JP5007985B2 - Polymer brush compound and preparation method thereof - Google Patents

Description

  The present invention relates to a polymer brush compound having a glucose chain as a basic skeleton and a method for preparing the same, and more particularly to a polymer brush compound obtained by reacting a polysaccharide and a ketene dimer, and a method for preparing the same.

  Polysaccharide esters such as cellulose have been studied as functional materials used in fibers, films, coating materials, thickeners, and the like. Recently, in order to search for a novel functional material, research for synthesizing a polymer brush having a cellulose skeleton has been conducted. The polymer brush is a compound having a relatively long side chain with respect to the repeating basic unit (glucose residue in the case of cellulose), and has attracted attention as a new functional material because of its special structure. Various researches on polymer brushes using cellulose as a raw material have been conducted. However, at present, no example of obtaining a cellulose polymer brush having a high degree of substitution by a simple method has been reported (J. Polym. Sci. Phys. 1996, 34, 1613-1620; J. Appl. Polym. Sci. 1997, 66, 293-305; Polym. Bull. 2000, 45, 381-388; J. Appl. Polym. Sci. 1986 , 31, 341-352; J. Polym. Bull. 1988, 20, 373-377; M. Langmuir 1991, 7, 2803-2807; M. Langmuir 1992, 8, 936-941; Polym. J. 1992, 24 , 641-652; see Macromolecules 1994, 27, 1651-1653, etc.).

  Previously, reports on homogeneous β-ketoesterification of cellulose and alkylketene dimers (AKD) using non-aqueous cellulose solvents have been reported (Journal of Pulp and Paper Science: Vol.26 No.9 (September, 2000). ): Non-Patent Document 1). However, the literature only reports alkyl ketene dimer β-ketoesters having a substitution degree of 0.14.

  On the other hand, Japanese Patent Application Laid-Open No. 10-511728 (Patent Document 1) discloses that DS / AGU (non-hydrophilic) is obtained by contacting cellulose or a cellulose derivative with an acylating reagent, a titanium-containing compound and a carboxamide diluent or a urea-based diluent. A method for producing a cellulose ester having a degree of substitution (with respect to glucose units) of 0.1 to 3.0 is disclosed. More specifically, the method comprises (i) a cellulose material, (ii) a solubilizing amount of solvent system comprising a carboxamide diluent or a urea diluent, (iii) an acylating reagent, and (iv) a titanium-containing compound. To produce a cellulose ester having a total DS / AGU of 0.1 to 3.0. This publication describes an enormous list of compound groups as acylating agents, and also includes ketene and diketene as examples. However, this publication only specifically describes cellulose esters having short side chains such as cellulose acetate, cellulose propionate, and cellulose acetate propionate. Absent.

JP-T-2003-532410 (Patent Document 2) describes esterification of polysaccharides with ketene dimers using enzymes and chemical methods. More specifically, in this publication, the general formula [RO] —CO—CH (R ₁ ) —CO—CH ₂ —R ₁ (wherein R is a polysaccharide and R ₁ has 2 carbon atoms) A product is disclosed comprising a modified polysaccharide product having ˜20 linear or branched aliphatic or olefinic chains in combination with an enzyme that catalyzes the formation of the modified polysaccharide. The uses of the products described in this publication are said to be paint thickeners, paint stabilizers, construction materials, polymer emulsifiers, antihalation coatings, cleaning compositions, and the like. This publication describes a synthesis example of cellulose ether and ketene dimer, but does not show an example in which a polymer brush was obtained.

Journal of Pulp and Paper Science: Vol.26 No.9 (September, 2000) Japanese National Patent Publication No. 10-511728 Special Table 2003-532410

  As described above, various researches on the synthesis of polymer brushes or cellulose esters having a cellulose skeleton have been conducted, but no examples of synthesizing highly substituted polymer brushes having a cellulose skeleton by a simple method have yet been reported. .

  The present inventors newly selected various compounds having different side chain lengths and shapes as β-ketoesterification reagents, and changed the optimum conditions in the reaction, changes in the structure and physical properties of the obtained cellulose derivatives, etc. As a result of the analysis, the present invention has been completed. That is, the present invention provides a polymer brush compound, a preparation method thereof, and the like as described below.

(1) A polymer brush compound having a substitution degree of 1 or more obtained by reacting a polysaccharide and a ketene dimer in the presence of a solvent capable of dissolving the polysaccharide.
(2) The compound according to (1), wherein the polysaccharide is selected from cellulose, starch, pullulan, chitin and curdlan.
(3) The ketene dimer is represented by the following formula (III):
(Wherein each R independently represents an _optionally substituted C _8-30 alkyl group or C _8-30 alkenyl group), the compound according to (1) above.
(4) the solvent capable of dissolving the polysaccharide, lithium chloride / N, N- dimethyl-2-imidazolidinone solvent mixture or lithium chloride / N, according to (1) is N- dimethylacetamide mixed solvent Compound.
(5) The compound according to (1), wherein the reaction between the polysaccharide and the ketene dimer is performed in the presence of a base.
(6) The polymer brush compound has the following general formula (I):
[Wherein R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R (wherein R is each independently substituted be also a good C _8-30 alkyl or C _8-30 alkenyl group); and chemical n is 7～10,000, represented by preferably 100 to 2000, more preferably an integer of 150-800] The compound according to (1) above, which is a compound having a structure.

(7) The following general formula (I):
[Wherein R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R (wherein R and R are each independently substituted be also be a good C _8-30 alkyl or C _8-30 alkenyl group); and, n represents has the chemical structure represented by an integer from 7～10,000, degree of substitution 1-3 A polymer brush compound.
(8) R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R (wherein R is independently C _8-16 alkyl group or The polymer brush compound according to (7) above, which is a C _8-16 alkenyl group.
(9) The polymer brush compound according to (8), wherein the degree of substitution is 1.4 to 3.0 (more preferably 1.7 to 3.0, still more preferably 1.9 to 3.0).

(10) A method of preparing a polymer brush compound having a substitution degree of 1 or more by reacting a polysaccharide and a ketene dimer in the presence of a solvent capable of dissolving the polysaccharide.
(11) The method according to (10), wherein the polysaccharide is selected from cellulose, starch, pullulan, chitin, and curdlan.
(12) The ketene dimer is represented by the following formula (III):
(Wherein, R is each independently selected from Ru optionally C _8-30 alkyl or C _8-30 alkenyl group Der also be substituted) is a compound represented by The method according to (10).
(13) The method according to (10), wherein the cellulose solvent is a lithium chloride / N, N-dimethyl-2-imidazolidinone mixed solvent or a lithium chloride / N, N-dimethylacetamide mixed solvent.

(14) The method according to (10), wherein the reaction between the polysaccharide and the ketene dimer is performed in the presence of a base.
(15) The following general formula (I):
[Wherein R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R (wherein R and R are each independently substituted be also be a good C _8-30 alkyl or C _8-30 alkenyl group); and, n represents has the chemical structure represented by an integer from 7～10,000, degree of substitution 1-3 A composite containing a polymer brush compound and a compound having a substance inclusion function.
(16) The complex according to (15), wherein the compound having a substance inclusion function is a macrocyclic ketene dimer multimer or a cyclodextrin.

The polymer brush compound of the present invention can be used as a surface modifier for base materials such as plastics, films, fibers and coatings, paper, plastics, metals, polymer catalysts, water repellents, polarizing filters, and conductive polymers. Can be used. Moreover, since the polymer brush compound of this invention has a liquid crystal structure according to the kind and substitution degree of the side chain, it can also be used as a novel liquid crystal substance.
Further, according to the method for preparing a polymer brush compound of the present invention, since a special reaction reagent or reaction condition is not used, a desired polymer brush compound can be easily prepared.
Furthermore, the composite formed by combining the polymer brush compound of the present invention with a compound having a substance inclusion function such as a macrocyclic ketene dimer multimer, which is a byproduct of the ketene dimer, is a substance such as the macrocyclic ketene dimer multimer. A drug delivery system can be constructed using the inclusion function.

  Hereinafter, the present invention will be described in detail.

  The first aspect of the present invention relates to a polymer brush compound having a substitution degree of 1 or more obtained by reacting a polysaccharide and a ketene dimer in the presence of a solvent capable of dissolving the polysaccharide. In the present specification, the term “degree of substitution” indicates the degree of substitution with respect to a glucose residue (AGU), that is, the degree of bonding of the substituent to the three hydroxyl groups of the glucose ring. For example, a substitution degree is 2 when two ketene dimer residues are bonded to three hydroxyl groups of a glucose ring. Such a degree of substitution can be easily measured by a known method such as NMR. In this specification, the term “polymer brush” refers to a chain or branched functional group that is relatively long (eg, having 10 or more carbon atoms) relative to the size of a monosaccharide that is a constituent unit of a polysaccharide, an ester bond, A polymeric compound introduced in plural by grafting or the like. In the case of cellulose, it refers to a polymeric compound having a plurality of relatively long side chains (for example, having 10 or more carbon atoms) relative to the size of the glucose residue which is a repeating basic unit, such as the compound shown in (I). .

The polysaccharide as a starting material used in the present invention is not particularly limited as long as it has a glucose chain. Examples of such polysaccharides include cellulose, starch, pullulan, chitin, curdlan and the like. In the present specification, the terms “cellulose, starch, pullulan, chitin, curdlan” are used in a sense including derivatives thereof. Examples of the cellulose derivative include cellulose nitrate, cellulose acetate, hydroxypropyl cellulose, hydroxyethyl cellulose, methyl cellulose, and ethyl cellulose. Examples of the cellulose used in the present invention include microcrystalline cellulose, hardwood pulp, softwood pulp, cellulose obtained from cotton linter, bacterial cellulose, regenerated cellulose, and the like. In the present invention, microcrystalline cellulose is preferably used because of its homogeneity. As the microcrystalline cellulose , for example , those commercially available as Avicel (trademark; manufactured by Asahi Kasei) and Whatman CF series cellulose powder (trademark: manufactured by Funakoshi) can be used. In addition, regarding the chemical structure, production method, and obtaining method of starch, pullulan, chitin, and curdlan, for example, sugar chemistry (Tatsuo Yamashina, Tamio Yamakawa, Satoshi Suzuki, Tokyo Chemical Dojin, published in 1976) , Wako Pure Chemical's reagent catalog (2003 edition), Tokyo Kasei's reagent catalog (2003 edition), Aldrich's reagent catalog (2003 edition), etc.

In the present specification, the ketene dimer is not particularly limited, but preferably used ketene dimer is represented by the following formula (III):
In the formula, each R is independently a C _8-30 alkyl group or a C _8-30 alkenyl group which may be substituted. Here, the “C _8-30 alkyl group” is a C _8-30 saturated hydrocarbon group including a straight chain group and a branched chain group. Further, the “C _8-30 alkenyl group” is a C _8-30 hydrocarbon group containing a double bond including both a straight chain and a branched one, preferably 1 to 3 double bonds Have Here, “ _optionally substituted” of “ _optionally substituted C _8-30 alkyl group or C _8-30 alkenyl group” means a substitution that does not interfere with the synthesis of the polymer brush compound as the final product. This means that the group may be bonded to a C _8-30 alkyl group or a C _8-30 alkenyl group. For example, as such a substituent, 1 to 3 C _1-6 alkyl groups, C _1-6 alkenyl groups, halogen groups, hydroxyl groups, carboxy groups, phenyl groups, heterocyclic groups, etc., C _8-30 alkyl groups Alternatively, it may be bonded to a C _8-30 alkenyl group.

Examples of ketene dimers that can be suitably used in the present invention include ketene dimers obtained from decanoic acid (C ₁₀ AKD), ketene dimers obtained from undecanoic acid (C ₁₂ AKD), and ketene dimers obtained from myristic acid. (C ₁₄ AKD), ketene dimer obtained from palmitic acid (C ₁₆ AKD), ketene dimer obtained from stearic acid (C ₁₈ AKD), ketene dimer obtained from isostearic acid (iso-AKD), oleic acid , Linoleic acid, linolenic acid alone, or a C ₁₈ alkenyl ketene dimer obtained from a mixture thereof, a ketene dimer obtained from a mixture of the above carboxylic acids (eg, C ₁₂ -C ₁₄ -C ₁₆ AKD, etc.), etc. The Such ketene dimers and their synthesis methods are known and described, for example, in JC Sauer, J. Am. Chem. Soc., 69, 2444 (1947). The ketene dimer preferably used in the present invention is a compound represented by the above formula (III), wherein R is a C _8-16 alkyl group or a C _8-16 alkenyl group, more preferably a C _8-16 alkenyl group. It is. The oleic acid ketene dimer is a compound having the above formula (III) and R being (CH ₂ ) ₆ —CH═CH— (CH ₂ ) ₇ —CH ₃ .

  The polymer brush compound of the present invention can synthesize the polysaccharide and ketene dimer as described above in the presence of a solvent capable of dissolving the polysaccharide. The solvent that can dissolve the polysaccharide used in the present invention can be selected according to the type of polysaccharide selected as the starting material. When cellulose is selected as a starting material, a known cellulose solvent can be used, for example, N, N-dimethyl-2-imidazolidinone, 1-methyl-2-pyrrolidinone (NMP), N, N- Dimethylpropionamide, N, N-diethylacetamide, N, N-dimethylacetamide (DMAC), succinimide, phthalimide, glutarimide and the like can be used. In the present invention, a system in which lithium chloride is added to these solvents can be preferably used. Solvents particularly preferably used in the present invention are lithium chloride / N, N-dimethyl-2-imidazolidinone mixture and lithium chloride / N, N-dimethylacetamide mixture.

  The above reaction is preferably performed in the presence of a base. Examples of the base used in the present invention include 1-methylimidazole, pyridine, triethylamine, sodium bicarbonate, sodium acetate and the like. A suitably used base is 1-methylimidazole.

Here, an example of the method for preparing the polymer brush compound of the present invention can be schematically shown by the following reaction formula.
Reaction formula (I)

  As shown in the above reaction formula (I), ketene dimer (III) is mixed with cellulose (II) as an example of polysaccharide, lithium chloride / N, N-dimethyl-2-imidazolidinone mixed solvent and 1-methyl. Cellulose β-ketoester (I ′) can be obtained by reacting in the presence of imidazole. More specifically, first, a starting material such as cellulose is dissolved in a solvent that dissolves the starting material. When microcrystalline cellulose is used as the cellulose sample, for example, it is dissolved in a lithium chloride / N, N-dimethyl-2-imidazolidinone mixed solvent by a heating method at 150 ° C., and then a base such as 1-methylimidazole is added thereto. To carry out the reaction.

  The reaction between the polysaccharide and the ketene dimer is performed, for example, at 10 to 140 ° C. for 10 minutes to 72 hours, preferably at 20 to 80 ° C. for 1 to 24 hours. In the above reaction, 3 to 10 times mol, preferably 8 to 10 times mol of ketene dimer is used per glucose residue in the polysaccharide to achieve a high degree of substitution. A base such as 1 methylimidazole is preferably used in an amount of 1 to 10 moles per glucose residue in the polysaccharide. The amount of the solvent used can be appropriately determined in consideration of the solubility in the polysaccharide as a starting material.

The above reaction only schematically shows the reaction form, and in fact, the polysaccharide is a compound having a plurality of glucose chains per molecule and thus having many hydroxyl groups, or a mixture thereof. Therefore, the final product actually obtained is, for example, the following general formula (I):
[Wherein R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R (wherein R is each independently substituted A compound having a chemical structure represented by the following formula: or a mixture of compounds having the above formula: a C _8-30 alkyl group and a C _8-30 alkenyl group: As obtained. Here, the meanings of the terms “alkyl group”, “alkenyl group” and “optionally substituted” are as described above.

A preferred polymer brush compound of the present invention is a compound of the above formula (I), wherein R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R. In the formula, each R is independently a C _8-16 alkyl group or a C _8-16 alkenyl group, and is a compound having a degree of substitution of 1 to 3. Such polymer brush compounds usually have a number average molecular weight of 3,000 to 20,000,000; a weight average molecular weight of 3,000 to 80,000,000; and a polydispersity (Mw / Mn) of 1 to 5, preferably 60,000 to 4,000,000; Having a weight average molecular weight of 60,000-10,000,000; and a polydispersity (Mw / Mn) of 1-3. For reference, FIG. 1 shows a chemical structure of a polymer brush compound having a degree of substitution of 2 obtained by reacting cellulose and oleic acid ketene dimer.

  The compound of the present invention can be purified by washing with an alcohol such as isopropyl alcohol and drying the reaction product.

  It has been found that the polymer brush compounds of the present invention obtained as described above behave as rod-like solids. This mechanism is not limited to this, but, for example, by introducing a long-chain alkyl group or alkenyl group into the glucose chain at a high density, the occupied volume of the molecular motion of the substituent in the solution is also included. It is considered that the rigidity of the glucose chain itself is maintained from the balance of the tensile force and the compressive force due to the balance and the movement of the substituent group, and it appears to have a rod-like structure. As described above, a polymer brush compound that exhibits a rod-like structure in a solution is not yet known and is a novel compound. Therefore, it is expected that a new application will be found as a material having a new function.

  Furthermore, the cellulose β-ketoester compound of the present invention (with a substitution degree of 1.4 or more obtained from microcrystalline cellulose and OKD) is solubilized in an organic solvent such as chloroform and THF, and the melting point is below room temperature. Presented a condition. Although it is in a gum state at room temperature, the X-ray diffraction pattern has a diffraction peak at a 2θ angle of 3-5 ° corresponding to a long period, and a result suggesting that it is in a liquid crystal state even at room temperature was obtained. Yes. Thus, it has been demonstrated that such polymer brush compounds can be used as liquid crystal materials.

  According to another aspect of the present invention, a composite that can be used as a drug delivery system or the like can be provided by combining the polymer brush compound with a compound having a substance inclusion function. Here, in this specification, the term “complex” means that each component exists in a physically or chemically bound state. In the composite of the present invention, the polymer brush compound and the compound having a substance inclusion function may be physically entangled and integrated, and these compounds may be chemically bonded via a functional group in each component. In some cases, they are integrated with each other.

Examples of the compound having a substance inclusion function used in the present invention include cyclodextrins and macrocyclic ketene dimer multimers. The cyclodextrins used here are known, for example, α-cyclodextrins, β-cyclodextrins, γ-cyclodextrins, derivatives of β-cyclodextrins substituted with hydroxyalkyl groups or sulfoalkyl ether groups, and the like. Can be mentioned. These cyclodextrins can be easily synthesized by known methods or are commercially available (Wako Pure Chemicals reagent catalog (2003 edition), Tokyo Kasei reagent catalog (2003 edition), Aldrich reagent catalog (2003 edition). ) Etc.). Examples of the macrocyclic ketene dimer multimer used here include those obtained as a by-product during the preparation of the cellulose β-ketoester, and have, for example, the following structure (IV).
(In the formula, R is as described above.)

  In the complex of the present invention, an appropriate amount of a substance-containing compound (for example, 0.01 to 3 mol per glucose unit of the compound of the formula (I)) is added to the above-mentioned compound of the formula (I) if necessary. Can be prepared by mixing in the presence of. In the complex thus obtained, the substance-containing compound such as cyclodextrin or macrocyclic ketene dimer multimer is physically entangled with the long side chain of the polymer brush compound having the structure of the above formula (I) Can exist in The macrocyclic ketene dimer multimer of the above formula (IV) may be synthesized as a by-product during the synthesis of the polymer brush compound having the structure of the above formula (I). The composite of the present invention can be prepared without adding a compound. In addition, when the two components are chemically bonded, they can be prepared by introducing appropriate functional groups that react with each other into the two components and reacting them under appropriate conditions. Such a complex can be used as a drug delivery system because it can encapsulate a desired drug with a compound moiety having a substance-encapsulating function and deliver it to a desired site.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these.

(Experimental material)
Microcrystalline cellulose (cellulose powder; manufactured by Advantec Tokyo) was vacuum-dried at room temperature for 1 day, and then used as a cellulose sample. The oleic acid ketene dimer (cis-9-octadecyl ketene dimer (OKD)) provided by NOF was used as the alkenyl ketene dimer. OKD prepared oleic acid chloride and triethylamine according to a conventional method for preparing alkyl ketene dimers. OKD is a light yellow liquid at room temperature, and the purity of OKD was 90% or more as measured by ¹ H-NMR. Anhydrous lithium chloride (LiCl), 1,3-dimethyl-2-imidazolidinone (DMI), 1-methylimidazole (MEI), other reagents and solvents are Wako Pure Chemical Industries laboratory grades Used without. The methyl β-ketoester was prepared as a reference sample by heating a mixture of OKD and methanol in the presence of a small amount of sodium acetate at 90 ° C. for 3 hours.

(Preparation of cellulose solution)
Based on a known method (Macromolecules 1985, 18, 2394-2401), microcrystalline cellulose powder (10 g) is suspended in DMI (450.8 g), this suspension is heated at 150 ° C. for 30 minutes, LiCl (39.2 g) was added at about 100 ° C. under natural cooling. By mixing at room temperature for 1 day, a transparent cellulose solution was obtained. After the cellulose was completely dissolved, DMI (500 g) was added to the solution to reduce the viscosity. A 1 wt% cellulose solution in 4 wt% LiCl / DMI was then obtained.

(Reaction of cellulose and oleic acid ketene dimer)
To the cellulose solution prepared as described above, 1-methylimidazole was added as a base in a molar amount of 0 to 10 times per glucose residue (AGU) of cellulose. Subsequently, 3 to 10 moles of oleic acid ketene dimer (OKD) was added per AGU, and the reaction was carried out at 20 to 100 ° C. for 0 to 12 hours. More specifically, the desired amount of oleic acid ketene dimer and 1-methylimidazole were slowly added to the stirred cellulose solution at room temperature. The mixture was stirred for a predetermined time at room temperature, 60 ° C., and 100 ° C., and the mixture was poured into a large volume of ethanol. The resulting precipitate was washed several times with fresh ethanol and filtered. The resulting dried material is further purified by extracting the non-cellulosic material with 1-propanol for several hours at 90 ° C., then washed thoroughly by filtration with 1-propanol and 40 ° C. in a vacuum oven. And dried for 1 hour.

In addition, when 1-propanol was used instead of ethanol, the non-cellulosic substance could be removed more efficiently by washing.
Here, FIG. 2A shows an HPSEC pattern of a typical reaction product (a reaction product of microcrystalline cellulose and OKD) dissolved in THF. As shown in FIG. 2A, this product contains β-ketoesters, low molecular weight byproducts and unreacted OKD. As shown in FIGS. 2B and 2C, it was found that most by-products and unreacted OKD can be removed by extraction with 1-propanol.

(Structural analysis by FT-IR spectrum)
Next, the FT-IR spectrum of the purified reaction product is shown in FIG. As shown in FIG. 3, as the degree of substitution increases, the amount of hydroxyl groups in cellulose decreases, and about 3400
absorption band decreases seen in cm ^-1, conversely β- ketoester C = O stretching absorption band seen in 1740 and 1710 cm ^-1 due to vibration is increasing. In addition, bands of 2800 to 3000 cm ⁻¹ , 1470 cm ⁻¹ and 1720 cm ⁻¹ based on CH stretch vibration and alkyl chain deformation increase with β-ketoesterification. Based on this information, it can be concluded that OKD is introduced into the hydroxyl group of cellulose through a β-ketoester bond by subjecting LiCl / DMI to a homogeneous reaction as a cellulose solvent.

(Relationship between reaction conditions and substitution degree)
(1) Reaction time: FIGS. 4, 5 and 6 show the relationship between the reaction time and the degree of substitution of cellulose β-ketoester obtained by changing the reaction conditions.
(2) Reaction temperature: FIG. 7 shows the relationship between the reaction temperature and the degree of substitution by rewriting the data shown in FIGS. 5 and 6 in relation to the reaction temperature. As shown in FIG. 7, it was found that the degree of substitution decreased as the reaction temperature increased. This result shows that the above reaction does not coincide with the normal reaction in the reaction between the alcohol compound and the esterifying agent.
(3) Molar ratio of 1-methylimidazole to oleic acid ketene dimer:
FIG. 8 shows the experimental results showing the relationship between the molar ratio of 1-methylimidazole and oleic acid ketene dimer and the degree of substitution. These reactions were carried out at room temperature or 100 ° C. for 3 hours. The molar ratio of OKD to anhydroglucose units was fixed at 10: 1. The degree of substitution increased with increasing amine catalyst loading from 10: 0 to 10: 4 (OKD: MEI). In this experiment, the optimal molar ratio of OKD to MEI was found to be 10: 4.
(4) Molar ratio of OKD to anhydroglucose unit: FIG. 9 shows the experimental results showing the relationship between the OKD: AGU molar ratio and the degree of substitution. Here, the OKD: MEI molar ratio was fixed at 1: 1. The reaction was carried out at room temperature for 3 hours. As shown in FIG. 9, the degree of substitution increased rapidly when the OKD: AGU molar day exceeded 6.

(Cellulose β-ketoester)
Table 1 shows the degree of substitution, molecular weight, degree of polymerization, molecular weight distribution, etc. of cellulose β-ketoester obtained by the above experiment.

(Structural analysis result by NMR)
FIGS. 10 and 11 show charts of ¹³ C-NMR spectrum and ¹ H-NMR spectrum of OKD, methanol β-ketoester and the obtained cellulose β-ketoester having a substitution degree of 2.1, respectively.

  The polymer brush compound of the present invention can be used as a surface modifier for base materials such as plastics, films, fibers and coatings, paper, plastics, metals, polymer catalysts, water repellents, polarizing filters, and conductive polymers. Can be used. Moreover, since the polymer brush compound of this invention has a liquid crystal structure according to the kind and substitution degree of the side chain, it can also be used as a novel liquid crystal substance.

  Further, according to the method for preparing a polymer brush compound of the present invention, since a special reaction reagent or reaction condition is not used, a desired polymer brush compound can be easily prepared. Further, for example, by adding a macrocyclic ketene dimer multimer, which is a by-product of a ketene dimer, to the polymer brush compound of the present invention, a drug delivery system using the substance inclusion function of the macrocyclic ketene dimer multimer can be obtained. Can be built.

  Furthermore, it has been found that the polymer brush compounds of the present invention behave as if they are rod-like solids due to the high density of long-chain alkyl or alkenyl groups introduced. A polymer brush having such a structure is not yet known, and it is expected that a new application will be found as a material having a new function.

The following documents can be referred to in order to better understand the present invention.
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FIG. 1 is a diagram showing the chemical structure of a polymer brush compound having a degree of substitution of 2 obtained by reacting cellulose and oleic acid ketene dimer. FIG. 2 is a diagram showing HPSEC patterns of representative reaction products in the examples. FIG. 3 is a diagram showing an FT-IR spectrum of the purified reaction product. FIG. 4 is a graph showing the relationship between the reaction time and the degree of substitution of cellulose β-ketoester. FIG. 5 is another diagram showing the relationship between the reaction time and the degree of substitution of cellulose β-ketoester. FIG. 6 is another diagram showing the relationship between the reaction time and the degree of substitution of cellulose β-ketoester. FIG. 7 is another diagram showing the relationship between the reaction temperature and the degree of substitution of cellulose β-ketoester. FIG. 8 is a graph showing experimental results showing the relationship between the molar ratio of 1-methylimidazole and oleic acid ketene dimer and the degree of substitution. FIG. 9 is a diagram showing experimental results showing the relationship between the OKD: AGU molar ratio and the degree of substitution. FIG. 10 is a diagram showing ¹³ C-NMR spectra of OKD, methanol β-ketoester and the obtained cellulose β-ketoester having a degree of substitution of 2.1. FIG. 11 is a chart showing ¹ H-NMR spectrum charts of OKD, methanol β-ketoester and the obtained cellulose β-ketoester having a degree of substitution of 2.1.

Claims (5)

The following general formula (I):
[Wherein R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R (wherein R is independently substituted A C _8-30 alkyl group or a C _8-30 alkenyl group; and n is an integer of 7 to 10,000], and the degree of substitution is 1 to 3 Brush compound. R ¹ , R ² and R ³ are each independently hydrogen or —CO—CH (R) —CO—CH ₂ —R (wherein R is independently C _8-16 alkyl group or C _{8- 16} alkenyl; group), polymer brushes compound according to claim 1. The polymer brush compound according to claim 2 , wherein the degree of substitution is 1.4 to 3.0. Cellulose and the following formula (III):
(In the formula, each R is independently an _optionally substituted C _8-30 alkyl group or a C _8-30 alkenyl group.)
A ketene dimer, which is a compound represented by the following formula, is reacted in the presence of a lithium chloride / N, N-dimethyl-2-imidazolidinone mixed solvent or a lithium chloride / N, N-dimethylacetamide mixed solvent to obtain a substitution degree of 1 or more A method for preparing a polymer brush compound. The method according to claim 4 , wherein the reaction between the cellulose and the ketene dimer is performed in the presence of a base.