Ammonium dinitramide(ADN)is considered as a potential substitute for ammonium perchlorate in energetic materials due to its high density,positive oxygen balance,and halogen-free characteristics.However,its application...Ammonium dinitramide(ADN)is considered as a potential substitute for ammonium perchlorate in energetic materials due to its high density,positive oxygen balance,and halogen-free characteristics.However,its application has been severely limited because of its strong hygroscopicity,difficult storage,and incompatibility with isocyanate curing agents.In order to better bloom the advantages of the highly energetic and environment-friendly ADN in the fields of energetic materials,an in-depth analysis of the current situation and discussion of key research points are particularly important.In this paper,a detailed overview on the synthesis,thermal decomposition,hygroscopic mechanism,and antihygroscopicity of ADN has been discussed,its application in powdes and explosives are also presented,and its future research directions are proposed.展开更多
Although ammonium dinitramide(ADN)has been targeted as a potential green monopropellant in future space vehicles,its application potential in Micro-electrical–Mechanical System(MEMS)thrusters or microthrusters has be...Although ammonium dinitramide(ADN)has been targeted as a potential green monopropellant in future space vehicles,its application potential in Micro-electrical–Mechanical System(MEMS)thrusters or microthrusters has been seldom reported in open literature.In this paper,electrolytic decomposition of Ammonium Dinitramide(ADN)-based liquid monopropellant FLP-103 was carried out in an open chamber and MEMS thrusters were fabricated from poly-dimethylsiloxane(PDMS)to characterize the power consumption.Two thrust measurement methods were employed to investigate the electrolytic decomposition of FLP-103 in MEMS microthrusters.The results show that the monopropellant can be successfully ignited at room temperature through 80 V,0.1 A(8 W)using copper wire as electrodes.In the current thruster design,low thrust was obtained at FLP-103 flowrate of 40μl·min^(-1)but it generated the highest specific impulse,Isp,among all the flowrates tested.The experiments successfully demonstrated the potential application of electrolytic decomposition of FLP-103 in MEMS thrusters.展开更多
The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and ...The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and operation parameters (mass fraction ratio of ADN/CH3OH) on the general performance within the ADN-based thruster. In the present research, the non-equilibrium temperature model is utilized to describe the heat transfer characteristics between the fluid phase and solid phase in the fixed bed. We determined the fluid resistance characteristics in the catalytic bed by experiments involving the method of pressure-mass. We have done the simulation study based on the available results in the literature and found the complex physical and chemical processes within the ADN thruster. Furthermore, an optimized catalytic bed slenderness ratio was observed w让h a value of 1.75 and the mass fraction ratio of 5.73 significantly influenced the propellant performance. These results could serve as a reference to explore the combustion characteristics within the thruster and the preparation of future propellants.展开更多
Ammonium dinitramide(ADN),which has the advantages of high energy density,no halogen and low characteristic signal,is not only considered as a new high-energy oxidizer that is expected to replace the traditional oxidi...Ammonium dinitramide(ADN),which has the advantages of high energy density,no halogen and low characteristic signal,is not only considered as a new high-energy oxidizer that is expected to replace the traditional oxidizer ammonium perchlorate(AP)in solid propellants,but also a good performance explosive in itself.However,due to the strong hygroscopicity of ADN,its application in solid propellants and explosives is greatly limited.Solving the hygroscopicity of ADN is the key to realize the wide application of ADN.In this paper,we systematically review the research progress of anti-hygroscopic strategies of ADN coating.The surface coating methods are focusing on solvent volatilization,solvent-non-solvent,melt crystallization and atomic layer deposition technology.The characteristics of the different methods are compared and analyzed,and the basis for the classification and selection of the coating materials are introduced in detail.In addition,the feasibility of material for surface coating of ADN is evaluated by several compatibility analysis methods.It is highly expected that the liquid phase method(solvent volatilization method,solvent-non-solvent method)would be the promising method for future ADN coating because of its effective,safety and facile operation.Furthermore,polymer materials,are the preferred coating materials due to their high viscosity,easy adhesion,good anti-hygroscopic effect,and heat resistance,which make ADN weak hygroscopicity,less sensitive,easier to preserve and good compatibility.展开更多
Hydrazine is toxic and carcinogenic, which greatly increases the difficulty of application and no longer meets the needs of green aerospace. As a green propellant, the Ammonium Dinitramide(ADN)-based liquid propellant...Hydrazine is toxic and carcinogenic, which greatly increases the difficulty of application and no longer meets the needs of green aerospace. As a green propellant, the Ammonium Dinitramide(ADN)-based liquid propellant has the advantages of higher specific impulse, being non-toxic,pollution-free, and easy storage. However, an ADN-based space engine in orbit has exposed the problems of high-temperature deactivation of catalysts and cold-start failure. An active ignition technology—electric ignition technology was explored in this paper to break through the technical bottleneck of catalyst deactivation and the inability to a cold start. An experimental system of a constant-volume combustor for the ADN-based liquid propellant based on the electric ignition method was established. The electric ignition and combustion characteristics of the ADN-based liquid propellant in a volume combustor with an electric ignition method were studied. The influencing mechanisms of the ignition voltage and the electrode structure on the electric ignition characteristics of the ADN-based liquid propellant were investigated. An elevation of the ignition voltage could facilitate the ignition process of the ADN-based liquid propellant, curtail electric energy input and heating effect, while exerting an adverse impact on the combustion process of the propellant.An increase in the ignition voltage enhanced the ignition process of the propellant while simultaneously suppressing its combustion process when utilizing mesh electrodes. Compared to the strip electrodes, the mesh electrodes increased the contact area between the electrodes and the propellant,increased the electric energy input power in the electric ignition process, and reduced the ignition delay time. The mesh electrodes could promote the combustion process of the propellant to a certain extent.展开更多
The investigation aims at the expansion of the basis of formulations of solid composite propellants by introducing new compositions with lower sensitivity to mechanic impact and improved thermal stability.The formulat...The investigation aims at the expansion of the basis of formulations of solid composite propellants by introducing new compositions with lower sensitivity to mechanic impact and improved thermal stability.The formulations based on trinitropyrazole(TNP)contains a binder(a hydrocarbon or active one),aluminum and inorganic oxidizer ADN.The results show that a binary formulation TNP+active binder(18%-19%)(volume fraction)with no metal is well designed which would achieve high specific impulse(at Pc∶Pa=40∶1)of 248s,high density of 1.80g/cm3 and combustion temperature Tcabout 3 450K.In terms of energy,metal-free compositions with TNP lose a bit to those with HMX,only if HMX fraction in formulation is higher than 45%-50%.展开更多
In this work,we utilize a cocrystallization technique to solve the problem of high hygroscopicity of the high-energy oxidant ammonium dinitramide(ADN).For this purpose,a non-hygroscopic oxidant,triaminoguanidine nitra...In this work,we utilize a cocrystallization technique to solve the problem of high hygroscopicity of the high-energy oxidant ammonium dinitramide(ADN).For this purpose,a non-hygroscopic oxidant,triaminoguanidine nitrate(TAGN),is selected as the cocrystallization ligand.The ADN/TAGN system is simulated by using Material Studio 5.5 software,and the DFT of ADN and TAGN molecules are calculated by Gaussian09 software.The most stable molar ratio of the ADN/TAGN cocrystallization is determined to be 1:1,and the hydrogen bonding between the H atom of ADN and the O atom in the TAGN is the driving force for the formation of cocrystals in this system.Moreover,the electrostatic potential interaction pairing energy difference(ΔEpair)<0 kJ·mol^(-1)(-12.71 kJ·mol^(-1))for nADN:nTAGN=1:1 again indicates cocrystallization at this molar ratio.The crystal structure and crystal morphology is predicted.And the hygroscopicity of ADN/TAGN cocrystal at 20℃and 40%relative humidity is calculated to be only 0.45%.The mechanism of hygroscopicity is investigated by examining the roughness of each crystal surface.Overall,the more hygroscopic it is in terms of surface roughness,with the roughest crystal surface(012)having a hygroscopicity of 1.78,which corresponds to a saturated hygroscopicity of 0.61%.The results show that the(001)crystal surface has the smallest band gap(1.06 eV)and the largest sensitivity.Finally,the oxygen equilibrium value for the ADN/TAGN system is calculated to be-8.2%.展开更多
Ammonium dinitramide(ADN)is a promising oxidizer with high energy characteristic,which is a relatively new environmentally friendly oxidizer without halogens and carbon elements.However,ADN has high hygroscopicity whe...Ammonium dinitramide(ADN)is a promising oxidizer with high energy characteristic,which is a relatively new environmentally friendly oxidizer without halogens and carbon elements.However,ADN has high hygroscopicity when exposed to high humidity air,restricting its applications on the solid propellants.In this paper,a novel energetic cocrystal composed of ammonium dinitramide and 3,4-diaminofurazan(DAF)was proposed and successfully synthesized by antisolvent crystallization method,and the properties of the cocrystal were systematically investigated by analytical characterization and theoretical simulation calculations.The formation of the cocrystal was confirmed by powder X-ray diffraction,differential scanning calorimetry,scanning electron microscopy,infrared spectroscopy and Raman spectroscopy,indicating that the synthesized product was a cocrystal.Through theoretical studies,the ADN/DAF cocrystal structure was predicted,and the powder X-ray diffraction,morphology,water sorption capacity of ADN/DAF cocrystal were calculated,which was consistent with experimental phenomena.The results showed that newly prepared cocrystal of ADN/DAF had lower hygroscopicity compared to pure ADN,and the water sorption capacity was reduced from 15.35%to 7.90%.This may be due to the formation of N-H…O medium-strength hydrogen bonds between the ammonium ion of ADN and the O atom of DAF in the cocrystal,which prevents the binding of water molecules in the air and ammonium ions and reduces the probability of ADN binding to water molecules,leading to the reduction of cocrystal hygroscopicity.The newly prepared energetic cocrystal can provide theoretical and technical guidance for the study of the anti-hygroscopicity of ADN and advance the practical application of ADN.展开更多
Recently,an emerging category green of energetic material ammonium dinitramide(ADN)has exhibited promising application in propellants due to its outstanding merits in energy release and environmental friendliness.It c...Recently,an emerging category green of energetic material ammonium dinitramide(ADN)has exhibited promising application in propellants due to its outstanding merits in energy release and environmental friendliness.It can be considered to substitute traditional oxidizer of ammonium perchlorate(AP)in military systems and aerospace.In this paper,a novel spherical energetic composite ADN/copper alginate(CA)with a microporous structure was designed and prepared by the W/O gel emulsion method,and a desirable porous microsphere structure was obtained.Multiple characterization techniques were used to investigate the structure and properties of ADN/CA composites.The results showed that ADN crystals were homogeneously encapsulated in an alginate-gel matrix.Thermal decomposition temperature was reduced to 151.7℃compared to ADN,while the activation energy of them was reduced from 129.73 k J/mol(ADN)to 107.50 k J/mol(ADN/CA-4).In addition,as-prepared samples had lower impact and frictional sensitivity than ADN.The mechanism of sensitivity reduction and decomposition are also discussed.Constant-volume combustion tests show that peak pressure of the ADN/CA-4 achieves 253.4 k Pa and pressurization rate of 2750.4 k Pa/s.Hence,this has a promising application in improving the combustion performance and safety performance of solid propellants.展开更多
Ammonium dinitramide(ADN)is a new type of green energetic oxidizer with excellent energy density and low pollution combustion characteristics.However,the strong hygroscopicity has a significant impact on its practical...Ammonium dinitramide(ADN)is a new type of green energetic oxidizer with excellent energy density and low pollution combustion characteristics.However,the strong hygroscopicity has a significant impact on its practical application.To assist in the research on moisture-proof modification of ADN materials,an innovative hygroscopic modeling approach was proposed to evaluate the hygroscopicity of ADN at various temperatures and humidities.By investigating the diffusion coefficient of water molecules in molecular dynamics processes,a visual insight into the hygroscopic process of ADN was gained.Furthermore,analyzing the non-covalent interactions between ADN and water molecules,the hygroscopicity of ADN could be evaluated qualitatively and quantitatively.The energy analysis revealed that electrostatic forces play a dominant role in the process of water adsorption by ADN,whereas van der Waals forces impede it.As a whole,the simulation results show that ADN presents the following hygroscopic law:At temperatures ranging from 273 K to 373 K and relative humidity(RH)from 10%to 100%,the hygroscopicity of ADN generally shows an increasing trend with the rise in temperature and humidity based on the results of three simulations.According to the non-hygroscopic point(298 K,52%RH)of ADN obtained by experiment in the literature,a non-hygroscopic range of temperature and humidity for ADN can be depicted when the simulation results in relative hygroscopicity is less than or equal to 17%.This study can provide effective strategies for screening anti-hygroscopic modified materials of ADN.展开更多
Ammonium dinitramide(ADN),as a high-energy oxidizer widely applied in the field of rocket and missile propellants,has a prominent issue of high hygroscopicity due to its strong polarity.The previous coating encapsulat...Ammonium dinitramide(ADN),as a high-energy oxidizer widely applied in the field of rocket and missile propellants,has a prominent issue of high hygroscopicity due to its strong polarity.The previous coating encapsulation methods have struggled to address the problems of uneven coating and polarity mismatch.This research innovatively introduces perfluorooctanoic acid(PFOA)as a polar transition intermediate layer.Utilizing the polarity of one end of it to adsorb on the surface of ADN through hydrogen bonds,the problem of polarity mismatch is effectively overcome.Meanwhile,the vibrational magnetron sputtering process has been first applied in the energetic field,with a special vibrating abutment enhancing ADN particle fluidity to solve coating non-uniformity,thus preparing prilled ADN@PFOA@PTFE core-dual-shell composites.Performance tests reveal that this composite material possesses excellent hydrophobic and anti-hygroscopic properties.When left at 25℃and 75%RH for 3 days,moisture absorption was reduced by more than 90%compared to pure ADN.Simultaneously,its thermal stability,heat release performance,and combustion performance have been improved.The research achievements optimize the storage conditions of ADN in the application of rocket and missile propellants,providing solid support and broad development prospects for technological innovation in military fields.展开更多
基金financially supported by the National Natural Science Foundation of China (Project No. 21805139, 12102194, 22005144 and 22005145)the Joint Funds of the National Natural Science Foundation of China (No. U2141202)+1 种基金Natural Science Foundation of Jiangsu Province (No. BK20200471)the Fundamental Research Funds for the Central Universities (No. 30920041106, 30921011203)
文摘Ammonium dinitramide(ADN)is considered as a potential substitute for ammonium perchlorate in energetic materials due to its high density,positive oxygen balance,and halogen-free characteristics.However,its application has been severely limited because of its strong hygroscopicity,difficult storage,and incompatibility with isocyanate curing agents.In order to better bloom the advantages of the highly energetic and environment-friendly ADN in the fields of energetic materials,an in-depth analysis of the current situation and discussion of key research points are particularly important.In this paper,a detailed overview on the synthesis,thermal decomposition,hygroscopic mechanism,and antihygroscopicity of ADN has been discussed,its application in powdes and explosives are also presented,and its future research directions are proposed.
基金Supported by the Project of Ministry of Science,Technology and Innovation,Malaysia(MOSTI)(No.04-02-12-SF0160)
文摘Although ammonium dinitramide(ADN)has been targeted as a potential green monopropellant in future space vehicles,its application potential in Micro-electrical–Mechanical System(MEMS)thrusters or microthrusters has been seldom reported in open literature.In this paper,electrolytic decomposition of Ammonium Dinitramide(ADN)-based liquid monopropellant FLP-103 was carried out in an open chamber and MEMS thrusters were fabricated from poly-dimethylsiloxane(PDMS)to characterize the power consumption.Two thrust measurement methods were employed to investigate the electrolytic decomposition of FLP-103 in MEMS microthrusters.The results show that the monopropellant can be successfully ignited at room temperature through 80 V,0.1 A(8 W)using copper wire as electrodes.In the current thruster design,low thrust was obtained at FLP-103 flowrate of 40μl·min^(-1)but it generated the highest specific impulse,Isp,among all the flowrates tested.The experiments successfully demonstrated the potential application of electrolytic decomposition of FLP-103 in MEMS thrusters.
文摘The decomposition and combustion characteristics of ammonium dinitramide (ADN) based non-toxic aerospace propellant are analytically studied to determine the effects of catalytic bed structure (slenderness ratio) and operation parameters (mass fraction ratio of ADN/CH3OH) on the general performance within the ADN-based thruster. In the present research, the non-equilibrium temperature model is utilized to describe the heat transfer characteristics between the fluid phase and solid phase in the fixed bed. We determined the fluid resistance characteristics in the catalytic bed by experiments involving the method of pressure-mass. We have done the simulation study based on the available results in the literature and found the complex physical and chemical processes within the ADN thruster. Furthermore, an optimized catalytic bed slenderness ratio was observed w让h a value of 1.75 and the mass fraction ratio of 5.73 significantly influenced the propellant performance. These results could serve as a reference to explore the combustion characteristics within the thruster and the preparation of future propellants.
基金financially supported by the National Natural Science Foundation of China(Grant Nos.21805139,12102194 and 22005144)the Joint Funds of the National Natural Science Foundation of China(Grant No.U2141202)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.30921011203)the Young Elite Scientists Sponsorship Program by CAST(YESS Program,2021QNRC001)。
文摘Ammonium dinitramide(ADN),which has the advantages of high energy density,no halogen and low characteristic signal,is not only considered as a new high-energy oxidizer that is expected to replace the traditional oxidizer ammonium perchlorate(AP)in solid propellants,but also a good performance explosive in itself.However,due to the strong hygroscopicity of ADN,its application in solid propellants and explosives is greatly limited.Solving the hygroscopicity of ADN is the key to realize the wide application of ADN.In this paper,we systematically review the research progress of anti-hygroscopic strategies of ADN coating.The surface coating methods are focusing on solvent volatilization,solvent-non-solvent,melt crystallization and atomic layer deposition technology.The characteristics of the different methods are compared and analyzed,and the basis for the classification and selection of the coating materials are introduced in detail.In addition,the feasibility of material for surface coating of ADN is evaluated by several compatibility analysis methods.It is highly expected that the liquid phase method(solvent volatilization method,solvent-non-solvent method)would be the promising method for future ADN coating because of its effective,safety and facile operation.Furthermore,polymer materials,are the preferred coating materials due to their high viscosity,easy adhesion,good anti-hygroscopic effect,and heat resistance,which make ADN weak hygroscopicity,less sensitive,easier to preserve and good compatibility.
基金supported by the National Natural Science Foundation of China (No. 52176097)。
文摘Hydrazine is toxic and carcinogenic, which greatly increases the difficulty of application and no longer meets the needs of green aerospace. As a green propellant, the Ammonium Dinitramide(ADN)-based liquid propellant has the advantages of higher specific impulse, being non-toxic,pollution-free, and easy storage. However, an ADN-based space engine in orbit has exposed the problems of high-temperature deactivation of catalysts and cold-start failure. An active ignition technology—electric ignition technology was explored in this paper to break through the technical bottleneck of catalyst deactivation and the inability to a cold start. An experimental system of a constant-volume combustor for the ADN-based liquid propellant based on the electric ignition method was established. The electric ignition and combustion characteristics of the ADN-based liquid propellant in a volume combustor with an electric ignition method were studied. The influencing mechanisms of the ignition voltage and the electrode structure on the electric ignition characteristics of the ADN-based liquid propellant were investigated. An elevation of the ignition voltage could facilitate the ignition process of the ADN-based liquid propellant, curtail electric energy input and heating effect, while exerting an adverse impact on the combustion process of the propellant.An increase in the ignition voltage enhanced the ignition process of the propellant while simultaneously suppressing its combustion process when utilizing mesh electrodes. Compared to the strip electrodes, the mesh electrodes increased the contact area between the electrodes and the propellant,increased the electric energy input power in the electric ignition process, and reduced the ignition delay time. The mesh electrodes could promote the combustion process of the propellant to a certain extent.
基金Ministry of Education and Science of the Russian Federation(14.613.21.0043)
文摘The investigation aims at the expansion of the basis of formulations of solid composite propellants by introducing new compositions with lower sensitivity to mechanic impact and improved thermal stability.The formulations based on trinitropyrazole(TNP)contains a binder(a hydrocarbon or active one),aluminum and inorganic oxidizer ADN.The results show that a binary formulation TNP+active binder(18%-19%)(volume fraction)with no metal is well designed which would achieve high specific impulse(at Pc∶Pa=40∶1)of 248s,high density of 1.80g/cm3 and combustion temperature Tcabout 3 450K.In terms of energy,metal-free compositions with TNP lose a bit to those with HMX,only if HMX fraction in formulation is higher than 45%-50%.
基金supported by the National Natural Science Foundation of China(22125802).
文摘In this work,we utilize a cocrystallization technique to solve the problem of high hygroscopicity of the high-energy oxidant ammonium dinitramide(ADN).For this purpose,a non-hygroscopic oxidant,triaminoguanidine nitrate(TAGN),is selected as the cocrystallization ligand.The ADN/TAGN system is simulated by using Material Studio 5.5 software,and the DFT of ADN and TAGN molecules are calculated by Gaussian09 software.The most stable molar ratio of the ADN/TAGN cocrystallization is determined to be 1:1,and the hydrogen bonding between the H atom of ADN and the O atom in the TAGN is the driving force for the formation of cocrystals in this system.Moreover,the electrostatic potential interaction pairing energy difference(ΔEpair)<0 kJ·mol^(-1)(-12.71 kJ·mol^(-1))for nADN:nTAGN=1:1 again indicates cocrystallization at this molar ratio.The crystal structure and crystal morphology is predicted.And the hygroscopicity of ADN/TAGN cocrystal at 20℃and 40%relative humidity is calculated to be only 0.45%.The mechanism of hygroscopicity is investigated by examining the roughness of each crystal surface.Overall,the more hygroscopic it is in terms of surface roughness,with the roughest crystal surface(012)having a hygroscopicity of 1.78,which corresponds to a saturated hygroscopicity of 0.61%.The results show that the(001)crystal surface has the smallest band gap(1.06 eV)and the largest sensitivity.Finally,the oxygen equilibrium value for the ADN/TAGN system is calculated to be-8.2%.
基金supported by the National Natural Science Foundation of China(22125802)Beijing Natural Science Foundation(2222017)National key research and development program(2021YFC2101202)。
文摘Ammonium dinitramide(ADN)is a promising oxidizer with high energy characteristic,which is a relatively new environmentally friendly oxidizer without halogens and carbon elements.However,ADN has high hygroscopicity when exposed to high humidity air,restricting its applications on the solid propellants.In this paper,a novel energetic cocrystal composed of ammonium dinitramide and 3,4-diaminofurazan(DAF)was proposed and successfully synthesized by antisolvent crystallization method,and the properties of the cocrystal were systematically investigated by analytical characterization and theoretical simulation calculations.The formation of the cocrystal was confirmed by powder X-ray diffraction,differential scanning calorimetry,scanning electron microscopy,infrared spectroscopy and Raman spectroscopy,indicating that the synthesized product was a cocrystal.Through theoretical studies,the ADN/DAF cocrystal structure was predicted,and the powder X-ray diffraction,morphology,water sorption capacity of ADN/DAF cocrystal were calculated,which was consistent with experimental phenomena.The results showed that newly prepared cocrystal of ADN/DAF had lower hygroscopicity compared to pure ADN,and the water sorption capacity was reduced from 15.35%to 7.90%.This may be due to the formation of N-H…O medium-strength hydrogen bonds between the ammonium ion of ADN and the O atom of DAF in the cocrystal,which prevents the binding of water molecules in the air and ammonium ions and reduces the probability of ADN binding to water molecules,leading to the reduction of cocrystal hygroscopicity.The newly prepared energetic cocrystal can provide theoretical and technical guidance for the study of the anti-hygroscopicity of ADN and advance the practical application of ADN.
基金supported by the National Natural Science Foundation of China(Grant No.22005253)。
文摘Recently,an emerging category green of energetic material ammonium dinitramide(ADN)has exhibited promising application in propellants due to its outstanding merits in energy release and environmental friendliness.It can be considered to substitute traditional oxidizer of ammonium perchlorate(AP)in military systems and aerospace.In this paper,a novel spherical energetic composite ADN/copper alginate(CA)with a microporous structure was designed and prepared by the W/O gel emulsion method,and a desirable porous microsphere structure was obtained.Multiple characterization techniques were used to investigate the structure and properties of ADN/CA composites.The results showed that ADN crystals were homogeneously encapsulated in an alginate-gel matrix.Thermal decomposition temperature was reduced to 151.7℃compared to ADN,while the activation energy of them was reduced from 129.73 k J/mol(ADN)to 107.50 k J/mol(ADN/CA-4).In addition,as-prepared samples had lower impact and frictional sensitivity than ADN.The mechanism of sensitivity reduction and decomposition are also discussed.Constant-volume combustion tests show that peak pressure of the ADN/CA-4 achieves 253.4 k Pa and pressurization rate of 2750.4 k Pa/s.Hence,this has a promising application in improving the combustion performance and safety performance of solid propellants.
基金supported by the National Natural Science Foundation of China(Grant Nos.22375098,21805139 and 12102194)the Joint Funds of the National Natural Science Foundation of China(Grant No.U2141202)Young Elite Scientists Sponsorship Program by CAST(Grant No.2021QNRC001).
文摘Ammonium dinitramide(ADN)is a new type of green energetic oxidizer with excellent energy density and low pollution combustion characteristics.However,the strong hygroscopicity has a significant impact on its practical application.To assist in the research on moisture-proof modification of ADN materials,an innovative hygroscopic modeling approach was proposed to evaluate the hygroscopicity of ADN at various temperatures and humidities.By investigating the diffusion coefficient of water molecules in molecular dynamics processes,a visual insight into the hygroscopic process of ADN was gained.Furthermore,analyzing the non-covalent interactions between ADN and water molecules,the hygroscopicity of ADN could be evaluated qualitatively and quantitatively.The energy analysis revealed that electrostatic forces play a dominant role in the process of water adsorption by ADN,whereas van der Waals forces impede it.As a whole,the simulation results show that ADN presents the following hygroscopic law:At temperatures ranging from 273 K to 373 K and relative humidity(RH)from 10%to 100%,the hygroscopicity of ADN generally shows an increasing trend with the rise in temperature and humidity based on the results of three simulations.According to the non-hygroscopic point(298 K,52%RH)of ADN obtained by experiment in the literature,a non-hygroscopic range of temperature and humidity for ADN can be depicted when the simulation results in relative hygroscopicity is less than or equal to 17%.This study can provide effective strategies for screening anti-hygroscopic modified materials of ADN.
基金funded by Open Research Fund Program of National Key Laboratory of Aerospace Chemical Power(NKLACP120241B04)National Natural Science Foundation of China Youth Science Foundation(12402450)。
文摘Ammonium dinitramide(ADN),as a high-energy oxidizer widely applied in the field of rocket and missile propellants,has a prominent issue of high hygroscopicity due to its strong polarity.The previous coating encapsulation methods have struggled to address the problems of uneven coating and polarity mismatch.This research innovatively introduces perfluorooctanoic acid(PFOA)as a polar transition intermediate layer.Utilizing the polarity of one end of it to adsorb on the surface of ADN through hydrogen bonds,the problem of polarity mismatch is effectively overcome.Meanwhile,the vibrational magnetron sputtering process has been first applied in the energetic field,with a special vibrating abutment enhancing ADN particle fluidity to solve coating non-uniformity,thus preparing prilled ADN@PFOA@PTFE core-dual-shell composites.Performance tests reveal that this composite material possesses excellent hydrophobic and anti-hygroscopic properties.When left at 25℃and 75%RH for 3 days,moisture absorption was reduced by more than 90%compared to pure ADN.Simultaneously,its thermal stability,heat release performance,and combustion performance have been improved.The research achievements optimize the storage conditions of ADN in the application of rocket and missile propellants,providing solid support and broad development prospects for technological innovation in military fields.
