JP6842777B2 - A method for producing a ladder-type polysilsesquioxane having a phosphonic acid group and a phosphonate group in a side chain, a ladder-type polysilsesquioxane laminate, and a ladder-type polysilsesquioxane laminate. - Google Patents

Description

The present invention is a ladder-type polysilsesquioxane having a phosphonic acid group and phosphonate group in the side chain, ladder polysilsesquioxane laminate及Beauty, a method for manufacturing a ladder polysilsesquioxane laminate.

Sylsesquioxane is a compound having a structure of _{(RSiO 1.5} ) _n in which one organic substituent (R) and an average of 1.5 oxygen atoms (O) are bonded to a silicon atom (Si). It is a generic term. Since silsesquioxane has excellent heat resistance and durability, and also has excellent compatibility with organic materials due to the presence of organic substituents, it has been attracting attention in recent years mainly in the field of organic-inorganic hybrid materials.

Ladder-type polysilsesquioxane has a polymer main chain that extends one-dimensionally, and ladder-type polysilsesquioxane that contains a substituent (for example, a sulfo group or a phosphonic acid group) that exhibits proton conductivity in the side chain is It is expected to have excellent thermal stability and good proton conductivity. Therefore, the use of such a ladder type polysilsesquioxane as a solid electrolyte of a solid polymer fuel cell is being studied. Regarding the application of the ladder-type polysilsesquioxane to a solid electrolyte, for example, Patent Documents 1 and 2 disclose a proton conductive film.

Japanese Unexamined Patent Publication No. 2005-339961 Japanese Unexamined Patent Publication No. 2006-73357

The proton conductive membranes of Patent Documents 1 and 2 are obtained by combining various silsesquioxane including a ladder type with an organic polymer material having a carbon having a sulfonic acid group as a main skeleton. The part responsible for proton conduction in this proton conduction film formation is mainly an organic polymer material. Sylsesquioxane containing a sulfonic acid group is also used in part, but its structure is unclear.

The present invention has been made in view of the above circumstances, and includes a ladder-type polysilsesquioxane having a phosphonic acid group and a phosphonate group having more excellent heat resistance in the side chain, a ladder-type polysilsesquioxane laminate , and a ladder-type polysilsesquioxane laminate. Another object of the present invention is to provide a method for producing a ladder-type polysilsesquioxane laminate.

The ladder-type polysilsesquioxane according to the first aspect of the present invention is
Represented by Equation 2

(In the formula 2, R ¹ is an alkylene group having 1 to 6 carbon atoms, n represents a positive real number, X represents an alkali metal cation, alkaline earth metal cations, ammonium cations, or imidazolium cation. )
It is characterized by that.

Further, the main chain may have a twisted rod structure.

The ladder-type polysilsesquioxane laminate according to the second aspect of the present invention is
A plurality of ladder-type polysilsesquioxane represented by the formula 2 having a rod structure in which the main chain is twisted are laminated in a hexagonal manner.

(In Formula 2, X represents an alkali metal cation, an alkaline earth metal cation, an ammonium cation, or an imidazolium cation, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and n represents a positive real number.)
It is characterized by that.

The method for producing a ladder-type polysilsesquioxane laminate according to the third aspect of the present invention is as follows.
The ladder-type polysilsesquioxane represented by the formula 1 obtained by hydrolyzing and condensing the compound represented by the formula 3 was treated with a base and treated with a base.

(In Formula 3, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents an alkyl group having 1 to 4 carbon atoms.)

(In Formula 1, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and n represents a positive real number.)
A laminate obtained by hexagonally laminating a plurality of ladder-type polysilsesquioxane represented by the formula 2 and having a rod structure in which the main chain is twisted is obtained.

(In Formula 2, X represents an alkali metal cation, an alkaline earth metal cation, an ammonium cation, or an imidazolium cation, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and n represents a positive real number.)
It is characterized by that.

INDUSTRIAL APPLICABILITY The present invention can provide a ladder-type polysilsesquioxane having a phosphonic acid group or a phosphonate group having a more excellent heat resistance in the side chain.

It is a figure which shows typically the twist structure of a ladder type polysilsesquioxane. It is a figure which shows typically the structure of the ladder type polysilsesquioxane laminate. It is a figure which shows ^{the 1} H NMR spectrum of the product in an Example. It is a figure which shows the IR spectrum of the product in an Example. It is a figure which shows ^{the 29} Si NMR spectrum of the product in an Example. It is a figure which shows the TGA analysis result under the oxygen atmosphere of PSQ-PO (OH) _{2 in an Example.} It is a figure which shows the TGA analysis result under the nitrogen atmosphere of PSQ-PO (OH) _{2 in an Example.} It is a figure which shows the IR spectrum of PSQ-PO (OH) _{2 in an Example.} It is a figure which shows the XRD pattern of PSQ-PO (OH) ₂ and PSQ-PO (OK) _{2 in an Example.} It is a TEM photograph of PSQ-PO (OK) _2.

(Ladder type polysilsesquioxane, ladder type polysilsesquioxane laminate)
The ladder-type polysilsesquioxane according to the present embodiment is represented by the formula 1 or the formula 2. In formulas 1 and 2, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and n represents a positive real number. Further, X in Formula 2 represents an alkaline cation, an alkaline earth metal cation, an ammonium cation, or an imidazolium cation.

The ladder-type polysilsesquioxane represented by the formulas 1 and 2 has a phosphonic acid group or a phosphonate group bonded to Si of the polymer main chain as a side chain, respectively. That is, one phosphonic acid group or one phosphonate group is bonded to one Si of the polymer main chain. As shown in FIG. 1, the ladder-type polysilsesquioxane represented by the formulas 1 and 2 has the polymer main chain extending one-dimensionally and the main chain twisting due to the repulsion of the electric charges between the side chains. It has a rod structure.

Then, in the ladder-type polysilsesquioxane represented by the formula 1, the phosphonic acid group in the side chain forms a continuous proton transfer pathway and exhibits high proton conductivity.

Further, the ladder-type polysilsesquioxane according to the present embodiment is derived from the excellent heat resistance and durability derived from the Si—O—Si bond of the main chain, and the rigid main chain having a double chain structure. It has a high glass transition point. Therefore, the ladder type polysilsesquioxane can be suitably used as a solid electrolyte of a polymer electrolyte fuel cell at a high temperature exceeding 100 ° C. (for example, 150 ° C. to 200 ° C.).

Furthermore, the ladder-type polysilsesquioxane according to the present embodiment also has flame retardancy derived from a phosphonic acid group or a phosphonate group. Therefore, the ladder-type polysilsesquioxane according to the present embodiment can be suitably used as a flame-retardant material. The ladder-type polysilsesquioxane has excellent compatibility with an aqueous solvent and a highly polar organic solvent, and is soluble. For example, a solution in which a ladder-type polysilsesquioxane is dissolved in a solvent can be coated on various materials to form a film, and it can also be used as a flame-retardant coating material.

Further, in the ladder type polysilsesquioxane having a phosphonate group represented by the formula 2, as shown in FIG. 2, a structure in which rod structures are regularly arranged and laminated in a hexagonal manner is constructed.

(Method for manufacturing ladder type polysilsesquioxane and ladder type polysilsesquioxane laminate)
The ladder-type polysilsesquioxane represented by the above formula 1 can be obtained by hydrolysis and polycondensation of the compound represented by the formula 3.

In formula 3, R ¹ is an alkylene group having 1 to 6 carbon atoms. If the alkylene group is longer than this, regular steric coordination becomes difficult, which may hinder the formation of a ladder structure. Further, the heat resistance and durability of the obtained ladder type polysilsesquioxane may be lowered.

Further, R ² is an alkyl group having 1 to 4 carbon atoms. If the alkyl chain is long, hydrolysis described later may be difficult to occur.

Examples of the compound represented by the formula 3 include 2-diethylphosphate ethyltriethoxysilane, 2-diethylphosphate butyltriethylsilane, 2-diethylphosphate hexyltriethylsilane, 2-dimethylphosphatemethyltrimethoxysilane, and 2-dipropylphosphatepropyltri. Various compounds such as propylsilane and 2-dibutylphosphate butyltributylsilane can be mentioned.

Hydrolysis and polycondensation of the compound represented by the formula 3 can be carried out by mixing the compound represented by the formula 3 with a strongly acidic aqueous solution such as concentrated hydrochloric acid and refluxing and stirring. The temperature may be about 100 ° C. and the reaction time may be about 12 hours. It is preferable to add an excess amount (for example, 120 times in molar ratio) of concentrated hydrochloric acid to the compound represented by the formula 3. This is because when the amount of concentrated hydrochloric acid is small, the hydroxyl group formation of the alkoxy group bonded to phosphorus is difficult to proceed.

Then, after the reaction, the solvent is heated in an open system (about 50 to 60 ° C.) to evaporate and remove the solvent, whereby a ladder-type polysilsesquioxane represented by the formula 1 can be obtained.

Below, a synthesis example of the ladder type polysilsesquioxane represented by the formula 1 is shown using 2-diethylphosphate ethyltriethoxysilane (DPETES) as the compound represented by the formula 3.

Further, by neutralizing the ladder-type polysilsesquioxane represented by the formula 1 with a base, as shown in the synthesis example below, the H of the hydroxyl group is replaced with various cations, and the phosphonic acid group is formed. A ladder-type polysilsesquioxane represented by the formula 2 having a phosphonate group is obtained. Then, the ladder-type polysilsesquioxane represented by the formula 2 constructs a hexagonal laminate in which the polymer main chains are regularly arranged, as shown in FIG.

An example of synthesizing the ladder-type polysilsesquioxane represented by the formula 1 by treating the ladder-type polysilsesquioxane represented by the formula 1 with KOH is shown below.

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to the examples.

10 mL of concentrated hydrochloric acid (120 mmol) was added to 1.0 mmol of DPETES, and the mixture was refluxed and stirred at 100 ° C. for 12 hours. The solution was then heated in an open system (about 50-60 ° C., 2-3 hours) to evaporate and remove the solvent to give the product (yield 93%).

It was attempted whether the obtained product was soluble in various solvents. The results are shown in Table 1. The product was soluble in water and dimethyl sulfoxide (DMSO).

The obtained product was dissolved in heavy water and ^{1 1} H NMR spectrum was measured. In addition, the IR spectrum of the product and the ²⁹ Si NMR spectrum were measured. ^{The 1} H NMR spectrum, IR spectrum, and ²⁹ Si NMR spectrum are shown in FIGS. 3, 4, and 5, respectively.

^{Looking at the 1} H NMR spectrum of FIG. 3, no peak derived from the phosphonate ester was observed, and only two broad peaks derived from the ethyl group were observed.

Looking at the IR spectrum of Figure ^4, 938cm ^-1, 1010cm -1 and, in 1187cm ^-1, P-OH phosphonic acid group, P (= O) O ^- and P = absorption peaks originating from O, respectively It was observed.

From these results, it was confirmed that the product had a phosphonic acid group as the hydrolysis reaction of the phosphonic acid ester group proceeded.

Moreover, looking at the IR spectrum of FIG. 4, absorption peaks derived from the Si—O—Si bond were observed at ^{1041 cm -1} and 1135 cm ^-1. Looking at the ²⁹ Si NMR spectrum of Figure 5, a broad ^{T 3} peaks derived from Si atom having three Si-O-Si bond was mainly observed. From these facts, it can be confirmed that the hydrolysis / condensation reaction of DPETES proceeded and a Si—O—Si bond was formed.

From these results, it was confirmed that the product was a ladder-type polysilsesquioxane (hereinafter, PSQ-PO (OH) _{2) having a phosphonic acid group in the side chain represented by the formula 4.}

Further, PSQ-PO (OH) _{2 was} subjected to TGA (Thermogravimetric Analysis) measurement under an oxygen atmosphere and a nitrogen atmosphere. The results are shown in FIGS. 6 and 7.

In both FIGS. 6 and 7, a slight weight loss is observed from around 210 ° C. This can be considered as follows. Looking at the IR spectrum of PSQ-PO (OH) ₂ after heating at 250 ° C. in FIG. 8, a peak derived from the P = O bond of the P— ^{OP = O bond is generated at 1279 cm -1.} That is, the weight was reduced due to the dehydration condensation of the phosphonic acid group in the side chain.

Further, in both FIGS. 6 and 7, a significant weight loss was observed from around 460 ° C., which is considered to be due to the decomposition of the ethylene group in the side chain bonded to the main chain.

From the above, it can be seen that PSQ-PO (OH) ₂ is thermally stable up to around 200 ° C. and can withstand use under temperature conditions exceeding 100 ° C. when used as a solid electrolyte.

Subsequently, XRD measurement of PSQ-PO (OH) _{2 was performed.} The measurement result is shown in FIG. In the spectrum of PSQ-PO (OH) ₂ , a broad diffraction peak was observed, and no peak derived from the regular laminated structure was observed.

Subsequently, a KOH methanol solution (0.2 mol / L) was added to PSQ-PO (OH) _{2, and the mixture was stirred at room temperature (1 hour). As a result, a ladder-type polysilsesquioxane (hereinafter, PSQ-PO (OK) 2} ) having a phosphonate group represented by the formula 5 in which -OH of the phosphonic acid group was converted to -OK was obtained in the side chain.

XRD measurement was performed on the synthesized PSQ-PO (OK) _2. The measurement result is shown in FIG. In the spectrum of PSQ-PO (OK) ₂ , a diffraction peak was observed in which the ratio of d values was 1: 1 / √3: 1/2: 1 / √7: 1/3 from the low angle side. This is a typical hexagonal phase diffraction pattern, and _{indicates that the rod-shaped PSQ-PO (OK) 2} formed a regularly laminated structure.

Calculated from the XRD patterns the rod PSQ-PO _{(OK) 2} diameter is at 2nm or less, also from the fact ^{that T 3} peaks than ²⁹ Si NMR spectrum of Figure 5 is primarily observed, very limited It is considered that a network structure composed of Si—O—Si bonds is formed in the space. That is, it was suggested that the synthesized PSQ-PO (OK) ₂ has a ladder-like structure in which an 8-membered ring composed of a Si—O—Si bond is connected in a one-dimensional direction. Further, PSQ-PO (OK) ₂ having a ladder-like structure forms a twisted structure (rod structure) which is considered to be a conformation in which the distance between the side chains is the longest due to the repulsion of charges between the anions of the side chains. It is considered that a hexagonal laminate is being constructed.

A TEM (Transmission Electron Microscope) photograph of PSQ-PO (OK) _{2 is shown in FIG.} From the TEM photograph, it can be seen that PSQ-PO (OK) _{2 is a hexagonal laminate.}

The above-described embodiments are for explaining the present invention and do not limit the scope of the present invention. That is, the scope of the present invention is indicated not by the embodiment but by the claims. Then, various modifications made within the scope of the claims and the equivalent meaning of the invention are considered to be within the scope of the present invention.

This application is based on Japanese Patent Application No. 2016-35903 filed on February 26, 2016. The specification, claims, and the entire drawing of Japanese Patent Application No. 2016-35903 shall be incorporated into this specification as a reference.

The ladder-type polysilsesquioxane according to the present invention is expected to be used as an electrolyte in a fuel cell because the phosphonic acid group in the side chain forms a continuous proton transfer pathway and exhibits high proton conductivity. To. Further, in addition to heat resistance and durability derived from the Si—O—Si bond of the main chain, flame retardancy derived from a phosphonic acid group or a phosphonate group is expected to be used as a flame retardant material.

Claims (4)

Represented by Equation 2

(In the formula 2, R ¹ is an alkylene group having 1 to 6 carbon atoms, n represents a positive real number, X represents an alkali metal cation, alkaline earth metal cations, ammonium cations, or imidazolium cation. )
A ladder-type polysilsesquioxane characterized by this. The main chain has a twisted rod structure,
The ladder-type polysilsesquioxane according to claim 1. A plurality of ladder-type polysilsesquioxane represented by the formula 2 having a rod structure in which the main chain is twisted are laminated in a hexagonal manner.

(In Formula 2, X represents an alkali metal cation, an alkaline earth metal cation, an ammonium cation, or an imidazolium cation, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and n represents a positive real number.)
A ladder-type polysilsesquioxane laminate characterized by this. The ladder-type polysilsesquioxane represented by the formula 1 obtained by hydrolyzing and condensing the compound represented by the formula 3 was treated with a base and treated with a base.

(In Formula 3, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and R ² represents an alkyl group having 1 to 4 carbon atoms.)

(In Formula 1, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and n represents a positive real number.)
A laminate obtained by hexagonally laminating a plurality of ladder-type polysilsesquioxane represented by the formula 2 and having a rod structure in which the main chain is twisted is obtained.

(In Formula 2, X represents an alkali metal cation, an alkaline earth metal cation, an ammonium cation, or an imidazolium cation, R ¹ represents an alkylene group having 1 to 6 carbon atoms, and n represents a positive real number.)
A method for producing a ladder-type polysilsesquioxane laminate.