CN113666792B

CN113666792B - Green slow-burning pyrotechnic composition binder and preparation method thereof

Info

Publication number: CN113666792B
Application number: CN202111144609.2A
Authority: CN
Inventors: 于跃; 韩志跃; 邓利; 王芳; 佟文超; 朱维熠; 李志禧; 连旭; 刘一; 桂雨音; 段雨萱
Original assignee: Beijing University of Chemical Technology; Beijing Institute of Technology BIT
Current assignee: Beijing University of Chemical Technology; Beijing Institute of Technology BIT
Priority date: 2021-09-28
Filing date: 2021-09-28
Publication date: 2022-04-26
Anticipated expiration: 2041-09-28
Also published as: CN113666792A

Abstract

The invention discloses a green slow-burning pyrotechnic composition binder and a preparation method thereof, belonging to the field of biocatalysis and binders. The green slow-burning pyrotechnic composition binder is an ester-based homopolymer; the ester-based homopolymer is obtained by taking homopolymer dibutyl ester of dibasic acid as a monomer through homopolymerization. The method can synthesize ester monomers which are difficult to synthesize by a chemical method through biological enzyme catalysis, and has mild reaction process and no generation of acid wastewater. And then, the ester-based homopolymer is prepared by low-temperature self-homopolymerization, the process is environment-friendly, the reaction progress is accelerated, the yield is improved, and the thermal stability of the product is good. The pyrotechnic composition adhesive prepared by the invention has good compatibility with pyrotechnic composition, can improve the combustion performance of pyrotechnic composition, reduce the combustion speed of pyrotechnic composition, and simultaneously reduce solid particles and toxic and harmful gases generated by combustion.

Description

Green slow-burning pyrotechnic composition binder and preparation method thereof

Technical Field

The invention relates to the field of biocatalysis and binders, in particular to a green slow-burning type pyrotechnic composition binder and a preparation method thereof.

Background

The pyrotechnic composition, which is also called pyrotechnic composition or pyrotechnic composition, produces a special effect through chemical reactions such as combustion or explosion, and is widely used in civil and military fields such as firework appreciation, signal bombs, smoke bombs, burning bombs, bait bombs, rapid inflation rescue and the like. The pyrotechnic composition mainly comprises an oxidant, a combustible agent, a binder and other auxiliary agents. The adhesive can bond the components in the pyrotechnic composition together, and has the effects of keeping the uniformity and mechanical strength of the medicament, reducing the mechanical sensitivity of the medicament, and improving the chemical stability and safety. The common pyrotechnic adhesive mainly comprises resin, polyether, nitrocellulose, polyvinyl alcohol, shellac and the like. Researches show that the natural adhesive has more impurities and weak adhesive force, and affects the combustion effect. Phenolic resin is a common adhesive which is industrially produced in the existing pyrotechnic composition industry. However, the phenolic resin is synthesized by chemically catalyzing formaldehyde and phenol with strong toxicity, a large amount of toxic wastewater is generated in the preparation process, and toxic formaldehyde gas is also released by a finished product, so that the environment and the human body are seriously injured.

The binder may also affect the burn performance of the pyrotechnic charge. The fields of civil cold light fireworks, environment-friendly fireworks, indoor fireworks, slow expansion parts of military spacecrafts, inflatable hemostatic bandages and the like are in urgent need of pyrotechnic compositions with slow combustion and low heat release. Therefore, the development of the environment-friendly slow-burning type binder has important significance for the pyrotechnic composition with slow burning and low heat release. However, few studies have been reported at home and abroad for green slow-burning adhesives.

Disclosure of Invention

The invention aims to provide a green slow-burning pyrotechnic composition binder and a preparation method thereof, which are used for solving the problems in the prior art, reducing the pollution to the environment in the binder synthesis process and the use process and reducing the burning rate and heat release of pyrotechnic compositions.

In order to achieve the purpose, the invention provides the following scheme:

according to one technical scheme of the invention, the green slow-burning pyrotechnic composition adhesive is an ester-based homopolymer;

the ester-based homopolymer is obtained by taking homopolymer dibutyl ester of dibasic acid as a monomer through homopolymerization.

Further, the dibasic acid is a dibasic acid containing an unsaturated double bond.

Further, the dibasic acid is one of itaconic acid and fumaric acid.

The second technical scheme of the invention is that the preparation method of the green slow-burning pyrotechnic composition adhesive comprises the following steps:

step 1, adding lipase into a mixed solution of monohydric alcohol and dibasic acid to perform esterification reaction to obtain homopolymer dibutyl ester of dibasic acid;

and 2, adding an initiator into the homopolymer dibutyl ester of the dibasic acid, and carrying out homopolymerization reaction to obtain the green slow-burning pyrotechnic composition adhesive.

Further, in step 1, the monohydric alcohol is one of butanol, pentanol, hexanol and octanol.

Further, the Lipase is one of commercial Novozym435, Novozym40086, porcine pancreatin, Candida rugosa, Lipozyme RM IM, Lipozyme TL IM and Lipase AS.

Further, in the step 1, the molar ratio of the monohydric alcohol to the dibasic acid is 1-15: 1.

Further, in the step 1, the addition amount of the lipase is 15-30% of the mass of the dibasic acid.

Further, in the step 1, the temperature of the esterification reaction is 50-90 ℃ and the time is 12-140 h.

Further, in step 2, the initiator is benzoyl peroxide.

Further, in the step 2, the mass ratio of the homopolymer dibutyl ester of the dibasic acid to the initiator is 1: 0.01-0.05.

Further, in the step 2, the temperature of the homopolymerization reaction is 50-70 ℃ and the time is 20-100 min.

The invention discloses the following technical effects:

(1) the invention provides a method for synthesizing an ester-based homopolymer through biocatalysis in a solvent-free system, which has a simple preparation process and greatly reduces the reaction energy consumption and the difficulty of separation and purification.

(2) The method can synthesize ester monomers which are difficult to synthesize by a chemical method through biological enzyme catalysis, and has mild reaction process and no generation of acid wastewater. Then, the ester-based homopolymer is prepared by low-temperature self-homopolymerization, the process is environment-friendly, the reaction progress is accelerated, the yield is improved, the product thermal stability is good, the number average molecular weight Mn of the obtained ester-based homopolymer is 1000-.

(3) The pyrotechnic composition adhesive prepared by the invention has good compatibility with pyrotechnic composition, can improve the combustion performance of pyrotechnic composition, reduce the combustion speed of pyrotechnic composition, and simultaneously reduce solid particles and toxic and harmful gases generated by combustion.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a nuclear magnetic hydrogen spectrum of a pure dibutyl itaconate prepared in example 1;

FIG. 2 shows the carbon spectrum and hydrogen spectrum of dibutyl polyitaconate prepared in example 1 and example 2; wherein (a) is a carbon spectrum and (b) is a hydrogen spectrum;

FIG. 3 is a graph showing the effect of the amount of lipase Novozym435 on the conversion of itaconic acid;

FIG. 4 is a graph of the effect of homopolymerization temperature on itaconic acid conversion;

FIG. 5 is a scanning electron micrograph of the pyrotechnic composition prepared in application example 1 and application comparative example 1;

FIG. 6 is a TG-DSC thermal analysis detection chart of the pyrotechnic composition prepared in application example 1 and application comparative example 1; wherein, (a) is TG analysis and (b) is DSC analysis;

FIG. 7 is a p-t curve of pyrotechnic compositions prepared using example 1 and using comparative example 1;

FIG. 8 is a graph showing gas compositions after combustion of pyrotechnic compositions prepared in application example 1 and application comparative example 1;

fig. 9 is a photograph of the flexible airbag inflated using the pyrotechnic composition prepared in example 1 and comparative example 1 as the gas generating agent.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The description and examples are intended to be illustrative only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

The raw materials used in the present invention can be obtained commercially without specific mention.

The experimental methods used in the examples of the present invention are all conventional experimental methods unless otherwise specified.

Example 1

Mixing n-butanol and itaconic acid according to a molar ratio of 13: 1, mixing to obtain a mixed solution, adding lipase Novozym435 into the mixed solution, wherein the adding amount of the lipase Novozym435 is 20% of the mass of itaconic acid, carrying out normal pressure esterification reaction for 12h under the stirring condition of 80 ℃ to obtain a mixture of dibutyl itaconate and monobutyl itaconate, dissolving the mixture in tetrahydrofuran, filtering to remove the lipase Novozym435, adding water into the mixture of dibutyl itaconate and monobutyl itaconate, standing for layering, and removing water and the upper monobutyl itaconate to obtain a pure dibutyl itaconate. Adding an initiator Benzoyl Peroxide (BPO) into the pure product of the dibutyl itaconate, wherein the adding amount of the BPO is 1 percent of the mass of the pure product of the dibutyl itaconate, and carrying out homopolymerization reaction for 40min at the temperature of 65 ℃ to obtain the dibutyl Polyitaconate (PDIB), namely the pyrotechnic composition binder.

The dibutyl polyitaconate prepared in this example was measured for its average relative molecular weight and molecular weight distribution index by the following method: after dissolving the dibutyl polyitaconate in tetrahydrofuran, passing through a 0.22-micron nylon filter membrane, taking polystyrene as an internal standard substance, and measuring the average relative molecular weight and the molecular weight distribution index of a product by using a Waters 1525 gel chromatograph.

As a result: the dibutyl polyitaconate prepared in this example had a number average molecular weight Mn of 5307g/mol, a weight average molecular weight Mw of 8919g/mol, and a dispersibility coefficient PDI of 1.28; the conversion rate of the dibasic acid reaches 97.6 percent.

The results of NMR detection of the dibutyl itaconate product obtained in example 1 are shown in FIG. 1. As can be seen from FIG. 1, CH₃The absorption peak of middle H atom is 0.92ppm, butanolThe major absorption peaks of the H atom on the methylene group in the unit are at 1.37, 1.58, 4.09 and 4.15ppm, respectively, and the major absorption peak of the H atom on the methylene group in the itaconic acid unit is at 3.32ppm, (C ═ CH ═₂) The absorption peaks of the medium H atom appear at 5.68ppm and 6.31ppm, and according to the peak value proportion of different H,¹the H NMR results confirmed that the double bond in the itaconic acid unit was retained and dibutyl itaconate was synthesized.

Example 2

The only difference was that the time for homopolymerization was 80min, as in example 1.

The same tests as in example 1 were carried out.

As a result: the dibutyl polyitaconate prepared in this example had a number average molecular weight Mn of 10178g/mol, a weight average molecular weight Mw of 19052g/mol, and a dispersibility coefficient PDI of 1.57; the conversion rate of the dibasic acid reaches 98.5 percent.

Dibutyl polyitaconate prepared in examples 1 and 2 was subjected to¹³C NMR spectra and¹HNMR detection, the result is shown in figure 2; wherein, (a) is a carbon spectrum, and (b) is a hydrogen spectrum. As can be seen from fig. 2(a), the peaks at 134.10ppm and 127.70ppm disappeared with time, representing the two olefin carbons which disappeared after polymerization; two (C ═ O) groups (167.70ppm and 171.80ppm) and (-OCH)₂-) units (64.60ppm) indicates that dibutyl itaconate units are present in the polymerization product. FIG. 2(b) shows that after polymerization, the two olefin H atom absorption peaks at 6.30ppm and 5.68ppm in dibutyl itaconate monomer substantially disappeared, demonstrating the consumption of double bonds, and the absorption peaks at 3.97 to 4.20ppm demonstrate the presence of dibutyl itaconate units in the polymerized product.

The effect of the amount of lipase Novozym435 on the conversion of itaconic acid is shown in FIG. 3. As can be seen from FIG. 3, the conversion of itaconic acid increased with increasing amounts of Novozym435 in the reaction mixture. The highest conversion was obtained when the mass of Novozym435 reached 20% of the mass of itaconic acid. The conversion decreased when the lipase mass increased from 20% to 30% of the itaconic acid mass. When the amount of the lipase added is too large, the reaction conversion rate decreases due to the aggregation of the lipase and the increase in viscosity.

The effect of homopolymerization temperature on itaconic acid conversion is shown in FIG. 4. As can be seen from fig. 4, as the reaction temperature increases from 50 ℃ to 65 ℃, the conversion of itaconic acid increases, and the conversion of itaconic acid decreases at 70 ℃, so the optimum temperature is 65 ℃. When the temperature is too low, the catalytic efficiency of the lipase is inhibited; the solubility of a reaction substrate can be improved by properly increasing the reaction temperature, the viscosity of a reaction system is reduced, and the lipase catalytic esterification reaction is promoted to be carried out in the positive direction; under proper temperature, the lipase can still keep the optimal activity; when the temperature is too high, the lipase easily loses catalytic activity.

Example 3

Same as example 1 except that itaconic acid was replaced with fumaric acid, the molar ratio of fumaric acid to n-butanol was 15: 1; the lipase is porcine pancreatin; adding water into the mixture of dibutyl fumarate and monobutyl fumarate instead of adding NaOH to remove the monobutyl fumarate; the addition amount of the initiator is 1 percent; the temperature of the homopolymerization was 50 ℃ and the time was 100 min.

The same tests as in example 1 were carried out.

As a result: the dibutyl polyfumarate prepared in this example had a number average molecular weight Mn of 5389g/mol, a weight average molecular weight Mw of 7899g/mol and a dispersibility coefficient PDI of 1.35. The conversion rate of the dibasic acid reaches 98.8 percent.

Example 4

Same as example 1, except that n-butanol was replaced by hexanol, the molar ratio of itaconic acid to hexanol was 1: 1; the Lipase is Lipase AS; the addition amount of the initiator is 3 percent; the temperature of the homopolymerization was 70 ℃ and the time was 20 min.

The same tests as in example 1 were carried out.

As a result: the dihexyl polyitaconate prepared in this example had a number average molecular weight Mn of 7878g/mol, a weight average molecular weight Mw of 9872g/mol and a dispersity coefficient PDI of 1.37. The conversion rate of the dibasic acid reaches 99.1 percent.

Example 5

The method is the same AS example 1, except that the Lipase is Lipase AS, and the addition amount of the Lipase is 30%; the temperature of the esterification reaction is 50 ℃ and the time is 140 h.

The same tests as in example 1 were carried out.

As a result: the dibutyl polyitaconate prepared in this example had a number average molecular weight Mn of 3243g/mol, a weight average molecular weight Mw of 5768g/mol and a dispersibility coefficient PDI of 1.24. The conversion rate of the dibasic acid reaches 96.6 percent.

Example 6

The same as example 1, except that the lipase was Lipozyme RM IM, and the amount of the lipase added was 15%; the temperature of the esterification reaction is 90 ℃ and the time is 90 h.

The same tests as in example 1 were carried out.

As a result: the dibutyl polyitaconate prepared in this example had a number average molecular weight Mn of 2889g/mol, a weight average molecular weight Mw of 4310g/mol and a dispersibility coefficient PDI of 1.39. The conversion rate of the dibasic acid reaches 95.9 percent.

Application example 1

Raw materials: pyrotechnic composition Binder dibutyl Polyitaconate (PDIB) prepared in example 1, flammable agent 5-aminotetrazole (CH)₃N₅5-AT), oxidizing agent KNO₃。

Dissolving the pyrotechnic composition binder in a solvent with the volume 10 times that of the pyrotechnic composition binder, and then uniformly mixing the pyrotechnic composition binder with a combustible agent and an oxidant, wherein the mass ratio of the combustible agent to the oxidant to the pyrotechnic composition binder is 40.86: 56.14: 3.00, obtaining the Pyrotechnic composition with the grain diameter of 2.5mm by adopting a wet mixing granulation method, and marking the Pyrotechnic composition as PDIB pyrotechnical.

Application comparative example 1

The only difference is that the pyrotechnic charge binder is a phenolic resin (PF) (available from shanghai lienson chemical limited), as in application example 1. Pyrotechnic powder was prepared and labeled PF Pyrotechnic.

Comparative application example 2

The only difference is that the addition of the pyrotechnic charge adhesive is omitted, as in application example 1. The pyrotechnic composition is prepared.

Scanning electron microscope analysis was performed on the Pyrotechnic compositions prepared in application example 1 and application comparative example 1, and the results are shown in fig. 5, in which (a) was PF pyrotechnical prepared in application comparative example 1, and (b) was PDIB pyrotechnical prepared in application example 1. As can be seen from fig. 5, the particles of the PDIB binder pyrotechnic composition are more rounded and have smoother peripheries than the PF binder pyrotechnic composition.

The pyrotechnic compositions prepared in example 1 and comparative examples 1 and 2 were subjected to impact sensitivity, friction sensitivity, moisture absorption and particle hardness tests, and the friction sensitivity of the pyrotechnic composition was measured at 1.23mpa and a swing angle of 70 ° using a MGY-1 type friction sensor (NANCHEN, China). The impact sensitivity of the pyrotechnic charge was tested with a 10kg drop weight at a head drop of 175 cm. The room temperature and relative humidity were 16.5 ℃ and 17%, respectively, during the test. Each formulation was tested 25 times. The sample (10g) was placed in a constant temperature and humidity cabinet HWS-70B (PERFECT, China) at 30. + -. 2 ℃ and 65% RH for 48 hours. The moisture absorption rate was calculated according to the following formula, and each sample was measured in parallel twice.

Wherein W is the final moisture absorption rate; m is₁The mass of the sample and the weighing bottle before moisture absorption; m is₂The mass of the sample and the weighing bottle after moisture absorption; m is₀The mass of the empty weighing bottle is poor after moisture absorption; and m is the mass of the sample.

The pyrotechnic grains were tested for hardness by an SGW-J hardness tester (SHSIWI, China). Each sample was tested in triplicate and the average was taken. The results are shown in Table 1.

TABLE 1

As can be seen from table 1, the impact sensitivity of the PDIB binder pyrotechnic composition is lower than the mechanical sensitivity of the PF binder pyrotechnic composition and the binderless pyrotechnic composition, which indicates that the mechanical safety of the PDIB binder pyrotechnic composition is good. The moisture absorption rate of the PDIB binder pyrotechnic composition is lower than that of the PF binder pyrotechnic composition and the binder-free pyrotechnic composition, which indicates that the PDIB binder pyrotechnic composition is not easy to absorb moisture in the using and storing process, has higher thermal stability, can be used and stored for a long time, and is beneficial to safe transportation and storage. The particle hardness of the PDIB binder pyrotechnic is close to that of PF binder pyrotechnic.

The results of TG-DSC thermal analysis of the pyrotechnic composition prepared in example 1 and comparative example 1 are shown in FIG. 6, in which (a) is TG analysis and (b) is DSC analysis. As can be seen from FIG. 6, the DSC curve trends of the pyrotechnic composition prepared by application example 1 and comparative application example 1 were substantially the same between 50 and 400 ℃. The first stage is an endothermic process from 88.7 ℃ to 115.86 ℃, mainly the 5-AT loss of water of crystallization and the melting of the adhesive; as the temperature continues to rise, due to KNO₃The lattice change shows a second endothermic peak at 136.83 ℃. The second stage includes an endothermic process and a mildly exothermic process. In the range of 185.46-200.55 ℃, the process is a 5-AT endothermic melting process. When 5-AT melts, it rapidly decomposes until the temperature rises to 300.06 ℃. The weight loss temperature range of the third stage is 288.76-400.00 ℃. It also has endothermic properties with a peak temperature of 334.95 ℃, which is comparable to KNO₃Is involved in the melting of (1). From 400 ℃ to 700 ℃, there are two different weight loss stages between the two samples. In the thermal profile of pyrotechnic compositions using phenolic resins as binders, the TG curve begins to increase rapidly and then decreases sharply. This phenomenon is caused by the decomposition reaction of the PF binder pyrotechnic charge to generate a large amount of energy, indicating that the pyrotechnic charge is undergoing a vigorous chemical reaction at this stage. At the end of the test, the residual solids mass of the phenolic resin binder pyrotechnic charge was about 34.18%. The residue rate of the pyrotechnic composition of the PDIB binder after thermal decomposition was 20.29%, which was 40.64% lower than that of the pyrotechnic composition of the PF binder. There are two endothermic peaks in the DSC curve of the pyrotechnic charge of PDIB binder, but the peak area is significantly lower than that of the pyrotechnic charge with PF as binder. Finally, there is another endothermic process, which may be due to sublimation of the sample. Compared with the pyrotechnic composition using PF as the adhesive, the pyrotechnic composition using PDIB as the adhesive has relatively mild overall weight loss and heat absorption and release trends.

The combustion performance of the pyrotechnic composition prepared in the application example 1 and the application comparative example 1 was tested: the combustion performance of pyrotechnic compositions can be evaluated using the p-t curve, and about 10.00g of pyrotechnic composition is placed in a closed exploder and tested using the electric ignition method. The closed exploder is connected with a CY450 high-frequency pressure sensor, the pressure change range is 0-60MPa, and the output electric signal under the condition of instantaneous combustion can be measured every 180 ms. And a DPO4104 oscilloscope is connected to record a voltage change curve, the measuring range is 0-10MPa, and the precision grade is 0.5. A plot of pressure versus time was obtained as shown in figure 7.

As can be seen from fig. 7, the maximum pressure generated by the combustion of the PF binder pyrotechnic composition was 2.732MPa, the time to reach the maximum pressure was 0.329s, and the pressure in the final closed exploder was 0.20 MPa; the maximum pressure generated by combustion of the PDIB binder pyrotechnic was 0.956MPa, the time to reach maximum pressure was 1.109s, and the pressure in the final closed exploder was 0.38 MPa. From this, it is known that, in the closed exploder, the maximum pressure generated by combustion of the PDIB binder pyrotechnic composition is reduced by 65.00%, the combustion speed is reduced by 2.37 times, and the final gas production is increased by 0.9 times.

The environmental protection performance of the pyrotechnic composition prepared in the application example 1 and the application comparative example 1 is detected as follows: the environment friendly performance of the pyrotechnic composition was evaluated using the particulate and gas components produced by combustion. Particulate matter concentration PM_2.5The concentration measuring device consists of a combustion chamber and a collector (BTPM-HS 5). The pyrotechnic composition is ignited in the combustion chamber through electricity, and particulate matters formed after the pyrotechnic composition is combusted are adsorbed on a filter membrane of the recoverer, so that the mass of the filter membrane is increased. The PM in the combustion process is calculated according to the equation. Both groups were tested in the same way and finally averaged.

Wherein M is_oIs the mass (mg) of the preparation, M_cFor the change in membrane mass (mg) before and after filtration, M_bFilm mass (mg) in blank test, W is PM Mass (PM) after combustion of pyrotechnic composition_2.5Or PM₁₀Mg); each set of experiments was performed twice, and the mean value was taken for calculation. The results are shown in Table 2.

TABLE 2

As can be seen from Table 2, when the pyrotechnic composition prepared in application example 1 was burned, PM was observed in comparison with that in application comparative example 1_2.5The amount of the produced was reduced by 53.51%. This is probably because the phenolic resin contains aromatic rings in its molecule, which do not adhere well to the pyrotechnic composition and burn rapidly and insufficiently, which causes carbon deposit and formation of particles during rapid combustion.

The pyrotechnic composition and the electric ignition head are wrapped together, and then are loaded into a gas generating device, and gas generated by the combustion of the pyrotechnic composition is collected by a gas collecting bag. The gas composition was detected by 7890B (Aglient, USA) gas chromatograph and NOVA PLUS (MRU, German) flue gas analyzer, and the results are shown in FIG. 8.

As can be seen from FIG. 8, O is not contained in the gas collected by burning the pyrotechnic composition prepared in application example 1 and application comparative example 1₂. H in gas generated by combustion of PDIB binder pyrotechnic composition₂、CO₂And CH₄Are all higher than PF binder pyrotechnic compositions. In the gas produced by combustion of a pyrotechnic charge of PDIB binder, N₂CO, NO and NO₂The contents of the components are all lower than that of PF adhesive pyrotechnic compositions. Wherein, compared with PF adhesive pyrotechnic composition, the content of CO generated by combustion is reduced by 94.53%, and NO is reduced by PDIB adhesive pyrotechnic composition_XThe content of (A) is reduced by 71.62%. Because the ignition of the PDIB binder pyrotechnic composition is slow and sufficient, the toxic gases CO and NO can be effectively avoided_XThe production of (2) is beneficial to environmental protection.

The performance of the pyrotechnic composition prepared in application example 1 and application comparative example 1 as a gas generant was evaluated: the pyrotechnic compositions prepared in application example 1 and application comparative example 1 were charged into a gas generating apparatus, respectively, and ignited. The results are shown in FIG. 9. As can be seen in fig. 9, the PF binder gas generant fills the flexible bladder for 3 seconds. The PDIB binder gas generating agent takes 30s to complete the smooth slow inflation of the flexible air bag. Without the addition of coolant, the capsule temperature did not rise significantly. MgCO must be added into gas producing agent prepared from PF binder₃As a coolant, the high heat generated by combustion would otherwise burn out the flexible bladder. PDIB as AdhesivesThe combustion of the pyrotechnic composition has low heat release and low temperature, does not need to add a coolant, and slows down the combustion. This experiment demonstrates that PDIB adhesives can be applied to components that require slow inflation, such as slow deployment of spacecraft flexible pods, inflatable hemostatic bandages, and the like.

The synthetic method disclosed by the invention is environment-friendly, less in side reaction, less in solvent consumption, small in dispersion coefficient, simple to operate and controllable in molecular weight. The pyrotechnic composition binder obtained by the invention is an ester-based homopolymer and has the advantages of mild reaction conditions, no pollution, no waste, PDI value close to 1 and uniform molecular weight distribution. The amount of the thermal weight loss residue of the pyrotechnic composition adhesive prepared by the invention is 2.63-3.41% compared with the amount of the phenolic resin residue of 10.81% after the pyrotechnic composition adhesive is continuously heated and decomposed, and the pyrotechnic composition adhesive prepared by the invention is completely thermally decomposed. After the pyrotechnic composition adhesive prepared by the invention is used as a raw material to prepare pyrotechnic composition, the speed (delta pmax/delta tmax) of gas generated by combustion is reduced to 0.86MPa/s, which is 89.6 percent lower than that of the pyrotechnic composition of phenolic resin adhesive, namely 8.3 MPa/s.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.

Claims

1. The green slow-burning pyrotechnic composition binder is characterized in that the green slow-burning pyrotechnic composition binder is an ester-based homopolymer;

the ester-based homopolymer is obtained by taking homopolymer dibutyl ester of dibasic acid as a monomer through homopolymerization;

the preparation method of the green slow-burning pyrotechnic composition binder comprises the following steps:

step 1, adding lipase into a mixed solution of fumaric acid and n-butyl alcohol or a mixed solution of itaconic acid and hexanol to perform esterification reaction to obtain a homopolymer dibutyl ester of dibasic acid;

step 2, adding an initiator into the homopolymer dibutyl ester of the dibasic acid, and carrying out homopolymerization reaction to obtain the green slow-burning pyrotechnic composition adhesive; the molar ratio of the fumaric acid to the n-butanol is 15:1, and the molar ratio of the itaconic acid to the hexanol is 1: 1;

the addition amount of the lipase is 15-30% of the mass of the dibasic acid;

in the step 1, the temperature of the esterification reaction is 50-90 ℃ and the time is 12-140 h;

the initiator is benzoyl peroxide;

in the step 2, the mass ratio of the homopolymer dibutyl ester of the dibasic acid to the initiator is 1: 0.01-0.05;

in the step 2, the temperature of the homopolymerization reaction is 50-70 ℃, and the time is 20-100 min;

the Lipase is one of Novozym435, porcine pancreatin, Lipase AS or Lipozyme RM IM.