JP4868909B2 - Nanocomposite - Google Patents

Description

  The present invention relates to a nanocomposite in which nanoparticles are dispersed in a matrix resin.

  Among resin compositions in which particles are dispersed in a matrix resin, a resin composition in which nanoparticles having a particle size in the nano order (several nm to several hundred nm) are dispersed in a matrix resin is called a nanocomposite. . Nanocomposites are used for optical materials, light-shielding materials, high-strength materials, high heat-resistant materials, flame-retardant materials, color filters, and the like.

  Nanoparticles have a very large surface energy due to their very small particle size. For this reason, it is very difficult to uniformly disperse the nanoparticles in the matrix resin, and various studies have been made so far.

  As a technique for uniformly dispersing the nanoparticles in the matrix resin, there is a technique in which the surface of the nanoparticles is modified by chemical modification or physical modification (see Patent Documents 1 and 2). However, this technique is effective only when the particle surface of the nanoparticles is reactive and cannot be applied when the reaction is inactive. That is, there is a problem that the technique is not applicable without depending on the state of the particle surface of the nanoparticle. Furthermore, this method has a problem that it takes time for surface modification and a problem that nanoparticles tend to aggregate during the surface modification.

  As another method for uniformly dispersing the nanoparticles in the matrix resin, there is a method using a dispersant (see Patent Documents 3 and 4). However, this method has a problem that it takes time since a dispersant compatible with the matrix resin has to be prepared.

JP 2002-338775 A JP 2003-73558 A JP 2002-177757 A JP-A-2005-8651

  The present invention has been made to solve the above-described problems, and the object of the present invention is to make the nanoparticles uniformly into the matrix resin without depending on the state of the surface of the nanoparticles and with good productivity. It is to provide dispersed nanocomposites. Another object of the present invention is to provide a novel graft polymer that can be preferably applied to such a matrix resin.

  The nanocomposite of the present invention is a nanocomposite in which nanoparticles are dispersed in a graft polymer as a matrix resin.

  In a preferred embodiment, the graft polymer comprises a mother polymer portion and a graft chain portion, and the graft chain portion is composed of an acidic functional group, a basic functional group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group. It has at least one functional group selected. In a more preferred embodiment, the base polymer portion has a structure belonging to any of polyolefin, polyvinyl acetal, cellulose derivative, polyester, poly (meth) acrylate, polycarbonate, polyarylate, and polystyrene.

  In a preferred embodiment, the graft polymer is obtained by graft polymerization of a vinyl monomer to a base polymer. In a more preferred embodiment, the vinyl monomer has at least one functional group selected from an acidic functional group, a basic functional group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group. In a more preferred embodiment, the mother polymer is any one of a homopolymer or copolymer of polyolefin, polyvinyl acetal, cellulose derivative, polyester, poly (meth) acrylate, polycarbonate, polyarylate, and polystyrene.

  The graft polymer of the present invention comprises a base polymer portion having a structure belonging to any of polyolefin, polyvinyl acetal, cellulose derivative, polyester, poly (meth) acrylate, polycarbonate, polyarylate, and polystyrene, an acidic functional group, and a basic functional group. A graft chain portion having at least one functional group selected from a group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group.

  Another graft polymer of the present invention includes a vinyl monomer having at least one functional group selected from an acidic functional group, a basic functional group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group. Acetal, cellulose derivative, polyester, poly (meth) acrylate, polycarbonate, polyarylate, and graft polymerized to a base polymer that is either a homopolymer or a copolymer of polystyrene.

  According to the present invention, without depending on the state of the nanoparticle surface, for example, the nanoparticle surface is reactive and inactive. A nanocomposite in which particles are uniformly dispersed in a matrix resin can be provided. According to the present invention, in order to uniformly disperse the nanoparticles in the matrix resin, there is no need to prepare a dispersant compatible with the matrix resin. According to the present invention, a wide variety of resins can be used as the matrix resin. According to the present invention, the matrix resin can be selected so that the maximum uniform dispersion effect can be exhibited according to the type of nanoparticles used. According to the present invention, since nanoparticles can be sufficiently uniformly dispersed in a matrix resin, a nanocomposite with very high transparency can be provided. Moreover, according to this invention, the novel graft polymer which can be applied preferably to such a matrix resin can be provided.

  Hereinafter, although preferable embodiment of this invention is described, this invention is not limited to these embodiment.

[Nanoparticles]
Any appropriate nanoparticle can be adopted as the nanoparticle in the present invention. Only 1 type may be used for the nanoparticle in this invention, and 2 or more types may be used together.

  The upper limit of the particle diameter of the nanoparticles in the present invention depends on the shape of the nanoparticles, but the maximum diameter is preferably 500 nm or less, more preferably 250 nm or less, and even more preferably 150 nm or less. The lower limit of the particle diameter of the nanoparticles in the present invention is preferably 1 nm or more, more preferably 3 nm or more, and further preferably 5 nm or more.

  The material of the nanoparticles in the present invention is not particularly limited, but for example, metal hydroxides such as magnesium hydroxide and aluminum hydroxide; metals such as silicon oxide, aluminum oxide, iron oxide, yttrium oxide, zinc oxide and silver oxide Examples thereof include oxides; metals such as gold, silver and copper; carbon materials such as graphite and carbon nanotubes; polymers such as polystyrene, polyacrylate and polyamide; organic compounds such as dyes and pharmacologically active substances.

  The nanoparticles in the present invention may have their surfaces modified by chemical modification or physical modification. Any appropriate method can be adopted as the chemical modification or physical modification. Although the shape of the nanoparticle in this invention is not specifically limited, For example, any of needle shape, spherical shape, rod shape, plate shape, indeterminate shape, and polyhedron shape may be sufficient.

  The nanoparticles in the present invention may contain at least one surface group selected from the group consisting of a hydrophobic group, a hydrophilic group, and a combination thereof.

[Matrix resin]
In the present invention, it is important to use a graft polymer as a matrix resin. The effect of the present invention is exhibited by using the graft polymer. For example, without depending on the state of the particle surface of the nanoparticle, specifically, for example, whether the particle surface of the nanoparticle is reactive or inactive, the productivity is high. A nanocomposite in which particles are uniformly dispersed in a matrix resin can be provided.

  Japanese Patent Application Laid-Open No. 2002-177757 (Patent Document 4) reports a technique of using a graft polymer as a “dispersant” in a nanocomposite in which nanoparticles are uniformly dispersed in a matrix resin. The present invention is completely different. An important aspect of the present invention is that the graft polymer is not used as a “dispersant” but as a “matrix resin” itself. Thereby, for example, in order to uniformly disperse the nanoparticles in the matrix resin, it is not necessary to prepare a dispersant compatible with the matrix resin.

  The graft polymer is preferably obtained by graft polymerization of a vinyl monomer to a base polymer.

  The mother polymer becomes a mother polymer portion in the graft polymer by graft polymerization of the vinyl monomer. The vinyl monomer becomes a graft chain portion in the graft polymer by being graft-polymerized to the mother polymer. That is, the graft polymer preferably comprises a base polymer portion and a graft chain portion.

  The graft chain portion preferably has at least one functional group selected from an acidic functional group, a basic functional group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group. By having these functional groups, an interaction (preferably at least one selected from an electrical interaction and a hydrogen bonding interaction) with a nanoparticle (preferably, the particle surface of the nanoparticle) occurs, for example, Even without the use of a dispersant, sufficiently uniform dispersibility of the nanoparticles in the matrix resin can be expressed.

Examples of the acidic functional group include a carboxyl group (—COOH), a sulfonic acid group (—SO ₃ H), a phenolic hydroxyl group (—Ph—OH), an enol group (—CH═CR (OH)), and a mercapto group. (—SH), acid imide group (—CONHCOR), oxime group (—CH═NOH), sulfonamide group (—SO ₂ NH ₂ ), phosphate group (—PO (OH) ₂ ), phosphate ester group ( -OPO (OR) (OH)) and the like. Examples of the basic functional group include a tertiary amino group and a nitrogen-containing heterocyclic group. As the amide group, in addition to a normal amide group (—CONH ₂ ), an N-substituted amide group (—CONRR ′, —CONHR), a urea group (—NHCONH ₂ ), an acetamide group (—NHCOCH ₃ ), a cyclic N Examples thereof include a substituted amide group.

  Any appropriate vinyl monomer can be adopted as the vinyl monomer. A vinyl monomer having at least one functional group selected from an acidic functional group, a basic functional group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group is preferable. Examples of vinyl monomers having at least one functional group selected from acidic functional groups, basic functional groups, quaternary ammonium groups, alkyl ether groups, amide groups, and hydroxyl groups include acrylic acid, methacrylic acid, itaconic acid, Vinyl monomers containing acidic functional groups such as maleic acid, fumaric acid and styrene sulfonic acid; vinyl monomers containing basic functional groups such as vinyl pyridine, vinyl triazine, vinyl imidazole and dimethylaminoethyl methacrylate; trimethylaminoethyl methacrylate chloride, N-chloride Quaternary ammonium group-containing vinyl monomers such as methyl vinyl pyridine; di, tri, or hexaethylene glycol monoacrylate, di, tri, or hexaethylene glycol monomethacrylate, di, tri, or hexaethylene glycol Alkyl ether group-containing vinyl monomers such as methyl ether acrylate, di, tri, or hexaethylene glycol methyl ether methacrylate; amide group-containing vinyl monomers such as vinyl acetamide, vinyl pyrrolidone, acrylamide, methacrylamide, vinyl urea, N-isopropylacrylamide; Hydroxyl group-containing vinyl monomers such as hydroxymethyl acrylate, hydroxyethyl acrylate, hydroxypropyl acrylate, hydroxymethyl methacrylate, hydroxyethyl methacrylate, hydroxypropyl methacrylate; and the like.

  The base polymer is not particularly limited as long as it is a polymer capable of graft polymerization of a vinyl monomer, but preferably has a structure (for example, a tertiary carbon, a double bond, a cyclic structure, etc.) that is likely to cause a hydrogen abstraction reaction by a radical. It is a polymer having. Specifically, linear or cyclic polyolefin such as polyethylene, polypropylene, polyisoprene, polycyclopentene, polynorbornene, polycyclohexene; polyvinyl acetal such as polyvinyl butyral; polyvinyl alcohol; polyvinyl ether; polyvinyl acetate such as ethylene vinyl acetate; Polysaccharides such as dextrin, starch and chitin; Cellulose derivatives such as ethyl cellulose and hydroxypropyl cellulose; Aliphatic polyesters such as polylactic acid; Aromatic polyesters such as polybutylene terephthalate; Polystyrene or copolymers thereof; Polys such as polymethyl methacrylate (Meth) acrylate or a copolymer thereof; polycarbonate; polyarylate;

一般式（１）中、Ｘは、脂肪族の２価基、環状脂肪族の２価基、一般式（２）で表される２価基から選ばれる少なくとも１種を示す。

一般式（２）中、Ｒ１、Ｒ２は、それぞれ独立して置換もしくは無置換のアルキル基、アリール基、またはハロゲン原子を示す。Ａは、単結合、炭素原子数１〜１２の直鎖状、分岐状、または環状のアルキレン基を示す。 The polycarbonate is preferably a polymer having a repeating unit represented by the general formula (1).

In general formula (1), X represents at least one selected from an aliphatic divalent group, a cycloaliphatic divalent group, and a divalent group represented by general formula (2).

In general formula (2), R 1 and R 2 each independently represent a substituted or unsubstituted alkyl group, aryl group, or halogen atom. A represents a single bond, a linear, branched or cyclic alkylene group having 1 to 12 carbon atoms.

一般式（３）または（４）中、Ｘは、脂肪族の２価基、環状脂肪族の２価基、上記一般式（２）で表される２価基から選ばれる少なくとも１種を示す。Ｙは、置換もしくは無置換のアリレン基を示す。 The polyarylate is preferably a polymer having a repeating unit represented by the general formula (3) or (4).

In general formula (3) or (4), X represents at least one selected from an aliphatic divalent group, a cycloaliphatic divalent group, and a divalent group represented by general formula (2). . Y represents a substituted or unsubstituted arylene group.

Specific examples of X in the general formulas (1), (3), and (4) are preferably divalent groups represented by the general formulas (2a) to (2n).

  Any appropriate method can be adopted as a method for producing the graft polymer. Examples thereof include methods described in JP-A Nos. 2002-143668, 2002-177757 (Patent Document 3), JP-A 2005-36220, JP-A 2005-42116, and the like.

  The method for producing the graft polymer is preferably a method in which the base polymer is dissolved in an organic solvent, and the vinyl monomer is contacted in the presence of a peroxide to cause a modification reaction.

  Any appropriate organic solvent can be adopted as the organic solvent used for the modification reaction, but a solvent capable of dissolving the mother polymer is preferable. For example, aromatic hydrocarbons such as toluene, xylene, ethylbenzene and t-butylbenzene; aliphatic hydrocarbons such as n-pentane, hexane and heptane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; chlorobenzene, Halogenated hydrocarbons such as dichlorobenzene and trichlorobenzene; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and benzophenone; ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, and anisole; N-methyl Pyrrolidone, N-ethylpyrrolidone, N-phenylpyrrolidone, N-benzylpyrrolidone, N, N-dimethylformamide, N, N-diethylformamide, N, N-dimethylacetamide, etc. Mido compounds; methyl formate, ethyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, amyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, butyl butyrate, amyl butyrate, ethyl lactate And esters such as dimethyl carbonate, dimethyl phthalate, diethyl phthalate, and γ-butyllactone; nitrile compounds such as acetonitrile, propionitrile, butyronitrile, benzonitrile, and capronitrile; sulfoxide compounds such as dimethyl sulfoxide; and the like. The said organic solvent may be used individually by 1 type, and may be used as a mixed solvent which used 2 or more types together. The organic solvent may be a nonpolar solvent alone from the start of the reaction to the beginning of the reaction, but in order to react stably at a high denaturation rate, it is preferable to add a polar solvent to the nonpolar solvent to make a mixed solvent. . Preferred nonpolar solvents are aromatic hydrocarbons, aliphatic hydrocarbons, and alicyclic hydrocarbons, and preferred polar solvents are ketones, ethers, and esters.

  Any appropriate peroxide can be adopted as the peroxide used in the modification reaction. For example, benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di (peroxide benzoate) hexyne-3,1,4-bis (tert-butylperoxy) Isopropyl) benzene, lauroyl peroxide, tert-butyl peracetate, 2,5-dimethyl-2,5-di (tert-butylperoxy) hexyne-3,2,5-dimethyl-2,5-di (tert-butylperoxy) ) Hexane, tert-butyl perbenzoate, tert-butyl perphenyl acetate, tert-butyl perisobutylate, tert-butyl per-sec-octoate, tert-butyl perpiparate, cumyl perpiparate, tert Butyl perdiethyl acetate, methyl ethyl ketone peroxide, cyclohexanone peroxide, 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane, 2,2-bis (t-butylperoxy) butane, t-butyl hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3, α, α'-bis (t-butyl Peroxy-m-isopropyl) benzene, octanoyl peroxide, isobutyryl peroxide, peroxydicarbonate and the like. The peroxide may be used alone or in combination of two or more.

  The amount of the peroxide used can be appropriately selected depending on the modification rate, reaction conditions, and the like, but is usually 1.0 to 50 parts by weight, preferably 1.5 to 40 parts by weight, based on 100 parts by weight of the vinyl monomer. More preferably, it is the range of 2.0-30 weight part. If the amount of peroxide used is excessively small, the modification rate does not increase. Conversely, if the amount of peroxide is excessively large, gelation proceeds, which is not preferable. Any appropriate addition method can be adopted as the method for adding the peroxide to the reaction system, but it is more likely to be added in a divided or sequential manner during the reaction, rather than all at the beginning of the modification reaction. It is preferable because a graft polymer without gel can be obtained at a modification rate. The temperature of the modification reaction is preferably 0 to 400 ° C, more preferably 30 to 350 ° C, and still more preferably 60 to 200 ° C. After completion of the modification reaction, the graft polymer is isolated according to a conventional method. For example, the reaction solution is dropped into a poor solvent to precipitate the modified product and is isolated.

  The total amount (grafting amount) of the vinyl monomer bonded to the base polymer is, for example, the number of radicals generated on the base polymer by the decomposition radical of the peroxide and the graft chain composed of the vinyl monomer polymerized by the radical. Determined by length. The number of radicals generated on the base polymer depends on the amount of peroxide used for the base polymer, the decomposition temperature, the decomposition time, and the type of solvent.

  The amount of peroxide with respect to the base polymer is preferably 0.001% to 30% by weight, more preferably 0.005% to 20% by weight, and still more preferably 0.01% by weight to the base polymer. 10% by weight. When the amount of the peroxide with respect to the base polymer is less than 0.001% by weight with respect to the base polymer, the effect of grafting hardly appears. If the amount of peroxide based on the base polymer is more than 30% by weight based on the base polymer, the properties of the base polymer may be lost.

  The decomposition temperature and the decomposition time are the combination of the temperature and the time as long as the conditions are such that 50% by weight or more, more preferably 60% by weight or more, and even more preferably 70% by weight or more of the introduced peroxide is decomposed. Can be set arbitrarily. If the peroxide to be decomposed is less than 50% by weight, a large amount of homopolymer consisting only of the introduced monomer is produced, and the graft efficiency may be lowered.

  The length of the graft chain is preferably 1 ≦ n ≦ 100, more preferably 1 ≦ n ≦ 50, and still more preferably 1 ≦ n ≦ 25, when expressed by the degree of polymerization n. When n is larger than 100, the graft chain portion tends to cause phase separation, and in this case, the dispersibility of the nanoparticles is lowered.

The amount of grafting can be quantified by detecting the grafted monomer unit using ¹ H-NMR, ¹³ C-NMR, IR or the like. For example, when acrylate is grafted, the carbonyl carbon of the acrylate unit can be quantified by ¹³ C-NMR or carbonyl C═O stretching vibration by IR.

  The number of radicals generated on the base polymer can be labeled chains such as fluorinated alkyl mercaptans, fluorinated alkyl disulfides, fluorinated aryl disulfides, tetraalkylthiilam disulfides, aryl disulfides with chromophores such as nitro groups. By labeling a graft chain terminal composed of a monomer polymerized by this radical using a transfer agent, it can be quantified indirectly by means such as NMR or visible ultraviolet absorption spectrum.

  The length of the graft chain can be calculated from the amount of grafts and the number of radicals obtained experimentally.

  Among the graft polymers described above, ie, graft polymers that can be used as the matrix resin of the nanocomposite of the present invention, in particular, polyolefin, polyvinyl acetal, cellulose derivative, polyester, poly (meth) acrylate, polycarbonate, polyarylate, and A graft polymer chain having a base polymer portion having a structure belonging to any of polystyrene and at least one functional group selected from an acidic functional group, a basic functional group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group A vinyl polymer having at least one functional group selected from an acidic functional group, a basic functional group, a quaternary ammonium group, an alkyl ether group, an amide group, and a hydroxyl group. Graft polymer, which is graft polymerized to a base polymer that is either homopolymer or copolymer of olefin, polyvinyl acetal, cellulose derivative, polyester, poly (meth) acrylate, polycarbonate, polyarylate, and polystyrene, There is no novel graft polymer, and the graft polymer of the present invention.

[Nanocomposite]
The nanocomposite of the present invention is obtained by uniformly dispersing nanoparticles at a primary particle level in a graft polymer as a matrix resin. Furthermore, preferably, since the additive such as a dispersant is not included, the nanocomposite is expected to improve various physical properties while maintaining translucency. For example, conventionally, when an inorganic filler is blended, it is known that the heat resistance and mechanical properties of the polymer are improved, but it becomes an opaque body. The nanocomposite of the present invention can improve heat resistance and mechanical properties while maintaining transparency.

  Any appropriate method can be adopted as the dispersion method. As a preferable method, for example, a dispersion of or dispersion of nanoparticles in any appropriate solvent and a dispersion of the graft polymer in any appropriate solvent are mixed and stirred, and heated as necessary. And then removing the solvent.

  The solvent for dispersing or dissolving the nanoparticles is selected from low molecular weight organic compounds that have an affinity for the surface and are liquid at room temperature, depending on the nanoparticles. Specifically, for example, alcohols such as ethanol; polyhydric alcohols such as ethylene glycol and glycerol; acetates, ethers and ether acetates of polyhydric alcohols; oxygen-containing heterocyclic compounds such as tetrahydrofuran and dioxane; and pyridine and piperazine Nitrogen heterocyclic compounds; oxygen-containing nitrogen heterocyclic compounds such as morpholine; carboxylic acids such as acetic acid; tertiary amines such as triethylamine; quaternary ammonium compounds such as trioctylethylamine chloride; nitrile compounds such as acetonitrile; N, N-dimethyl Amide compounds such as formamide; and the like.

  The solvent for dissolving the graft polymer is selected from organic solvents having no affinity for nanoparticles and having no polarity. If the solvent is compatible with the nanoparticles or is a polar solvent, the interaction between the graft polymer and the nanoparticles becomes weak, and the uniform dispersion of the nanoparticles decreases. Specific examples include aromatic hydrocarbons such as toluene; aliphatic hydrocarbons such as hexane and cyclohexane; chlorine-based compounds such as methylene chloride; fluorine-based compounds such as fluorinated benzene;

  The content ratio of the nanoparticles in the nanocomposite of the present invention is preferably 0.01 to 65% by volume, more preferably 0.1 to 60% by volume, and still more preferably 0.5 to 50% by volume. When the content ratio of the nanoparticles in the nanocomposite of the present invention is less than 0.01% by volume, the effects due to the incorporation of the nanoparticles may not be sufficiently exhibited. If the content ratio of the nanoparticles in the nanocomposite of the present invention is more than 65% by volume, it may be difficult to form the nanocomposite.

  The driving force of uniform dispersion of the nanoparticles is the interaction (electrical interaction or hydrogen bonding interaction) between the graft chain portion bonded to the mother polymer and the surface of the nanoparticle. Therefore, the maximum dispersion effect can be obtained by selecting a vinyl monomer for grafting in accordance with the properties of the nanoparticle surface.

  When the nanoparticle surface has a charge in an organic solvent (basically, it can be determined by the zeta potential of the particle in the organic solvent), it is preferable to use a vinyl monomer having an opposite charge. In many cases, vinyl monomers having a hydroxyl group (such as hydroxyethyl methacrylate (HEMA)) can be used for general purposes.

  The nanocomposite of the present invention contains a graft polymer as a matrix resin and nanoparticles, but may contain any other appropriate additive as long as the effects of the present invention are not impaired. Examples of the additive include a dispersant, a colorant, a preservative, a moisturizer, an ultraviolet absorber, an ultraviolet stabilizer, a fragrance, and a polymer other than a graft polymer.

  EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to these Examples. Unless otherwise indicated, parts and percentages in the examples are based on weight. Evaluation was performed as follows.

(Synthesis of grafted polylactic acid (PLA-HEMA))
A mixture of 3 g of polylactic acid (PLA) and 27 g of dioxane was placed in a vial and sealed, and the interior was purged with nitrogen, and heated to 100 ° C. to dissolve. Nitrogen-substituted benzoyl peroxide 0.1 g / dioxane 1 ml solution was added thereto and stirred at 100 ° C. for 1 hour. Next, a nitrogen-substituted hydroxyethyl methacrylate (HEMA) 0.3 g / dioxane 1 ml solution was added, and the mixture was further stirred for 17 hours.
The reaction solution was poured into 100 ml of methanol to precipitate the produced polymer. The precipitated polymer was recovered and dissolved in 30 ml of tetrahydrofuran, and 100 ml of methanol was added thereto to precipitate the polymer. The precipitated polymer was collected and dried at 60 ° C. for 10 hours. This is PLA-HEMA.
In the IR spectrum, a new peak attributed to C = O stretching vibration different from the peak attributed to PLA C = O stretching vibration was observed, confirming that hydroxyethyl methacrylate was grafted to polylactic acid. It was.

(Synthesis of grafted polylactic acid (PLA-DMAEMA))
A reaction was carried out in the same manner as in Example 1 except that hydroxyethyl methacrylate (HEMA) was replaced with dimethylaminoethyl methacrylate (DMAEMA) in Example 1, and the produced polymer was recovered and dried. This is called PLA-DMAEMA.
In the IR spectrum, a new peak attributed to C = O stretching vibration different from the peak attributed to PLA C = O stretching vibration was observed, confirming that dimethylaminoethyl methacrylate was grafted to polylactic acid. It was done.

(Synthesis of grafted polyolefin (PO-HEMA))
A 40 ml toluene solution of 3 g of polyolefin (PO) (Zeonex 330R, manufactured by Nippon Zeon Co., Ltd.) and 0.1 g of benzoyl peroxide was placed in a vial and sealed, and the inside was purged with nitrogen, followed by stirring at 100 ° C. for 1 hour. Next, a nitrogen-substituted hydroxyethyl methacrylate (HEMA) 0.3 g / toluene 1 ml solution was added, and the mixture was further stirred for 17 hours.
The reaction solution was poured into 100 ml of methanol to precipitate the produced polymer. The precipitated polymer was recovered and dissolved in 30 ml of toluene, and 100 ml of methanol was added thereto to precipitate the polymer. The precipitated polymer was collected and dried at 60 ° C. for 10 hours. This is referred to as PO-HEMA.
In the IR spectrum, a peak attributed to a new C═O stretching vibration that was not found in the raw material polyolefin was observed, and it was confirmed that hydroxyethyl methacrylate was grafted onto the polyolefin.

(Synthesis of grafted polyolefin (PO-DMAEMA))
The reaction was performed in the same manner as in Example 3 except that hydroxyethyl methacrylate was replaced with dimethylaminoethyl methacrylate (DMAEMA) in Example 3, and the produced polymer was recovered and dried. This is referred to as PO-DMAEMA.
In the IR spectrum, a new peak attributed to C = O stretching vibration that was not found in the raw polyolefin was observed, confirming that dimethylaminoethyl methacrylate was grafted onto the polyolefin.

(Synthesis of grafted polyolefin (PO-AA))
The reaction was conducted in the same manner as in Example 3 except that hydroxyethyl methacrylate was replaced with acrylic acid (AA) in Example 3, and the produced polymer was recovered and dried. This is referred to as PO-AA.
In the IR spectrum, a peak attributed to a new C═O stretching vibration that was not found in the raw material polyolefin was observed, and it was confirmed that acrylic acid was grafted onto the polyolefin.

(Synthesis of grafted polyolefin (PO-HEA))
1 g of benzoyl peroxide (manufactured by Nacalai Tesque, containing 25% water) was dissolved in 14 g of toluene and dried over anhydrous magnesium sulfate. 12 g of a 5% toluene solution of benzoyl peroxide and 48 g of toluene were placed in a 100 ml vial, and 6 g of a cycloolefin polymer (Zeonex 330R manufactured by Nippon Zeon Co., Ltd.) was dissolved therein. Further, 0.2 g of 2-hydroxyethyl acrylate (HEA) was added and sealed, and nitrogen was bubbled for 20 minutes to replace the nitrogen.
The mixture was stirred for 4 hours in an oil bath at 100 ° C.
The reaction solution was cooled to room temperature and then poured into 500 ml of methanol to precipitate and collect the reaction polymer. The recovered polymer was dried, dissolved in 100 ml of tetrahydrofuran, and poured into 500 ml of acetone for reprecipitation. The precipitate was dissolved again in 100 ml of THF, poured into acetone for precipitation, further washed with acetone, and dried with a hot air dryer at 60 ° C.
The obtained graft polymer was dissolved in deuterated chloroform, and the graft amount was measured by ¹ H-NMR. From the ratio of 4.2 ppm peak area of 2-hydroxyethyl acrylate to 0.5-2.0 ppm peak area of cycloolefin polymer, the amount of 2-hydroxyethyl acrylate monomer units in 1 g of polymer is: It calculated with 6 * 10 <^-5> mol.

(Synthesis of grafted polyolefin (PO-VP))
The reaction polymer was recovered and dried in the same manner as in Example 6 except that 2-hydroxyethyl acrylate (HEA) was replaced with vinylpyridine (VP) in Example 6.
^From the ratio of the peak area of the pyridine ring (8.3 ppm) and the peak area of 0.5 to 2.0 ppm of the cycloolefin polymer in ¹ H-NMR, the amount of vinylpyridine monomer units in 1 g of the polymer was 9 × 10 ⁻ Calculated as ⁵ mol.

(Synthesis of grafted polyolefin (PO-MPS))
The reaction was conducted in the same manner as in Example 6 except that, in Example 6, 2-hydroxyethyl acrylate (HEA) was replaced with 1.2 g of acrylic acid-3- (trimethoxysilyl) propyl (MPS) (manufactured by Tokyo Chemical Industry). The reaction polymer was recovered and dried.
^From the ratio of the peak area of 4.02-ppm of acrylic acid-3- (trimethoxysilyl) propyl and the peak area of 0.5-2.5 ppm of cycloolefin polymer by ¹ H-NMR, acrylic acid-3 in 1 g of polymer The amount of-(trimethoxysilyl) propyl was calculated as 13 × 10 ⁻⁵ mol.

(Synthesis of grafted polycarbonate (PC-VP))
In a 50 ml vial, 3 g of polycarbonate (PC) (manufactured by Teijin Chemicals, Panlite TS2050), 0.1 g of dried benzoyl peroxide, and 0.3 g of vinylpyridine (VP) are dissolved in 30 ml of toluene, and then the vial is sealed. The tube was purged with nitrogen (20 minutes bubbling).
The mixture was reacted for 5 hours while stirring at 100 ° C. in an oil bath.
The reaction solution was poured into 150 ml of methanol to precipitate the polymer. Next, the precipitated polymer was dissolved in 40 ml of THF and then poured again into 150 ml of methanol for precipitation. After this operation was repeated twice, the precipitated polymer was washed with diethyl ether and dried for 6 hours in a draft dryer at 60 ° C.
^From the ratio of the peak area of the pyridine ring (8.3 ppm) and the peak area of the 7.0 to 7.5 ppm benzene ring of the polycarbonate by ¹ H-NMR, the amount of vinylpyridine monomer unit in 1 g of the polymer was 1.4. It calculated with x10 <^-5> mol.

(Synthesis of grafted polycarbonate (PC-HEA))
The reaction was conducted in the same manner as in Example 9 except that vinylpyridine (VP) was replaced with 2-hydroxyethyl acrylate (HEA) in Example 9, and the reaction polymer was recovered and dried.
^From the ratio of the peak area of 4.2 ppm of 2-hydroxyethyl acrylate to the peak area of 7.0 to 7.5 ppm of benzene ring in polycarbonate by ¹ H-NMR, 2-hydroxyethyl acrylate in 1 g of polymer The amount of monomer units was calculated to be 1.1 × 10 ⁻⁵ mol.

(Synthesis of grafted polycarbonate (PC2-VP))
In a 50 ml vial, 3 g of polycarbonate (PC2) (manufactured by Teijin Chemicals, Panlite L1225L), 0.1 g of dried benzoyl peroxide, and 0.3 g of vinylpyridine (VP) are dissolved in 30 ml of toluene, and then the vial is sealed. The tube was purged with nitrogen (20 minutes bubbling).
The mixture was reacted for 5 hours while stirring at 100 ° C. in an oil bath.
The reaction solution was poured into 150 ml of methanol to precipitate the polymer. Next, the precipitated polymer was dissolved in 40 ml of THF and then poured again into 150 ml of methanol for precipitation. After this operation was repeated twice, the precipitated polymer was washed with diethyl ether and dried for 6 hours in a draft dryer at 60 ° C.
^From the ratio of the 8.3 ppm peak area of the pyridine ring to the 7.0 to 7.5 ppm benzene ring peak area of the polycarbonate by ¹ H-NMR, the amount of vinylpyridine monomer units in 1 g of the polymer was 1.7 ×. It calculated with 10 ^<-5> mol.

(Synthesis of grafted polycarbonate (PC2-HEA))
The reaction was conducted in the same manner as in Example 11 except that vinylpyridine (VP) was replaced with 2-hydroxyethyl acrylate (HEA) in Example 11, and the reaction polymer was recovered and dried.
^From the ratio of the peak area of 4.2 ppm of 2-hydroxyethyl acrylate to the peak area of 7.0 to 7.5 ppm of benzene ring in polycarbonate by ¹ H-NMR, 2-hydroxyethyl acrylate in 1 g of polymer The amount of the monomer unit was calculated as 1.3 × 10 ⁻⁵ mol.

(Synthesis of grafted polyarylate (PA-VP))
In a 50 ml vial, polyarylate (Unitika, U-100), 0.1 g of dried benzoyl peroxide, and 0.3 g of vinylpyridine (VP) were dissolved in 30 ml of toluene, and the vial was sealed with nitrogen. Substitution (20 minutes bubbling).
The mixture was reacted for 5 hours while stirring at 100 ° C. in an oil bath.
The reaction solution was poured into 150 ml of methanol to precipitate the polymer. Next, the precipitated polymer was dissolved in 40 ml of THF and then poured again into 150 ml of methanol for precipitation. After this operation was repeated twice, the precipitated polymer was washed with diethyl ether and dried for 6 hours in a draft dryer at 60 ° C.
^From the ratio of the peak area of 8.3 ppm of the pyridine ring and the peak area of the 7.0 to 7.5 ppm benzene ring of polyarylate by ¹ H-NMR, the amount of vinylpyridine monomer units in 1 g of polymer was 1.2. It calculated with x10 <^-5> mol.

(Synthesis of grafted polystyrene (PS-HEMA))
A toluene 40 ml solution of 3 g of polystyrene (PS) and 0.1 g of benzoyl peroxide was placed in a vial and sealed, and the inside was purged with nitrogen, followed by stirring at 100 ° C. for 1 hour. Next, a nitrogen-substituted hydroxyethyl methacrylate (HEMA) 0.3 g / toluene 1 ml solution was added, and the mixture was further stirred for 17 hours.
The reaction solution was poured into 100 ml of methanol to precipitate the produced polymer. The precipitated polymer was recovered and dissolved in 30 ml of toluene, and 100 ml of methanol was added thereto to precipitate the polymer. The precipitated polymer was collected and dried at 60 ° C. for 10 hours. This is PS-HEMA.
In the IR spectrum, a new peak attributed to C = O stretching vibration that was not found in the raw polystyrene was observed, confirming that hydroxyethyl methacrylate was grafted onto the polystyrene.

(Magnesium hydroxide nanoparticles / PLA-HEMA composition)
10 g of magnesium chloride hexahydrate was dissolved in 100 ml of water, and 20 ml of 5N sodium hydroxide was added dropwise thereto to precipitate magnesium hydroxide. The resulting gel was centrifuged to settle. The precipitated gel was dispersed in water and centrifuged again. After performing this operation three times in total, the precipitated gel was redispersed in methanol and centrifuged again to obtain a gel substituted with methanol. The magnesium hydroxide solid content in the gel was 25% by weight.
The volume-based particle diameter of the produced magnesium hydroxide was 191 nm in methanol. When observed with a transmission electron microscope, it was a hexagonal plate crystal having a major axis of about 100 nm or less and a thickness of about 20 nm or less.
When 0.3 g of the magnesium hydroxide gel was stirred and mixed with the PLA-HEMA 0.3 g / methylene chloride 5 ml solution obtained in Example 1, a transparent liquid that slightly scattered light was obtained. When the solvent was slowly removed from the transparent liquid, a transparent solid was obtained. When this transparent solid was observed with a transmission electron microscope, it was observed that magnesium hydroxide nanoparticles were uniformly distributed without aggregation.
When the transparent solid was placed at 110 ° C. for 40 minutes, no whitening was observed.
Moreover, when the glass transition temperature Tg of the said solid was measured, it was Tg = 82 degreeC. This is shifted to a higher temperature side than normal PLA, indicating that the heat resistance is improved.

(Magnesium hydroxide nanoparticles / PLA-HEMA composition)
When 1.6 g of the magnesium hydroxide gel prepared in Example 15 was stirred and mixed with the PLA-HEMA 0.4 g / methylene chloride 5 ml solution obtained in Example 1, a transparent liquid that slightly scattered light was obtained. When the solvent was slowly removed from the transparent liquid, a translucent solid that slightly scattered light was obtained. When this translucent solid was observed with a transmission electron microscope, it was observed that magnesium hydroxide nanoparticles were uniformly distributed without aggregation.
When the translucent solid was exposed to the flame of a burner for 1 minute, it turned white but did not burn.

(Magnesium hydroxide nanoparticles / PO-HEMA composition)
When 0.4 g of magnesium hydroxide gel prepared in Example 15 was stirred and mixed with the PO-HEMA 0.3 g / toluene 5 ml solution obtained in Example 3, a transparent liquid that slightly scattered light was obtained. When the solvent was slowly removed from the transparent liquid, a transparent solid was obtained. When this transparent solid was observed with a transmission electron microscope, it was observed that magnesium hydroxide nanoparticles were uniformly distributed without aggregation.

(Iron oxide nanoparticles / PO-AA composition)
When 0.4 g of a methanol dispersion containing 0.1 g of iron oxide nanoparticles having an average particle diameter of 18 nm was stirred and mixed with the PO-AA 0.3 g / toluene 5 ml solution obtained in Example 5, a yellowish brown transparent liquid was obtained. . When the solvent was slowly removed from the transparent liquid, a tan translucent solid was obtained. When this yellowish brown translucent solid was observed with a transmission electron microscope, it was observed that the iron oxide nanoparticles were uniformly distributed without aggregation.

(Silica nanoparticles / PC-VP composition 1)
A silica nanoparticle / methanol dispersion with a volume-based particle size of 31 nm was prepared by a sol-gel method and purified by dialysis. When the ζ potential of the silica nanoparticles was measured, it was −20 mV. Subsequently, after replacing methanol with ethanol, a dehydrated ethanol dispersion (concentration 5% by weight) was formed by benzene azeotropy. This ethanol was replaced with dioxane to obtain a silica nanoparticle / dioxane dispersion (concentration: 10% by weight).
When 0.6 g of PC-VP obtained in Example 9 was dissolved in 5 g of this dioxane dispersion, a transparent liquid that slightly scattered light was obtained. When this transparent liquid was applied to a glass plate using a bar coater and dried with a 100 ° C. ventilator, a transparent film was obtained. When this transparent film was observed with a field emission electron microscope, it was a film in which silica nanoparticles were uniformly dispersed with primary particles.

(Silica nanoparticles / PC-VP composition 2)
The PC-VP 0.6 g / THF 30 ml / toluene 20 ml solution obtained in Example 9 was added to 10 g of silica nanoparticles having a volume standard particle diameter of 31 nm / dehydrated ethanol dispersion (concentration 5 wt%), and ethanol and THF were removed with an evaporator. Silica nanoparticles / PC-VP toluene dispersion (concentration: 10% by weight) was used. The dispersion became a transparent liquid that slightly scattered light. When this transparent liquid was applied to a glass plate using a bar coater and dried with a 100 ° C. ventilator, a transparent film was obtained. When this transparent film was observed with a field emission electron microscope, it was a film in which silica nanoparticles were uniformly dispersed with primary particles.

(Alumina nanoparticles / PC-HEA composition)
When alumina particles having an average particle diameter of 200 nm were dispersed in methanol and the ζ potential was measured, it was +19 mV. When 0.2 g of this alumina particle was added to the PC-HEA 0.8 g / toluene 10 ml solution obtained in Example 10 and stirred, a translucent dispersion was obtained.
When this dispersion was applied to a glass plate using a bar coater and dried with an air dryer at 100 ° C., a translucent film was formed. When this transparent film was observed with a field emission electron microscope, it was a film in which alumina particles were uniformly dispersed with primary particles.

(Magnesium hydroxide nanoparticles / PS-HEMA composition)
When 0.4 g of magnesium hydroxide gel prepared in Example 7 was stirred and mixed with the PS-HEMA 0.3 g / toluene 5 ml solution obtained in Example 14, a transparent liquid that slightly scattered light was obtained. When the solvent was slowly removed from the transparent liquid, a translucent solid was obtained. When this translucent solid was observed with a transmission electron microscope, it was observed that magnesium hydroxide nanoparticles were uniformly distributed without aggregation.

[Comparative Example 1]
A benzoyl peroxide 0.1 g / dioxane 28 ml solution was placed in a vial and sealed, and the inside was purged with nitrogen, followed by stirring at 100 ° C. for 1 hour. Next, a nitrogen-substituted hydroxyethyl methacrylate (HEMA) 0.3 g / dioxane 1 ml solution was added, and the mixture was further stirred for 17 hours.
Next, after dissolving 3 g of polylactic acid (PLA), the mixed solution was divided into two, and one of them was added to 100 ml of methanol to precipitate the produced polymer. Next, the precipitated polymer was recovered and dissolved in 30 ml of tetrahydrofuran, and 100 ml of methanol was added thereto to precipitate the polymer. The precipitated polymer was recovered and dried at 60 ° C. for 10 hours. This is referred to as mixing / cleaning PLA.
On the other hand, the solvent was removed under reduced pressure and dried to obtain an opaque solid. This is a mixed PLA.
When both IR spectra were measured, only the peak attributed to C = O stretching vibration of PLA was observed in the former mixed / washed PLA, and it was found that the ungrafted polymer was removed by the washing operation.
On the other hand, in the latter mixed PLA, a peak attributed to C = O stretching vibration of PLA and a peak attributed to C = O stretching vibration different from that (C = O of polyhydroxyethyl methacrylate) were observed.
Next, when 0.4 g of magnesium hydroxide gel prepared in Example 15 was mixed with stirring in a mixed PLA 0.4 g / methylene chloride 5 ml solution, a translucent solution was obtained. When the solvent was slowly removed from the translucent liquid, an opaque solid was obtained. When this opaque solid is observed with a transmission electron microscope, it is observed that magnesium hydroxide nanoparticles are agglomerated, and the mixture of PLA with polyhydroxyethyl methacrylate cannot disperse the magnesium hydroxide nanoparticles well. all right.

The nanocomposite of the present invention and the graft polymer of the present invention are, for example, optical materials (high refractive index, transparency), light shielding materials (specific wavelength cut, high transparency), high strength materials, high heat resistance materials, flame retardancy It can be used for materials and color filters.

Claims (4)

A nanocomposite in which nanoparticles (excluding nanoparticles having polar groups and some hydrophobic groups on the surface) are dispersed in a graft polymer as a matrix resin ,
The graft polymer comprises a mother polymer portion and a graft chain portion,
The graft chain portion has at least one functional group selected from an acidic functional group, a basic functional group, and a hydroxyl group;
The mother polymer portion has a structure belonging to any of polyolefin, polyester, polycarbonate, and polystyrene,
Nanocomposite.   The nanocomposite according to claim 1, wherein the graft polymer is obtained by graft polymerization of a vinyl monomer to a base polymer. The nanocomposite according to claim 2 , wherein the vinyl monomer has at least one functional group selected from an acidic functional group, a basic functional group, and a hydroxyl group. The nanocomposite according to claim 2 or 3 , wherein the base polymer is any one of a homopolymer or a copolymer of polyolefin, polyester, polycarbonate, and polystyrene .