KR20240104935A - Polyurethane for solid propellant and its manufacturing method - Google Patents

Abstract

The present invention relates to polyurethane for solid propellants and a method for producing the same. Specifically, the present invention includes the steps of click-reacting a ferrocene compound containing an alkyne group and a polyurethane polymer containing an azide group to produce a polyurethane to which the ferrocene compound is covalently bonded; It relates to a method for producing polyurethane for solid propellants comprising.

Description

Polyurethane for solid propellant and its manufacturing method {Polyurethane for solid propellant and its manufacturing method}

The present invention relates to polyurethane for solid propellants and a method for producing the same.

Metallocenes have been used not only for catalytic reactions but also as oxidants, plasticizers, and combustion additives for solid propellants to improve mechanical properties. However, when the metallocene and the polymer are simply mixed, there is a problem in that the dispersibility is reduced.

In the case of conventional polyethylene oxide or polypropylene oxide structures covalently bonded to ferrocene, ferrocene has the advantage of excellent dispersibility and excellent explosive properties, but depending on the polyolefin oxide series, processability and mechanical strength are low, so the structure is damaged by external impact. Problems such as explosion or self-explosion may occur.

Polyurethane has excellent processability and mechanical properties, and in particular, can have appropriate elasticity and mechanical strength due to an appropriate combination of hard and soft segments. However, in the case of general polyurethane, the amount of heat generated when heated is low, making it difficult to use as a solid propellant. Accordingly, the present invention seeks to provide a polyurethane for solid propellants that has excellent mechanical properties and a certain level of elasticity, has excellent durability, and at the same time has excellent smoke properties.

The present invention seeks to provide a polyurethane for solid propulsion that has superior processability and mechanical properties compared to conventional polyethylene oxide or polypropylene oxide structures covalently bonded with ferrocene and at the same time has excellent calorific value.

The present invention provides a method for producing polyurethane for a solid propellant, including the step of producing a polyurethane to which the ferrocene compound is covalently bonded by clicking reacting a ferrocene compound containing an alkyne group and a polyurethane polymer containing an azide group.

According to one aspect of the present invention, the molal ratio of the azide group-containing polyurethane polymer and the alkyne group-containing ferrocene may be 1:0.1 to 1.

According to one aspect of the present invention, the polyurethane containing an azide group may be produced by reacting a diol-based compound containing a diol containing an azide group and an isocyanate-based compound.

According to one aspect of the present invention, the diol containing the azide group may be prepared through cation ring-opening polymerization of tetrahydrofuran and epic chlorohydrin.

According to one aspect of the present invention, the molar ratio of tetrahydrofuran and epicchlorohydrin may be 1:0.3 to 3.

According to one aspect of the present invention, the diol containing the azide group may include at least one selected from diols or polyalkylenediols with a number average molecular weight of 100 to 50,000 g/mol.

According to one aspect of the present invention, the polyurethane for solid propellant may have a calorific value of 6,000 cal/g or more according to the Isoperibel Bomb Calorimeter Parr Instrument 6300EF device.

According to one aspect of the present invention, it may be manufactured by clicking reaction of a ferrocene compound containing an alkyne group and a polyurethane polymer containing an azide group.

According to one aspect of the present invention, the molal ratio of the azide group-containing polyurethane polymer and the alkyne group-containing ferrocene may be 1:0.1 to 1.

According to one aspect of the present invention, the polyurethane containing an azide group may be produced by reacting a diol-based compound containing a diol containing an azide group and an isocyanate-based compound.

According to one aspect of the present invention, the diol containing the azide group may include any one or more selected from diols or polyalkylene diols with a number average molecular weight of 100 to 50,000 g/mol.

According to one aspect of the present invention, the polyurethane for solid propellant may have a calorific value of 6,000 cal/g or more according to the Isoperibel Bomb Calorimeter Parr Instrument 6300EF device.

According to one aspect of the present invention, a solid propellant containing the polyurethane for solid propellant can be provided.

By providing a method for producing polyurethane for solid propellants, the present invention can provide polyurethane for solid propellants that maintains the excellent mechanical properties and processability of conventional polyurethanes while simultaneously achieving a calorific value of more than 6,000 cal/g.

Figure 1 shows the structure of polyurethane for solid propellants and FT-IR graphs of Preparation Example 2, Example 2, and Example 3.
Figure 2 is an FT-IR and ¹³ C-NMR image of Poly(Epichlorohydrin-co-Tetrahydrofuran)diol in Preparation Examples 1 to 3.
Figure 3 shows FT-IR and ¹³ C-NMR graphs of Poly(Epichlorohydrin-co-Tetrahydrofuran)diol of Preparation Examples 1 to 3.
Figure 4 is a FT-IR and ¹³ C-NMR graph of the azido-polyurethane of Preparation Examples 1 to 3.
Figure 5 is a ¹ H-NMR image of Preparation Example 1 and Examples 1 to 3.
Figure 6 is a graph measuring the mechanical strength of Preparation Example 2, Example 2, and Comparative Example 1.

Hereinafter, the present invention will be described in more detail through specific examples or examples including the attached drawings. However, the following specific examples or examples are only a reference for explaining the present invention in detail, and the present invention is not limited thereto, and may be implemented in various forms.

Additionally, unless otherwise defined, all technical and scientific terms have the same meaning as commonly understood by one of ordinary skill in the art to which the present invention pertains. The terminology used in the description herein is merely to effectively describe specific embodiments and is not intended to limit the invention.

Additionally, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to also include the plural forms, unless the context clearly dictates otherwise.

Additionally, when a part "includes" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

In addition, in the present invention, “explosiveness” and “flammability” are related to each other. If explosiveness is high, smokeability is high, and conversely, if smokeability is high, explosiveness is high.

In the case of conventional polyethylene oxide or polypropylene oxide structures containing ferrocene, they have the advantage of excellent explosive properties due to the inclusion of ferrocene, but depending on the polyolefin oxide series, processability and mechanical strength are low, so the structure is damaged by external impact or self-sealing. Problems such as explosion may occur.

Polyurethane has excellent processability and mechanical properties, and in particular, can have appropriate elasticity and mechanical strength due to an appropriate combination of hard and soft segments. However, in the case of general polyurethane, the amount of heat generated when heated is low, making it difficult to use as a solid propellant. Accordingly, the present invention seeks to provide a polyurethane for solid propellants that has excellent mechanical properties and a certain level of elasticity, has excellent durability, and at the same time has excellent smoke properties.

Accordingly, the present invention includes the steps of click-reacting a ferrocene compound containing an alkyne group and a polyurethane polymer containing an azide group to produce a polyurethane to which the ferrocene compound is covalently bonded; By providing a method for manufacturing polyurethane for solid propellants including, it is possible to manufacture polyurethane for solid propellants that can have better processability and calorific value than conventional ferrocene solid propellants.

Although it is possible to provide polyurethane for solid propellants by mixing ferrocene with general polyurethane, simple blending of ferrocene and polyurethane has the disadvantage of not having excellent mechanical strength and at the same time, low explosiveness. Accordingly, the present invention can provide polyurethane for solid propulsion containing ferrocene by manufacturing polyurethane with a special structure containing an azide group and clicking reaction with ferrocene containing an alkyne group.

The solid propulsion polyurethane contains azide and ferrocene, which have excellent explosive properties, in the polyurethane structure, and at the same time, the ferrocene is bonded to the polyurethane in a covalent triazole structure, thereby dramatically increasing the durability of the polyurethane and at the same time generating heat. This has the advantage of being significantly improved. It has excellent mechanical properties and external impact stability that are incomparable to conventional polyethylene oxide or polypropylene oxide containing ferrocene, and at the same time has excellent calorific value.

The molal ratio of the ferrocene containing an azide group and an alkyne group of the polyurethane polymer containing an azide group may be 1: 0.1 to 1, and specifically, the molal ratio of the ferrocene containing an azide group and an alkyne group may be 1: 0.3 to 1. It may be 7, and specifically, the molal ratio of ferrocene including an azide group and an alkyne group may be 1:0.4 to 0.6, but is not limited thereto.

As the molar ratio of the azide group and ferrocene of the solid propulsion polyurethane satisfies the above conditions, it has the advantage of excellent processability and mechanical properties and at the same time excellent smoke properties.

According to one aspect of the present invention, the polyurethane containing an azide group may be produced by reacting a diol-based compound containing a diol containing an azide group and an isocyanate-based compound.

The polyurethane containing an azide group is a polyurethane composition with a special structure that is polymerized with a diol containing an azide group and an isocyanate-based compound.

The diol containing the azide group may have the structure of Formula 1 below.

[Formula 1]

(In Formula 1, R ₁ is each an alkylene group of C ₁ to C ₂₀ , and m and n are each integers from 1 to 100.)

According to one aspect of the present invention, the molar ratio of m and n in Formula 1 may be 1:9 to 9:1, and preferably the molar ratio of m and n may be 3:7 to 7:3. , but is not limited to this.

Specifically, the diol containing the azide group may be prepared through cation ring-opening polymerization of tetrahydrofuran and epic chlorohydrin, and the molar ratio of tetrahydrofuran and epic chlorohydrin is 1:0.3 to 3. Specifically, the molar ratio of tetrahydrofuran and epic chlorohydrin may be 1:0.4 to 2.5, specifically 1:0.8 to 1.2, but is not limited thereto. Polyurethane for solid propulsion containing a diol containing an azide group that satisfies the molar ratio of tetrahydrofuran and epic chlorohydrin can simultaneously satisfy excellent mechanical properties and smoke properties.

As the molar ratio is satisfied, the molecular weight distribution (PDI) value of the polyurethane containing the azide group may be 2 or less.

According to one aspect of the present invention, the diol containing the azide group may include at least one selected from diols or polyalkylene diols with a number average molecular weight of 100 to 50,000 g/mol.

The diol containing the azide group may preferably have a number average molecular weight of 200 to 30,000 g/mol, more preferably 500 to 10,000 g/mol, but is not limited thereto.

In addition, the types of polyalkylene diols are not greatly limited, but include 1,4-butanediol, 1,6-hexanediol, 1,2-hexanediol, 1,3-hexanediol, 2-methyl-1 , a group consisting of 3-propanediol, 2,5-hexanediol, 2-methyl-1,3-pentanediol, 2-methyl-2,4-pentanediol, ethylene glycol, propylene glycol, tripropylene glycol, glycerol, etc. It may be one or more selected from .

The type of the isocyanate-based compound is not greatly limited, but aromatic isocyanate-based compounds, alicyclic isocyanate-based compounds, aliphatic isocyanate-based compounds, etc. may be used, and aromatic isocyanate-based compounds are preferable.

The polyurethane containing the azide group may specifically satisfy the following formula (2).

[Formula 2]

(In Formula 2, A is a C ₆ to C ₃₀ aromatic group or a C ₆ to C ₃₀ aromatic group substituted with a C ₁ to C ₆ alkyl group, and R ₁ and R ₂ are each independently C ₁ to C ₂₀ is an alkylene group, and m, n, x and y are each integers from 1 to 100.)

The weight average molecular weight of the polyurethane having the azide group is not greatly limited, but may be 2,000 to 100,000 g/mol, specifically 3,000 to 80,000 g/mol. Within the above range, it has advantageous properties for improving mechanical properties such as tensile strength and elongation, but this is only a non-limiting example and is not limited to the above numerical range. At this time, the weight average molecular weight was measured using a gel permeation chromatography (GPC) equipment manufactured by Waters. The analytical column used was Styragel HR from WATERS, and polystyrene was used as a standard material. HPLC grade tetrahydrofuran (THF) was used as the mobile phase solvent and was measured under the conditions of a column heater temperature of 40°C and a mobile phase solvent flow rate of 1.0 mL/min.

Polyurethane containing the azide group can undergo a click reaction with a compound containing an alkyne group due to the azide group.

According to one aspect of the present invention, the polyurethane for solid propellants is a ferrocene polyurethane with a molar ratio of azide group and ferrocene of 1: 0.5 according to the Isoperibel Bomb Calorimeter Parr Instrument 6300EF device, and the calorific value of ferrocene polyurethane is measured to be higher than that of azide polyurethane. , it may have a calorific value of 6,000 cal/g or more.

According to one aspect of the present invention, the polyurethane for solid propellant may have a tensile strength of 3 to 10 MPa, specifically 5 to 10 MPa, and specifically 5 to 6 MPa according to ASTM D412, and a tensile elongation according to ASTM D412. It may be 300% or more, specifically 350 to 700%, specifically 400 to 600%, specifically 400 to 500%.

The polyurethane for solid propulsion of the present invention satisfies the above tensile strength and tensile elongation and has a calorific value of more than 6,000 cal/g, so it has the advantage of excellent processability and durability, as well as excellent explosive resistance.

The present invention can provide a polyurethane for solid propellants manufactured by clicking reaction of a ferrocene compound containing an alkyne group and a polyurethane polymer containing an azide group.

Since the polyurethane for solid propulsion has been described in detail previously, it is omitted here.

According to one aspect of the present invention, the molal ratio of the azide group-containing polyurethane polymer and the alkyne group-containing ferrocene may be 1:0.1 to 1.

According to one aspect of the present invention, the polyurethane containing an azide group may be produced by reacting a diol-based compound containing a diol containing an azide group and an isocyanate-based compound.

According to one aspect of the present invention, the diol containing the azide group may include at least one selected from diols or polyalkylenediols with a number average molecular weight of 100 to 50,000 g/mol.

According to one aspect of the present invention, the polyurethane for solid propellant may have a calorific value of 6,000 cal/g or more according to the Isoperibel Bomb Calorimeter Parr Instrument 6300EF device.

According to one aspect of the present invention, a solid propellant containing the polyurethane for solid propellant can be provided.

The present invention will be described in more detail below based on examples and comparative examples. However, the following Examples and Comparative Examples are only one example to explain the present invention in more detail, and the present invention is not limited by the following Examples and Comparative Examples.

[Mechanical properties]

Mechanical properties were measured by testing according to the test method described in ASTM D412.

[Production Example 1]

[Production method of poly(epichlorohydrin-co-tetrahydrofuran)diol]

270 g of methylene chloride (Dichloromethane, aldrich) was added to a reactor equipped with a condenser. While stirring the reaction solution, 5.66 ml of 1,4-butanediol (aldrich), used as an initiator, was added using a syringe. 1.746ml of BF ₃ -THF, a cationic catalyst, was added using a syringe and stirred for 20 minutes. To the reactor, 74.5 g of epichlorohydrin (ECH) and 135.49 g of tetrahydrofuran (THF) (molar ratio 3:7) were slowly added dropwise for 4 hours. After addition of all mixed monomers for 4 hours, the reaction was further performed at room temperature (25°C) for 2 hours. The reaction was terminated by adding 20 ml of distilled water using a syringe. After adding the distilled water, the mixture was stirred for an additional 20 minutes to form Poly(epichlorohydrin-co- tetrahydrofuran)diol was prepared.

[Production method of poly(glycidyl azide polymer-co-tetrahydrofuran)diol]

100 g of Poly(epichlorohydrin-co-tetrahydrofuran)diol was added to the flask and dissolved in 100 g of DMF. While stirring the dissolved solution, 87 g of sodium azide (NaN ₃ ) was added and reacted at 90°C for 17 hours. The solution was filtered under reduced pressure to remove the produced salt. Poly(glycidyl azide polymer-co-tetrahydrofuran)diol was prepared by pouring the solution into a beaker containing 1,000 ml of distilled water and performing the purification process five times. The purified Poly(glycidyl azide polymer-co-tetrahydrofuran)diol was dried in a vacuum oven at 60°C for 24 hours, then raised to 120°C and dried for an additional 4 hours to prepare Poly(glycidyl azide polymer-co-tetrahydrofuran)diol. .

[Manufacturing method of Azido-Polyurethane]

In the reactor, 20 g of Poly(glycidyl azide polymer-co-tetrahydrofuran)diol, 1.53 ml of 1,4-butanediol, 6.5 g of MDI (Methylene Diphenyl Diisocyanate), 28 g of dimethylformamide as a solvent, 0.02 ml of T-12 (Dibutyltin dilaurate) was added as a catalyst and stirred at 60°C for 6 hours to prepare an Azido-Polyurethane solution. The solution was dried at 80° C. for 24 hours to obtain azido polyurethane powder.

[Production Example 2]

In Preparation Example 1, except that when preparing [Poly(epichlorohydrin-co-tetrahydrofuran)diol, 118 g of epicchlorohydrin (ECH) and 92 g of tetrahydrofuran (THF) (molar ratio 5:5) were used. The same procedure was performed.

[Production Example 3]

In Preparation Example 1, when preparing [Poly(epichlorohydrin-co-tetrahydrofuran)diol, except that 82.6 g of epicchlorohydrin (ECH) and 27.6 g of tetrahydrofuran (THF) (molar ratio 7:3) were used. Then, the same procedure was performed.

[Example 1]

After completely dissolving 4 g of azido polyurethane of Preparation Example 2 in 40 ml of solvent dimethylformamide, 0.3633 g of catalyst copper (II) sulfate (Copper (II 0.1 mol%)) and sodium- as a reducing agent were added for an azide-alkyne click reaction. 0.5765 g of L-ascorbate (Sodium-L-ascorbate, 0.2 mol%) was added.

Afterwards, the [Azide]:[Alkyne] equivalence ratio was adjusted to 1:0.3 and ethynylferrocene (Aldrich) was slowly added. After reaction at 40°C for 24 hours, the remaining catalyst and reducing agent were removed by precipitation in distilled water 2 to 3 times. After washing with methanol 2-3 times to remove unreacted substances, the final product was obtained by drying in a vacuum oven at 60°C for 24 hours.

[Example 2]

After completely dissolving 4 g of azido polyurethane of Preparation Example 2 in 40 ml of solvent dimethylformamide, 0.3633 g of catalyst copper (II) sulfate (Copper (II 0.1 mol%)) and sodium- as a reducing agent were added for an azide-alkyne click reaction. 0.5765 g of L-ascorbate (Sodium-L-ascorbate, 0.2 mol%) was added.

Afterwards, the [Azide]:[Alkyne] equivalence ratio was adjusted to 1:0.5 and ethynylferrocene (Aldrich) was slowly added. After reaction at 40°C for 24 hours, the remaining catalyst and reducing agent were removed by precipitation in distilled water 2 to 3 times. After washing with methanol 2-3 times to remove unreacted substances, the final product was obtained by drying in a vacuum oven at 60°C for 24 hours.

[Example 3]

After completely dissolving 4 g of azido polyurethane of Preparation Example 2 in 30 ml of solvent dimethylformamide, 0.3633 g of copper (II) sulfate as a catalyst (Copper (II 0.1 mol%)) and sodium as a reducing agent were added for the Azide-alkyne click reaction. 0.5765 g of L-ascorbate (Sodium-L-ascorbate, 0.2 mol%) was added.

Afterwards, the [Azide]:[Alkyne] equivalence ratio was adjusted to 1:0.8 and ethynylferrocene (Aldrich) was slowly added. After reaction at 40°C for 24 hours, the remaining catalyst and reducing agent were removed by precipitation in distilled water 2 to 3 times. After washing with methanol 2-3 times to remove unreacted substances, the final product was obtained by drying in a vacuum oven at 60°C for 24 hours.

[Comparative Example 1]

The same procedure was performed except that ethynylferrocene in the amount of Example 2 was added to the Azido-TPU of Preparation Example 1, the Ferrocene TPU of Example 2, and the Azido-TPU of Preparation Example 1 and mixed unilaterally.

Figure 2 shows the Cl content of Poly(Epichlorohydrin-co-Tetrahydrofuran)diol in Preparation Examples 1 to 3 measured through FT-IR and ¹³ C-NMR. Based on Figure 2, the higher the ratio of epichlorohydrin, the Cl. It can be seen that is increasing.

In addition, in Figure 3, it was confirmed through FT-IR and ¹³ C-NMR that all Cl groups of Poly(Epichlorohydrin-co-Tetrahydrofuran)diol of Preparation Examples 1 to 3 were substituted with azide groups. In addition, Figure 4 shows FT-IR and ¹³ C-NMR measurements of the azido-polyurethanes of Preparation Examples 1 to 3, and the presence of azide peaks was confirmed in both FT-IR and ¹³ C-NMR.

In Figure 5, ¹ H-NMR was measured for Preparation Example 1 and Examples 1 to 3. Through ¹ H-NMR, it was confirmed that the Cp ring peak of ferrocene increases as the click equivalent increases, and the Cp ring peak of ferrocene increases as the click reaction progresses. Triazole peak was confirmed.

Figure 6 shows the difference in mechanical properties between Example 2 and Comparative Example 1 and Preparation Example 2. It can be confirmed that the sample of Example 2 covalently bonded through a click reaction has the best mechanical properties.

In addition, as a result of comparing the calorific value of the azido-polyurethane of Preparation Example 2 and the ferrocene-polyurethane of Example 2 in Table 2, it was found that the material of Example 2 had a higher calorific value than Preparation Example 2 at 6,129 cal/g. I was able to confirm.

As described above, the present invention has been described with specific details, limited embodiments, and drawings, but these are provided only to facilitate a more general understanding of the present invention, and the present invention is not limited to the above embodiments, and the present invention Anyone skilled in the art can make various modifications and variations from this description.

Accordingly, the spirit of the present invention should not be limited to the described embodiments, and the scope of the patent claims described later as well as all things that are equivalent or equivalent to the scope of this patent claim shall fall within the scope of the spirit of the present invention. .

Claims (13)

Click-reacting a ferrocene compound containing an alkyne group and a polyurethane polymer containing an azide group to produce a polyurethane to which the ferrocene compound is covalently bonded; A method for producing polyurethane for solid propellants comprising.
According to claim 1,
The molal ratio of the azide group-containing polyurethane polymer and the alkyne group-containing ferrocene is 1: 0.1 to 1. A method for producing polyurethane for a solid propellant.
According to claim 1,
A method for producing polyurethane for a solid propellant, wherein the polyurethane containing an azide group is produced by reacting a diol-based compound containing a diol containing an azide group and an isocyanate-based compound.
According to clause 3,
A method for producing polyurethane for a solid propellant, wherein the diol containing the azide group is manufactured through cation ring-opening polymerization of tetrahydrofuran and epic chlorohydrin.
According to clause 4,
A method for producing polyurethane for a solid propellant, wherein the molar ratio of tetrahydrofuran and epic chlorohydrin is 1:0.3 to 3.
According to clause 3,
A method for producing polyurethane for a solid propellant, wherein the diol containing the azide group includes at least one selected from diols or polyalkylene diols with a number average molecular weight of 100 to 50,000 g/mol.
According to claim 1,
A method of manufacturing polyurethane for solid propellant, wherein the polyurethane for solid propellant has a calorific value of 6,000 cal/g or more according to the Isoperibel Bomb Calorimeter Parr Instrument 6300EF device.
Polyurethane for solid propellants produced by click reaction of a ferrocene compound containing an alkyne group and a polyurethane polymer containing an azide group.
According to clause 8,
The molal ratio of the azide group-containing polyurethane polymer and the alkyne group-containing ferrocene is 1:0.1 to 1, a polyurethane for solid propellant.
According to clause 8,
The polyurethane containing the azide group is a polyurethane for solid propellants manufactured by reacting a diol-based compound containing a diol containing an azide group and an isocyanate-based compound.
According to clause 8,
The diol containing the azide group is a polyurethane for a solid propellant including any one or more selected from diols or polyalkylene diols with a number average molecular weight of 100 to 50,000 g/mol.
According to clause 8,
The polyurethane for solid propellants has a calorific value of 6,000 cal/g or more according to the Isoperibel Bomb Calorimeter Parr Instrument 6300EF device.
A solid propellant comprising the polyurethane for solid propellants of any one of claims 8 to 12.