JP7232399B2 - Carbon material precursor composition, method for producing same, and method for producing carbon material using same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a carbon material precursor composition, a method for producing the same, and a method for producing a carbon material using the same.

Conventionally, as a method for producing a carbon material such as carbon fiber, a method of subjecting a carbon material precursor made of polyacrylonitrile to a heat treatment in an inert atmosphere has been known (for example, Japanese Unexamined Patent Application Publication No. 2016-113276 (Patent Reference 1)). Since the polyacrylonitrile used in this method is difficult to dissolve in inexpensive general-purpose solvents, it is necessary to use expensive organic solvents such as dimethylsulfoxide and N,N-dimethylacetamide during polymerization and spinning. However, there is a problem that the manufacturing cost of the carbon material is high.

On the other hand, polyacrylamide is a water-soluble polymer, and water, which is inexpensive and has a low environmental impact, can be used as a solvent during polymerization and spinning, so it is expected to reduce the production cost of carbon materials.

JP 2016-113276 A

Since the carbon material is difficult to mold, in order to obtain a carbon material having a desired shape (for example, fiber or film), it is necessary to carbonize the carbon material precursor after molding it into a desired shape. there were. However, when a carbon material precursor made of polyacrylamide molded into a desired shape is carbonized, there is a problem that the carbon material obtained does not necessarily retain the desired shape before carbonization.

The present invention has been made in view of the above problems of the prior art, and contains a carbon material precursor made of an acrylamide-based copolymer, and retains a desired shape before carbonization even when carbonized. It is an object of the present invention to provide a carbon material precursor composition, a method for producing the same, and a method for producing a carbon material using the same.

The present inventors have made intensive studies to achieve the above object, and as a result, have found that a carbon material precursor comprising an acrylamide-based copolymer containing a vinyl-based monomer unit having a carboxyl group as a copolymerization component is added with an acid and its acid. By adding at least one additive component selected from the group consisting of salts and a compound having a polyfunctional amino group, it is possible to retain the desired shape before carbonization even when carbonization is performed. The inventors have found that a carbon material precursor composition can be obtained, and have completed the present invention.

That is, the carbon material precursor composition of the present invention contains acrylamide-based monomer units in an amount of 50 mol% or more, and contains 0.5 mol% or more of vinyl-based monomer units having a carboxyl group as a copolymer component. A carbon material precursor composed of a coalescence, at least one additive component selected from the group consisting of phosphoric acid, polyphosphoric acid, boric acid, sulfuric acid, sulfonic acid, and salts thereof, aromatic diamines, aliphatic diamines, and at least one compound having a polyfunctional amino group selected from the group consisting of alicyclic diamines, and the content of the additive component is 0.1 to 0.1 with respect to 100 parts by mass of the carbon material precursor 50 parts by mass, and the content of the compound having a polyfunctional amino group is 0.01 to 40 equivalents with respect to the content of the carbon material precursor.

In the carbon material precursor composition of the present invention, it is preferable that the carboxyl group in the acrylamide-based copolymer and the polyfunctional amino group form a covalent bond, and the additive component is phosphoric acid. , boric acid, sulfuric acid, and salts thereof.

In the method for producing a carbon material precursor composition of the present invention, acrylamide is added in the presence of at least one additive component selected from the group consisting of phosphoric acid, polyphosphoric acid, boric acid, sulfuric acid, sulfonic acid, and salts thereof. a carbon material precursor comprising an acrylamide-based copolymer containing 50 mol% or more of a vinyl monomer unit having a carboxyl group as a copolymerization component, an aromatic diamine, an aliphatic and a compound having at least one polyfunctional amino group selected from the group consisting of group diamines and alicyclic diamines, and the amount of the additive component is 0.1 to 0.1 parts per 100 parts by mass of the carbon material precursor. 50 parts by mass, and the amount of the compound having a polyfunctional amino group is 0.01 to 40 equivalents with respect to the amount of the carbon material precursor, and heating and reacting at a temperature of 300° C. or less. to obtain a carbon material precursor composition in which the covalent bond is formed.

Further, the method for producing a carbon material of the present invention is characterized in that the carbon material precursor composition of the present invention is subjected to a heat treatment at a temperature of 500 to 3000° C. in an inert atmosphere to carry out a carbonization treatment. is.

Although it is not entirely clear why the carbon material precursor composition of the present invention can retain the desired shape before carbonization even when carbonized, the present inventors have made the following observations. to guess. That is, when a carbon material precursor made of an acrylamide copolymer is subjected to a carbonization treatment, the acrylamide copolymer softens in the temperature rising process (especially in the temperature range of 200 to 250° C.). It is difficult to obtain a carbon material that retains its shape.

On the other hand, the carbon material precursor composition of the present invention comprises an acrylamide copolymer containing vinyl monomer units having a carboxyl group (hereinafter referred to as "carboxyl group-containing acrylamide copolymer") as a copolymerization component. Containing a carbon material precursor, at least one additive component selected from the group consisting of acids and salts thereof, and a compound having a polyfunctional amino group (hereinafter referred to as a "polyfunctional amino group-containing compound") It is something to do. In this carbon material precursor composition, the carboxyl group of the carboxyl group-containing acrylamide-based copolymer and the polyfunctional amino group of the polyfunctional amino group-containing compound form an ionic bond due to the catalytic action of the additive component, Furthermore, a dehydration reaction forms a covalent bond, and a crosslinked structure is introduced into the carboxyl group-containing acrylamide copolymer. For example, a carboxyl group-containing acrylamide-based copolymer and ethylenediamine react in the presence of an acid catalyst by the following reaction formula:

dehydration reaction to form a covalent bond, and a crosslinked structure is introduced into the carboxyl group-containing acrylamide copolymer. When a carbon material precursor made of an acrylamide copolymer having such a crosslinked structure is subjected to a carbonization treatment, the acrylamide copolymer is less likely to soften in the process of increasing the temperature. It is presumed that it becomes possible to obtain a retained carbon material.

According to the present invention, a carbon material precursor composition containing a carbon material precursor comprising an acrylamide-based copolymer and capable of retaining a desired shape before carbonization treatment even when subjected to carbonization treatment is obtained. be able to. Further, by subjecting the carbon material precursor composition of the present invention to a carbonization treatment, it is possible to obtain a carbon material that retains the desired shape before the carbonization treatment.

A film composed of the carbon material precursor composition obtained in Example 1, a film composed of the carbon material precursor obtained in Comparative Example 1, and a film composed of the comparative carbon material precursor composition obtained in Comparative Example 2. , and a graph showing the temperature dependence of the storage elastic modulus of the film made of the carbon material precursor obtained in Comparative Example 3. FIG. A film composed of the carbon material precursor compositions obtained in Examples 1 to 3, a film composed of the carbon material precursor obtained in Comparative Example 3, and a comparative carbon material precursor composition obtained in Comparative Example 4. It is a graph which shows the temperature dependence of the storage elastic modulus of the film which consists of. A film made of the carbon material precursor composition obtained in Examples 4 and 5, a film made of the carbon material precursor obtained in Comparative Example 3, and a comparative carbon material precursor composition obtained in Comparative Example 4. It is a graph which shows the temperature dependence of the storage elastic modulus of the film which consists of. A film composed of the carbon material precursor composition obtained in Example 6, a film composed of the carbon material precursor obtained in Comparative Example 5, and a comparative carbon material precursor composition obtained in Comparative Example 6. 4 is a graph showing the temperature dependence of the storage modulus of a film. Films made of the carbon material precursor compositions obtained in Examples 1, 7, and 8, films made of the carbon material precursors obtained in Comparative Example 3, and comparative carbon material precursors obtained in Comparative Example 7 4 is a graph showing the temperature dependence of the storage elastic modulus of a film made of the composition. A film composed of the carbon material precursor composition obtained in Example 1, a film composed of the carbon material precursor obtained in Comparative Example 3, and a comparative carbon material precursor composition obtained in Comparative Example 4. It is a graph which shows the thermogravimetric analysis result of a film. It is the schematic which shows the jig|tool used by the carbonization test. 1 is a graph showing an X-ray diffraction pattern of a carbon material obtained from the carbon material precursor composition of Example 1. FIG. 4 is a graph showing the FT-IR spectrum of the carbon material obtained from the carbon material precursor composition of Example 1. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail with reference to its preferred embodiments.

First, the carbon material precursor composition of the present invention will be described. The carbon material precursor composition of the present invention is an acrylamide copolymer ( A carbon material precursor consisting of a carboxyl group-containing acrylamide copolymer), at least one additional component selected from the group consisting of acids and salts thereof, and a compound having a polyfunctional amino group (polyfunctional amino group containing compound). By subjecting the carbon material precursor composition of the present invention to a carbonization treatment, it is possible to obtain a carbon material that retains the desired shape before the carbonization treatment.

(carbon material precursor)
The carbon material precursor used in the present invention is composed of an acrylamide copolymer containing a vinyl monomer unit having a carboxyl group as a copolymerization component. This carboxyl group-containing acrylamide copolymer contains 50 mol % or more of acrylamide monomer units with respect to 100 mol % of all monomer units. When the content of the acrylamide-based monomer units is less than the above lower limit, the carboxyl group-containing acrylamide-based copolymer becomes difficult to dissolve in the aqueous solvent or aqueous mixed solvent described below. In addition, from the viewpoint of improving the solubility of such a carboxyl group-containing acrylamide-based copolymer in an aqueous solvent or an aqueous mixed solvent and improving the carbonization yield of the carbon material precursor, the content of the acrylamide-based monomer unit is is preferably 60 mol % or more, more preferably 70 mol % or more, and particularly preferably 80 mol % or more. On the other hand, the upper limit of the content of acrylamide-based monomer units is 99.5 mol % or less with respect to 100 mol % of all monomer units. If the content of acrylamide-based monomer units exceeds the above upper limit, the content of vinyl-based monomer units having a carboxyl group is relatively small, so that the carboxyl-containing acrylamide-based copolymer is not introduced into a crosslinked structure and carbonized. It becomes difficult to obtain a carbon material that retains the desired shape before treatment. In addition, a crosslinked structure is sufficiently introduced into the carboxyl group-containing acrylamide-based copolymer, and a carbon material sufficiently retaining the desired shape before carbonization treatment is obtained. From the viewpoint of improvement, the upper limit of the acrylamide-based monomer unit content is preferably 99 mol% or less, more preferably 97 mol% or less, even more preferably 95 mol% or less, and particularly preferably 90 mol% or less.

The carboxyl group-containing acrylamide copolymer contains 0.5 mol % or more of vinyl monomer units having a carboxyl group with respect to 100 mol % of all monomer units. When the content of vinyl-based monomer units having a carboxyl group is less than the lower limit, the carbon material is not introduced into the crosslinked structure of the carboxyl-containing acrylamide-based copolymer and retains the desired shape before carbonization. becomes difficult. In addition, from the viewpoint that a crosslinked structure is sufficiently introduced into the carboxyl group-containing acrylamide-based copolymer to obtain a carbon material sufficiently retaining the desired shape before the carbonization treatment, vinyl-based monomer units having a carboxyl group are added. The lower limit of the content is preferably 1 mol % or more, more preferably 3 mol % or more, still more preferably 5 mol % or more, and particularly preferably 10 mol % or more. On the other hand, the upper limit of the content of vinyl-based monomer units having a carboxyl group is 50 mol % or less with respect to 100 mol % of all monomer units. If the content of the vinyl-based monomer unit having a carboxyl group exceeds the above upper limit, the content of the acrylamide-based monomer unit becomes relatively small, so that the carboxyl-group-containing acrylamide-based copolymer is added to the aqueous solvent or aqueous mixed solvent described later. less soluble. In addition, from the viewpoint of improving the solubility of such a carboxyl group-containing acrylamide copolymer in an aqueous solvent or an aqueous mixed solvent, the upper limit of the content of vinyl monomer units having a carboxyl group is 40 mol% or less. It is preferably 30 mol % or less, more preferably 20 mol % or less.

Examples of the acrylamide-based monomer include acrylamide; alkylacrylamide such as N-methylacrylamide; dialkylacrylamide such as N,N-dimethylacrylamide; dialkylaminoalkylacrylamide such as dimethylaminoethylacrylamide and dimethylaminopropylacrylamide; Hydroxyalkylacrylamides such as hydroxymethyl)acrylamide and N-(2-hydroxyethyl)acrylamide; diacetoneacrylamide; methacrylamide; alkylmethacrylamides such as N-methylmethacrylamide; dialkylmethacrylamides such as N,N-dimethylmethacrylamide ; dialkylaminoalkyl methacrylamides such as dimethylaminoethyl methacrylamide and dimethylaminopropyl methacrylamide; hydroxyalkyl methacrylamides such as N-(hydroxymethyl) methacrylamide and N-(2-hydroxyethyl) methacrylamide; diacetone methacrylamide are mentioned. Such acrylamide-based monomers may be used alone or in combination of two or more. Among these acrylamide-based monomers, acrylamide is preferable from the viewpoint of excellent water solubility.

Examples of vinyl-based monomers having a carboxyl group include unsaturated carboxylic acids such as acrylic acid, methacrylic acid and itaconic acid and salts thereof; aromatic carboxylic acids having a vinyl group such as carboxystyrene; carboxymethyl acrylate and carboxyethyl carboxyalkyl acrylates such as acrylate; carboxyalkyl methacrylates such as carboxymethyl methacrylate and carboxyethyl methacrylate; acryloylaminocarboxylic acids such as acryloylaminoacetic acid; methacryloylaminocarboxylic acids such as methacryloylaminoacetic acid; be done. These vinyl-based monomers having a carboxyl group may be used singly or in combination of two or more. Among these vinyl-based monomers having a carboxyl group, acrylic acid and methacrylic acid are preferred from the viewpoints of cost, solubility in aqueous solvents or aqueous mixed solvents, and copolymerizability.

Further, in the carboxyl group-containing acrylamide-based copolymer used in the present invention, other polymerizable monomers may be used in addition to acrylamide-based monomer units and vinyl-based monomer units having a carboxyl group within a range that does not impair the effects of the present invention. Units may be included. The content of such other polymerizable monomer units is preferably 49.5 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less, relative to 100 mol% of the total monomer units. 20 mol % or less is particularly preferred. Examples of other polymerizable monomers include vinyl cyanide-based monomers, unsaturated carboxylic anhydrides, unsaturated carboxylic acid esters, vinyl-based monomers, and olefin-based monomers. Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, 2-hydroxyethyl acrylonitrile, chloroacrylonitrile, chloromethacrylonitrile, methoxyacrylonitrile, methoxymethacrylonitrile and the like. Examples of the unsaturated carboxylic acid anhydride include maleic anhydride and itaconic anhydride. Examples of the unsaturated carboxylic acid ester include methyl acrylate and methyl methacrylate. Examples of the vinyl-based monomer include , styrene, α-methylstyrene, vinyl chloride, vinyl alcohol, etc. Examples of the olefinic monomer include ethylene, propylene, and the like. These other polymerizable monomers may be used singly or in combination of two or more.

In addition, the carboxyl group-containing acrylamide-based copolymer is an aqueous solvent (water, N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylacetamide (DMAC), etc., and a mixed solvent thereof) and an aqueous mixture. It is preferably soluble in at least one of solvents (a mixed solvent of the aqueous solvent and an organic solvent (tetrahydrofuran, alcohol, acetonitrile, etc.)). As a result, when the carbon material precursor composition is produced, wet mixing using the aqueous solvent or the aqueous mixed solvent becomes possible, and the carboxyl group-containing acrylamide copolymer, the additive component, and the polyfunctional amino Group-containing compounds can be mixed uniformly and safely at low cost. Further, when molding the obtained carbon material precursor composition, dry molding (dry spinning), dry-wet molding (dry-wet spinning), wet molding (wet spinning) using the aqueous solvent or the aqueous mixed solvent. ), or electrospinning becomes possible, and it becomes possible to manufacture carbon materials safely at low cost. The content of the organic solvent in the aqueous mixed solvent is not particularly limited as long as the carboxyl group-containing acrylamide copolymer, which is insoluble or sparingly soluble in the aqueous solvent, dissolves when mixed with the organic solvent. do not have. In addition, among such carboxyl group-containing acrylamide-based copolymers, from the viewpoint that it is possible to produce a carbon material precursor composition and a carbon material safely at a lower cost, A carboxyl group-containing acrylamide copolymer is preferable, and a water-soluble (water-soluble) carboxyl group-containing acrylamide copolymer is more preferable.

As a method for producing such a carboxyl group-containing acrylamide-based copolymer, a known polymerization method such as solution polymerization, suspension polymerization, precipitation polymerization, dispersion polymerization, emulsion polymerization (e.g., inverse emulsion polymerization) is employed. be able to. When solution polymerization is employed, the solvent is not particularly limited as long as it dissolves the raw material monomer and the resulting carboxyl group-containing acrylamide copolymer. Aqueous solvents (water, N,N-dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylacetamide (DMAC), etc., and mixed solvents thereof) or the aqueous mixed solvents (the aqueous solvent and an organic solvent (tetrahydrofuran, It is preferable to use a mixed solvent with alcohol, acetonitrile, etc.), it is more preferable to use the aqueous solvent, and it is particularly preferable to use water. Further, as the polymerization initiator, at least one of the aqueous solvent and the aqueous mixed solvent such as 4,4′-azobis(4-cyanovaleric acid), ammonium persulfate and potassium persulfate (preferably the aqueous solvent, Water-soluble radical polymerization initiators are more preferred.

(Additional component)
The additive component used in the present invention is at least one selected from the group consisting of acids and salts thereof. It acts as a catalyst in the dehydration reaction with the functional amino group. Examples of the acid include inorganic acids such as phosphoric acid, polyphosphoric acid, boric acid, sulfuric acid, nitric acid and carbonic acid, and organic acids such as oxalic acid, citric acid and sulfonic acid. Examples of such acid salts include metal salts (eg, sodium salts, potassium salts), ammonium salts, amine salts and the like, with ammonium salts and amine salts being preferred, and ammonium salts being more preferred. In particular, among these additive components, phosphoric acid is used from the viewpoint of obtaining high catalytic activity in the reaction between the carboxyl group of the carboxyl group-containing acrylamide copolymer and the polyfunctional amino group of the polyfunctional amino group-containing compound. , boric acid, sulfuric acid and their salts are preferred, and phosphoric acid, boric acid, sulfuric acid and their ammonium salts are more preferred. Further, from the viewpoint of further improving the carbonization yield of the obtained carbon material precursor, phosphoric acid, polyphosphoric acid, boric acid, sulfuric acid, and ammonium salts thereof are preferable. Phosphoric acid, polyphosphoric acid, boric acid, and is more preferred, and phosphoric acid, polyphosphoric acid, ammonium salts of phosphoric acid, and ammonium salts of polyphosphoric acid are particularly preferred.

The additive component is preferably a component soluble in at least one of the aqueous solvent and the aqueous mixed solvent (preferably the aqueous solvent, more preferably water). As a result, when the carbon material precursor composition is produced, wet mixing using the aqueous solvent or the aqueous mixed solvent becomes possible, and the carboxyl group-containing acrylamide copolymer, the additive component, and the polyfunctional amino Group-containing compounds can be mixed uniformly and safely at low cost. Further, when molding the obtained carbon material precursor composition, dry molding (dry spinning), dry-wet molding (dry-wet spinning), wet molding (wet spinning) using the aqueous solvent or the aqueous mixed solvent. ), or electrospinning becomes possible, and it becomes possible to manufacture carbon materials safely at low cost.

(Polyfunctional amino group-containing compound)
The polyfunctional amino group-containing compound used in the present invention forms an ionic bond with the carboxyl group-containing acrylamide copolymer, and further undergoes a dehydration reaction to form a covalent bond to form a crosslinked structure. Examples of such polyfunctional amino group-containing compounds include aromatic diamines such as phenylenediamine and diaminonaphthalene; aliphatic diamines such as diaminohexane and diaminooctane; and alicyclic diamines such as diaminocyclohexane. Such polyfunctional amino group-containing compounds may be used alone or in combination of two or more. Among these polyfunctional amino group-containing compounds, phenylenediamine, diaminohexane, and diaminooctane are preferred from the viewpoint of reactivity with the carboxyl group-containing acrylamide copolymer.

The polyfunctional amino group-containing compound is preferably a component soluble in at least one of the aqueous solvent and the aqueous mixed solvent (preferably the aqueous solvent, more preferably water). As a result, when the carbon material precursor composition is produced, wet mixing using the aqueous solvent or the aqueous mixed solvent becomes possible, and the carboxyl group-containing acrylamide copolymer, the additive component, and the polyfunctional amino Group-containing compounds can be mixed uniformly and safely at low cost. Further, when molding the obtained carbon material precursor composition, dry molding (dry spinning), dry-wet molding (dry-wet spinning), wet molding (wet spinning) using the aqueous solvent or the aqueous mixed solvent. ), or electrospinning becomes possible, and it becomes possible to manufacture carbon materials safely at low cost.

[Carbon material precursor composition]
The carbon material precursor composition of the present invention contains the carbon material precursor comprising the carboxyl group-containing acrylamide copolymer, the additive component, and the polyfunctional amino group-containing compound. In the carbon material precursor composition of the present invention, the carboxyl group of the carboxyl group-containing acrylamide copolymer and the polyfunctional amino group of the polyfunctional amino group-containing compound form a covalent bond. preferably. As a result, a crosslinked structure is introduced into the carboxyl group-containing acrylamide copolymer, so softening of the carboxyl group-containing acrylamide copolymer is suppressed, and a carbon material that retains the desired shape before carbonization is obtained. be able to.

In such a carbon material precursor composition of the present invention, the content of the polyfunctional amino group-containing compound is such that the content of the crosslinked structure in the carboxyl group-containing acrylamide-based copolymer increases and the carboxyl group content increases. From the viewpoint that softening of the acrylamide-based copolymer is more sufficiently suppressed and a carbon material sufficiently retained in a desired shape before carbonization treatment is obtained, the content of the carbon material precursor is 0.5. 01 to 40 equivalents are preferred, 0.1 to 20 equivalents are more preferred, 0.1 to 10 equivalents are even more preferred, 0.2 to 5 equivalents are particularly preferred, and 0.5 to 2 equivalents are most preferred. Further, the content of the additive component is such that sufficient catalytic activity is obtained in the dehydration reaction between the carboxyl group of the carboxyl group-containing acrylamide copolymer and the multifunctional amino group of the polyfunctional amino group-containing compound, In addition, from the viewpoint of improving the carbonization yield of the carbon material precursor composition, it is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 30 parts by mass, with respect to 100 parts by mass of the carbon material precursor. It is preferably 0.1 to 20 parts by mass, particularly preferably 1 to 10 parts by mass.

Further, an aqueous solution or an aqueous mixed solution containing such a carbon material precursor composition of the present invention has a low viscosity even when the concentration of the carbon material precursor is high (for example, 20% by mass or more). , and has excellent moldability. Specifically, the viscosity of the aqueous solution or the aqueous mixed solution in which the concentration of the carbon material precursor is 30% by mass is preferably 20 Pa s or less at room temperature under a shear rate of 10 s ⁻¹ . . As a result, for example, when a film is formed by a solution casting method using the aqueous solution or the aqueous mixed solution, a film with little thickness unevenness (10% or less) and excellent surface appearance can be obtained. On the other hand, when the viscosity of the aqueous solution or the aqueous mixed solution exceeds 20 Pa s, the surface appearance of the obtained film tends to deteriorate, and when it exceeds 100 Pa s, the thickness unevenness of the obtained film increases ( 10%), and if it exceeds 200 Pa s, the handling property during casting is low, and a film cannot be obtained, or even if a film is obtained, the film contains air bubbles, and the thickness unevenness is further increased. It tends to be large (more than 20%).

As a method for producing the carbon material precursor composition of the present invention, the carbon material obtained by directly mixing (melt-mixing) the additive component and the polyfunctional amino group-containing compound with the carbon material precursor in a molten state. A method of forming a precursor composition into a desired shape (e.g., film, sheet, fibrous, or block), and dry blending the carbon material precursor, the additive component, and the polyfunctional amino group-containing compound ( dry mixing) and molding the resulting carbon material precursor composition into a desired shape (e.g., film, sheet, fiber, block); The carbon material precursor having a desired shape (e.g., film, sheet, fibrous, block) is immersed in or passed through the aqueous solution or aqueous mixed solution to obtain the desired shape of the carbon material. A method for obtaining a precursor composition, a solvent in which the carbon material precursor is insoluble (e.g., alcohol, acetone, chlorine-based solvent, ether-based solvent, ester-based solvent, aromatic solvent), the additive component, and the polyfunctionality The carbon material precursor formed into a desired shape (for example, film, sheet, fiber, block) is immersed in or passed through a solution containing an amino group-containing compound to form carbon in a desired shape. Although it is possible to adopt a method of obtaining a material precursor composition, the carbon material precursor, the additive component, and the polyfunctional amino group-containing compound to be used are compatible with the aqueous solvent or the aqueous mixed solvent. When the carbon material precursor, the additive component, and the polyfunctional amino group-containing compound can be uniformly mixed, the carbon material precursor, the additive component, and the polyfunctional amino group-containing compound can be uniformly mixed. and a functional amino group-containing compound in the aqueous solvent or the aqueous mixed solvent (wet mixing), and the obtained solution is used to form the carbon material precursor composition into a desired shape (e.g., film, sheet, etc.). , fibrous, lumpy), and then removing the solvent. In the wet mixing, the aqueous solvent is preferably used as the solvent, and water is more preferably used, from the viewpoint that the carbon material precursor composition can be produced safely at a lower cost. Furthermore, the method for removing the solvent is not particularly limited, and known drying methods such as hot air drying, vacuum drying, and freeze drying can be employed, but hot air drying is preferable from the viewpoint of simple equipment. .

Further, in the method for producing a carbon material precursor composition of the present invention, the carbon material precursor composition in a desired shape is subjected to a heat treatment at a temperature of 300° C. or less (preferably 250° C. or less) to remove the additive component. It is preferable to cause a dehydration reaction between the carbon material precursor and the compound having a polyfunctional amino group in the presence. This promotes the formation of ionic bonds and/or covalent bonds between the carboxyl groups of the carboxyl group-containing acrylamide-based copolymer and the polyfunctional amino groups of the polyfunctional amino group-containing compound. A crosslinked structure is sufficiently introduced into the acrylamide copolymer. As a result, softening of the acrylamide-based copolymer is more sufficiently suppressed, and a carbon material sufficiently retaining the desired shape before the carbonization treatment can be obtained. The lower limit of the heating temperature is preferably room temperature (25° C.) or higher, more preferably 50° C. or higher, from the viewpoint that the effect of heating can be sufficiently obtained. The heating time is preferably 1 minute to 5 hours, more preferably 1 minute to 2 hours.

[Method for producing carbon material]
Next, the method for producing the carbon material of the present invention will be described. In the method for producing a carbon material of the present invention, the carbon material precursor composition of the present invention is heated to 500 to 3000° C. (preferably 500 to 2500° C.) under an inert atmosphere (in an inert gas such as nitrogen, argon or helium). C., more preferably 1000 to 2000.degree. C.) for carbonization. This makes it possible to obtain a carbon material that sufficiently retains the desired shape before carbonization. Moreover, the heating time in the carbonization treatment is preferably 1 minute to 10 hours.

Further, in the method for producing a carbon material of the present invention, the carbon material precursor composition of the present invention is subjected to heat treatment (flameproof treatment) in an oxidizing atmosphere (for example, in air) before the carbonization treatment. may As a result, the additive component in the carbon material precursor composition acts to convert the structure of the carboxyl group-containing acrylamide-based copolymer into a structure with high heat resistance, thereby improving the carbonization yield of the carbon material precursor. do. A crosslinked structure can also be introduced into the carboxyl group-containing acrylamide copolymer by this flameproofing treatment. The heating temperature in such a flameproofing treatment is preferably 500°C or less, more preferably 150 to 400°C, and even more preferably 200 to 350°C. Moreover, the heating time in the flameproofing treatment is not particularly limited. For example, heating for more than 1 hour is possible, but 1 to 60 minutes is preferable from the viewpoint of reducing the production cost.

Furthermore, in the method for producing a carbon material of the present invention, the carbon material precursor composition to be used is preliminarily formed into a desired shape (for example, film-like, It is preferable to mold into a sheet, fibrous, bulk). At this time, the carbon material precursor composition is pressure-molded as it is, or the carbon material precursor composition in a molten state is melt-molded (for example, melt casting, melt extrusion molding, injection molding, melt spinning). However, in the case where the carbon material precursor composition of the present invention is soluble in the aqueous solvent or the aqueous mixed solvent, the carbon material precursor composition is mixed with the aqueous solvent from the viewpoint of improving moldability. It is preferable to mold using an aqueous solution or aqueous mixed solution obtained by dissolving in a solvent or the aqueous mixed solvent. As such a molding method, solution cast molding, wet molding (wet spinning), dry-wet molding (dry-wet spinning), dry molding (dry spinning), and electrospinning are preferably performed. Thereby, a carbon material precursor composition having a desired shape can be produced safely at low cost. Moreover, from the viewpoint that the carbon material can be produced safely at a lower cost, it is more preferable to use the aqueous solvent as the solvent, and it is particularly preferable to use water.

EXAMPLES The present invention will be described in more detail below based on examples and comparative examples, but the present invention is not limited to the following examples. The acrylamide-based copolymers used in Examples and Comparative Examples and the acrylamide-based homopolymers used in Comparative Examples were synthesized by the following method.

(Synthesis example 1)
After dissolving 5 g (70 mmol) of acrylamide (AAm) and 0.62 g (8.6 mmol) of acrylic acid (AA) in 90 g of water, the solution was replaced with nitrogen by repeatedly reducing the pressure and introducing nitrogen gas using a vacuum pump. Next, an aqueous solution of potassium persulfate (75 mg of potassium persulfate dissolved in 1.1 ml of water) and 75 μl of tetramethylethylenediamine were added under a nitrogen stream, followed by nitrogen substitution, and then a magnetic stirrer was added under a nitrogen stream. and stirred. Thirty minutes after the start of stirring, the stirrer stopped rotating due to an increase in viscosity, but the reaction was continued for 12 hours. After that, water was added and uniformly stirred using a mechanical stirrer to obtain an aqueous solution of an acrylamide/acrylic acid copolymer (PAAm/AA (90 mol %: 10 mol %)).

(Synthesis example 2)
An aqueous solution of an acrylamide/acrylic acid copolymer (PAAm/AA (95 mol%: 5 mol%)) was prepared in the same manner as in Synthesis Example 1, except that the amount of acrylic acid (AA) was changed to 0.26 g (3.6 mmol). got In this synthesis, no increase in viscosity was observed during the reaction, and stirring with a magnetic stirrer was continued for 12 hours.

(Comparative Synthesis Example 1)
After 10 g (140 mmol) of acrylamide (AAm) was dissolved in 90 g of water, pressure reduction and introduction of nitrogen gas were repeated using a vacuum pump to perform nitrogen replacement. Next, an aqueous solution of potassium persulfate (50 mg of potassium persulfate dissolved in 1.1 ml of water) and 50 μl of tetramethylethylenediamine were added under a nitrogen stream, followed by nitrogen substitution, and then a magnetic stirrer was added under a nitrogen stream. and stirred. Thirty minutes after the start of stirring, the stirrer stopped rotating due to an increase in viscosity, but the reaction was continued for 12 hours. Then, 350 ml of water was added and stirred uniformly using a mechanical stirrer to obtain an aqueous solution of acrylamide homopolymer (PAAm) (PAAm concentration: 22 g/L).

(Example 1)
To 1.1 g of the PAAm/AA (90 mol %:10 mol %) aqueous solution obtained in Synthesis Example 1, 0.9 mg of phosphoric acid and 4.9 mg of p-phenylenediamine (p-PDA) were added and dissolved. A portion of p-phenylenediamine is partially neutralized by phosphoric acid, and the neutralized p-phenylenediamine does not participate in the cross-linking reaction with PAAm/AA. - Considering the amount of phenylenediamine (phosphoric acid is calculated as a trivalent acid), the amount of p-phenylenediamine involved in the cross-linking reaction with PAAm/AA by adding the amount of p-phenylenediamine mentioned above. becomes 1 equivalent . In addition, since the phosphoric acid consumed in the neutralization reaction does not act as a catalyst in the cross-linking reaction between PAAm/AA and p-phenylenediamine, considering the amount of phosphoric acid consumed in the neutralization reaction, the above-mentioned By adding an amount of phosphoric acid, the amount of phosphoric acid that acts as a catalyst in the cross-linking reaction between PAAm/AA and p-phenylenediamine is reduced to 100 parts by mass of PAAm/AA (90 mol%: 10 mol%). 2 parts by mass. The aqueous solution thus obtained is placed in a Teflon (registered trademark) petri dish with a diameter of 40 mm, dried in a constant temperature bath at 70° C. for 1 hour, and further vacuum-dried to obtain a sample having a thickness of 20 to 30 μm and a mass of about approx. A film made of a carbon material precursor composition containing 30 mg of PAAm/AA (90 mol %: 10 mol %) (carbon material precursor), phosphoric acid and p-phenylenediamine was obtained.

(Example 2)
PAAm/AA (90 mol%: 10 mol%) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg was prepared in the same manner as in Example 1 except that the amount of p-phenylenediamine was changed to 3.25 mg. A film made of a carbon material precursor composition containing phosphoric acid and p-phenylenediamine was obtained. As in Example 1, considering the amount of p-phenylenediamine consumed by the neutralization reaction, adding the above-mentioned amount of p-phenylenediamine contributes to the cross-linking reaction with PAAm/AA. The amount of p-phenylenediamine is 0.5 equivalents .

(Example 3)
PAAm/AA (90 mol%: 10 mol%) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg was prepared in the same manner as in Example 1 except that the amount of p-phenylenediamine was changed to 6.75 mg. A film made of a carbon material precursor composition containing phosphoric acid and p-phenylenediamine was obtained. As in Example 1, considering the amount of p-phenylenediamine consumed by the neutralization reaction, adding the above-mentioned amount of p-phenylenediamine contributes to the cross-linking reaction with PAAm/AA. The amount of p-phenylenediamine is 1.5 equivalents .

(Example 4)
PAAm/AA (90 mol%: 10 mol%) (carbon A film composed of a carbon material precursor composition containing (precursor material), phosphoric acid, and diaminohexane was obtained. As in Example 1, considering the amount of diaminohexane consumed by the neutralization reaction, the amount of diaminohexane involved in the cross-linking reaction with PAAm/AA can be reduced by adding the above-described amount of diaminohexane. becomes 1 equivalent .

(Example 5)
In the same manner as in Example 4, except that the amount of diaminohexane was changed to 9 mg, PAAm/AA (90 mol%: 10 mol%) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg, phosphoric acid and diamino A film made of a carbon material precursor composition containing hexane was obtained. As in Example 1, considering the amount of diaminohexane consumed by the neutralization reaction, the amount of diaminohexane involved in the cross-linking reaction with PAAm/AA can be reduced by adding the above-described amount of diaminohexane. is 2 equivalents .

(Comparative example 1)
1.1 g of the PAAm aqueous solution obtained in Comparative Synthesis Example 1 was placed in a Teflon (registered trademark) petri dish with a diameter of 40 mm, dried in a constant temperature bath at 70 ° C. for 1 hour, and further vacuum dried to obtain a thickness of 20 mm. A film of PAAm (carbon material precursor) having a thickness of ~30 μm and a mass of about 30 mg was obtained.

(Comparative example 2)
In the same manner as in Example 1 except that 1.4 g of the PAAm aqueous solution obtained in Comparative Synthesis Example 1 was used instead of the PAAm/AA (90 mol%: 10 mol%) aqueous solution obtained in Synthesis Example 1, a thickness of 20 A film of a comparative carbon material precursor composition containing PAAm (carbon material precursor), phosphoric acid and p-phenylenediamine having a thickness of ~30 μm and a mass of about 30 mg was obtained.

(Comparative Example 3)
In the same manner as in Comparative Example 1 except that 1.1 g of the PAAm/AA (90 mol%: 10 mol%) aqueous solution obtained in Synthesis Example 1 was used instead of the PAAm aqueous solution obtained in Comparative Synthesis Example 1, a thickness of 20 A film of PAAm/AA (90 mol %:10 mol %) (carbon material precursor) having a thickness of ˜30 μm and a mass of about 30 mg was obtained.

(Comparative Example 4)
PAAm/AA (90 mol %: 10 mol %) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg and phosphoric acid were prepared in the same manner as in Example 1 except that p-phenylenediamine was not used. A film consisting of the containing comparative carbon material precursor composition was obtained.

(Example 6)
Using 1.1 g of the PAAm/AA (95 mol%: 5 mol%) aqueous solution obtained in Synthesis Example 2 instead of the PAAm/AA (90 mol%: 10 mol%) aqueous solution obtained in Synthesis Example 1, p-phenylenediamine In the same manner as in Example 1 except that the amount was changed to 4.1 mg, PAAm/AA (95 mol%: 5 mol%) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg, phosphoric acid and p- A film made of a carbon material precursor composition containing phenylenediamine was obtained. As in Example 1, considering the amount of p-phenylenediamine consumed by the neutralization reaction, adding the above-mentioned amount of p-phenylenediamine contributes to the cross-linking reaction with PAAm/AA. The amount of p-phenylenediamine is 1.5 equivalents .

(Comparative Example 5)
In the same manner as in Comparative Example 1 except that 1.1 g of the PAAm/AA (95 mol%: 5 mol%) aqueous solution obtained in Synthesis Example 2 was used instead of the PAAm aqueous solution obtained in Comparative Synthesis Example 1, a thickness of 20 A film of PAAm/AA (95 mol %:5 mol %) (carbon material precursor) having a thickness of ~30 μm and a mass of about 30 mg was obtained.

(Comparative Example 6)
PAAm/AA (95 mol %: 5 mol %) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg and phosphoric acid were prepared in the same manner as in Example 6 except that p-phenylenediamine was not used. A film consisting of the containing comparative carbon material precursor composition was obtained.

(Example 7)
In the same manner as in Example 1 except that 9 μl of sulfuric acid was used instead of phosphoric acid, PAAm/AA (90 mol %: 10 mol %) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg, sulfuric acid and p - A film made of a carbon material precursor composition containing phenylenediamine was obtained. As in Example 1, considering the amount of sulfuric acid consumed by the neutralization reaction, the addition of the aforementioned amount of sulfuric acid acts as a catalyst in the cross-linking reaction between PAAm/AA and p-phenylenediamine. The amount of sulfuric acid used is 2 parts by mass with respect to 100 parts by mass of PAAm/AA (90 mol %: 10 mol %).

(Example 8)
PAAm/AA (90 mol%: 10 mol%) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg in the same manner as in Example 1 except that 0.9 mg of boric acid was used instead of phosphoric acid. A film composed of a carbon material precursor composition containing boric acid and p-phenylenediamine was obtained. As in Example 1, considering the amount of boric acid consumed by the neutralization reaction, the addition of the boric acid in the amount described above can be used as a catalyst in the cross-linking reaction between PAAm/AA and p-phenylenediamine. The amount of boric acid that acts as is 2 parts by mass with respect to 100 parts by mass of PAAm/AA (90 mol %: 10 mol %).

(Comparative Example 7)
PAAm/AA (90 mol %: 10 mol %) (carbon material precursor) having a thickness of 20 to 30 μm and a mass of about 30 mg and p-phenylenediamine were prepared in the same manner as in Example 1 except that phosphoric acid was not used. A film consisting of the containing comparative carbon material precursor composition was obtained.

<Carbonization treatment>
The films obtained in Examples 1 to 8 and Comparative Examples 1 to 7 were cut into rectangles of 1.5 cm x 1.25 cm, placed in a crucible with a diameter of 2.5 cm, and placed in a quartz tubular furnace with a diameter of 5 cm at 500 ml/ After raising the temperature from room temperature to 900° C. over 4 hours under a nitrogen stream of 10 minutes, the carbonization treatment was performed by heating at 900° C. for 1 hour.

The appearance of the obtained carbon material was visually observed. In addition, the ratio of the area of the portion of the carbon material that was formed as a self-supporting film without melting or sticking to the crucible (film shape retention ratio) was determined. Furthermore, the mass of the carbon material was measured, and the ratio (carbonization yield) to the initial mass (mass of the carbon material precursor) was determined. The results are shown in Tables 1-3.

As shown in Tables 1 to 3, carbon material precursors composed of PAAm or PAAm/AA (Comparative Examples 1, 3, and 5) and comparative carbon material precursor compositions composed of PAAm/AA and p-phenylenediamine When (Comparative Example 7) was subjected to a heat treatment (carbonization treatment) at 900°C, PAAm and PAAm/AA were melted and the film shape before carbonization could not be maintained. Further, when phosphoric acid and p-phenylenediamine were added to PAAm (Comparative Example 2), although PAAm partially melted by heat treatment (carbonization treatment) at 900 ° C., the resulting carbon material was , 17% of the film shape before carbonization was retained. Furthermore, when phosphoric acid was added to PAAm/AA (Comparative Examples 4 and 6), although PAAm/AA was partially melted by heat treatment (carbonization treatment) at 900 ° C., the obtained carbon material was , 29-35% of the film shape before carbonization was retained.

On the other hand, as shown in Tables 1 to 3, PAAm / AA contains any acid of phosphoric acid, sulfuric acid and boric acid and any polyfunctional amino group of p-phenylenediamine and diaminohexane When the compound was added (Examples 1 to 8), the film shape before carbonization was maintained even after heat treatment (carbonization) at 900°C. This is because the carboxyl group of PAAm/AA and the amino group of p-phenylenediamine or diaminohexane undergo a dehydration reaction by the catalytic action of an acid during heat drying when a film made of a carbon material precursor composition is produced, resulting in a shared It is considered that a bond was formed and a crosslinked structure was introduced to PAAm/AA.

Further, as shown in Tables 1 to 3, when phosphoric acid and p-phenylenediamine or diaminohexane were added to PAAm/AA (Examples 1 to 8), PAAm or PAAm/AA alone Compared with (Comparative Examples 1, 3 and 5), the carbonization yield was higher. Furthermore, as shown in Table 3, when any of phosphoric acid, sulfuric acid and boric acid and p-phenylenediamine were added to PAAm/AA (Examples 1, 7-8) , and p-phenylenediamine alone (Comparative Example 7), the carbonization yield was higher.

From the above results, the carbon material precursor composed of PAAm/AA was combined with any acid of phosphoric acid, sulfuric acid and boric acid and any polyfunctional amino group-containing compound of p-phenylenediamine and diaminohexane. By adding and, even if heat treatment (carbonization treatment) is performed at a high temperature, a carbon material can be obtained with a high carbonization yield while maintaining the shape (shape of the carbon material precursor) before carbonization treatment. was confirmed.

<Viscoelasticity test>
The films obtained in Examples 1 to 8 and Comparative Examples 1 to 7 were cut into rectangles of 2 cm x 0.5 cm, and were measured using a viscoelastic spectrometer under the conditions of a strain of 0.5% and a frequency of 10 Hz in an air atmosphere. The viscoelasticity measurement was performed while the temperature was raised from room temperature to 370°C at a rate of 5°C/min. FIG. 1 is a graph showing the temperature dependence of the storage elastic modulus of the films obtained in Example 1 and Comparative Examples 1-3, and FIG. FIG. 3 is a graph showing the temperature dependence of the storage elastic modulus of the films obtained in Examples 4-5 and Comparative Examples 3-4. FIG. 4 is a graph showing the temperature dependence of the storage elastic modulus of the films obtained in Example 6 and Comparative Examples 5 to 6, and FIG. 4 is a graph showing the temperature dependence of the storage elastic modulus of the obtained film.

As shown in FIGS. 1 to 2, the films obtained in Comparative Examples 1 to 4 were found to soften in the temperature range of 200 to 250° C. with a decrease in storage modulus. On the other hand, the films obtained in Examples 1-3 had higher storage elastic moduli in the temperature range of 200-250° C. than the films obtained in Comparative Examples 1-4. This is because in the carbon material precursor composition of the present invention containing PAAm/AA, phosphoric acid and p-phenylenediamine (Examples 1 to 3), the carboxyl group of PAAm/AA and the amino group of p-phenylenediamine This is probably because the groups and groups undergo a dehydration reaction by the catalytic action of phosphoric acid to form covalent bonds and introduce a crosslinked structure (diamine crosslink) to PAAm/AA. In addition, in the carbon material precursor compositions of the present invention (Examples 1 to 3), a crosslinked structure was introduced into PAAm/AA. It is thought that the shape of On the other hand, in the carbon material precursor consisting only of PAAm (Comparative Example 1) and the comparative carbon material precursor composition containing PAAm, phosphoric acid and p-phenylenediamine (Comparative Example 2), the carbon material precursor A carbon material precursor (Comparative Example 3) containing only PAAm/AA and a carbon material precursor composition containing PAAm/AA and phosphoric acid (Comparison In Example 4), since no p-phenylenediamine was present, a crosslinked structure was not formed, and the storage elastic modulus decreased, resulting in softening.

Similarly, when diaminohexane was used instead of p-phenylenediamine, films made of the carbon material precursor composition of the present invention containing PAAm/AA, phosphoric acid and diaminohexane (Examples 4 and 5 ), the carboxyl group of PAAm/AA and the amino group of diaminohexane undergo a dehydration reaction by the catalytic action of phosphoric acid to form a covalent bond, and a crosslinked structure (diamine crosslink) is introduced to PAAm/AA. , the storage elastic modulus in the temperature range of 200 to 250 ° C. is higher than that of the film containing no polyfunctional amino group-containing compound (Comparative Examples 3 to 4), and Table 1 , it is thought that the shape before carbonization was maintained even after carbonization.

Furthermore, when PAAm/AA (95 mol%: 5 mol%) is used instead of PAAm/AA (90 mol%: 10 mol%), the present invention containing PAAm/AA, phosphoric acid and p-phenylenediamine As shown in FIG. 4, the film (Example 6) made of the carbon material precursor composition of No. 1 has a storage elastic modulus in the temperature range of 200 to 250° C. As shown in Table 2, it is considered that the shape before carbonization was maintained even after carbonization.

Similarly, when sulfuric acid or boric acid is used instead of phosphoric acid, a film (implementation Examples 7 to 8), as shown in FIG. 5, have a higher storage modulus in the temperature range of 200 to 250° C. than films containing no acid (Comparative Examples 3 and 7). , as shown in Table 3, the shape before carbonization was maintained even after carbonization. In the carbon material precursor composition of the present invention containing PAAm/AA, sulfuric acid or boric acid, and p-phenylenediamine (Examples 7 and 8), the carboxyl group of PAAm/AA and p-phenylenediamine and the amino group of PAAm/AA form a covalent bond through a dehydration reaction by the catalytic action of sulfuric acid or boric acid, and a crosslinked structure (diamine crosslink) is introduced to PAAm/AA, whereas a carbon material composed only of PAAm/AA In the precursor (Comparative Example 3) and the comparative carbon material precursor composition containing PAAm/AA and p-phenylenediamine (Comparative Example 7), since the catalyst acid is not included, PAAm/AA This is probably because the dehydration reaction between the carboxyl group of p-phenylenediamine and the amino group of p-phenylenediamine did not proceed and no crosslinked structure was formed.

From the above results, by adding an acid and a polyfunctional amino group-containing compound to a carbon material precursor composed of PAAm/AA, softening of PAAm/AA in the temperature range of 200 ° C. to 250 ° C. is suppressed, and carbonization It was found that the shape before the carbonization treatment was retained even after the treatment.

<Thermogravimetric analysis>
The films obtained in Example 1 and Comparative Examples 3 and 4 were subjected to thermogravimetric analysis while the temperature was raised from room temperature to 1000° C. at a rate of 10° C./min under a nitrogen stream of 500 ml/min. The results are shown in FIG. As shown in FIG. 6, the films obtained in Example 1 and Comparative Example 4 had less weight loss than the film obtained in Comparative Example 3 in the temperature range of 400° C. or higher. From this result, when phosphoric acid is added to PAAm/AA (Comparative Example 4), the carbonization yield is higher than when only PAAm/AA is added (Comparative Example 3). When p-phenylenediamine is added (Example 1), the carbonization yield is equivalent to that when phosphoric acid is added to PAAm/AA (Comparative Example 4), and the improvement in carbonization yield is due to the addition of phosphoric acid. It was found that the addition of p-phenylenediamine did not reduce the carbonization yield.

<Carbonization test>
The films obtained in Example 1 and Comparative Example 4 were cut into rectangles of 5 mm × 20 mm, and sandwiched between an alumina plate 1 and an alumina block 2 (1 cm square, 0.7 g) as shown in FIG. After raising the temperature from room temperature to 900° C. over 4 hours in a 5 cm quartz tubular furnace under a nitrogen stream of 500 ml/min, the material was carbonized by heating at 900° C. for 1 hour.

When the appearance of the obtained carbon material was visually observed, it was found that the film obtained in Example 1 was carbonized while maintaining the film shape, although the film was slightly shrunk. On the other hand, it was found that the film of Comparative Example 4 was carbonized in a partially molten state.

Further, the carbon material obtained from the film of Example 1 was measured for X-ray diffraction pattern and Fourier transform infrared spectrum (FI-IR spectrum). Those results are shown in FIGS. 8 and 9. FIG. In FIGS. 8 and 9, polyacrylonitrile (PAN) is carbonized (heated from room temperature to 900° C. over 4 hours under a nitrogen stream of 500 ml/min, and then heated at 900° C. for 1 hour). The X-ray diffraction pattern and FI-IR spectrum of the carbide obtained by application are also shown.

As shown in FIGS. 8 and 9, the carbon material obtained from the film of Example 1 has an X-ray diffraction pattern and FI-IR spectrum similar to PAN carbide, and is similar to PAN carbide. was confirmed to be a carbon material.

As described above, according to the present invention, a carbon material that contains a carbon material precursor made of an acrylamide-based copolymer and is capable of retaining a desired shape before carbonization even when carbonized. It becomes possible to obtain a precursor composition.

Therefore, since the method for producing a carbon material of the present invention uses such a carbon material precursor composition, it is possible to produce a carbon material that retains the desired shape before carbonization. It is useful as a method.

1: Alumina plate 2: Alumina block 3: Film

Claims (5)

a carbon material precursor composed of an acrylamide-based copolymer containing 50 mol% or more of acrylamide-based monomer units and containing 0.5 mol% or more of vinyl-based monomer units having a carboxyl group as a copolymerization component;
at least one additive component selected from the group consisting of phosphoric acid, polyphosphoric acid, boric acid, sulfuric acid, sulfonic acid, and salts thereof;
a compound having at least one polyfunctional amino group selected from the group consisting of aromatic diamines, aliphatic diamines, and alicyclic diamines;
contains
The content of the additive component is 0.1 to 50 parts by mass with respect to 100 parts by mass of the carbon material precursor,
A carbon material precursor composition, wherein the content of the compound having a polyfunctional amino group is 0.01 to 40 equivalents relative to the content of the carbon material precursor. 2. The carbon material precursor composition according to claim 1, wherein the carboxyl group in the acrylamide copolymer and the polyfunctional amino group form a covalent bond. 3. The carbon material precursor composition according to claim 1, wherein the additive component is at least one selected from the group consisting of phosphoric acid, boric acid, sulfuric acid, and salts thereof. In the presence of at least one additive component selected from the group consisting of phosphoric acid, polyphosphoric acid, boric acid, sulfuric acid, sulfonic acid, and salts thereof, a copolymer component containing 50 mol% or more of acrylamide-based monomer units, is selected from the group consisting of a carbon material precursor composed of an acrylamide copolymer containing 0.5 mol% or more of a vinyl monomer unit having a carboxyl group, and an aromatic diamine, an aliphatic diamine, and an alicyclic diamine. and a compound having at least one polyfunctional amino group, wherein the amount of the additive component is 0.1 to 50 parts by mass with respect to 100 parts by mass of the carbon material precursor, and has the polyfunctional amino group. The carbon material precursor composition according to claim 2 is prepared by heating and reacting at a temperature of 300° C. or less under the condition that the amount of the compound is 0.01 to 40 equivalents with respect to the amount of the carbon material precursor. A method for producing a carbon material precursor composition, characterized by obtaining A carbon material characterized in that the carbon material precursor composition according to any one of claims 1 to 3 is subjected to a heat treatment at a temperature of 500 to 3000 ° C. in an inert atmosphere to perform a carbonization treatment. manufacturing method.

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