A novel alcoholamine bonding agent, its preparation method and application

Abstract

This invention relates to the field of polymer synthesis technology, specifically disclosing a novel alkanolamine bonding agent, its preparation method, and its application. The method includes weighing an alkanolamine compound and a reaction solvent into a reaction apparatus, and then adding a weighed amount of perchloric acid dropwise into the apparatus. After the perchloric acid addition is complete, the temperature is raised, the reaction proceeds, and the novel alkanolamine bonding agent is obtained by vacuum distillation. This novel alkanolamine bonding agent contains only tertiary amine groups in its molecule, lacking primary and secondary amines. The bonding agent itself is weakly basic, and the tertiary amine groups have low reactivity with ammonia (AP), preventing the ammonia release rate from being too rapid and thus affecting propellant solidification.

Description

Technical Field

[0001] This invention relates to the field of solid propellant technology, specifically to a novel alkanolamine bonding agent, its preparation method, and its application. Background Technology

[0002] During the mixing and curing process of solid propellants, the binder matrix network structure (continuous phase) "wets" the solid filler particles (dispersed phase) through physical and chemical interactions, forming additional cross-linking points to enhance the mechanical properties of the composite solid propellant. However, this interaction force is generally small. When the composite solid propellant is subjected to external loads, tiny pores or cracks can form between the solid filler and the binder matrix, eventually leading to the complete detachment of the binder from the solid particles, i.e., "dewetting." Dewetting reduces the number of additional cross-linking points and causes volume expansion and decreased mechanical properties of the composite solid propellant. Therefore, studying the interfacial interaction between the binder matrix and filler particles is of great significance for regulating and improving the mechanical properties of composite solid propellants.

[0003] The application of bonding agents in solid propellants began with Oberth's research, which discovered that they could prevent "dewetting" at the propellant interface, a crucial method for improving the mechanical properties of solid propellants. However, with the development of higher-energy, higher-performance, less vulnerable, and green propellants, various new materials have been introduced into propellants, bringing new problems related to "dewetting" at the propellant filler matrix interface. Existing bonding agents are no longer sufficient to meet the mechanical performance requirements of composite solid propellants; therefore, it is essential to develop new, highly efficient bonding agents to meet the stringent mechanical performance requirements of propellants.

[0004] Corresponding bonding agent systems are designed for different binder / solid filler formulations to improve the interfacial performance of the continuous and dispersed phases in composite solid propellants. From the perspective of improving network structure, alkanolamines and their derivatives are widely used in composite solid propellants, playing a significant role in improving the interfacial properties and network structure. However, current alkanolamine bonding agents have high active hydrogen functionality, enabling them to form hydrogen bonds with both fillers and binders, which can increase the viscosity of the propellant slurry to some extent. Furthermore, the bonding agents themselves are highly alkaline, catalyzing the matrix curing reaction and shortening the slurry's pot life. The combined effect of these factors results in generally poor processability of propellants containing novel bonding agents. Summary of the Invention

[0005] To address the aforementioned problems, the first objective of this invention is to provide a novel alkanolamine bonding agent. This novel alkanolamine bonding agent contains only tertiary amine groups in its molecule, without primary or secondary amines. The bonding agent itself is weakly basic, and the tertiary amine groups have low reactivity with AP, so that the ammonia release rate is not too fast and thus does not affect the propellant solidification.

[0006] A second objective of this invention is to provide a method for preparing the aforementioned novel alkanolamine bonding agent.

[0007] A third objective of this invention is to provide the application of the aforementioned novel alcoholamine bonding agent.

[0008] The first technical solution adopted in this invention is: a novel alkanolamine bonding agent, the structural formula of which is:

[0009]

[0010] The second technical solution adopted in this invention is: a method for preparing a novel alkanolamine bonding agent as described in the first technical solution, comprising the following steps:

[0011] The alkanolamine compound and reaction solvent were weighed into the reaction apparatus, and the weighed perchloric acid was added dropwise to the reaction apparatus. After the perchloric acid was added, the temperature was raised and the reaction was carried out. The novel alkanolamine bonding agent was obtained by vacuum distillation.

[0012] Preferably, the alkanolamine compound includes one or more of diethanolamine, triethanolamine, and N-(2-cyanoethyl)diethanolamine.

[0013] Preferably, the molar ratio of perchloric acid to alkanolamine compound is 0.25 to 0.66:1.

[0014] Preferably, the reaction solvent is one or more of deionized water, ethanol, and acetone.

[0015] Preferably, the amount of the reaction solvent used is 80-150 mL.

[0016] Preferably, the preparation method of the novel alkanolamine bonding agent includes:

[0017] Weigh the alkanolamine compound and reaction solvent into a reaction flask equipped with a dehydration device. Add the weighed perchloric acid into a dropping funnel. Open the dropping funnel without water bath heating and add the perchloric acid dropwise into the reaction flask. After the perchloric acid has been added, raise the water bath temperature to 75-80°C and react for 6-8 hours. Obtain the novel alkanolamine bonding agent by vacuum distillation for 7 hours.

[0018] The third technical solution adopted in this invention is: the application of a novel alkanolamine bonding agent as described in the first technical solution in the preparation of solid propellants.

[0019] Preferably, the application of the novel alkanolamine bonding agent in the preparation of solid propellants includes: adding the novel alkanolamine bonding agent to a solid propellant premix slurry and mixing it evenly to obtain a solid propellant containing the novel alkanolamine bonding agent;

[0020] The solid propellants containing novel alkanolamine bonding agents include NEPE system propellants, HTPB system propellants, PET propellants, PEG propellants, or GAP propellants containing novel alkanolamine bonding agents.

[0021] Preferably, the mass ratio of the novel alkanolamine bonding agent to the solid propellant is 0.2% to 2.0%.

[0022] The beneficial effects of the above technical solution are as follows:

[0023] (1) Current alkanolamine bonding agents have high active hydrogen functionality, which can form hydrogen bonds with fillers and binders simultaneously, increasing the viscosity of the propellant slurry to some extent. Furthermore, the bonding agent itself is highly alkaline, catalyzing the matrix curing reaction and shortening the slurry's pot life. The combined effect of these factors results in generally poor process performance of propellants containing novel bonding agents. The novel alkanolamine bonding agent disclosed in this invention contains only tertiary amine groups, lacking primary and secondary amines. The bonding agent itself is less alkaline, and the tertiary amine groups have low reactivity with AP, preventing excessive ammonia release and thus minimizing its impact on propellant curing.

[0024] (2) In view of the characteristics of the composite solid propellant formulation with a variety of solid fillers and high content, the present invention designs an alkanolamine bonding agent for the AP / binder interface to prevent the composite solid propellant from "dewetting". Alkanolamine and its derivatives are used to improve the network structure of the propellant. The novel alkanolamine bonding agent disclosed in the present invention is a triethanolamine derivative, which can significantly improve the interfacial adhesion performance between ammonium perchlorate oxidant (AP) and solid propellant binder matrix, and significantly improve the mechanical properties of composite solid propellant. The novel alkanolamine bonding agent has broad application prospects in high-energy propellants and can also be applied to other composite solid propellants.

[0025] (3) The novel alkanolamine bonding agent disclosed in this invention is a compound used to enhance the interface between AP particles and adhesive matrix. The nitrogen atom in its structure has unshared electron pairs, which can form coordinate bonds with the hydrogen atoms in AP to form strong chemical and physical adsorption. The hydroxyl group in the alkanolamine can react with the isocyanate curing agent and enter the elastomer network structure, thereby forming a strong interface layer between AP and adhesive matrix.

[0026] (4) Through a large number of experiments, the optimal mass percentage of the novel alkanolamine bonding agent in the propellant was found to be 0.2% to 2%. Under this ratio, both the novel alkanolamine bonding agent and the propellant have the best quality and performance.

[0027] (5) The novel amine bonding agent of the present invention can adjust the network structure, thereby improving the mechanical properties of the composite solid propellant and meeting the requirements of the mechanical properties of the composite solid propellant. Attached Figure Description

[0028] Figure 1 This is a schematic flowchart illustrating a method for preparing a novel alkanolamine bonding agent according to an embodiment of the present invention. Detailed Implementation

[0029] The present invention will be further illustrated below with specific embodiments. It should be noted that those skilled in the art can make several modifications and improvements without departing from the principle of the present invention, and these should also be considered to fall within the protection scope of the present invention.

[0030] The contents not described in detail in this specification are common knowledge to those skilled in the art.

[0031] This invention discloses a novel alkanolamine bonding agent, which is an alkanolamine bonding agent with the following structural formula:

[0032]

[0033] This invention discloses a method for preparing a novel alkanolamine bonding agent, comprising:

[0034] Weigh the alkanolamine compound and reaction solvent into a reaction flask equipped with a dehydration device. Add the weighed perchloric acid (HClO4) into a dropping funnel. Without water bath heating, open the dropping funnel and slowly add HClO4 dropwise into the reaction flask. After the HClO4 has been added, raise the water bath temperature to 75-80°C, preferably 75°C, and react for 6-8 hours. Distill off the solvent and unreacted raw materials by vacuum distillation for 7 hours to obtain a brownish-yellow viscous liquid product, which is a novel alkanolamine bonding agent.

[0035] The molar ratio of perchloric acid to alkanolamine compound is 0.25–0.66:1, and the amount of reaction solvent used is 80–150 mL.

[0036] The alkanolamine compounds include one or more of diethanolamine, triethanolamine, and N-(2-cyanoethyl)diethanolamine.

[0037] The reaction solvent is one or more of deionized water, ethanol, and acetone.

[0038] This invention also discloses the application of a novel alkanolamine bonding agent in the preparation of solid propellants, which includes adding the novel alkanolamine bonding agent to a solid propellant premix slurry and mixing it evenly to obtain a solid propellant; for example, based on the novel alkanolamine bonding agent, NEPE system propellants (i.e., propellants containing polyether binders), HTPB system propellants (i.e., hydroxyl butyrate propellants), PET propellants, PEG propellants, or GAP propellants can be prepared.

[0039] The propellant in the NEPE system includes, for example, novel alkanolamine bonding agents, binders, oxidants, fuels, curing agents, and other functional components; wherein the novel alkanolamine bonding agents account for 0.2% to 2.0% of the propellant by mass; the binder is, for example, poly(glycidyl azide) (GAP); the oxidant is, for example, ammonium perchlorate (AP) and octogen (HMX); the fuel is, for example, aluminum powder (Al); the curing agent is, for example, isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), 1,6-hexamethylene diisocyanate (HDI), etc.; and other functional components include, for example, burning rate catalysts and curing catalysts.

[0040] Example 1

[0041] Perchloric acid, 100 ml of deionized water, and triethanolamine were added to a reaction flask. The molar ratio of perchloric acid to triethanolamine was 0.25:1. The reaction temperature was controlled between 75-80℃. The vacuum distillation apparatus was replaced, and the solvent and unreacted raw materials were distilled off under reduced pressure to obtain a brownish-yellow viscous liquid product, namely the novel alkanolamine bonding agent BAG-25A. Infrared analysis revealed that the novel alkanolamine bonding agent BAG-25A contains amino, hydroxyl, and perchlorate groups, with 3355 cm⁻¹ being the most abundant. -1 The absorption peak is at 1636 cm⁻¹, which is the absorption peak of the hydroxyl group. -1 The absorption peak is at 1094 cm⁻¹, which is the absorption peak of the amine group. -1 It is the absorption peak of the perchlorate group.

[0042] Example 2

[0043] Perchloric acid, 100 ml of deionized water, and triethanolamine were added to a reaction flask. The molar ratio of perchloric acid to triethanolamine was 0.5:1. The reaction temperature was controlled between 75-80℃. The vacuum distillation apparatus was replaced, and the solvent and unreacted raw materials were distilled off under reduced pressure to obtain a brownish-yellow viscous liquid product, namely the novel alkanolamine bonding agent BAG-25B. The structure of the novel alkanolamine bonding agent BAG-25B was identified by infrared analysis as containing amine, hydroxyl, and perchlorate groups.

[0044] Example 3

[0045] Perchloric acid, 100 ml of deionized water, and triethanolamine were added to a reaction flask. The molar ratio of perchloric acid to triethanolamine was 0.66:1. The reaction temperature was controlled between 75-80℃. The vacuum distillation apparatus was replaced, and the solvent and unreacted raw materials were distilled off under reduced pressure to obtain a brownish-yellow viscous liquid product, namely the novel alkanolamine bonding agent BAG-25C. The structure of the novel alkanolamine bonding agent BAG-25C was identified by infrared analysis as containing amine, hydroxyl, and perchlorate groups.

[0046] Example 4

[0047] Perchloric acid, 100 ml of ethanol, and diethanolamine were added to a reaction flask. The molar ratio of perchloric acid to diethanolamine was 0.5:1. The reaction temperature was controlled at 75°C. The vacuum distillation apparatus was replaced, and the solvent and unreacted raw materials were distilled off under reduced pressure to obtain a brownish-yellow viscous liquid product, namely the novel alkanolamine bonding agent BAG-25D. The structure of the novel alkanolamine bonding agent BAG-25D was identified by infrared analysis as containing amine, hydroxyl, and perchlorate groups.

[0048] Example 5

[0049] Perchloric acid, 100 ml of acetone, triethanolamine, and N-(2-cyanoethyl)diethanolamine were added to a reaction flask. The molar ratio of perchloric acid to the total amount of triethanolamine and N-(2-cyanoethyl)diethanolamine was 0.5:1. The reaction temperature was controlled at 80°C. The vacuum distillation apparatus was replaced, and the solvent and unreacted raw materials were distilled off under reduced pressure to obtain a brownish-yellow viscous liquid product, namely the novel alkanolamine bonding agent BAG-25E. The structure of the novel alkanolamine bonding agent BAG-25E was identified by infrared analysis as containing amine, hydroxyl, and perchlorate groups.

[0050] Example 6

[0051] The applications of three different novel alkanolamine bonding agents (BAG-25A, BAG-25B, and BAG-25C) in PET propellant formulations are shown in Table 1. The tensile strength σ of the propellant was determined according to the uniaxial tensile method (413.1 Maximum tensile strength, breaking strength, maximum elongation, and elongation at break) of GJB 770B-2005 "Test Methods for Gunpowder". m Elongation ε m The measurement results are shown in Table 2.

[0052] Table 1. PET propellant formulation composition

[0053]

[0054]

[0055] Table 2 Performance of bonding agents in PET propellants

[0056]

[0057] Based on the propellant performance data in Table 2, the novel amine bonding agent can significantly improve the mechanical properties of PET propellants at normal, high, and low temperatures. In particular, BAG-25B, synthesized with a molar ratio of perchloric acid to triethanolamine of 0.5:1, exhibits the best overall performance.

[0058] Example 7

[0059] The application of three different bonding agents (BAG-25A, BAG-25B, and BAG-25C) in the PEG propellant formulation is shown in Table 3. The tensile strength σ of the propellant was determined according to the uniaxial tensile method of section 413.1 of GJB 770B-2005 "Test Methods for Gunpowder" to determine the maximum tensile strength, breaking strength, maximum elongation, and elongation at break. m Elongation ε m The measurement results are shown in Table 4.

[0060] Table 3. PEG propellant formulation composition

[0061]

[0062] Table 4 Performance Results of Bonding Agents

[0063]

[0064] Based on propellant performance data, novel amine bonding agents can significantly improve the mechanical properties of PEG propellants at normal, high, and low temperatures. In particular, BAG-25C, synthesized with a molar ratio of perchloric acid to triethanolamine of 0.66:1, exhibits the best overall performance.

[0065] Example 8

[0066] The application of three different bonding agents (BAG-25A, BAG-25B, and BAG-25C) in GAP propellant formulations is shown in Table 5. The tensile strength σ of the propellant was determined according to the uniaxial tensile method (413.1 Maximum tensile strength, breaking strength, maximum elongation, and elongation at break) of GJB 770B-2005 "Test Methods for Gunpowder". m Elongation ε m The measurement results are shown in Table 6.

[0067] Table 5 GAP Propellant Formulation Composition

[0068]

[0069] Table 6 Performance Results

[0070]

[0071]

[0072] Based on propellant performance data, the novel alkanolamine bonding agent can significantly improve the mechanical properties of GAP propellants at normal, high, and low temperatures. In particular, BAG-25C, synthesized with a molar ratio of perchloric acid to triethanolamine of 0.66:1, exhibits the best overall performance.

[0073] Example 9

[0074] The application of three different bonding agents (BAG-25A, BAG-25B, and BAG-25C) in the formulation of hydroxyl-butyl propellant is shown in Table 7. The tensile strength σ of the propellant was determined according to the uniaxial tensile method of section 413.1 of GJB 770B-2005 "Test Methods for Pyrotechnics" for maximum tensile strength, breaking strength, maximum elongation, and elongation at break. m Elongation ε m The measurement results are shown in Table 8.

[0075] Table 7. Composition of Hydroxybutyric Acid Propellant Formulation

[0076]

[0077] Table 8 Performance Results

[0078]

[0079] Based on propellant performance data, the novel alkanolamine bonding agent can significantly improve the mechanical properties of HTPB propellants at normal, high, and low temperatures. In particular, BAG-25A, synthesized with a molar ratio of perchloric acid to triethanolamine of 0.25:1, exhibits the best overall performance.

[0080] Comparative Example 1

[0081] Boron trifluoride triethanolamine was added to the butylated hydroxyl propellant formulation shown in Table 7. The tensile strength σ of the propellant was determined according to the uniaxial tensile method (413.1 Maximum tensile strength, breaking strength, maximum elongation, and elongation at break) of GJB 770B-2005 "Test Methods for Gunpowder". m Elongation ε m The measurement results are shown in Table 9.

[0082] Table 9 Performance Results of Novel Alkylamine Bonding Agents and Boron Trifluoride Triethanolamine

[0083]

[0084] The novel alkanolamine bonding agent prepared by this invention has advantages over the triethanolamine bonding agent in the prior art, such as simple synthesis process, wide availability of raw materials, and lower toxicity. It also releases less ammonia when reacting with ammonium perchlorate. Moreover, as shown in Table 9, compared with boron trifluoride triethanolamine, the novel alkanolamine bonding agent disclosed in this invention can significantly improve the mechanical properties of composite solid propellants and meet the requirements of mechanical properties of composite solid propellants.

Claims

1. The application of an alkanolamine bonding agent in the preparation of solid propellants, characterized in that, The structural formula of the alkanolamine bonding agent is: 。 2. The application of the alkanolamine bonding agent according to claim 1 in the preparation of solid propellants, characterized in that, The alkanolamine bonding agent is added to a solid propellant premix slurry and mixed evenly to obtain a solid propellant containing an alkanolamine bonding agent; The solid propellants containing alkanolamine bonding agents include NEPE system propellants, HTPB system propellants, PET propellants, PEG propellants, or GAP propellants containing alkanolamine bonding agents.

3. The application of the alkanolamine bonding agent according to claim 1 in the preparation of solid propellants, characterized in that, The mass ratio of the alkanolamine bonding agent to the solid propellant is 0.2% to 2.0%.

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