are required.

  As described above, attempts have been made to improve the gas permeation characteristics by incorporating inorganic nanoparticles into the polymer membrane. However, the problem of aggregation of the nanoparticles is also related to the production of an organic-inorganic composite gas separation membrane. Similarly, in the existing organic-inorganic composite gas separation membranes, since inorganic nanoparticles aggregate in the polymer matrix, the strength of the membrane cannot be reduced and high particle content cannot be achieved. The problem is that the transparency can only be improved up to several times.

  For example, as a method for improving the gas separation membrane characteristics by incorporating inorganic nanoparticles into the polymer membrane, the silica nanoparticle surface is treated with an amino group-containing silane coupling agent to silylate the surface, and the silylated particles are then polymerized. The polymer grafted silica particles were prepared by treating with the above, and the polymer grafted silica particles thus obtained were dispersed in a polymer to form a resin membrane, and the performance of this membrane as a gas separation membrane was also reported ( However, a result that can be said to be sufficient in the amount of gas permeation has not been obtained.

JP 2007-99607 A

Polymer, 47 (2006), pp. 7535-7547

  The present invention has improved such conventional problems, that is, there is no aggregation in an organic solvent or a polymer matrix, the surface is chemically modified inorganic nanoparticles excellent in uniform dispersibility, and the uniform dispersion An object of the present invention is to provide a gas separation membrane having excellent gas permeability and containing inorganic nanoparticles whose surface is chemically modified and having excellent gas permeability.

  The inventors of the present invention have made extensive studies to solve such problems, and by binding a bulky hyperbranched polymer or dendrimer polymer to the surface of the inorganic nanoparticles, they have excellent uniform dispersibility, The present inventors have found that a gas separation membrane having a greatly improved gas permeation amount of gas can be formed, and the present invention has been made based on this finding.

  That is, the present invention relates to the following surface-modified inorganic nanoparticles and a gas separation membrane containing the surface-modified inorganic nanoparticles.

(1) Surface hyperbranched or dendrimer-modified inorganic nanoparticles obtained by adding a hyperbranched polymer or dendrimer polymer to the surface of inorganic nanoparticles having a nano-order particle size.

(2) Surface hyperbranched or dendrimer-modified inorganic nanoparticles according to (1), wherein the inorganic nanoparticles are silica nanoparticles.

(3) In the surface hyperbranched or dendrimer-modified inorganic nanoparticles described in (1) or (2) above, the hyperbranched polymer or dendrimer polymer is covalently bonded to the surface group of the inorganic nanoparticles. Surface hyperbranched or dendrimer modified inorganic nanoparticles characterized by.

(4) Surface hyperbranched or dendrimer modified inorganic nanoparticles according to (3) above, wherein the surface of the inorganic nanoparticles is treated with a functional group-containing compound to prepare surface functional group modified inorganic nanoparticles, and then hyperbranch A surface hyperbranched or dendrimer-modified inorganic nanoparticle, wherein a hyperbranched polymer or a dendrimer polymer is added to the functional group by treatment with a monomer or a dendrimer monomer.

(5) Surface hyperbranched or dendrimer-modified inorganic nanoparticles according to (4) above, wherein the functional group-containing compound is a functional group-containing silane coupling agent. .

(6) In the surface hyperbranched or dendrimer-modified inorganic nanoparticles described in (5) above, the functional group-containing silane coupling agent is a compound represented by the following general formula (1), and the surface is treated with this compound. A surface hyperbranched or dendrimer modified inorganic nanoparticle characterized by obtaining an amino group modified inorganic nanoparticle.

（式中、Ｒ_１はメチル基またはエチル基を表し、Ｒ_２は炭素数１〜５のアルキレン基を表す。）

(In the formula, R ₁ represents a methyl group or an ethyl group, and R ₂ represents an alkylene group having 1 to 5 carbon atoms.)

(7) In the surface hyperbranched or dendrimer-modified inorganic nanoparticle according to (6) above, the surface amino group-modified inorganic nanoparticle is further represented by the general formula (2):
_HOOC-R 3 -COOH (2)
(In the formula, represents an alkylene group having 1 to 20 carbon atoms or an aromatic group.)
A surface hyperbranched or dendrimer modified inorganic nanoparticle characterized by preparing a surface carboxyl group modified inorganic nanoparticle by treating with a compound represented by the formula:

(8) In the surface hyperbranched or dendrimer-modified inorganic nanoparticles described in (6) above, by using a compound having one carboxyl group and two or more amino groups or halogen atoms as the hyperbranched monomer, hyperbranch is used. Surface hyperbranched modified inorganic nanoparticles characterized in that a polymer is added.

(9) In the surface hyperbranched or dendrimer-modified inorganic nanoparticles described in (7) above, by using a compound having one amino group and two or more carboxyl groups or halogen atoms as the hyperbranched monomer, Surface hyperbranched modified inorganic nanoparticles characterized in that a polymer is added.

(10) In the surface hyperbranched or dendrimer-modified inorganic nanoparticles described in (6) above, by using a compound having three or more carboxyl groups and a compound having two amino groups as a dendrimer-forming monomer, A surface dendrimer-modified inorganic nanoparticle having a molecule added thereto.

(11) In the surface hyperbranched or dendrimer-modified inorganic nanoparticles described in (7) above, by using a compound having three or more amino groups and a compound having two carboxyl groups as a dendrimer-forming monomer, A surface dendrimer-modified inorganic nanoparticle having a molecule added thereto.

(12) A gas separation membrane comprising the surface hyperbranch or dendrimer-modified inorganic nanoparticles according to any one of (1) to (11) and a matrix resin.

(13) In the gas separation membrane according to (12), the matrix resin is at least one of polyimide, polysulfone, polydimethylsiloxane, polysubstituted acetylene, poly-4-methylpentene-1 and natural rubber. Gas separation membrane.

(14) The gas separation membrane according to the above (12) or (13), wherein the content of surface hyperbranched or dendrimer-modified inorganic nanoparticles is 1 to 50% by weight.

(15) The gas separation membrane according to any one of (12) to (14), wherein the gas separation membrane is formed by a casting method and has a thickness of 10 to 100 μm.

  Surface hyperbranched or dendrimer-modified inorganic nanoparticles obtained by adding a hyperbranched polymer or dendrimer polymer to the surface of inorganic nanoparticles having a nano-order particle diameter of the present invention are excellent in uniform dispersibility in a resin, and By dispersing and containing the surface-modified inorganic nanoparticles in the matrix resin, the gas separation membrane is excellent in gas separation characteristics and can form a gas separation membrane having a very large gas permeation amount.

2 is a spectrum diagram of FT-IR of surface hyperbranched modified silica nanoparticles of Example 1. FIG. It is a spectrum figure of FT-IR of a surface unmodified silica nanoparticle.

Hereinafter, the present invention will be described in more detail.
The inorganic nanoparticles used to form the surface hyperbranched or dendrimer-modified inorganic nanoparticles to which the hyperbranched polymer or dendrimer polymer of the present invention has been added are conventionally used as fillers in the formation of polymer films. Any inorganic compound may be used as long as it has a nano-order particle size (number average particle size) and the surface thereof can be chemically modified. The preparation of the surface hyperbranched or dendrimer-modified inorganic nanoparticles of the present invention involves the formation of a hyperbranched polymer or dendrimer polymer by reacting with a group present on the surface of the inorganic nanoparticle to form a covalent bond. First, inorganic nanoparticles are treated with a compound having a functional group that functions as a group to form surface functional group-modified inorganic nanoparticles, and a compound that forms a hyperbranched polymer or dendrimer polymer on this functional group (hyperbranch) A monomer or a dendrimer-forming monomer). Hereinafter, a method for producing surface hyperbranched or dendrimer-modified nanoparticles in which hyperbranched polymer or dendrimer polymer is bonded to the surface using silica nanoparticles as inorganic nanoparticles will be described in detail.

  First, the inorganic silica nanoparticles used in the present invention may have any nano-order particle diameter (in the present invention, the particle diameter is a number average particle diameter), but considering gas permeation characteristics and the like. The particle diameter is usually about 5 to 500 nm, preferably about 5 to 300 nm, more preferably about 5 to 100 nm.

  The silica nanoparticles are first treated with a silane coupling agent having a functional group that reacts with the hyperbranched monomer or dendrimer-forming monomer to add a reactive functional group to the surface of the silica nanoparticle. As a silane coupling agent, for example, the general formula (1):

(In the formula, R ₁ represents a methyl group or an ethyl group, and R ₂ represents an alkylene group having 1 to 5 carbon atoms.)
An example in which the silica nanoparticle surface is modified with an amino group using a compound having an amino group at the end, represented by The reaction in this treatment is as shown by the following formula. By this treatment, as shown in the following formula, an amino group is bonded to the surface of the silica by the reaction of the silanol groups of the silica nanoparticles and the silane coupling agent.

In the silane coupling agent represented by the general formula (1), the amino group is preferably at the terminal, but may not be at the terminal, and the group R ₂ may be a group other than the alkylene group. In addition to the amino group, the reactive functional group may be another group such as an isocyanate group, a mercapto group, a glycidyl group, a ureido group, or a halogen group.

  Examples of the compound represented by the general formula (1) include 3-aminopropyltriethoxysilane and 3-aminopropyltrimethoxysilane. Other examples of the silane coupling agent having an amino group include 3- (2-aminoethylamino) propyltriethoxysilane and 3- (2-aminoethylamino) propyltrimethoxysilane. Can be mentioned.

  Examples of the silane coupling agent having a functional group other than an amino group include 3-isocyanatopropyltriethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl). ) Ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-ureidopropyltriethoxysilane, 3-chloropropyltri And methoxysilane.

  Further, the silane coupling agent may not be a trialkoxysilane compound as in the general formula (1), for example, a dialkoxysilane compound or a monodialkoxysilane compound, or a silanol group of silica. The functional group of the reactive silane coupling agent may be a group other than an alkoxy group, such as an isocyanate group, a mercapto group, a glycidyl group, a ureido group, or a halogen atom.

  In the treatment of the silica nanoparticles using the alkoxysilane coupling agent, the silane coupling agent is dissolved in pure water, and the silica nanoparticles are put into this aqueous solution and stirred, whereby the silane coupling and the silanol groups of the silica nanoparticles are mixed. Reaction takes place. Moreover, when using compounds other than alkoxylane, you may carry out in solvents other than water.

The addition of the functional group to the surface of the silica nanoparticles may be performed by a one-step reaction as described above, or may be performed in two steps as necessary. An example of preparing surface carboxyl group-modified silica nanoparticles by a two-step reaction will be described in detail. For example, as described above, surface amino group-modified silica nanoparticles are prepared by first treating silica nanoparticles with aminoalkyltrialkoxysilane. The obtained surface amino group-modified silica nanoparticles are represented by the general formula (2):
_HOOC-R 3 -COOH (2)
(Wherein, _{R 3} represents an alkylene group or an aromatic group having 1 to 20 carbon atoms.)
Surface carboxyl group-modified silica nanoparticles can be prepared by treatment with a dicarboxylic acid compound represented by the formula (1) or an acid anhydride thereof. The reaction of this example is schematically shown by the reaction formula as follows. In the formula, R ₂ and R ₃ represent groups as described above.

  Examples of the compound represented by the general formula (2) include malonic acid, adipic acid, terephthalic acid, and the like. Of course, the dicarboxylic acid compound is not limited to those mentioned in the above formula.

  A hyperbranched polymer or dendrimer polymer having a multi-branched structure is added to the silica nanoparticles having functional groups on the surface thus prepared. There are a divergent method and a convergent method as a method for synthesizing a tendrimer. The divergent method is a method in which a building block is protected and deprotected outward from a central nuclear molecule and reacted. The convergent method is a method in which dendron, which is a subunit of dendrimer, is synthesized from the outside, and finally a coupling reaction is performed with a nuclear molecule. On the other hand, hyperbranched polymers are basically synthesized by self-condensation of AB2 type monomers, and can be synthesized much more easily than dendrimers, and the structural regulation and molecular weight distribution are not as precise as dendrimers. It is a mixture of compounds having different molecular weights and branching degrees, and can be handled as a so-called polymer. In view of ease of production, it is preferable to add a hyperbranched polymer in the present invention.

For example, a method for adding a hyperbranched polymer to the surface amino group-modified silica nanoparticles prepared above is schematically shown below. In the following reaction formula, in the hyperbranched polymer-added silica nanoparticles, the description of —R ₂ —Si (—O—) ₃ group between silica and —NH— group is included in order to avoid the description complexity. It is omitted. Moreover, although many amino groups exist on a silica nanoparticle, in the following formula, four of them are illustrated.

In the above example, as the hyperbranched monomer, the general formula (3):

(In the formula, R ₄ represents an alkylene group or an aromatic group.)
A compound having one carboxyl group and two amino groups is used, but it may be a compound having three or more amino groups, and R ₄ is a group other than an alkylene group or an aromatic group. It may be. Examples of the hyperbranched monomer represented by the general formula (3) include 3,5-diaminobenzoic acid and 3,5-diamino-4-methylbenzoic acid.

Further, as the hyperbranched monomer, the general formula (4):

(In the formula, R ₅ represents an alkylene group or an aromatic group, and X ₁ and X ₂ represent a halogen atom.)
An example using a compound having one carboxyl group and two halogen atoms is schematically shown below. In this formula as well, in the formed hyperbranched polymer-added silica nanoparticles, in order to avoid the complexity of the description, —R ₂ —Si (—O—) ₃ group between silica and —NH— group is used. Is omitted.

  Examples of the compound represented by the general formula (4) include 3,5-dibromo-4-methylbenzoic acid, 3,5-dibromosalicylic acid, 3,5-dibromo-4-hydroxy-benzoic acid, and the like. It is done.

  The hyperbranched monomer is not limited to the compound containing one carboxyl group and two or more amino groups or one carboxyl group and two or more halogen atoms. Depending on the group, an appropriate monomer that forms a hyperbranched polymer may be used.

  Furthermore, in the case of silica nanoparticles that have been surface modified with carboxyl groups in a two-step reaction, the general formula (6):

(In the formula, R ₆ represents an alkylene group or an aromatic group.)
A hyperbranched polymer can be added using a compound having one amino group and two carboxyl groups represented by the formula: This example is shown in the reaction formula below. R ₆ may be a group other than an alkylene group or an aromatic group. In the reaction formula, groups in the vicinity of silica are omitted as in the above (the same applies hereinafter).

  Examples of the compound represented by the general formula (6) include 2-aminoterephthalic acid, 4-aminoterephthalic acid, DL-2-aminosuberic acid, and the like.

（式中、Ｒ_７はアルキレン基または芳香族基を表し、Ｘハロゲン原子を表す。）
で表されるモノマーでも同様にハイパーブランチ高分子が形成可能である。 In addition, as shown in the following reaction formula, general formula (7) having one amino group and two or more halogens as other monomer species:

(Wherein R ₇ represents an alkylene group or an aromatic group, and represents an X halogen atom.)
Similarly, a hyperbranched polymer can be formed even with the monomer represented by

Examples of the compound represented by the general formula (7) include 3,5-dibromo-4-methylaniline, 2,4-dibromo-6-nitroaniline, and the like.
In the case of using silica nanoparticles that have been surface-modified with carboxyl groups in the two-step reaction, as in the case of using silica nanoparticles that have been surface-amino-modified in the first step, the above general formulas (6) and (6) Of course, two or more carboxyl groups and halogen atoms in 7) may be used, and other monomers having a functional group other than an amino group that reacts with the carboxyl group may be used.

  The weight average molecular weight of the hyperbranched polymer single chain formed by these reactions is preferably about 200 to 2,000,000, for example, and the degree of branching is preferably about 0.5 to 1.

  In the reaction, the hyperbranched monomer is acetone, chloroform, ethanol, isopropanol, methanol, toluene, tetrahydrofuran (THF), water, benzene, toluene, xylene, benzyl alcohol, 1,4-dioxane, propanol, carbon tetrachloride, cyclohexane, Cyclohexanone, methylene chloride, phenol, pyridine, 1,1,2-trichloroethane, acetic acid, N, N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N, N-dimethylacetamide (DMAc), dichloromethane (DCM), N-methylpyrrolidone (NMP), ethylene carbonate (EC), propylene carbonate (PC), dimethyl carbonate (DMC), acetonitrile (AN), N-methylmorpholine-N- Xoxide, butylene carbonate (BC), 1,4-butyrolactone (BL), diethyl carbonate (DEC), diethyl ether (DEE), 1,2-dimethoxyethane (DME), 1,3-dimethyl-2-imidazolidinone (DMI), 1,3-dioxolane (DOL), ethyl methyl carbonate (EMC), methyl formate (MF), 3-methyl oxazolidine-2-one (MO), methyl propionate (MP), tetrahydrofuran (THF ), 2-methyltetrahydrofuran (MeTHF), sulfolane (SL), methyl sulfoxide (DMSO), γ-butyrolactone, cyclopentanone and the like, dissolved in an appropriate solvent, and surface amino group-modified silica nanoparticles were put into this solution, After stirring, subsequently (2,3-dihydro-2-thio It can be performed by adding diphenyl-3-benzoxazolyl) phosphonate diphenyl (DBOP), adding triethylamine as a nucleophile immediately after the addition of DBOP, and further stirring. DBOP is added to activate the carboxylic acid, but other than the combination of DBOP and triethylamine, a combination of triphenylphosphine and pyridine may be used.

  The hyperbranched polymer-added inorganic nanoparticles have been described in detail so far, but the dendrimer polymer-added inorganic nanoparticles will be described below. In the following, first, dendrimer addition to surface amino group-modified silica nanoparticles will be described.

  In the present invention, in performing dendrimer addition to the surface amino group-modified silica nanoparticles, first, for example, the general formula (8):

(In the formula, R ₈ represents an alkylene group or an aromatic group.)
It is necessary to add a monomer having 3 carboxyl groups or a monomer having 4 or more carboxyl groups. Examples of the monomer used at this time include trimesic acid and pyromellitic acid.

Next, the general formula (9) having two amino groups at the terminal of this particle:
_{H 2 N-R 9 -NH 2} (9)
(Wherein R ₉ represents an alkylene group, or — (C ₂ H ₅ —O—) _n and / or — (C ₃ H ₇ —O—) _n, and each n is independently an integer of 1 or more. .)
A monomer represented by is added. Examples of the monomer represented by the general formula (9) used at this time include ethylenediamine, polyoxyethylenebisamine (molecular weight 2,000), o, o′-bis (2-aminopropyl) polypropylene glycol block. Examples include polyethylene glycol (molecular weight 500). The reaction at this time is performed as shown in the following reaction formula. Hereinafter, surface dendrimer-modified silica nanoparticles are prepared by repeating these additions.

  In the above example, dendrimer addition was performed by repeating the addition of a monomer having three carboxyl groups represented by general formula (8) and the addition of a monomer having two amino groups represented by general formula (9). However, when silica nanoparticles modified with a carboxyl group as a functional group by the above two-step reaction are used, the reaction is performed as shown in the following formula. First, general formula (10) having three amino groups of surface carboxyl group-modified silica nanoparticles:

(In the formula, R ₁₀ represents an alkylene group or an aromatic group.)
Or a monomer having 4 or more amino groups. Examples of the monomer represented by the general formula (10) include 1,2,5-pentanetriamine and 1,2,4,5-benzenetetraamine.

The particles are then general formula (11):
_HOOC-R 11 -COOH (11)
A monomer having two carboxyl groups at the end represented by Examples of the monomer used at this time include succinic acid, levulinic acid, o, o′-bis [2- (succinylamino) ethyl] polyethylene glycol (molecular weight 2,000), and the like. Hereinafter, surface dendrimer-modified silica nanoparticles are prepared by repeating these additions. In addition, you may use groups other than an amino group or a carboxyl group as a dendrimer formation monomer.

  The hyperbranched polymer or dendrimer polymer-added inorganic nanoparticles thus prepared are mixed with a matrix resin to form a film. As the matrix resin, for example, a suitable resin such as a known resin conventionally used for forming a gas separation membrane may be used. Specific examples include various materials such as polyimide, polysulfone, polydimethylsiloxane, poly-substituted acetylene, poly-4-methylpentene-1, and natural rubber, but are not limited thereto.

  The polyimide resin is particularly excellent in strength, durability, and heat resistance as compared with other resins, and is excellent in various gas permeation selectivity, and is therefore preferable as a matrix resin for the gas separation membrane of the present invention. . Examples of such polyimide-based resins include, for example, an aromatic polyimide obtained from a phenylenediamine component in which all positions in the ortho position with respect to an amine functional group are substituted with an alkyl group or an aromatic group, and an amine functional group. A divalent phenylenediamine residue component having substituents at all positions of ortho, pyromellitic acid and / or naphthalene and / or 4,4 ′-(hexafluoroisopropylidene) diphthalic dianhydride (hereinafter, A tetravalent acid dianhydride residue (abbreviated as 6FDA) and other specific divalent diamine residues and tetravalent acid dianhydride residues within a range not exceeding 5% each. Aromatic polyimide, polyimide containing a divalent diamine residue in which two or more aromatic units are incorporated as a divalent diamine residue constituting the polyimide A polyimide composed of a tetravalent 6FDA residue and an alkylated divalent bisaniline residue, and the divalent diamine residue is a 2,5-di-t-butyl-1,4-phenylenediamine residue Polyimide, acid component is a tetravalent 6FDA residue, amine component is a polyimide containing both an aromatic diamine and an alkenylated diamine residue having an allyl or allylaryl group, at least 3 or more substituted with groups other than hydrogen Examples include various polyimides having a divalent benzidine residue, a tetravalent 6FDA residue, a diaminonaphthidine or a polyimide of a specific brominated diamine.

The polysulfone resin is not particularly limited as long as it is a resin having at least one (—SO ₂ —) site in the molecular structure, such as a repeating unit of the following formula (12).

(Wherein R ₁₂ represents an aliphatic group, an aromatic group, etc., and m is 0 or an integer of 1 or more.)
Specific examples include resins having the following repeating units.

  The inorganic nanoparticles to which the hyperbranched polymer or dendrimer polymer of the present invention is added are usually put into a solution in which a matrix resin is dissolved, stirred and mixed to form a uniform solution, and then formed into a film by a casting method or the like. The Examples of the solvent used at this time include the same solvents as those exemplified in the reaction for adding the hyperbranched polymer.

  The content of the surface hyperbranched or dendrimer-modified inorganic nanoparticles is not particularly limited as long as it is an amount capable of forming a film, but is usually about 1 to 50% by weight of the total composition of the film. The thickness of the film may be an appropriate thickness, but is usually about 10 to 100 μm.

  The resin membrane thus produced is excellent in gas permeation performance such as gas selectivity and oxygen permeation amount. In particular, the oxygen permeation amount shows a significantly improved effect. This is thought to be due to the improved dispersibility of surface hyperbranches or dendrimer-modified inorganic nanoparticles in the polymer matrix. This is due to the excluded volume effect between the added polymer chains, It is presumed that the inorganic fine particles are uniformly dispersed without associating in the solvent and in the polymer matrix.

  Moreover, as another factor, since it contains surface hyperbranched or dendrimer-modified silica nanoparticles, a free volume is formed between the hyperbranched or dendrimer chains, which is presumed to be due to this. However, the present invention is not limited by these assumptions.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited at all by this.

Example 1 (Synthesis of surface 3-aminopropyltriethoxysilane (APTES) modified silica nanoparticles)

  Non-porous silica nanoparticles (particle size: 15 nm) were purified by vacuum drying at 120 ° C. overnight before use. In an Erlenmeyer flask, 10.12 ml of 3-aminopropyltriethoxysilane (APTES) was weighed and dissolved in 480 ml of ultrapure water, and then stirred for 30 minutes. Subsequently, 7.20000 g of non-porous silica nanoparticles were added to this solution and subjected to ultrasonic treatment for 30 minutes, and then the reaction solution was stirred for 2 days. The reaction solution was allowed to stand to precipitate the particles and discard the supernatant solution, and then washed the particles several times with ultrapure water to remove unreacted APTES to obtain surface APTES modified particles. The recovered surface APTES modified particles were vacuum dried at 150 ° C. for 24 hours.

<Thermogravimetry for surface APTES-modified silica nanoparticles>
Thermogravimetric measurement was performed on the produced surface APTES-modified silica nanoparticles, and the modification status of APTES on the silica nanoparticle surface was confirmed. As a result, when the weight breakdown of the surface APTES-modified particles was estimated, it was confirmed that 8.3% were APTES and 91.7% were silica nanoparticles.

Example 2 (Synthesis of surface hyperbranched modified silica nanoparticles)

The APTES-modified silica nanoparticles prepared in Example 1 were dried at 70 ° C. for 12 hours before use. 1.37476 g of 3,5-diaminobenzoic acid was weighed into a three-necked flask previously flowed with nitrogen, 20.0 ml of purified N-methyl-2-pyrrolidone (NMP) was added, and 3,5-diaminobenzoic acid was added. Stir until the acid is completely dissolved. To this reaction solution, 2.01336 g of APTES-modified silica nanoparticles were added and stirred for 1 hour, followed by 4.60207 g of (2,3-dihydro-2-thioxo-3-benzoxazolyl) phosphonate diphenyl ( 1.4 mol of triethylamine (same mole as 3,5-diaminobenzoic acid) and 1.2 ml of 3,5-diaminobenzoic acid were added and stirred at room temperature for 24 hours.
This reaction solution is allowed to stand overnight, the particles are precipitated and the supernatant solution is discarded. Then, to remove unreacted and polymerized 3,5-diaminobenzoic acid, the particles are washed several times with NMP, and surface hyperbranched modification is performed. Silica nanoparticles were obtained. The recovered particles were vacuum dried at 100 ° C. for 12 hours to remove the solvent.

<Thermogravimetry for surface hyperbranched modified silica nanoparticles>
The surface dendrimer-modified silica nanoparticles prepared were subjected to thermogravimetry, and the modification status of APTES and 3,5-diaminobenzoic acid on the silica nanoparticle surface was confirmed. As a result, when the weight breakdown of the surface dendrimer modified particles was estimated, it was confirmed that 63.5% were silica nanoparticles, 5.7% were APTES, and 30.8% were 3,5-diaminobenzoic acid.

<FT-IR measurement of surface hyperbranched modified silica nanoparticles by KBr tablet method>
FIG. 1 shows the FT-IR measurement results of the prepared surface hyperbranched modified silica nanoparticles, and FIG. 2 shows the FT-IR measurement results of the surface unmodified silica nanoparticles for comparison. In FIG. 1, peaks that may be attributed to trisubstituted benzene of 3,5-diaminobenzoic acid were confirmed in the vicinity of 3200, 1600, 1500, and 900 cm ⁻¹ , and the amide bond between APTES and 3,5-diaminobenzoic acid was observed. Derived peaks were confirmed around 1600 and 1500 cm ⁻¹ . From this result, the progress of the addition reaction of 3,5-diaminobenzoic acid to the surface APTES modified particles was confirmed.

Example 3 (Formation of organic-inorganic composite gas separation membrane using 6FDA-3MPA and surface hyperbranched modified silica nanoparticles)
After dissolving 1.2 g of fluorine-containing polyimide, 6FDA-3MPA (see the following formula (13)) in 25.6 ml of tetrahydrofuran (THF), the surface of the polymer solution was adjusted so that the content of the polymer was 20 wt%. Hyperbranch modified silica nanoparticles were added and sonicated for 1 hour. The polymer solution was stirred overnight at a stirring speed of 1,200 rpm. After stirring, the polymer solution was again subjected to ultrasonic treatment for 1 hour and then cast on a glass petri dish. This glass petri dish was placed in an oven set at 40 ° C. and evacuated for 11 hours to prepare a composite film. The produced composite film was heat-treated at 150 ° C. for 15 hours. The film thickness of the obtained film was 50 μm.

<Gas Permeation Characteristics of 6FDA-3MPA / Surface Hyperbranch Modified Silica Nanoparticle Composite Gas Separation Membrane>
The gas permeation measurement of the composite membrane obtained above was performed. The measurement was performed using a measurement temperature of 35 ° C., a measurement pressure of 76 cmHg, and a supply gas of oxygen and nitrogen using (Science Seiki Kogyo Co., Ltd .: K-315N-01C). The results are shown in Table 1.

Example 4 (Formation of an organic-inorganic composite gas separation membrane using 6FDA-3MPA and surface hyperbranched modified silica nanoparticles)
An organic-inorganic composite gas separation membrane was produced in the same manner as in Example 3 except that the addition amount of the surface hyperbranched modified silica nanoparticles was 40 wt%. Gas permeation measurement of the obtained composite membrane was performed in the same manner as in Example 3. The results are shown in Table 1.

Comparative Example 1 (Filming of 6FDA-3MPA gas separation membrane)
Except that the addition amount of the surface hyperbranched modified silica nanoparticles is 0 wt%, that is, without adding the surface hyperbranched modified silica nanoparticles, the others are performed in the same manner as in Example 3 to produce a 6FDA-3MPA gas separation membrane. did. Gas permeation measurement of the obtained composite membrane was performed in the same manner as in Example 3. The results are shown in Table 1.

※Ｐ：Ｂａｒｒｅｒ＝１×１０^−１０（ｃｍ^３（ＳＴＰ）ｃｍ/ｃｍ^２・ｓｅｃ・ｃｍＨｇ）

* P: Barrer = 1 × 10 ⁻¹⁰ (cm ³ (STP) cm / cm ² · sec · cmHg)

  From Table 1, it can be seen that the gas permeability coefficient of the composite membrane increased with the increase in the content of surface hyperbranched modified silica nanoparticles, and the gas permeability coefficient was increased up to about 20 times that when no particles were added.

Example 5 (Formation of organic-inorganic composite gas separation membrane using polyethersulfone (PES) and surface hyperbranched modified silica nanoparticles)
After 1.2 g of polyethersulfone (PES) represented by the following formula (14) was dissolved in 24.3 ml of N, N-dimethylacetamide (DMAc), the content of the polymer in the polymer solution was 20 wt%. The surface hyperbranched modified silica nanoparticles were added so that an ultrasonic treatment was performed for 1 hour. This polymer solution was stirred overnight at a stirring speed of 1,200 rpm. After stirring, the polymer solution was again subjected to ultrasonic treatment for 1 hour and then cast on a glass petri dish. The glass petri dish was placed in an oven set at 120 ° C. and evacuated for 11 hours to prepare a composite film. The produced composite film was heat-treated at 150 ° C. for 15 hours. The film thickness of the obtained film was 50 μm.

<Gas Permeation Properties of PES / Surface Hyperbranched Modified Silica Nanoparticle Composite Gas Separation Membrane>
The gas permeation measurement of the composite membrane obtained above was performed. The measurement was carried out using a measurement temperature of 35 ° C., a measurement pressure of 76 cmHg, and a supply gas of oxygen, nitrogen, carbon dioxide, and methane, using (Science Seiki Kogyo Co., Ltd .: K-315N-01C). The results are shown in Table 2.

Comparative Example 2 (Formation of PES gas separation membrane)
A PES gas separation membrane was prepared in the same manner as in Example 5 except that the amount of the surface hyperbranched modified silica nanoparticles was 0 wt%, that is, without adding the surface hyperbranched modified silica nanoparticles. Gas permeation measurement of the obtained composite membrane was performed in the same manner as in Example 5. The results are shown in Table 2.

※Ｐ：Ｂａｒｒｅｒ＝１×１０^−１０（ｃｍ^３（ＳＴＰ）ｃｍ/ｃｍ^２・ｓｅｃ・ｃｍＨｇ）

* P: Barrer = 1 × 10 ⁻¹⁰ (cm ³ (STP) cm / cm ² · sec · cmHg)

  From Table 2, an increase in gas permeability coefficient could be confirmed even when PES was used as a matrix resin by adding surface hyperbranched modified silica nanoparticles.

  The surface hyperbranched or dendrimer-modified inorganic nanoparticles obtained by the present invention can form a gas separation membrane as a mixture with a matrix resin, thereby forming a membrane with excellent gas permeation characteristics, and preferably used as a filter can do.

Claims (15)

  Surface hyperbranched or dendrimer-modified inorganic nanoparticles obtained by adding a hyperbranched polymer or dendrimer polymer to the surface of inorganic nanoparticles having a nano-order particle size.   The surface hyperbranch or dendrimer modified inorganic nanoparticle according to claim 1, wherein the inorganic nanoparticle is a silica nanoparticle.   The surface hyperbranched or dendrimer-modified inorganic nanoparticle according to claim 1 or 2, wherein the hyperbranched polymer or dendrimer polymer is covalently bonded to a group on the surface of the inorganic nanoparticle. Branched or dendrimer modified inorganic nanoparticles.   The surface hyperbranched or dendrimer modified inorganic nanoparticles according to claim 3, wherein the surface of the inorganic nanoparticles is treated with a functional group-containing compound to prepare surface functional group modified inorganic nanoparticles, and then the hyperbranched monomer or dendrimer monomer Surface hyperbranched or dendrimer-modified inorganic nanoparticles, wherein a hyperbranched polymer or dendrimer polymer is added to the functional group by treatment with   The surface hyperbranch or dendrimer modified inorganic nanoparticles according to claim 4, wherein the functional group-containing compound is a functional group containing silane coupling agent. The surface hyperbranched or dendrimer-modified inorganic nanoparticles according to claim 5, wherein the functional group-containing silane coupling agent is a compound represented by the following general formula (1), and surface amino group-modified inorganic nanoparticles are treated with the compound. Surface hyperbranched or dendrimer modified inorganic nanoparticles characterized by obtaining nanoparticles.

(In the formula, R ₁ represents a methyl group or an ethyl group, and R ₂ represents an alkylene group having 1 to 5 carbon atoms.) The surface hyperbranched or dendrimer-modified inorganic nanoparticles according to claim 6, wherein the surface amino group-modified inorganic nanoparticles are further represented by the general formula (2):
_HOOC-R 3 -COOH (2)
(In the formula, represents an alkylene group having 1 to 20 carbon atoms or an aromatic group.)
A surface hyperbranched or dendrimer modified inorganic nanoparticle characterized by preparing a surface carboxyl group modified inorganic nanoparticle by treating with a compound represented by the formula:   The surface hyperbranched or dendrimer-modified inorganic nanoparticles according to claim 6, wherein a hyperbranched polymer is added by using a compound having one carboxyl group and two or more amino groups or halogen atoms as a hyperbranched monomer. Surface hyperbranched modified inorganic nanoparticles characterized by being made.   The surface hyperbranched or dendrimer-modified inorganic nanoparticles according to claim 7, wherein a hyperbranched polymer is added by using a compound having one amino group and two or more carboxyl groups or halogen atoms as a hyperbranched monomer. Surface hyperbranched modified inorganic nanoparticles characterized by being made.   In the surface hyperbranched or dendrimer-modified inorganic nanoparticles according to claim 6, a dendrimer polymer is added by using a compound having three or more carboxyl groups and a compound having two amino groups as a dendrimer-forming monomer. Surface dendrimer-modified inorganic nanoparticles characterized by comprising   The surface hyperbranched or dendrimer-modified inorganic nanoparticles according to claim 7, wherein a dendrimer polymer is added by using a compound having three or more amino groups and a compound having two carboxyl groups as a dendrimer-forming monomer. Surface dendrimer-modified inorganic nanoparticles characterized by comprising   A gas separation membrane comprising the surface hyperbranch or dendrimer-modified inorganic nanoparticles according to claim 1 and a matrix resin.   The gas separation membrane according to claim 12, wherein the matrix resin is at least one of polyimide, polysulfone, polydimethylsiloxane, polysubstituted acetylene, poly-4-methylpentene-1 and natural rubber. film.   The gas separation membrane according to claim 12 or 13, wherein the content of surface hyperbranched or dendrimer-modified inorganic nanoparticles is 1 to 50% by weight.   The gas separation membrane according to any one of claims 12 to 14, wherein the gas separation membrane is formed by a casting method and has a thickness of 10 to 100 µm.

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