CN117069949A - Glycidyl azide polyether-tetrahydrofuran energetic copolyether with alternating multiblock structure and synthesis method thereof - Google Patents

Abstract

The invention discloses a glycidyl azide polyether-tetrahydrofuran energetic copolyether with an alternating multi-block structure and a synthesis method thereof. Polytetrahydrofuran (PTHF) and glycidyl azide polyether homopolymer (GAP) are used as the The raw material uses KOH as the catalyst. After nucleophilic substitution reaction, an alternating multi-block azide-based energetic adhesive is obtained. The obtained alternating multi-block GAP-THF energetic copolyether can give the propellant better mechanical properties. , the present invention gets rid of the copolymerization method of cationic polymerization commonly used in the prior art, realizes the condensation polymerization between oligomers through Wilson ether synthesis method, and successfully obtains GAP-THF energetic copolyether with alternating multi-block structure. , compared with the commonly used random copolymerization and triblock copolymerization of cationic polymerization, this method can effectively control the block length and prepare alternating block copolyethers with more blocks than triblocks.

Description

A kind of glycidyl azide polyether-tetrahydrofuran containing with alternating multi-block structure Energy copolyether and synthesis method thereof

Technical field

The invention belongs to the technical field of polymer materials, and in particular relates to a glycidyl azide polyether-tetrahydrofuran energetic copolyether with an alternating multi-block structure and a synthesis method thereof.

Background technique

As a polymer composite material, solid propellant is mainly composed of oxidants, binders and other additives. It is the power source of solid engines for rockets, missiles, and space vehicles. Its constituent substances undergo chemical reactions in the engine to release energy, thereby causing the engine to produce a certain thrust. Typical azide binders such as PBAMO, PAMMO, GAP, etc. have been extensively studied by propellant researchers at home and abroad due to their high energy content and in line with the research trend of propellants with high energy, insensitivity and low vulnerability. Glycidyl azide polyether (GAP) is an energetic prepolymer with azide groups in the side chain and a polyether structure in the main chain. The prepolymer has a positive heat of formation and therefore a high energy level. However, due to the poor mechanical properties and relatively high glass transition temperature of glycidyl azide ether monomer, in order to obtain an energetic binder for solid propellant, it needs to be copolymerized with other substances to improve the flexibility of the molecular chain and improve Low temperature mechanical properties of adhesives.

Since GAP has some performance deficiencies, such as a high glass transition temperature or poor low-temperature mechanical properties, it is considered to introduce links such as THF with better flexibility into the homopolyether or to copolymerize it with other polymers. To improve its performance through modification and other means, Kawamoto et al. made attempts in 2002 and Enoki in 2006 respectively. They used 1,4-butanediol/boron trifluoride ether (BDO/BF ₃ · Et ₂ O) as the initiator system. , 3,3-bisbromomethyloxetane and epichlorohydrin are used as raw materials to undergo cationic ring-opening polymerization first, and then azide substitution is performed to synthesize GAP-GAP copolymer. Experiments show that GAP is well block In the prepolymer, its mass fraction reaches about 35%, the number average relative molecular mass is 1380, and the glass transition temperature is -54.39°C. Moreover, the viscosity of the synthesized prepolymer is low, which reduces the mechanical properties of the adhesive. A good improvement has been obtained, but the GAP obtained by this synthesis method has a random block structure, and there is great uncertainty in the properties of regular block copolyethers. In order to obtain a more accurate understanding of the relationship between block length and mechanical properties, Therefore, it is necessary to synthesize a glycidyl azide polyether-tetrahydrofuran energetic copolyether with an alternating multi-block structure.

Contents of the invention

Purpose of the invention: In view of the above-mentioned existing problems and deficiencies, the purpose of the present invention is to provide a glycidyl azide polyether-tetrahydrofuran energetic copolyether with an alternating multi-block structure and a synthesis method thereof. The Ersen ether synthesis method realizes the condensation polymerization between oligomers, and successfully obtains a GAP-THF energetic copolyether with an alternating multi-block structure, which can effectively control the block length compared with the existing technology.

Technical solution: In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solution:

Polytetrahydrofuran (PTHF) and glycidyl azide polyether homopolymer (GAP) are used as raw materials, KOH is used as the catalyst, and an alternating multi-block azide-based energetic adhesive is obtained through a nucleophilic substitution reaction. The resulting alternating Multi-block GAP-THF energetic copolyether can give propellants better mechanical properties. Its structural formula is as follows:

Among them, m, n and 1 are integers. The specific steps are as follows:

Step 1. In a three-necked flask equipped with magnetic stirring, thermometer and reflux device, add small molecular weight glycidyl azide polyether oligomer, tetrahydrofuran and excess potassium hydroxide, stir the reaction under reflux to obtain potassium/sodium terminal alcohol Glycidyl azide polyether oligomer;

Step 2: Add the tetrahydrofuran solution of terminal p-toluenesulfonate esterified polytetrahydrofuran dropwise to the potassium terminal alcohol/sodium glycidyl azide polyether oligomer, stir the reaction under reflux, and filter to obtain a yellow liquid after the reaction is completed;

Step 3: Remove the tetrahydrofuran solvent in the yellow liquid by rotary evaporation, dissolve it in methylene chloride, adjust the pH value to neutral with aqueous hydrochloric acid solution and saturated aqueous sodium chloride solution, dry it with anhydrous sodium sulfate, then rotary evaporate it to dryness; then use petroleum ether to dry it. Extract with methanol to remove cyclic ethers and low molecular oligomers to obtain GAP-THF energetic copolyether with alternating multi-block structure.

Preferably, in step 1, the molecular weight of the glycidyl azide polyether oligomer is Mn=0-2000.

Preferably, in step 1, the volume ratio of the glycidyl azide polyether oligomer and tetrahydrofuran is 1:1-3.

Preferably, in step 1, the catalyst can be potassium hydroxide, sodium hydride or sodium methoxide.

Preferably, in step 2, the molar ratio of the terminal alkoxide sodium/potassium glycidyl azide polyether and the terminal p-toluenesulfonic acid polytetrahydrofuran is 1 to 2:1.

Preferably, in step 2, the volume ratio of the p-toluenesulfonic acid-terminated polytetrahydrofuran to tetrahydrofuran is 1:1 to 3.

Preferably, in step 2, the reflux reaction time is 12 to 72 hours.

Beneficial effects: Get rid of the copolymerization method of cationic polymerization commonly used in the existing technology, realize the condensation polymerization between oligomers through Wilson ether synthesis method, and successfully obtain GAP-THF energetic copolyether with alternating multi-block structure , compared with the commonly used random copolymerization and triblock copolymerization of cationic polymerization, this method can effectively control the block length and prepare alternating block copolyethers with more blocks than triblocks.

Description of the drawings

Figure 1 is a physical diagram of the GAP-THF alternating multi-block copolymer prepared in Example 1 of the present invention;

Figure 2 is a Fourier transform infrared characteristic spectrum of the GAP-THF alternating multi-block copolymer in Example 1 of the present invention;

Figure 3 is a hydrogen nuclear magnetic resonance spectrum of the GAP-THF alternating multi-block copolymer in Example 1 of the present invention;

Figure 4 is a gel chromatogram of the GAP-THF alternating multi-block copolymer in Example 1 of the present invention;

Figure 5 is a gel chromatogram of the GAP-THF alternating multi-block copolymer in Example 2 of the present invention.

Implementation

The present invention will be further clarified below in conjunction with the accompanying drawings and specific examples. It should be understood that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention. After reading the present invention, those skilled in the art will be familiar with various aspects of the present invention. Modifications in the form of equivalents fall within the scope defined by the appended claims of this application.

Polytetrahydrofuran (PTHF) and glycidyl azide polyether homopolymer (GAP) are used as raw materials, KOH is used as the catalyst, and an alternating multi-block azide-based energetic adhesive is obtained through a nucleophilic substitution reaction. The resulting alternating Multi-block GAP-THF energetic copolyether can give propellants better mechanical properties. Its structural formula is as follows:

Among them, m, n and 1 are integers. The specific steps are as follows:

Step 1. In a three-necked flask equipped with magnetic stirring, thermometer and reflux device, add small molecular weight glycidyl azide polyether oligomer, tetrahydrofuran and excess potassium hydroxide, stir the reaction under reflux to obtain potassium/sodium terminal alcohol Glycidyl azide polyether oligomer;

Step 2: Add the tetrahydrofuran solution of terminal p-toluenesulfonate esterified polytetrahydrofuran dropwise to the potassium terminal alcohol/sodium glycidyl azide polyether oligomer, stir the reaction under reflux, and filter to obtain a yellow liquid after the reaction is completed;

Step 3: Remove the tetrahydrofuran solvent in the yellow liquid by rotary evaporation, dissolve it in methylene chloride, adjust the pH value to neutral with aqueous hydrochloric acid solution and saturated aqueous sodium chloride solution, dry it with anhydrous sodium sulfate, then rotary evaporate it to dryness; then use petroleum ether to dry it. Extract with methanol to remove cyclic ethers and low molecular oligomers to obtain GAP-THF energetic copolyether with alternating multi-block structure.

Embodiment 1

Dissolve 2.89g GAP (Mn=550, 5.25mmol) in 10 mL THF, add 2.67g KOH (66mmol), and move the system to a 65°C constant temperature oil bath. Slowly drop 1.12g of THF solution of tosylate-terminated polytetrahydrofuran (Mn=396, 2.83mmol) into the above reaction system. After the dropwise addition, the system continued to react at 65°C for 48 hours. Then filter and rotary evaporate, dissolve the crude product in methylene chloride, and wash with distilled water until neutral. Then it was dried with anhydrous magnesium sulfate, suction filtered, and rotary evaporated. Petroleum ether with a boiling point of 60-90°C and methanol were added in sequence to wash and rotary evaporate to obtain a yellow viscous substance (1.32g).

Structure Identification:

FT-IR infrared: After PTHF-OTs is p-toluenesulfonated to obtain terminal toluenesulfonate polytetrahydrofuran, the infrared hydroxyl group 3000-3500cm ^-1 disappears, proving that the end groups of polytetrahydrofuran have been completely modified. The hydroxyl peak of GAP-THF prepared by GAP and PTHF-OTs is significantly reduced compared with GAP, and the characteristic peak of p-toluenesulfonyl chloride 1000-1500 cm ^-1 disappears.

Nuclear magnetism: 1H-NMR (CDCl ₃ , 500MHz): δ3.3-3.4 (CH ₂ -O in THF), δ3.23-3.28 (CH ₂ -N ₃ ), 3.18-3.23 (CH ₂ - in GAP O), 1.44-1.64 (C-CH ₂ -C in THF).

The above data indicate that the synthesized compound is a GAP-THF energetic copolyether with an alternating multi-block structure.

Embodiment 2

Dissolve 2.01g GAP (Mn=497, 4.04mmol) in 20 mL THF, add 2.32g KOH (58mmol), and move the system to a 65°C constant temperature oil bath. 1..01g THF solution of terminal tosylate glycol (Mn=460, 2.2mmol) was slowly dropped into the above reaction system. After the dropwise addition, the system continued to react at 65°C for 24 hours. Then filter and rotary evaporate, dissolve the crude product in methylene chloride, and wash with distilled water until neutral. Then it was dried with anhydrous magnesium sulfate, suction filtered, and rotary evaporated. Petroleum ether with a boiling point of 60-90°C and methanol were added in sequence to wash and rotary evaporate to obtain a yellow viscous substance (1.5g).

The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field can, within the technical scope disclosed in the present invention, implement the technical solutions of the present invention. Any equivalent substitution or change of the technical concepts thereof shall be included in the protection scope of the present invention.

Claims (8)

1. A glycidyl azide polyether-tetrahydrofuran energetic copolyether with an alternating multi-block structure, characterized in that: the structural formula of the alternating multi-block energetic adhesive is as follows: Among them, m, n and l are integers. 2. A glycidyl azide polyether-tetrahydrofuran energetic copolyether with an alternating multi-block structure and its synthesis method, which is characterized in that it includes the following steps: Step 1. In a three-necked flask equipped with a magnetic stirrer, a thermometer and a reflux device, add glycidyl azide polyether oligomer, tetrahydrofuran and a catalyst, and stir the reaction under reflux to obtain potassium terminal alcohol/sodium glycidyl azide polyether. oligomer; Step 2: Add a tetrahydrofuran solution containing terminal p-toluenesulfonic acid polytetrahydrofuran (PEG-OTS) dropwise to the potassium terminal alcohol/sodium glycidyl azide polyether oligomer, stir the reaction under reflux, and filter to obtain a white solid after the reaction is completed. or dark yellow liquid; Step 3: Remove the tetrahydrofuran solvent from the yellow liquid by rotary evaporation, dissolve it in methylene chloride, adjust the pH value to neutral with aqueous hydrochloric acid solution and saturated aqueous sodium chloride solution, dry it over anhydrous sodium sulfate, filter and rotary evaporate it to dryness, and then use Petroleum ether and methanol are used to extract cyclic ether compounds and low molecular oligomers to obtain BAMO-EG energetic copolyether with an alternating multi-block structure. 3. The glycidyl azide polyether-tetrahydrofuran energetic copolyether with alternating multi-block structure according to claim 2 and its synthesis method, characterized in that: the molecular weight of the glycidyl azide polyether oligomer is Mn=0~2000. 4. The glycidyl azide polyether-tetrahydrofuran energetic copolyether with alternating multi-block structure according to claim 2 and its synthesis method, characterized in that: the glycidyl azide polyether oligomer and tetrahydrofuran solvent The volume ratio is 1:1~3. 5. The glycidyl azide polyether-tetrahydrofuran energetic copolyether with alternating multi-block structure and its synthesis method according to claim 2, characterized in that: the catalyst is potassium hydroxide, sodium hydride or sodium methoxide. 6. The glycidyl azide polyether-tetrahydrofuran energetic copolyether with alternating multi-block structure according to claim 2 and its synthesis method, characterized in that: the sodium terminal alcohol/potassium glycidyl azide polyether is composed of The molar ratio of the polymer to the terminal p-toluenesulfonic acid polytetrahydrofuran is 1 to 4:1. 7. The glycidyl azide polyether-tetrahydrofuran energetic copolyether with alternating multi-block structure according to claim 2 and its synthesis method, characterized in that: the volume ratio of the terminal p-toluenesulfonic acid polytetrahydrofuran to tetrahydrofuran It is 1:1~3. 8. The glycidyl azide polyether-tetrahydrofuran energetic copolyether with alternating multi-block structure according to claim 2 and its synthesis method, characterized in that: the reflux reaction time is 12 to 72 hours.