Branched chain type fluorine-containing hydroxyl-terminated copolyether and preparation method thereof

Abstract

The invention relates to the field of polyether molecule synthesis and energetic materials, in particular to branched chain type fluorine-containing hydroxyl-terminated copolyether and a preparation method thereof. The problems that combustion is insufficient and energy release efficiency is low in a common technology are solved. Comprising the following steps: purging a flask with nitrogen to remove internal air, adding a solvent and hydroxyl-terminated polyether, stirring until the hydroxyl-terminated polyether and the solvent are uniformly mixed, then adding a catalyst, mixing and reacting to prepare a reaction liquid, dropwise adding a fluorine-containing oxetane monomer into the reaction liquid through a constant-pressure separating funnel, after the reaction is finished, adding deionized water, continuously stirring, and cooling to room temperature to obtain the fluorine-containing oxetane monomer. And neutralizing and washing with an alkaline solution, standing and separating liquid after washing to be neutral, and removing the solvent through rotary evaporation of an organic phase to obtain a final product. According to the branched chain type fluorine-containing hydroxyl-terminated copolyether disclosed by the invention, a fluorine component is introduced into a typical polyurethane adhesive basic raw material, so that the branched chain type fluorine-containing hydroxyl-terminated copolyether is endowed with a special energy release effect, combustion of aluminum powder in a solid propellant can be effectively promoted, and agglomeration and sintering phenomena of the aluminum powder are reduced.

Description

Technical Field

[0001] The invention relates to the fields of polyether molecule synthesis and energetic materials, and in particular to a branched fluorine-terminated hydroxyl copolyether and a preparation method thereof. Background Art

[0002] Solid propellant is an energetic composite material composed of an oxidant, a combustion agent and a binder. Aluminum powder is widely used in propellants to improve the specific impulse of solid propellants due to its advantages such as high density, low oxygen consumption, high heat of combustion, abundant geological reserves and low price. However, micro-nano aluminum powder has high reactivity due to the size effect. The presence of high boiling point Al2O3 in the surface oxide layer reduces the content of active aluminum and hinders the contact between the oxidant and the active aluminum. At the same time, during the ignition and combustion process, aluminum powder will agglomerate and sinter, resulting in incomplete combustion, aggravating the two-phase flow loss and reducing the energy release level.

[0003] As a combustion promoter with special energy-releasing effect, fluorine-containing organic matter can not only react with activated aluminum to release a large amount of heat, but also undergo a pre-ignition reaction with the inert alumina shell to release heat to promote the main combustion reaction, open up the channel for the active aluminum to contact the external oxidant, and the low-boiling point AlF3 generated is easier to vaporize and leave the surface of the active aluminum during the combustion process. Therefore, the introduction of fluorine-containing materials can effectively inhibit the agglomeration and sintering of micro-nano aluminum powder and promote the combustion of aluminum powder.

[0004] Polyethylene glycol / polytetrahydrofuran copolymer is a hydroxy-terminated polyether (HTPE) with excellent tantalum properties. It is a typical polyurethane adhesive raw material used in aluminum-based solid propellants. However, its main elements are C, H, and O, which have limited ability to promote the combustion of aluminum powder, limiting the energy level in practical applications. Chemical modification of HTPE with fluorinated organic matter can give it the energy release characteristics of fluorinated materials, promote the combustion of aluminum powder, and reduce the occurrence of agglomeration and sintering.

[0005] Therefore, it is urgent to propose a branched fluorinated hydroxyl-terminated copolyether and a preparation method thereof to solve the above technical problems. Summary of the invention

[0006] The present invention is to solve the problems of insufficient combustion and low energy release efficiency formed by conventional technologies. A brief summary of the present invention is given below to provide a basic understanding of certain aspects of the present invention. It should be understood that this summary is not an exhaustive summary of the present invention. It is not intended to determine the key or important parts of the present invention, nor is it intended to limit the scope of the present invention.

[0007] The technical solution of the present invention:

[0008] A branched fluorinated hydroxyl-terminated copolyether, the structural formula of the branched fluorinated hydroxyl-terminated copolyether is:

[0009]

[0010] Among them, -ORO- is

[0011] x is 0 or a positive integer, and a, b, y, and n are positive integers.

[0012] A method for preparing a branched fluorinated hydroxyl-terminated copolyether comprises the following steps:

[0013] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the flask, then add the solvent and the terminal hydroxyl polyether, and stir magnetically at a reaction temperature of 0 to 30° C. until the terminal hydroxyl polyether and the solvent are evenly mixed, and then add the catalyst and mix and react for 10 to 60 minutes to obtain a reaction solution;

[0014] Step 2: Add the fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 1 to 4 hours. After the addition is complete, react for 2 to 30 hours.

[0015] Step 3: After the reaction is completed, deionized water is added and stirred for 10 minutes, and then neutralized and washed with a 0.5-10wt% alkaline solution. After washing to neutrality, the liquid is allowed to stand and separate, and then the solvent is removed by rotary evaporation of the organic phase to obtain the final product, a branched fluorinated hydroxyl-terminated copolyether.

[0016] Preferably, the mass fraction of the solvent is 40-120 parts, the mass fraction of the hydroxyl-terminated polyether is 10-50 parts, the mass fraction of the catalyst is 1-5 parts, and the mass fraction of the fluorinated oxetane monomer is 20-60 parts.

[0017] Preferably, the solvent is one or more of dichloromethane, dichloroethane, chloroform, ethyl acetate, dimethyl carbonate, methyl formate and acetone.

[0018] Preferably, the hydroxyl-terminated polyether is a polyethylene glycol / polytetrahydrofuran copolymer, and its structural formula is:

[0019]

[0020] Wherein a and b are positive integers.

[0021] Preferably, the number average molecular weight of the hydroxyl-terminated polyether is 400 to 8000 g / mol.

[0022] Preferably, the catalyst is one or more of boron trifluoride diethyl ether, boron trifluoride dibutyl ether, boron trifluoride tetrahydrofuran complex, stannous octoate, dibutyltin oxide, triethylaluminum, triisobutylaluminum.

[0023] Preferably, the structural formula of the fluorinated oxetane monomer is:

[0024]

[0025] Wherein n is an integer from 1 to 10.

[0026] Preferably, the alkaline solution is one or more of Na2CO3 aqueous solution, NaHCO3 aqueous solution, K2CO3 aqueous solution, and KHCO3 aqueous solution.

[0027] The present invention has the following beneficial effects:

[0028] The branched fluorinated hydroxyl-terminated copolyether of the present invention is obtained by ring-opening polymerization of hydroxyl-terminated polyether and fluorinated oxetane, and the synthesis process is simple and efficient, and is suitable for mass production.

[0029] The branched fluorine-terminated hydroxyl copolyether of the present invention introduces fluorine components into the basic raw materials of typical polyurethane adhesives to give them special energy release effects, which can effectively promote the combustion of aluminum powder in solid propellants and reduce the agglomeration and sintering of aluminum powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is the FTIR graph of the branched fluorinated hydroxyl-terminated copolyether prepared in Example 1;

[0031] Figure 2 This is the GPC chart of the branched fluorinated hydroxyl-terminated copolyether prepared in Example 1. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is described below through specific embodiments. However, it should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0033] Specific implementation method 1: Combination Figure 1-Figure 2 The present embodiment is described as follows. A branched fluorinated hydroxyl-terminated copolyether of the present embodiment has a structural formula of:

[0034]

[0035] Among them, -ORO- is

[0036] x is 0 or a positive integer, and a, b, y, and n are positive integers.

[0037] Specific implementation method 2: Combination Figure 1-Figure 2The present embodiment is described. A method for preparing a branched fluorinated hydroxyl-terminated copolyether of the present embodiment comprises the following steps:

[0038] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the flask, ensure that the air inside the flask is completely removed to create an oxygen-free and water-free reaction environment, then add the solvent and the terminal hydroxyl polyether, and stir magnetically at a reaction temperature of 0 to 30° C. until the terminal hydroxyl polyether and the solvent are evenly mixed, and then add the catalyst and mix for 10 to 60 minutes to obtain a reaction solution;

[0039] Step 2: Add the fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 1 to 4 hours. After the addition is complete, react for 2 to 30 hours.

[0040] Step 3: After the reaction is completed, add deionized water and continue stirring for 10 minutes, then use 0.5-10wt% alkaline solution for neutralization and washing. After neutralization and washing, let the reaction solution stand for stratification. The upper layer is the aqueous phase (containing unreacted catalyst, salts and other impurities), and the lower layer is the organic phase (containing the target product). The solvent (such as dichloroethane) in the lower organic phase is evaporated through a rotary evaporator to obtain a pure branched fluorinated hydroxyl-terminated copolyether product. The temperature should be controlled during the rotary evaporation process to avoid impurities or oxidation of the product, and the final product, the branched fluorinated hydroxyl-terminated copolyether, is obtained.

[0041] The temperature of the rotary evaporation process is 30-100° C., and the vacuum degree is controlled at 0.02-0.08 MPa.

[0042] Specific implementation method three: Combination Figure 1-Figure 2 The present embodiment is described. A method for preparing a branched fluorinated hydroxyl-terminated copolyether according to the present embodiment, wherein the mass fraction of the solvent is 40-120 parts, the mass fraction of the hydroxyl-terminated polyether is 10-50 parts, the mass fraction of the catalyst is 1-5 parts, and the mass fraction of the fluorinated oxetane monomer is 20-60 parts. This ratio has significant benefits in improving the performance of the branched fluorinated hydroxyl-terminated copolyether, the synthesis efficiency, and expanding the application field.

[0043] The branched fluorinated hydroxyl-terminated copolyether is obtained by ring-opening polymerization of hydroxyl-terminated polyether and fluorinated oxetane monomer.

[0044] Specific implementation method four: Combination Figure 1-Figure 2 The present embodiment is described. A method for preparing a branched fluorinated hydroxyl-terminated copolyether is provided in the present embodiment. The solvent is one or more of dichloromethane, dichloroethane, chloroform, ethyl acetate, dimethyl carbonate, methyl formate, and acetone. The solubility, reaction rate, and difficulty of post-treatment of the reaction can be flexibly adjusted, thereby realizing efficient and stable synthesis of branched fluorinated hydroxyl-terminated copolyether.

[0045] The combination of different solvents maximizes solubility and reaction efficiency while ensuring the quality and functionality of the final product.

[0046] Specific implementation method five: Combination Figure 1-Figure 2 The present embodiment is described as follows. A method for preparing a branched fluorinated hydroxy-terminated copolyether is provided in the present embodiment. The hydroxy-terminated copolyether is a polyethylene glycol / polytetrahydrofuran copolymer, and its structural formula is:

[0047]

[0048] Wherein a and b are positive integers.

[0049] Specific implementation method six: Combination Figure 1-Figure 2 The present embodiment is described as a method for preparing a branched fluorinated hydroxy-terminated copolyether. The hydroxy-terminated copolyether has a number average molecular weight of 400 to 8000 g / mol and has excellent chemical stability, thermal stability and water resistance.

[0050] Specific implementation method seven: Combination Figure 1-Figure 2 The present embodiment is described. A method for preparing a branched fluorinated hydroxyl-terminated copolyether is provided in the present embodiment. The catalyst is one or more of boron trifluoride diethyl ether, boron trifluoride dibutyl ether, boron trifluoride tetrahydrofuran complex, stannous octoate, dibutyltin oxide, triethylaluminum, triisobutylaluminum. The use of boron trifluoride, tin and aluminum catalysts can effectively regulate the polymerization process and give the polymer more excellent properties.

[0051] Specific implementation method eight: Combination Figure 1-Figure 2 This embodiment is described. This embodiment is a method for preparing a branched fluorinated hydroxyl-terminated copolyether. The structural formula of the fluorinated oxetane monomer is:

[0052]

[0053] Wherein n is an integer from 1 to 10.

[0054] Specific implementation method nine: Combination Figure 1-Figure 2 The present embodiment describes a method for preparing a branched fluorinated hydroxyl-terminated copolyether, wherein the alkaline solution is one or more of a Na2CO3 aqueous solution, a NaHCO3 aqueous solution, a K2CO3 aqueous solution, and a KHCO3 aqueous solution. These alkaline solutions can quickly adjust the pH value of the reaction solution, which is beneficial to the separation and purification of the product.

[0055] Example 1

[0056] A method for preparing a branched fluorinated hydroxyl-terminated copolyether comprises the following steps:

[0057] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the reaction container, add 80g of dichloromethane and 25g of terminal hydroxyl polyether, control the reaction temperature at 0°C, perform magnetic stirring until the terminal hydroxyl polyether and dichloromethane are evenly mixed, add 1g of boron trifluoride dimethyl ether and mix for 20 minutes to obtain a reaction solution;

[0058] Step 2: Add 40 g of fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 2 hours. After the addition is complete, continue to keep the temperature constant and react for 6 hours.

[0059] Step 3: After the reaction is completed, deionized water is added and stirred for 10 minutes to quench the reaction. A 2 wt % Na2CO3 solution is used for neutralization and washing until neutral. The mixture is allowed to stand for separation, and the organic phase is evaporated to remove the solvent to obtain a branched fluorinated hydroxyl-terminated copolyether.

[0060] Example 2

[0061] A method for preparing a branched fluorinated hydroxyl-terminated copolyether comprises the following steps:

[0062] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the reaction container, add 90g of ethylene dichloride and 25g of terminal hydroxyl polyether, control the reaction temperature at 5°C, perform magnetic stirring until the terminal hydroxyl polyether and the ethylene dichloride are evenly mixed, add 1.5g of boron trifluoride diethyl ether and mix for 30 minutes to obtain a reaction solution;

[0063] Step 2: Add 40 g of fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 2 hours. After the addition is complete, continue to keep the temperature constant and react for 12 hours.

[0064] Step 3: After the reaction is completed, deionized water is added and stirred for 10 minutes to quench the reaction, and a 2 wt% NaHCO3 solution is used for neutralization and washing until neutrality. The mixture is allowed to stand for separation, and the organic phase is evaporated to remove the solvent to obtain a branched fluorinated hydroxyl-terminated copolyether.

[0065] Example 3

[0066] A method for preparing a branched fluorinated hydroxyl-terminated copolyether comprises the following steps:

[0067] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the reaction container, add 70g of chloroform and 25g of terminal hydroxyl polyether, control the reaction temperature at 10°C, perform magnetic stirring until the terminal hydroxyl polyether and chloroform are evenly mixed, add 3g of boron trifluoride dibutyl ether and mix for 40 minutes to obtain a reaction solution;

[0068] Step 2: Add 40 g of fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 2 hours. After the addition is complete, continue to keep the temperature constant and react for 16 hours.

[0069] Step 3: After the reaction is completed, deionized water is added and stirred for 10 minutes to quench the reaction. A 2 wt % K2CO3 solution is used for neutralization and washing until neutral. The mixture is allowed to stand for separation, and the organic phase is evaporated to remove the solvent to obtain a branched fluorinated hydroxyl-terminated copolyether.

[0070] Example 4

[0071] A method for preparing a branched fluorinated hydroxyl-terminated copolyether comprises the following steps:

[0072] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the reaction container, add 100g of ethylene dichloride and 25g of terminal hydroxyl polyether, control the reaction temperature at 15°C, perform magnetic stirring until the terminal hydroxyl polyether and the ethylene dichloride are evenly mixed, add 3.5g of boron trifluoride tetrahydrofuran complex and mix for 45 minutes to obtain a reaction solution;

[0073] Step 2: Add 50 g of fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 3 hours. After the addition is complete, continue to keep the temperature constant and react for 20 hours.

[0074] Step 3: After the reaction is completed, deionized water is added and stirred for 10 minutes to quench the reaction, and a 3 wt % KHCO3 solution is used for neutralization and washing until neutrality is achieved. The mixture is allowed to stand for separation, and the organic phase is evaporated to remove the solvent to obtain a branched fluorinated hydroxyl-terminated copolyether.

[0075] Example 5

[0076] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the reaction container, add 100g of ethyl acetate and 25g of terminal hydroxyl polyether, control the reaction temperature at 20°C, perform magnetic stirring until the terminal hydroxyl polyether and ethyl acetate are evenly mixed, add 3.5g of stannous octoate and mix for 50 minutes to obtain a reaction solution;

[0077] Step 2: Add 50 g of fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 3 hours. After the addition is complete, continue to keep the temperature constant and react for 24 hours.

[0078] Step 3: After the reaction is completed, deionized water is added and stirred for 10 minutes to quench the reaction. A 3 wt % Na2CO3 solution is used for neutralization and washing until neutral. The mixture is allowed to stand for separation, and the organic phase is evaporated to remove the solvent to obtain a branched fluorinated hydroxyl-terminated copolyether.

[0079] Example 6

[0080] A method for preparing a branched fluorinated hydroxyl-terminated copolyether comprises the following steps:

[0081] Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the reaction container, add 120g of dimethyl carbonate and 25g of terminal hydroxyl polyether, control the reaction temperature at 25°C, perform magnetic stirring until the terminal hydroxyl polyether and dimethyl carbonate are evenly mixed, add 4g of triisobutylaluminum and mix for 60 minutes to obtain a reaction solution;

[0082] Step 2: Add 50 g of fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 3 hours. After the addition is complete, continue to keep the temperature constant and react for 30 hours;

[0083] Step 3: After the reaction is completed, deionized water is added and stirred for 10 minutes to quench the reaction, and a 3 wt % NaHCO3 solution is used for neutralization and washing until neutrality is achieved. The mixture is allowed to stand for separation, and the organic phase is evaporated to remove the solvent to obtain a branched fluorinated hydroxyl-terminated copolyether.

[0084] The Mn results of the branched fluorinated hydroxyl-terminated copolyethers prepared in Examples 1 to 6 are shown in the following table:

[0085]

[0086] It should be noted that in the above embodiments, as long as the technical solutions are not contradictory, they can be arranged and combined, and those skilled in the art can exhaust all possibilities based on the mathematical knowledge of arrangement and combination. Therefore, the present invention will no longer describe the technical solutions after arrangement and combination one by one, but it should be understood that the technical solutions after arrangement and combination have been disclosed by the present invention.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A branched fluorinated hydroxyl-terminated copolyether, characterized in that: The structural formula of the branched fluorinated hydroxyl-terminated copolyether is: Among them, -ORO- is x is 0 or a positive integer, and a, b, y, and n are positive integers.

2. A method for preparing a branched fluorinated hydroxyl-terminated copolyether, characterized in that: The steps include: Step 1: Use high-purity nitrogen to purge the flask for 30 minutes to remove the air inside the flask, then add the solvent and the terminal hydroxyl polyether, and stir magnetically at a reaction temperature of 0 to 30° C. until the terminal hydroxyl polyether and the solvent are evenly mixed, and then add the catalyst and mix and react for 10 to 60 minutes to obtain a reaction solution; Step 2: Add the fluorinated oxetane monomer dropwise into the reaction solution through a constant pressure separatory funnel for 1 to 4 hours. After the addition is complete, react for 2 to 30 hours. Step 3: After the reaction is completed, add deionized water and continue stirring for 10 minutes, then use 0.5-10wt% alkaline solution for neutralization and washing, let it stand to separate after washing to neutrality, and then remove the solvent by rotary evaporation of the organic phase to obtain the final product, branched fluorine-terminated hydroxyl copolyether.

3. The method for preparing a branched fluorinated hydroxyl-terminated copolyether according to claim 2, characterized in that: The mass fraction of the solvent is 40-120 parts, the mass fraction of the terminal hydroxyl polyether is 10-50 parts, the mass fraction of the catalyst is 1-5 parts, and the mass fraction of the fluorine-containing oxetane monomer is 20-60 parts.

4. The method for preparing a branched fluorinated hydroxyl-terminated copolyether according to claim 3, characterized in that: The solvent is one or more of dichloromethane, dichloroethane, chloroform, ethyl acetate, dimethyl carbonate, methyl formate and acetone.

5. The method for preparing a branched fluorinated hydroxyl-terminated copolyether according to claim 3, characterized in that: The hydroxyl-terminated polyether is a polyethylene glycol / polytetrahydrofuran copolymer, and its structural formula is: Wherein a and b are positive integers.

6. The method for preparing a branched fluorinated hydroxyl-terminated copolyether according to claim 3, characterized in that: The number average molecular weight of the hydroxyl-terminated polyether is 400 to 8000 g / mol.

7. The method for preparing a branched fluorinated hydroxyl-terminated copolyether according to claim 3, characterized in that: The catalyst is one or more of boron trifluoride diethyl ether, boron trifluoride dibutyl ether, boron trifluoride tetrahydrofuran complex, stannous octoate, dibutyltin oxide, triethylaluminum, triisobutylaluminum.

8. The method for preparing a branched fluorinated hydroxyl-terminated copolyether according to claim 3, characterized in that: The structural formula of the fluorinated oxetane monomer is: Wherein n is an integer from 1 to 10.

9. The method for preparing a branched fluorinated hydroxyl-terminated copolyether according to claim 3, characterized in that: The alkaline solution is one or more of a Na2CO3 aqueous solution, a NaHCO3 aqueous solution, a K2CO3 aqueous solution, and a KHCO3 aqueous solution.

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