Organosilane bonding agent, preparation method thereof and application in solid propellant

Abstract

The present invention relates to the technical field of solid propellants, and specifically discloses an organosilane bonding agent, a preparation method thereof, and an application thereof in solid propellants. The organosilane bonding agent is prepared by reacting N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane with acrylonitrile, then adding acrylonitrile to react and performing reduced pressure distillation to remove unreacted small molecule compounds, thereby preparing the organosilane bonding agent. The siloxane in the organosilane bonding agent avoids highly active primary and secondary amine groups, while introducing a cyano group with an inductive effect, which can improve stress concentration under propellant tensile conditions. In addition, multiple hydroxyl groups are introduced into the molecule to participate in the curing reaction. When used in a propellant, it can increase the crosslinking density of the propellant, thereby improving the mechanical properties of the propellant.

Description

Technical Field

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

[0002] Bonding agent is an essential auxiliary agent in composite propellant. It improves the interface between oxidant and adhesive and inhibits the interface "dewetting" phenomenon of propellant, thus ensuring the stability and reliability of propellant.

[0003] Currently, propellant bonding agents primarily include aziridine compounds, alkanolamine compounds, borate compounds, polyamine compounds, neutral polymers, organic phthalates, and organosilanes. The siloxane in organosilane bonding agents reacts with water on the filler surface to form silanols, which adsorb to the filler surface, thereby providing a bonding agent. Existing silane bonding agents are mostly those containing primary or secondary amine groups, such as N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. Primary and secondary amine groups are highly reactive and can react rapidly with isocyanates, resulting in a decrease in the propellant's process performance. Therefore, these silane coupling agents are typically used to treat coated APs. Furthermore, these silane bonding agents lack inducing groups, preventing them from releasing stress concentration points in the propellant, which negatively impacts the propellant's mechanical properties. Therefore, developing organosilane bonding agents with minimal impact on propellant process performance and superior performance is of great application value. Summary of the Invention

[0004] The invention provides an organosilane bonding agent, a preparation method thereof and application in solid propellants, which has the characteristics of low activity and no influence on the process performance of the propellant.

[0005] The technical solution of the present invention is to provide an organosilane bonding agent, the molecular structure of which is as follows:

[0006] ;

[0007] Wherein, R is one of -OH, -OCH2CH2CH3, -OCH2CH=CH2 or -OCH2CH2CH2Si(OCH3)3 functional groups.

[0008] The present invention also relates to a method for preparing the organosilane bonding agent, comprising the following steps:

[0009] S1, using N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane as a raw material, mixing it with acrylonitrile for reaction;

[0010] Modified glycidyl ether is added to the materials obtained in S2 and S1 to react again. After the reaction is completed, unreacted small molecular compounds are removed by distillation, and the remaining light yellow or yellow viscous liquid is the organosilane bonding agent.

[0011] Optionally, the molar ratio of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to acrylonitrile in S1 is 1:1.00~1.10.

[0012] Optionally, the reaction temperature in S1 is 30-50° C., the reaction time is 3-5 hours, and after the reaction is completed, the mixture is cooled to room temperature before proceeding to the next step.

[0013] Optionally, the amount of the modified glycidyl ether added in S2 is 2.00 to 2.20 times the molar amount of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

[0014] Alternatively, the modified glycidyl ether includes, but is not limited to, glycidol, n-propyl glycidyl ether, allyl glycidyl ether or γ-glycidyloxypropyltrimethoxysilane.

[0015] Optionally, the reaction temperature in S2 is 30-50° C., and the reaction time is 3-5 hours.

[0016] Optionally, the distillation temperature in S2 is 70-90°C.

[0017] The invention also relates to application of the obtained organosilane bonding agent in composite solid propellant.

[0018] Optionally, the amount of the organic silane bonding agent added is 0.05-0.1%.

[0019] The present invention has the following beneficial effects:

[0020] The siloxane in the organosilane bonding agent of the present invention contains only tertiary amines, thereby avoiding highly active primary and secondary amine groups, which are unable to react with isocyanates in the propellant. At the same time, the present invention introduces a cyano group with an inductive effect into the organosilane bonding agent, which can improve stress concentration under tensile conditions of the propellant. In addition, multiple hydroxyl groups are introduced into the molecule to participate in the curing reaction, thereby increasing the cross-linking density of the propellant and thus improving the mechanical properties of the propellant.

[0021] The organosilane bonding agent provided by the present invention has the advantages of simple synthesis method, mild reaction conditions, and the like. DETAILED DESCRIPTION

[0022] 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.

[0023] The present invention provides an organosilane bonding agent, the molecular structure of which is as follows:

[0024] ;

[0025] Wherein, R is one of -OH, -OCH2CH2CH3, -OCH2CH=CH2 or -OCH2CH2CH2Si(OCH3)3 functional groups.

[0026] The present invention also relates to a method for preparing the organosilane bonding agent, comprising the following steps:

[0027] S1, using N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane as a raw material, mixing it with acrylonitrile for reaction;

[0028] Modified glycidyl ether is added to the materials obtained in S2 and S1 to react again. After the reaction is completed, unreacted small molecular compounds are removed by distillation, and the remaining light yellow or yellow viscous liquid is the organosilane bonding agent.

[0029] In some embodiments, the molar ratio of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to acrylonitrile is 1:1.00-1.10, preferably 1:1.05. In S1, the reaction temperature is 30-50°C, the reaction time is 3-5 hours, and the reaction is cooled to room temperature before proceeding to the next step.

[0030] In some embodiments, the amount of the modified glycidyl ether added in S2 is 2.00-2.20 times the molar amount of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane; the modified glycidyl ether includes but is not limited to glycidol, n-propyl glycidyl ether, allyl glycidyl ether, or γ-glycidoxypropyltrimethoxysilane; the reaction temperature in S2 is 30-50° C., the reaction time is 3-5 hours, and the distillation temperature is 70-90° C.

[0031] 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.

[0032] Example 1

[0033] (1) Weigh 0.50 mol of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, add it to a three-necked reaction flask, and slowly add 0.50 mol of acrylonitrile through a dropping funnel. After the addition is complete, control the reaction temperature of the system to 40°C, react for 3 hours, and then cool to room temperature;

[0034] (2) Slowly add 1.10 mol of allyl glycidyl ether to the product of step 1. After the addition is complete, continue to heat the system to 40°C, react for 4 hours, and then remove unreacted small molecular compounds by vacuum distillation at 70°C. After cooling to room temperature, the target yellow viscous liquid product can be obtained.

[0035] Example 2

[0036] (1) Weigh 0.50 mol of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, add it to a three-necked reaction flask, and slowly add 0.52 mol of acrylonitrile through a dropping funnel. After the addition is complete, control the reaction temperature of the system to 40°C, react for 5 hours, and then cool to room temperature;

[0037] (2) Slowly add 1.02 mol of glycidol to the product of step 3. After the addition is complete, continue to heat the system to 50°C. After reacting for 2 hours, remove the unreacted small molecular compounds by vacuum distillation at 90°C. Cool to room temperature to obtain the target light yellow viscous liquid product.

[0038] Example 3

[0039] (1) Weigh 0.50 mol of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, add it to a three-necked reaction flask, and slowly add 0.53 mol of acrylonitrile through a dropping funnel. After the addition is complete, the reaction temperature of the system is controlled to 50°C. The reaction is carried out for 3 hours and then cooled to room temperature.

[0040] (2) Slowly add 1.08 mol of n-propyl glycidyl ether to the product of step 3. After the addition is complete, continue to heat the system to 40°C, react for 4 hours, and then remove the unreacted small molecular compounds by vacuum distillation at 90°C. After cooling to room temperature, the target yellow viscous liquid product can be obtained.

[0041] Example 4

[0042] (1) Weigh 0.50 mol of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, add it to a three-necked reaction flask, and slowly add 0.55 mol of acrylonitrile through a dropping funnel. After the addition is complete, control the reaction temperature of the system to 30°C, react for 4 hours, and then cool to room temperature;

[0043] (2) Slowly add 1.05 mol of γ-glycidyloxypropyltrimethoxysilane to the product of step 3. After the addition is complete, continue to heat the system to 40°C, react for 4 hours, and then remove the unreacted small molecular compounds by vacuum distillation at 80°C. After cooling to room temperature, the target yellow viscous liquid product can be obtained.

[0044] The organosilane bonding agent obtained in the above examples and comparative examples was used in a 4-component HTPB propellant (solid content 88.0%), with the addition amount of the bonding agent being 0.08%. The properties of the resulting propellant are shown in Table 1.

[0045] Table 1 Application performance of organosilane bonding agent

[0046]

[0047] As can be seen from Table 1 above, the organosilane bonding agent of the present invention has good application performance.

[0048] 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. An organosilane bonding agent, characterized in that The molecular structure of the organosilane bonding agent is as follows: ； Wherein, R is one of -OH, -OCH2CH2CH3, -OCH2CH=CH2 or -OCH2CH2CH2Si(OCH3)3 functional groups.

2. The method for preparing an organosilane bonding agent according to claim 1, wherein The following steps are involved: S1, using N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane as a raw material, mixing it with acrylonitrile for reaction; Modified glycidyl ether is added to the materials obtained in S2 and S1 to react again. After the reaction is completed, unreacted small molecular compounds are removed by distillation, and the remaining light yellow or yellow viscous liquid is the organosilane bonding agent.

3. The method for preparing the organosilane bonding agent according to claim 2, characterized in that: The molar ratio of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane to acrylonitrile in S1 is 1:1.00~1.

10.

4. The preparation method according to claim 2 or 3, characterized in that: In S1, the reaction temperature is 30-50°C, the reaction time is 3-5 hours, and after the reaction is completed, the reaction is cooled to room temperature before proceeding to the next step.

5. The preparation method according to claim 2, wherein: The amount of modified glycidyl ether added to S2 is 2.00 to 2.20 times the molar amount of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane.

6. The preparation method according to claim 2, wherein: Modified glycidyl ethers include, but are not limited to, glycidol, n-propyl glycidyl ether, allyl glycidyl ether, or γ-glycidyloxypropyltrimethoxysilane.

7. The preparation method according to claim 2, wherein: In S2, the reaction temperature is 30-50° C., and the reaction time is 3-5 hours.

8. The preparation method according to any one of claims 3 to 7, characterized in that: The distillation temperature in S2 is 70~90℃.

9. Use of the organosilane bonding agent obtained according to claim 1 or the organosilane bonding agent obtained by the preparation method according to any one of claims 2 to 8 in composite solid propellants.

10. The use according to claim 9, characterized in that: The amount of organosilane bonding agent added to the propellant is 0.05%~0.1%.

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