Polycyanide and polyhydroxy bonding agent, preparation method and application thereof in HTPB propellant

Abstract

The present invention relates to the technical field of solid propellants, and specifically discloses a polycyanide-polyhydroxy bonding agent, a preparation method, and its application in hydroxybutyl propellant. When preparing the bonding agent, acrylonitrile is added dropwise to polyethylene polyamine, and the temperature is raised to react to prepare an intermediate; then glyceric acid is added to the intermediate, the temperature is raised to carry out an amidation reaction, and then distilled until no liquid is distilled out to obtain the target bonding agent. The bonding agent has a polycyanide-polyhydroxy molecular structure, in which the hydroxyl groups can enter a cross-linked network through chemical bonding with toluene diisocyanate, and the cyano group can produce a strong physical adsorption effect with the surface of nitramine oxidant particles, and is used as a nitramine or nitramine-modified hydroxybutyl solid propellant system. After adding the bonding agent provided by the present invention to the solid propellant system, the room temperature, high and low temperature mechanical properties of the solid propellant are significantly improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid propellants, and in particular to a polycyanide-polyhydroxy bonding agent, a preparation method thereof, and application thereof in HTPB propellants. Background Art

[0002] In the pursuit of higher energy, solid propellants often incorporate oxidizer particles, such as ammonium perchlorate (AP), RDX, and HMX. These oxidizer particles are non-reinforcing fillers. When the propellant is subjected to a certain external load, the filler and matrix can easily separate, resulting in "dewetting." Dewetting occurs when the interface between the polymer binder and the solid particles is disrupted by external forces, leading to adhesion failure and the binder detaching from the solid particle surface. This dewetting phenomenon severely impacts the mechanical properties of the propellant.

[0003] Bonding agents are key additives for improving the interfacial adhesion between high-energy fillers and binders, inhibiting dewetting, and thereby enhancing the mechanical properties of propellants. First, bonding agents should possess groups capable of adsorbing solid filler particles, which determine the strength of the bond between the two. Second, they should possess a sufficient number of appropriately reactive groups capable of reacting with the curing agent, which determine the strength of the bond between the bonding agent and the binder system.

[0004] To address these issues, a bonding agent with an amphiphilic structure and a sufficient number of bonding groups is added to the propellant. This agent reacts physicochemically with the filler while simultaneously bonding to the matrix, thereby strengthening the interfacial adhesion between the two and improving the overall mechanical properties of the propellant. Currently, the most commonly used bonding agents in HTPB four-component propellants are borate esters and hydantoin. Borates absorb moisture from solid particles and undergo hydrolysis, eliminating the weak boundary layer around the particles caused by the presence of moisture. Furthermore, borate ester bonding agents can enhance the high-temperature mechanical properties of the propellant, but borate esters have poor hydrolytic stability. Hydantoin triazine bonding agents, while significantly improving the mechanical properties of HTPB propellants, are less effective at high temperatures. In particular, during high-temperature accelerated aging tests, the mechanical properties of the grain degrade rapidly, making it difficult to meet the application requirements of the model. Summary of the Invention

[0005] The present invention provides a polycyanide-polyhydroxy bonding agent, a preparation method and application thereof in HTPB propellant. The bonding agent has a polycyanide-polyhydroxy molecular structure, wherein the hydroxyl groups can enter a cross-linked network through chemical bonding with toluene diisocyanate, and the cyanide groups can produce a strong physical adsorption effect with the surface of nitramine oxidant particles, and is used as a nitramine or nitramine-modified HTPB solid propellant system.

[0006] The technical solution of the present invention is to provide a polycyanide-polyhydroxy bonding agent, the molecular structure of which is as follows:

[0007] ;

[0008] Where n=1~4.

[0009] Optionally, n in the molecular structural formula is 1, 2, 3 or 4.

[0010] The present invention also relates to a method for preparing the polycyanide-polyhydroxy bonding agent, comprising the following steps:

[0011] S1, adding acrylonitrile dropwise to polyethylene polyamine, and heating the reaction to prepare an intermediate;

[0012] S2. Add glyceric acid to the intermediate, raise the temperature to carry out amidation reaction, and then distill until no liquid is distilled out to obtain a polycyanide-polyhydroxy bonding agent.

[0013] Optionally, the molar ratio of polyene polyamine to acrylonitrile in S1 is 1:2.0-2.5.

[0014] Optionally, the polyene polyamine is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or ethylenehexamine.

[0015] Optionally, the reaction temperature in S1 is 35-90° C., and the reaction time is 0.5-8 hours.

[0016] Optionally, the molar ratio of polyene polyamine to glyceric acid in S2 is 1:2.0-2.5.

[0017] Optionally, the amidation reaction temperature is 140 to 190° C., and the reaction time is 0.5 to 5 hours.

[0018] The invention also relates to the application of the polycyanide-polyhydroxy bonding agent in propellants.

[0019] Furthermore, the propellant is HTPB propellant.

[0020] The present invention has the following beneficial effects:

[0021] The present invention uses polyethylene polyamine as a raw material, reacts with acrylonitrile and glyceric acid, and the resulting bonding agent contains multiple hydroxyl and cyano groups. The hydroxyl groups react with isocyanate to enter the curing network system, and the cyano groups have a strong physical interaction with the nitramine molecules, which inhibits the dissolution of the nitramine molecules in the plasticizer, prevents the appearance of a "soft interface layer", and improves the mechanical properties of the HTPB propellant.

[0022] The polycyanide-polyhydroxy bonding agent provided by the present invention also has good hydrolysis resistance and still has a good bonding effect in a high-temperature environment. The preparation method of the bonding agent is simple, the reaction conditions are mild, and the reaction time is short. The obtained product has high purity and yield; the reaction process does not require additional reagents and solvents, the raw material utilization rate is high, and there is no solvent recovery operation, and no hazardous waste is generated during the preparation process; and the bonding agent is suitable for industrial production. DETAILED DESCRIPTION

[0023] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagents, etc. used in the following examples are commercially available products unless otherwise specified.

[0024] The present invention provides a polycyanide-polyhydroxy bonding agent, the molecular structure of which is as follows:

[0025] ;

[0026] Where n=1~4.

[0027] Optionally, n in the molecular structural formula is 1, 2, 3 or 4.

[0028] The present invention also relates to a method for preparing the polycyanide-polyhydroxy bonding agent, comprising the following steps:

[0029] S1, adding acrylonitrile dropwise to polyethylene polyamine, and heating the reaction to prepare an intermediate;

[0030] S2. Add glyceric acid to the intermediate, raise the temperature to carry out amidation reaction, and then distill until no liquid is distilled out to obtain a polycyanide-polyhydroxy bonding agent.

[0031] In some embodiments, the molar ratio of polyene polyamine to acrylonitrile in S1 is 1:2.0 to 2.5, preferably 1:2.2.

[0032] In some embodiments, the polyene polyamine is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or ethylenehexamine, preferably pentaethylenehexamine.

[0033] In some embodiments, the reaction temperature in S1 is 35-90°C, preferably 75°C; the reaction time is 0.5-8 hours, preferably 3 hours.

[0034] In some embodiments, the molar ratio of polyene polyamine to glyceric acid in S2 is 1:2.0 to 2.5, preferably 1:2.1.

[0035] In some embodiments, the amidation reaction temperature is 140-190° C., preferably 160° C. The reaction time is 0.5-5 hours, preferably 3 hours.

[0036] The present invention is described in detail below with reference to specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0037] Example 1

[0038] Weigh 0.5 mol of ethylenediamine into a three-necked flask, slowly drop 1.1 mol of acrylonitrile into the flask, while adding acrylonitrile, keep the temperature at about 60 ° C, and stir continuously at a stirring speed of about 110 r / min. Raise the system temperature to 70 ° C, stir at a speed of 130 r / min, and keep warm for 3 hours to obtain an intermediate; slowly drop 1.1 mol of glyceric acid into the intermediate, while keeping the temperature at about 120 ° C, and stir continuously at a stirring speed of about 150 r / min. After the addition of glyceric acid is completed, raise the temperature to 145 ° C, remove water while stirring, and keep warm for 3 hours and perform vacuum distillation, controlling the system pressure to 0.06 MPa, until no liquid is distilled and the distillation is ended. The product is the target bonding agent 1.

[0039] Example 2

[0040] Weigh 0.5 mol of diethylenetriamine into a three-necked flask, slowly drop 1.12 mol of acrylonitrile into the flask, while adding acrylonitrile, keep the temperature at about 60 ° C, and stir continuously at a stirring speed of about 110 r / min. Raise the system temperature to 70 ° C, stir at a speed of 130 r / min, and keep warm for 3 hours to obtain an intermediate; slowly drop 1.1 mol of glyceric acid into the intermediate, while keeping the temperature at about 120 ° C, and stir continuously at a stirring speed of about 150 r / min. After the addition of glyceric acid is completed, heat to 145 ° C, remove water while stirring, and after keeping warm for 3 hours, perform vacuum distillation, control the system pressure to 0.06 MPa, and end the distillation until no liquid is distilled out. The product is the target bonding agent 2.

[0041] Example 3

[0042] Weigh 0.5 mol of triethylenetetramine into a three-necked flask, slowly drip 1.2 mol of acrylonitrile into the flask, while adding acrylonitrile, keep the temperature at about 60 ° C, and stir continuously at a stirring speed of about 110 r / min. Raise the system temperature to 70 ° C, stir at a speed of 130 r / min, and keep warm for 3 hours to obtain an intermediate; slowly drip 1.1 mol of glyceric acid into the intermediate, while keeping the temperature at about 120 ° C, and stir continuously at a stirring speed of about 150 r / min. After the addition of glyceric acid is completed, heat to 160 ° C, remove water while stirring, and after keeping warm for 3 hours, perform vacuum distillation, control the system pressure to 0.06 MPa, and end the distillation until no liquid is distilled out. The product is the target bonding agent 3.

[0043] Example 4

[0044] Weigh 0.5 mol of tetraethylenepentamine into a three-necked flask, slowly drop 1.1 mol of acrylonitrile into the three-necked flask, while adding acrylonitrile, keep the temperature at about 60 ° C, and stir continuously at a stirring speed of 110 r / min. Raise the system temperature to 75 ° C, stir at a speed of 140 r / min, and keep warm for 3 hours to obtain an intermediate; slowly drop 1 mol of glyceric acid into the intermediate, while keeping the temperature at about 120 ° C, and stir continuously at a stirring speed of about 150 r / min. After the addition of glyceric acid is completed, heat to 160 ° C, remove water while stirring, and after keeping warm for 3 hours, perform vacuum distillation, control the system pressure to 0.09 MPa, and end the distillation until no liquid is distilled out. The product is the target bonding agent 4.

[0045] Example 5

[0046] Weigh 0.5 mol of pentaethylenehexamine into a three-necked flask, slowly drip 1.2 mol of acrylonitrile into the flask, while adding acrylonitrile, keep the temperature at about 60 ° C, and stir continuously at a stirring speed of 120 r / min. Raise the system temperature to 75 ° C, stir at a speed of 140 r / min, and keep warm for 3 hours to obtain an intermediate; slowly drip 1.1 mol of glyceric acid into the intermediate, while keeping the temperature at about 120 ° C, and stir continuously at a stirring speed of about 150 r / min. After the addition of glyceric acid is completed, heat to 180 ° C, remove water while stirring, and after keeping warm for 3 hours, perform vacuum distillation, control the system pressure to 0.09 MPa, and end the distillation until no liquid is distilled out. The product is the target bonding agent 5.

[0047] Comparative Example 1

[0048] Weigh 0.25 mol of polypropylene glycol diglycidyl ether-400 and add 0.53 mol of pentaethylenehexamine dropwise to a three-necked flask. Maintain the temperature at 40°C after addition, react for 4 hours, and then cool to room temperature. Slowly add 1.2 mol of acrylonitrile dropwise to the flask, maintaining the temperature at around 60°C while stirring continuously at 120 rpm. Raise the system temperature to 75°C and stir at 140 rpm for 3 hours to obtain the product.

[0049] The bonding agents obtained in the above examples and comparative examples were respectively applied to a certain formula of a hydroxybutane four-component propellant (solid content 88%), and the amount of bonding agent added was 0.05% of the hydroxybutane four-component propellant; the mechanical property test results are shown in Table 1 (the test reference standard is GJB770B-2005).

[0050] Table 1 Mechanical properties of different bonding agents

[0051]

[0052] As can be seen from the data in Table 1, compared with a blank sample (no bonding agent added) and polypropylene glycol diglycidyl ether-400 with a low hydroxyl content, the addition of the bonding agent provided by the present invention to the solid propellant system significantly improves the mechanical properties of the solid propellant at both room temperature and high and low temperatures. This indicates that the bonding agent prepared by the present invention, under the action of multiple cyano and hydroxyl groups, has a good bonding effect on the hydroxybutane propellant system containing ammonium nitrate.

[0053] The above embodiments describe preferred embodiments of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent of the present invention shall be based on the appended claims.

Claims

1. A polycyanide-polyhydroxy bonding agent, characterized in that: The molecular structure of the bonding agent is as follows: ； Where n=1~4.

2. The polycyanide-polyhydroxy bonding agent according to claim 1, wherein: In the molecular structural formula, n is 1, 2, 3 or 4.

3. The method for preparing the polycyanide-polyhydroxy bonding agent according to claim 1 or 2, characterized in that: The following steps are involved: S1, adding acrylonitrile dropwise to polyethylene polyamine, and heating the reaction to prepare an intermediate; S2. Add glyceric acid to the intermediate, raise the temperature to carry out amidation reaction, and then distill until no liquid is distilled out to obtain a polycyanide-polyhydroxy bonding agent.

4. The preparation method according to claim 3, wherein: The molar ratio of polyene polyamine to acrylonitrile in S1 is 1:2.0~2.

5.

5. The preparation method according to claim 3, wherein: The polyene polyamine is one or more of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine or ethylenehexamine.

6. The preparation method according to any one of claims 3 to 5, characterized in that: In S1, the reaction temperature is 35 to 90° C., and the reaction time is 0.5 to 8 hours.

7. The preparation method according to claim 3, wherein: The molar ratio of polyene polyamine to glyceric acid in S2 is 1:2.0~2.

5.

8. The preparation method according to claim 7, characterized in that: The temperature of the amidation reaction is 140 to 190° C., and the reaction time is 0.5 to 5 hours.

9. Use of the polycyanide-polyhydric bonding agent according to claim 1 or 2 or the polycyanide-polyhydric bonding agent obtained by the preparation method of any one of claims 3 to 8 in a propellant.

10. The use according to claim 9, characterized in that: The propellant is HTPB propellant.

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