Hyperbranched neutral polymer bonding agent as well as preparation method and application thereof

Abstract

The invention discloses a hyperbranched neutral polymer bonding agent as well as a preparation method and application thereof, and relates to the technical field of solid rocket propellant bonding agents. The preparation method of the hyperbranched neutral polymer bonding agent comprises the following steps: carrying out coupling esterification reaction on hyperbranched polyol and halogenated acyl halide and / or acyl halide alkyl hydrocarbon, and introducing active halogen end groups and / or alkyl groups to obtain hyperbranched polyol containing halogen and / or alkyl groups; carrying out azido substitution reaction on the hyperbranched polyalcohol and excessive sodium azide to introduce azido reaction sites, so as to obtain azidated hyperbranched polyalcohol; and carrying out click chemical reaction on the hyperbranched polymer and an alkynyl compound containing CN and / or NH2 under the action of a catalyst to obtain the hyperbranched neutral polymer bonding agent. The method is mild in reaction condition and simple to operate; the hyperbranched neutral polymer bonding agent is controllable in functional group type and proportion, can be randomly adjusted by changing reaction raw materials and proportion thereof, and can be widely applied to preparation of various solid propellants as a bonding agent.

Description

Technical Field

[0001] The invention relates to the technical field of solid rocket propellant bonding agents, and in particular to a hyperbranched neutral polymer bonding agent and a preparation method and application thereof. Background Art

[0002] The synthesis of ordinary neutral polymer bonding agents is generally achieved by free radical copolymerization of multiple monomers. However, when two or more monomers are copolymerized by free radicals, the polymer segment structure is determined by the instantaneous composition and relative reactivity of the monomers, which can easily cause component "drift", uneven polymer composition, and difficulty in accurately controlling the content of each functional group.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The purpose of the present invention is to provide a hyperbranched neutral polymer bonding agent and a preparation method and application thereof.

[0005] The present invention is achieved in that:

[0006] In a first aspect, the present invention provides a method for preparing a hyperbranched neutral polymer bonding agent, comprising:

[0007] S1, subjecting a hyperbranched polyol, a halogenated acyl halide and / or an acyl halide alkyl hydrocarbon to a coupling esterification reaction to introduce an active halogen end group and / or a hydrocarbon group to obtain a hyperbranched polyol containing a halogen and / or a hydrocarbon group;

[0008] S2, subjecting the halogen and / or hydrocarbon-containing hyperbranched polyol to an azidation substitution reaction with an excess of sodium azide to introduce an azide reaction site to obtain an azidated hyperbranched polyol;

[0009] S3, subjecting the azidated hyperbranched polyol to a click chemical reaction with an alkynyl compound containing CN and / or NH2 under the action of a catalyst to obtain a hyperbranched neutral polymer bonding agent;

[0010] The hyperbranched neutral polymer bonding agent with different contents of hydroxyl, cyano, amine and hydrocarbon groups can be obtained by adjusting the molar amounts of the hyperbranched polyol, the halogenated acyl halide, the acyl halide alkyl hydrocarbon and the alkynyl compound.

[0011] In an optional embodiment, the hyperbranched polyol is a polyester hyperbranched polyol or a polyether hyperbranched polyol;

[0012] Preferably, the hyperbranched polyol is at least one of the hyperbranched polyesters Hyper H10, Hyper H20, Hyper H30, Hyper H40 and Boltorn H40.

[0013] In an optional embodiment, the halogenated acyl halide comprises at least one of 2-bromoisobutyryl bromide, 2-chloroisobutyryl chloride and 2-bromo-2-methylpropionyl bromide;

[0014] Preferably, the halogenated acyl halide is 2-bromoisobutyryl bromide.

[0015] In an optional embodiment, the alkyl acyl halide comprises an alkyl acyl bromide or an alkyl acyl chloride;

[0016] Preferably, the alkyl halide is an alkyl bromide having no more than 16 carbon atoms;

[0017] Preferably, the alkyl acyl halide is an alkyl acyl bromide containing 3 to 10 carbon atoms.

[0018] In an optional embodiment, the alkynyl compound includes at least one of propargylnitrile, 4-cyano-1-butyne, 5-cyano-1-pentyne, propargylamine, 3-butyn-1-amine and 4-pentyn-1-amine;

[0019] Preferably, the alkynyl compound is propiolonitrile and propargylamine.

[0020] In an optional embodiment, the catalyst includes a first catalytic component and a second catalytic component, the first catalytic component is an organic amine or a reducing agent, and the second catalytic component is a halide of an intermediate valence transition element or a salt of a high valence transition element;

[0021] Preferably, the organic amine is pentamethyldiethyltriamine and / or triethylamine, the halide of the intermediate valence transition element is CuBr and / or CuCl, the salt of the high valence transition element is copper sulfate, and the reducing agent is copper or ascorbic acid;

[0022] Preferably, the amount of the catalyst additive is related to the amount of the azidated hyperbranched polyol azido substance, and the molar ratio of -N3: first catalyst component: second catalyst component is 1 to 2:1:1.

[0023] In an optional embodiment, in step S1, the coupling esterification reaction is carried out in an ice water bath at 0°C±5°C for 1 to 24 hours, followed by neutralization with aqueous ammonia or sodium hydroxide or aqueous sodium carbonate solution to neutralize, followed by washing with water to remove by-products and drying;

[0024] In step S2, the azidation substitution reaction is carried out at 50° C. to 90° C. for 4 to 24 hours, followed by washing with water to remove by-products and drying;

[0025] In step S3, the click chemistry reaction is carried out at 50° C. to 70° C. for 10 to 24 hours, followed by washing with water to remove byproducts and drying;

[0026] Preferably, step S1, step S2 and step S3 are all reacted in the presence of a solvent, and the solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, pyridine and tetrahydrofuran;

[0027] Preferably, step S1, step S2 and step S3 are performed continuously, and the final washing and drying process is not performed after step S1 and step S2 are completed.

[0028] In a second aspect, the present invention provides a hyperbranched neutral polymer bonding agent, which is prepared by the method for preparing a hyperbranched neutral polymer bonding agent as described in any one of the aforementioned embodiments.

[0029] In an optional embodiment, the hyperbranched neutral polymer bonding agent has a hydroxyl content of 5% to 10%, a cyano content of 0% to 90%, an amine content of 0% to 90%, and a hydrocarbon content of 0 to 5%, calculated by amount of substance. The total amount of the substance is 100%, wherein at least one of the cyano group and the amine group is present.

[0030] In a third aspect, the present invention provides use of the hyperbranched neutral polymer bonding agent as described in the aforementioned embodiment in the preparation of a solid propellant.

[0031] The present invention has the following beneficial effects:

[0032] The preparation method of the hyperbranched neutral polymer bonding agent provided by the present invention uses hyperbranched polyol as a matrix, introduces non-polar hydrocarbon groups through acyl halide esterification, azidation, and click chemistry reactions, especially azo ring structures with CN groups and NH2 functional groups, which are conducive to the adsorption of solid substances such as ammonium salts, nitramine compounds, and aluminum powder. The retained unreacted hydroxyl groups can react with propellant curing agents and be grafted on the propellant adhesive network. Its hyperbranched spherical structure is used as a solid rocket propellant bonding agent, which has the advantages of good process performance and good bonding effect. The raw materials used in the preparation method of the hyperbranched neutral polymer bonding agent provided by the present invention are all commercial products, the reaction conditions are mild, and the operation is simple; the types and proportions of functional groups of the hyperbranched neutral polymer bonding agent are controllable and can be adjusted at will by changing the reaction raw materials and their proportions. The hyperbranched neutral polymer bonding agent prepared by the preparation method of the hyperbranched neutral polymer bonding agent is easy to form a spherical configuration due to its hyperbranched structure. When used in different polar matrices, the inner and outer layer groups of the sphere will change accordingly, so its surface and interface properties are different from those of the neutral polymer bonding agent of free radical polymerization. The hyperbranched neutral polymer bonding agent can be widely used in the preparation of various solid propellants. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0034] Figure 1 This is the infrared spectrum of raw material H40;

[0035] Figure 2 This is the infrared spectrum of the product obtained by step S1 of H40 in Example 1;

[0036] Figure 3 This is the infrared spectrum of the product obtained by step S2 of H40 in Example 1;

[0037] Figure 4 This is the infrared spectrum of the product obtained by step S3 of H40 in Example 1;

[0038] Figure 5 For raw material H40 1 HNMR spectrum;

[0039] Figure 6 For raw material H40 13 CNMR spectrum;

[0040] Figure 7 is the product obtained by step S1 of H40 in Example 1 1 HNMR spectrum;

[0041] Figure 8 is the product obtained by step S1 of H40 in Example 1 13 CNMR spectrum;

[0042] Fig. 9 is the product obtained by step S2 of H40 in Example 1 1 HNMR spectrum;

[0043] Fig.10 is the product obtained by step S2 of H40 in Example 1 13 CNMR spectrum;

[0044] Fig.11 is the product obtained by step S3 of H40 in Example 1 1 HNMR spectrum;

[0045] Fig.12 is the product obtained by step S3 of H40 in Example 1 13 CNMR spectrum;

[0046] Fig.13 It is the transmission electron microscope image of the raw material H40 solution;

[0047] Fig.14 is a transmission electron micrograph of the product solution obtained by H40 in step S3 in Example 1;

[0048] Fig.15 This is the infrared spectrum of the product obtained by step S3 of H30 in Example 2;

[0049] Fig.16 The product obtained by step S3 of H30 in Example 2 1 HNMR;

[0050] Fig.17 The product obtained by step S3 of H30 in Example 2 13 CNMR spectrum. DETAILED DESCRIPTION

[0051] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0052] The present invention provides a method for preparing a hyperbranched neutral polymer bonding agent, which comprises:

[0053] S1. Coupling esterification reaction.

[0054] The hyperbranched polyol is coupled with a halogenated acyl halide to react with a coupling esterification reaction to introduce an active halogen end group to obtain a halogen-containing hyperbranched polyol. When a hydrocarbon group needs to be introduced, an acyl halide alkyl hydrocarbon can also be added to obtain a halogen- and hydrocarbon-containing hyperbranched polyol.

[0055] Taking 2-bromoisobutyryl bromide and alkyl bromide as examples, the chemical reaction formulas are shown in formula (1) and formula (2):

[0056]

[0057] Among them, R-OH is a hyperbranched polyol. Hyperbranched polymers are a class of highly branched three-dimensional macromolecules, which are highly branched but irregularly structured polymers composed of branching units. Hyperbranched polymers have many branching points, the molecular chains are not easy to entangle, the viscosity does not change with the increase of molecular weight, and they have abundant terminal functional groups, which are easy to modify and modify, and are conducive to the synthesis of various functional materials.

[0058] Specifically, in the present invention, hyperbranched polyols are used as raw materials, and active halogens and hydrocarbon groups are introduced through coupling esterification reactions. The active halogens are convenient for subsequent replacement to introduce other groups. By controlling the amount of active halogens and hydrocarbon groups introduced, the content of different groups in the final product can be controlled.

[0059] In the present invention, the hyperbranched polyol includes but is not limited to polyester hyperbranched polyol or polyether hyperbranched polyol; preferably, the hyperbranched polyol is at least one of hyperbranched polyester Hyper H10, Hyper H20, Hyper H30, Hyper H40 and Boltorn H40.

[0060] The halogenated acyl halide includes, but is not limited to, at least one of 2-bromoisobutyryl bromide, 2-chloroisobutyryl chloride and 2-bromo-2-methylpropionyl bromide; preferably, the halogenated acyl halide is 2-bromoisobutyryl bromide.

[0061] The alkyl acyl halide includes but is not limited to alkyl acyl bromide or alkyl acyl chloride; preferably, the alkyl acyl halide is an alkyl acyl bromide having no more than 16 carbon atoms; further preferably, the alkyl acyl halide is an alkyl acyl bromide having 3 to 10 carbon atoms.

[0062] In the present invention, a hyperbranched polyol is dissolved in a solvent, and then a halogenated acyl halide is added, and an acyl halide alkyl hydrocarbon can be selectively added, and a coupling esterification reaction is carried out in an ice water bath at 0°C±5°C for 1-24 hours. Then, ammonia water or sodium hydroxide or sodium carbonate aqueous solution is added to neutralize the mixture, and the mixture is washed with water to remove by-products and dried.

[0063] The solvent includes but is not limited to at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide, N-methylpyrrolidone, pyridine and tetrahydrofuran, and there are various drying methods, including but not limited to heating drying or vacuum drying.

[0064] S2. Azide substitution reaction.

[0065] The hyperbranched polyol containing halogen and / or hydrocarbon group is subjected to an azidation substitution reaction with excess sodium azide to introduce an azide reaction site to obtain an azidated hyperbranched polyol.

[0066] Taking the product of formula (1) as an example, its reaction formula is:

[0067]

[0068] In the present invention, sodium azide easily undergoes a substitution reaction with halogens. By introducing sodium azide, the halogen atoms on the hyperbranched polyol containing halogens and / or hydrocarbon groups are replaced with azide groups. Sodium azide acts as a reducing agent in the reaction, causing the hyperbranched polyol containing halogens and / or hydrocarbon groups to undergo electron donor conversion to generate azide compounds.

[0069] Among them, the azidation substitution reaction is also carried out in the presence of a solvent. After mixing the hyperbranched polyol containing halogen and / or hydrocarbon groups, sodium azide and the solvent, react at 50°C to 90°C for 3 to 24 hours, then wash with water to remove by-products, and heat and / or vacuum dry.

[0070] The choice of solvent is the same as the choice of solvent in step S1, including but not limited to at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, pyridine and tetrahydrofuran.

[0071] S3. Click chemistry reaction.

[0072] The azidized hyperbranched polyol and an alkynyl compound containing CN and / or NH2 are subjected to a click chemical reaction under the action of a catalyst to obtain a hyperbranched neutral polymer bonding agent;

[0073] Taking propargyl nitrile and propargylamine as examples, when the catalyst is CuBr and pentamethyldiethyltriamine, the reaction formula is:

[0074]

[0075] "Click chemistry" is a method of splicing small molecules with complete carbon skeletons using nitrogen atoms or oxygen atoms as bridges. It is characterized by mild reaction conditions and high selectivity, thereby obtaining a wider range of molecular diversity. In the present invention, the azide group on the azidized hyperbranched polyol is reacted with an alkynyl compound containing CN and / or NH2. The cycloaddition reaction between the azide group and the alkynyl group is a typical click chemistry reaction, which is highly efficient and controllable, and the product has high stereoselectivity and stability. Through the above reaction, an azo ring structure with CN and NH2 functional groups can be introduced, which is beneficial to the adsorption of solid substances such as ammonium salts, nitramine compounds and aluminum powder.

[0076] In the present invention, the alkynyl compound includes but is not limited to at least one of propargyl nitrile, 4-cyano-1-butyne, 5-cyano-1-pentyne, propargylamine, 3-butyne-1-amine and 4-pentyne-1-amine; preferably, the alkynyl compound is propargyl nitrile and propargylamine. By using propargyl nitrile and propargylamine as alkynyl compounds at the same time, it is possible to simultaneously introduce an azo ring structure with a CN group and an NH2 functional group.

[0077] Furthermore, the click chemistry reaction needs to be carried out under the action of a catalyst, and the catalyst includes a first catalytic component and a second catalytic component, the first catalytic component is an organic amine or a reducing agent, and the second catalytic component is a halide of an intermediate valence transition element or a salt of a high valence transition element; preferably, the organic amine is pentamethyldiethyltriamine and / or triethylamine, the halide of the intermediate valence transition element is CuBr and / or CuCl, the salt of the high valence transition element is copper sulfate, and the reducing agent is copper or ascorbic acid; in the present invention, the first catalytic component and the second catalytic component are used together as catalysts. Preferably, the amount of the catalyst additive is related to the amount of the azidated hyperbranched polyol azide substance, and the molar ratio is -N3: first catalyst component: second catalyst component (1-2): 1:1. Specifically, the second catalyst is Cu + (or Cu 2+ )count.

[0078] Click chemistry reaction is also carried out in the presence of a solvent. After mixing the azidized hyperbranched polyol, the acetylenic compound containing CN and / or NH2, the catalyst and the solvent, the mixture is reacted at 50°C to 70°C for 10 to 24 hours, followed by washing with water to remove by-products, and heating and / or vacuum drying.

[0079] The choice of solvent is the same as the choice of solvent in step S1, including but not limited to at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, pyridine and tetrahydrofuran.

[0080] In the present invention, the amount of raw materials fed to each reaction is not limited, and the amount of feed can be regulated according to the required specific structure, and the molar amount of the hyperbranched polyol, halogenated acyl halide, and alkynyl compound can be regulated to obtain a hyperbranched neutral polymer bonding agent with different hydroxyl, cyano, amine and hydrocarbon content. In addition, in some other embodiments of the present invention, step S1, step S2 and step S3 can be performed continuously, and the final washing and drying process is not performed after step S1 and step S2 are completed.

[0081] It should be understood that the total amount of hydroxyl, cyano, amine and hydrocarbon groups reaches 100%, and the value of any one of the groups can be 0, that is, the above hydroxyl, cyano, amine and hydrocarbon groups can be selected according to actual conditions.

[0082] Preferably, the content of hydroxyl group is 5% to 10%, the content of cyano group is 0% to 90%, the content of amine group is 0% to 90%, the content of hydrocarbon group is 0% to 5%, wherein at least one of cyano group and amine group exists.

[0083] The preparation method of the hyperbranched neutral polymer bonding agent provided by the present invention takes a hyperbranched polyol as a matrix, introduces a non-polar hydrocarbon group through acyl halide esterification, azidation, and click chemistry reaction, especially an azo ring structure with a CN group and an NH2 functional group, which is conducive to the adsorption of solid substances such as ammonium salts, nitramine compounds and aluminum powder, and the retained unreacted hydroxyl groups can react with a propellant curing agent to be grafted on the propellant adhesive network. Its hyperbranched spherical structure has the advantages of good process performance and good bonding effect as a solid propellant bonding agent. The hyperbranched neutral polymer bonding agent prepared by the preparation method of the hyperbranched neutral polymer bonding agent is easy to form a spherical configuration due to its hyperbranched structure. When used in different polar matrices, the inner and outer groups of the sphere will change accordingly, so its surface and interface properties are different from those of the neutral polymer bonding agent of free radical polymerization. The hyperbranched neutral polymer bonding agent can be widely used in the preparation of solid propellants.

[0084] The features and performance of the present invention are further described in detail below in conjunction with the embodiments.

[0085] Example 1

[0086] This embodiment provides a method for preparing a Hyper H40-based hyperbranched neutral polymer bonding agent, wherein the feed amount is calculated according to OH 10%, CN 85%, and alkyl 5%, and the method comprises the following steps:

[0087] S1. Mix 1.0 g of hyperbranched polyol Hyper H40, 10 mL of DMF solvent, 1.72 g of 2-bromoisobutyryl bromide, and 0.06 g of octanoyl bromide. The reaction was carried out in an ice-water bath at 3°C ​​for 1 h. The mixture was neutralized with ammonia water to a pH of 7, then washed with water and dried. The yield was 90%. Please refer to Figure 1 and Figure 2 , the infrared spectrum showed the presence of newly added bromine fingerprint peaks and ester shoulder peaks; Figure 5 , Figure 6 , Figure 7 and Figure 8 The hydrogen and carbon NMR spectra also show obvious bromomethyl and newly added carbonyl peaks.

[0088] S2. Take the purified and dried brominated H40 in step S1, add 0.6 g of excess sodium azide and 10 mL of DMF, react at 80°C for 8 h, then wash with hot water to remove by-products, and heat to dry. The yield is 90%, please refer to Figure 3 , the infrared spectrum shows an ester shoulder peak and an azide characteristic peak; Fig. 9 and Fig.10 The methyl peaks in H and C NMR spectra shifted to high field.

[0089] S3, take the purified and dried azidized H40 in step S2, add 0.54g of CuBr catalyst, 0.65g of pentamethyldiethyltriamine, 10mL of DMF solvent, stir evenly, add 0.6g of propiolonitrile, react at 50℃ for 8h; then wash with hot water to remove by-products, and heat to dry. The yield is 90%, please refer to Figure 4 The infrared spectrum shows an ester shoulder peak and a CN characteristic peak, while the azide characteristic peak disappears. Fig.11 and Fig.12 The H NMR spectrum showed that the methylene peak connected to N was significantly enlarged, the C spectrum showed the characteristic peak of CN group, and the methyl peak shifted to the low field.

[0090] The actual detected results are OH11%, cyano84%, and alkyl5%, which are very close to the designed results.

[0091] Fig.13 and Fig.14 Transmission electron microscopy showed that the configurations of hyperbranched polyol H40 and the synthesized neutral polymer bonding agent were both spherical, which was consistent with the hyperbranched configuration.

[0092] Example 2

[0093] This embodiment provides a method for preparing a Hyper H30-based hyperbranched neutral polymer bonding agent, wherein the feed amount is calculated according to 10% OH, 85% amine, and 5% alkyl, and the method comprises the following steps:

[0094] S1. Mix 10g of Hyper H30, 30mL of solvent dimethylacetamide, 18.4g of 2-bromoisobutyryl bromide, and 0.11g of decanoyl bromide. The reaction was carried out in an ice-water bath at 0°C for 2h, and then neutralized with sodium carbonate aqueous solution to pH 7, washed with water, and dried. The infrared spectrum showed characteristic peaks of bromine fingerprint peaks and ester shoulder peaks.

[0095] S2, take the brominated H30 purified and dried in step S1, add 6g (excess) of sodium azide and 20mL of solvent dimethylacetamide, react at 80°C for 8h, then wash with hot water to remove by-products, and dry in vacuum. The infrared spectrum shows characteristic peaks of ester group and azide group.

[0096] S3, take the purified and dried azidized H30 in step S2, add 5.8g of CuBr catalyst, 7.0g of pentamethyldiethyltriamine, 20mL of dimethylacetamide solvent, stir evenly, add 4.6g of propargylamine, react at 50℃ for 8h; then wash with hot water to remove by-products, and dry in vacuum. The infrared spectrum shows the characteristic peaks of ester group and NH2, and the characteristic peak of azido group disappears ( Fig.15 ).from Fig.16 and Fig.17 It can be seen that the methylene peak connected to N in the H NMR spectrum is significantly increased, and the H spectrum and C spectrum show that the methyl peak moves to a high field.

[0097] The actual OH is 8%, the amine is 89%, and the alkyl is 3%, which is very close to the designed results.

[0098] Example 3

[0099] This embodiment provides a method for preparing a Hyper H20-based hyperbranched neutral polymer bonding agent, wherein the feed amount is calculated according to 10% OH, 63% CN, 22% amine, and 5% alkyl, and the method comprises the following steps:

[0100] S1. 5.0 g of Hyper H20, 20 mL of solvent N-methylpyrrolidone, and 10.2 g of 2-chloroisobutyryl chloride were added. The reaction was carried out in an ice-water bath at 4°C for 2 h, and then neutralized with aqueous sodium hydroxide solution to pH 7, washed with water, and dried. The infrared spectrum showed characteristic peaks of chlorine group and newly added ester group shoulder peaks.

[0101] S2, take the purified and dried chloro-H2O in step S1, add 3.0 g (excess) of sodium azide and 20 mL of solvent N-methylpyrrolidone, react at 90°C for 12 h, then wash with hot water to remove by-products, and dry in vacuum. The infrared spectrum shows characteristic peaks of ester group and azide group.

[0102] S3, take the purified and dried azidized H20 in step S2, add 3.0g of CuCl catalyst, 4.0g of triethylamine, 10mL of N-methylpyrrolidone solvent, stir evenly, add 2.0g of 4-cyano-1-butyne, 0.6g of 3-butyne-1-amine, react at 30°C for 24h; then wash with hot water to remove by-products, and heat to dry. The infrared spectrum shows characteristic peaks of ester group, CN group and NH2.

[0103] The actual OH is 9%, CN is 65%, amine is 22%, and alkyl is 4%, which is very close to the designed results.

[0104] Example 4

[0105] This embodiment provides a continuous preparation method of a Boltorn H40-based hyperbranched neutral polymer bonding agent, wherein the feed amount is calculated according to OH 8%, CN 70%, amine 22%, and alkyl 5%, and the three steps are performed continuously, which includes the following steps:

[0106] S1. Mix 2.0 g of hyperbranched polyol Boltorn H40, 10 mL of solvent N,N-dimethylacetamide, 3.3 g of 2-bromoisobutyryl bromide, and 0.1 g of propionyl bromide. The reaction was carried out in an ice-water bath at 0°C for 3 h, and then neutralized with 0.76 g of NaOH and 0.5 mL of water to a pH of 7;

[0107] S2. Add 1.0 g (excess) of sodium azide into the reaction bottle of step S1 and react at 80° C. for 8 h;

[0108] S3, add 0.6g of catalyst CuSO4 and 0.3g of Cu powder to the reaction bottle in step S2, stir evenly, add 0.7g of 5-cyano-1-pentyne and 0.3g of 4-pentyne-1-amine, react at room temperature for 24h; then wash with hot water to remove by-products, and heat to dry. The yield is 90%, and the infrared spectrum shows characteristic peaks of ester group, CN group and NH2.

[0109] The actual detected results are OH 6%, CN 69%, amine 21%, and alkyl 4%, which are very close to the designed results.

[0110] Example 5

[0111] This embodiment provides a continuous preparation method of a Hyper H10-based hyperbranched neutral polymer bonding agent, wherein the feed amount is calculated according to OH 8%, CN 82%, amine 10%, and alkyl 0%, and the method comprises the following steps:

[0112] S1. Mix 10 g of hyperbranched polyol Hyper H10, 20 mL of solvent pyridine, 10 mL of tetrahydrofuran, and 15 g of 2-bromo-2-methylpropionyl bromide. The reaction was carried out in an ice-water bath at 2°C for 1 h, and then neutralized with sodium hydroxide to a pH of 7. Take 1 mL of the reaction solution, dialyze it, and dry it. The yield was 90%, and the infrared spectrum showed characteristic peaks of bromine and ester groups.

[0113] S2. After the brominated H10 in step S1 is neutralized, 4.5 g (excess) of sodium azide is added to the reaction solution, and the mixture is reacted at 80° C. for 8 h. Then, sodium hydroxide is added to neutralize the mixture. 1 mL of the reaction solution is dialyzed and dried. The yield is 90%. The infrared spectrum shows characteristic peaks of ester and azide groups.

[0114] S3, after neutralization of the reaction liquid with H40 in step S2, add 5g of catalyst CuSO4 and 9g of ascorbic acid, stir evenly, add 3g of propyne nitrile and 0.5g of propargylamine, react at 50℃ for 8h; then wash with hot water to remove by-products, and dry in vacuum. The total yield is 80%, and the infrared spectrum shows characteristic peaks of ester group, CN group and NH2.

[0115] The actual detected results are OH7%, CN81%, amine12%, and alkyl0%, which are very close to the designed results.

[0116] In summary, the preparation method of the hyperbranched neutral polymer bonder provided by the present invention uses a hyperbranched polyol as a matrix, introduces non-polar hydrocarbon groups through acyl halide esterification, azidation, and click chemistry reactions, especially azo ring structures with CN groups and NH2 functional groups, which are conducive to the adsorption of solid substances such as ammonium salts, nitramine compounds, and aluminum powder. The retained unreacted hydroxyl groups can react with the propellant curing agent to be grafted on the propellant adhesive network. Its hyperbranched spherical structure has the advantages of good process performance and good bonding effect as a solid rocket propellant bonder. The hyperbranched neutral polymer bonder prepared by the above-mentioned preparation method of the hyperbranched neutral polymer bonder is easy to form a spherical configuration due to its hyperbranched structure. When used in different polar matrices, the inner and outer groups of the sphere will change accordingly, so its surface and interface properties are different from those of neutral polymer bonders polymerized by free radicals. The hyperbranched neutral polymer bonder can be widely used in the preparation of solid propellants.

[0117] 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 method for preparing a hyperbranched neutral polymer bonding agent, characterized in that: It includes: S1, subjecting a hyperbranched polyol, a halogenated acyl halide and / or an acyl halide alkyl hydrocarbon to a coupling esterification reaction to introduce an active halogen end group and / or a hydrocarbon group to obtain a hyperbranched polyol containing a halogen and / or a hydrocarbon group; S2, subjecting the halogen and / or hydrocarbon-containing hyperbranched polyol to an azidation substitution reaction with an excess of sodium azide to introduce an azide reaction site to obtain an azidated hyperbranched polyol; S3, subjecting the azidated hyperbranched polyol to a click chemical reaction with an alkynyl compound containing CN and / or NH2 under the action of a catalyst to obtain a hyperbranched neutral polymer bonding agent; The hyperbranched neutral polymer bonding agent with different contents of hydroxyl, cyano, amine and hydrocarbon groups can be obtained by adjusting the molar amounts of the hyperbranched polyol, the halogenated acyl halide, the acyl halide alkyl hydrocarbon and the alkynyl compound.

2. The method for preparing a hyperbranched neutral polymer bonding agent according to claim 1, characterized in that: The hyperbranched polyol is a polyester hyperbranched polyol or a polyether hyperbranched polyol; Preferably, the hyperbranched polyol is at least one of the hyperbranched polyesters Hyper H10, Hyper H20, Hyper H30, HyperH40 and Boltorn H40.

3. The method for preparing a hyperbranched neutral polymer bonding agent according to claim 1, characterized in that: The halogenated acyl halide comprises at least one of 2-bromoisobutyryl bromide, 2-chloroisobutyryl chloride and 2-bromo-2-methylpropionyl bromide; Preferably, the halogenated acyl halide is 2-bromoisobutyryl bromide.

4. The method for preparing a hyperbranched neutral polymer bonding agent according to claim 1, characterized in that: The alkyl acyl halide includes an alkyl acyl bromide or an alkyl acyl chloride; Preferably, the alkyl halide is an alkyl bromide having no more than 16 carbon atoms; Preferably, the alkyl acyl halide is an alkyl acyl bromide containing 3 to 10 carbon atoms.

5. The method for preparing a hyperbranched neutral polymer bonding agent according to claim 1, characterized in that: The alkynyl compound includes at least one of propargyl nitrile, 4-cyano-1-butyne, 5-cyano-1-pentyne, propargylamine, 3-butyne-1-amine and 4-pentyne-1-amine; Preferably, the alkynyl compound is propiolonitrile and propargylamine.

6. The method for preparing a hyperbranched neutral polymer bonding agent according to claim 1, characterized in that: The catalyst comprises a first catalytic component and a second catalytic component, wherein the first catalytic component is an organic amine or a reducing agent, and the second catalytic component is a halide of an intermediate valence transition element or a salt of a high valence transition element; Preferably, the organic amine is pentamethyldiethyltriamine and / or triethylamine, the halide of the intermediate valence transition element is CuBr and / or CuCl, the salt of the high valence transition element is copper sulfate, and the reducing agent is copper or ascorbic acid; Preferably, the amount of the catalyst additive is related to the amount of the azide substance in the azidated hyperbranched polyol, and the molar ratio of -N3: first catalyst component: second catalyst component is 1 to 2:1:

1.

7. The method for preparing a hyperbranched neutral polymer bonding agent according to claim 1, characterized in that: In step S1, the coupling esterification reaction is carried out in an ice water bath at 0°C±5°C for 1-24 hours, followed by neutralization with aqueous ammonia or sodium hydroxide or aqueous sodium carbonate solution, followed by washing with water to remove by-products and drying; In step S2, the azidation substitution reaction is carried out at 50° C. to 90° C. for 4 to 24 hours, followed by washing with water to remove by-products and drying; In step S3, the click chemistry reaction is carried out at 50° C. to 70° C. for 10 to 24 hours, followed by washing with water to remove byproducts and drying; Preferably, step S1, step S2 and step S3 are all reacted in the presence of a solvent, and the solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, pyridine and tetrahydrofuran; Preferably, step S1, step S2 and step S3 are performed continuously, and the final washing and drying process is not performed after step S1 and step S2 are completed.

8. A hyperbranched neutral polymer bonding agent, characterized in that The hyperbranched neutral polymer bonding agent is prepared by the preparation method of the hyperbranched neutral polymer bonding agent as described in any one of claims 1 to 7.

9. The hyperbranched neutral polymer bonding agent according to claim 8, characterized in that Calculated by percentage of amount of substance, the hydroxyl content of the hyperbranched neutral polymer bonding agent is 5% to 10%, the cyano group is 0% to 90%, the amine group is 0% to 90%, and the hydrocarbon group is 0 to 5%. The total amount of the substance is 100%, wherein at least one of the cyano group and the amine group exists.

10. Use of the hyperbranched neutral polymer bonding agent according to claim 9 in the preparation of solid propellants.

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