阅读说明：本技术 一种双固化型硝酸酯聚醚及其合成方法 (Dual-curing nitrate polyether and synthetic method thereof ) 是由 莫洪昌 卢先明 徐明辉 刘宁 张倩 葛忠学 于 2020-05-21 设计创作，主要内容包括：本发明公开了一种双固化型硝酸酯聚醚及其合成方法,双固化型硝酸酯聚醚的结构式如式(Ⅰ)所示,其合成过程包括以下步骤：以端羟基聚3-硝酸酯甲基-3-甲基氧杂环丁烷为原料,丙烯酸酯取代氧杂环丁烷为单体,经阳离子开环聚合反应得到双固化型硝酸酯聚醚。本发明的双固化型硝酸酯聚醚合成方法简单,易于放大,并且含有羟基和丙烯酸酯基两种活性反应基团,既能采用多叠氮化合物固化,又能采用多异氰酸酯化合物固化。本发明主要用于复合固体推进剂。<Image he="256" wi="700" file="DDA0002502405480000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>其中,R<Sub>1</Sub>为H或CH<Sub>3</Sub>,R<Sub>2</Sub>为CH<Sub>3</Sub>或CH<Sub>2</Sub>CH<Sub>3</Sub>,n＝10～60,为整数,x＝1～3,为整数,y＝1～3,为整数。(The invention discloses a dual-curing nitrate polyether and a synthesis method thereof, wherein the structural formula of the dual-curing nitrate polyether is shown as a formula (I), and the synthesis process comprises the following steps: hydroxyl-terminated poly-3-nitrate methyl-3-methyl oxetane is used as a raw material, acrylate substituted oxetane is used as a monomer, and the dual-curing type nitrate polyether is obtained through cationic ring-opening polymerization reaction. The synthetic method of the dual-curing type nitrate polyether is simple and easy to amplify, contains two active reaction groups of hydroxyl and acrylate, and can be cured by a polyazide compound and a polyisocyanate compound. The invention is mainly used for composite solid propellant. Wherein R is 1 Is H or CH 3 ，R 2 Is CH 3 Or CH 2 CH 3 N is an integer of 10 to 60, x is an integer of 1 to 3, and y is an integer of 1 to 3.)

1. The dual-curing nitrate polyether is characterized by having a structural formula shown as a formula (I):

wherein R is₁Is H or CH₃，R₂Is CH₃Or CH₂CH₃N is an integer of 10 to 60, x is an integer of 1 to 3, and y is an integer of 1 to 3.

2. The method for synthesizing the dual curing nitrate polyether according to claim 1, which comprises the following steps:

adding hydroxyl-terminated poly (3-nitrate methyl-3-methyloxetane) and dichloromethane into a reaction bottle at room temperature, uniformly stirring, then adding boron trifluoride-diethyl ether complex, reacting for 30-60 min under stirring, cooling to-5 ℃, starting to slowly dropwise add acrylate to replace oxetane, continuing to react for 24-36 h after dropwise adding is finished, neutralizing with sodium carbonate aqueous solution, washing to neutrality, separating out an oil phase, reducing pressure and steaming to remove dichloromethane to obtain dual-curing type nitrate polyether;

wherein the acrylate-substituted oxetane is 3-acryloyloxymethyl-3-methyloxetane, 3-acryloyloxymethyl-3-ethyloxetane, 3-methacryloyloxymethyl-3-methyloxetane or 3-methacryloyloxymethyl-3-ethyloxetane;

the molar ratio of boron trifluoride-diethyl ether complex, acrylate-substituted oxetane and hydroxyl-terminated poly-3-nitrate methyl-3-methyloxetane is 0.8-1.2: 2-6: 1.

Technical Field

The invention relates to a dual-curing nitrate polyether and a synthesis method thereof, wherein the compound is mainly used as an adhesive of a solid propellant, and belongs to the field of solid propellants.

Background

The hydroxyl-terminated ethylene oxide-tetrahydrofuran copolyether (PET) adhesive has the characteristics of good intersolubility with nitrate plasticizer, good main chain flexibility, low viscosity, low glass transition temperature and the like, and has been widely applied to nitrate plasticized polyether (NEPE) propellant. PET generally forms an isocyanate curing system with a polyisocyanate curing agent, and a polyurethane elastomer is prepared through a curing reaction between a terminal hydroxyl group and an isocyanate group, but the isocyanate curing system is harsh in curing conditions and sensitive to moisture, and the isocyanate group can rapidly react with water or an organic acid to generate CO₂And air holes are easily formed in the propellant, so that the mechanical property, the storage property and the safety performance of the propellant are influenced.

In order to solve the problems of the isocyanate curing system, researchers develop a terminal alkynyl adhesive based on the principle that 1, 3-dipolar cycloaddition reaction can be carried out on alkynyl and azido to generate triazole ring, and the terminal alkynyl adhesive and an azido curing agent can form a polytriazole crosslinking curing system. For example, Quzhengyang et al, terminal alkynyl PET Synthesis and curing research, 2011, 230-234, the fifth national chemical propellant academic conference proceedings of the Chinese chemical society, disclose a terminal alkynyl polyether adhesive, namely, terminal alkynyl ethylene oxide-tetrahydrofuran copolyether (C ≡ PET 4000). The structural formula is as follows:

the tail end of the C ≡ PET4000 adhesive only contains alkynyl one active reaction group, only can be cured with an azide curing agent, the adjustable range of mechanical properties is narrow, and when a plasticizer, namely a mixture of 2, 2-dinitropropanol formal and 2, 2-dinitropropanol acetal (A3), is added, the influence of the molar ratio (R value) of different azido groups to alkynyl groups on the mechanical properties of a cured film is examined when the plasticizing ratio is 0.5. The results show that: when the R value is 1.0, the mechanical property of the film obtained by curing is optimal, and the breaking elongation of the film isThe length rate is 72 percent and the tensile strength is 0.76MP_a. The film has low mechanical properties such as tensile strength and elongation at break.

Disclosure of Invention

The invention aims to overcome the defects of the background technology and provide a dual-curing nitrate polyether which can endow a crosslinked elastomer with higher mechanical property and wider adjustment range and a synthesis method thereof.

The conception of the invention is as follows: the C [ ident ] PET 4000-based elastomer film has low mechanical property and narrow adjustable range because the C [ ident ] PET4000 adhesive only contains one kind of alkynyl of active reaction group, the average functionality of the alkynyl is 2, the number and the types of the active reaction groups are less, and a compact cross-linking network structure cannot be formed after cross-linking. In order to improve the mechanical properties of the elastomer film, the invention envisages: hydroxyl-terminated poly (3-nitrate methyl-3-methyloxetane) with stronger acting force between molecular chains is used as a parent structure of the adhesive, a plurality of active acrylate groups and hydroxyl groups are introduced at two ends of the parent structure, and the types and the number of active reaction groups are increased, so that the mechanical property and the adjustment range of the cured elastomer are improved.

In order to solve the technical problems, the structural formula of the dual-curing nitrate polyether is shown as follows:

wherein R is₁Is H or CH₃，R₂Is CH₃Or CH₂CH₃N is an integer of 10 to 60, x is an integer of 1 to 3, and y is an integer of 1 to 3.

The synthetic route of the dual-curing nitrate polyether is as follows:

wherein R is₁Is H or CH₃，R₂Is CH₃Or CH₂CH₃N is an integer of 10 to 60, x is an integer of 1 to 3, and y is an integer of 1 to 3.

The synthetic method of the dual-curing nitrate polyether comprises the following steps:

adding hydroxyl-terminated poly (3-nitrate methyl-3-methyloxetane) and dichloromethane into a reaction bottle at room temperature, uniformly stirring, then adding boron trifluoride-diethyl ether complex, reacting for 30-60 min under stirring, cooling to-5 ℃, starting to slowly dropwise add acrylate to replace oxetane, continuing to react for 24-36 h after dropwise adding is finished, neutralizing with sodium carbonate aqueous solution, washing to neutrality, separating out an oil phase, reducing pressure and steaming to remove dichloromethane to obtain dual-curing type nitrate polyether; wherein the acrylate-substituted oxetane is 3-acryloyloxymethyl-3-methyloxetane, 3-acryloyloxymethyl-3-ethyloxetane, 3-methacryloyloxymethyl-3-methyloxetane or 3-methacryloyloxymethyl-3-ethyloxetane, and the molar ratio of boron trifluoride-diethyl ether complex, acrylate-substituted oxetane and hydroxyl-terminated poly-3-nitrate methyl-3-methyloxetane is 0.8-1.2: 2-6: 1.

The invention has the advantages that:

(1) the dual-curing type nitrate polyether contains two active reaction groups of hydroxyl and acrylate, can be cured by one or two of polyazide compounds and polyisocyanate compounds, and can endow a cross-linked elastomer with higher mechanical property and wider adjustment range.

(2) The synthetic method of the dual-curing type nitrate polyether is simple and easy to amplify, and the dual-curing type nitrate polyether with different acrylate group contents can be obtained by adjusting the feeding molar ratio of the acrylate substituted oxetane and the hydroxyl-terminated poly 3-nitrate methyl-3-methyl oxetane.

(3) The dual-curing type nitrate polyether and the poly azide can form a novel poly-triazoline crosslinking curing system, and the system has the advantages of insensitivity to water, no need of a catalyst, moderate curing rate and the like during curing.

Detailed Description

Testing an instrument:

the infrared spectrum test adopts a Nexus 870 Fourier transform infrared spectrometer of Nicolet company in the United states;

the nuclear magnetic resonance test adopts AVANCE AV500 type nuclear magnetic resonance instrument of Bruker company of Germany;

the number average molecular weight was measured by GPC-50 gel permeation chromatography (PL corporation, UK); GPC test conditions: the chromatographic column is series connected by PLGel MIXED-E; the mobile phase is THF; the column temperature was 40 ℃; the detector is a differential refraction detector;

the elastomer mechanical property test adopts an Instron model 4505 universal material tester of the American Instron company.