The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves...The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves the pretreatment of HMX to endow—OH groups on the surface via polyalcohol bonding agent modification and in situ coating with nitrate ester-containing polymer,was proposed to address the problem.Two types of energetic polyether—glycidyl azide polymer(GAP)and nitrate modified GAP(GNP)were grafted onto HMX crystal based on isocyanate addition reaction bridged through neutral polymeric bonding agent(NPBA)layer.The morphology and structure of the HMX-based composites were characterized in detail and the core-shell structure was validated.The grafted polymers obviously enhanced the adhesion force between HMX crystals and fluoropolymer(F2314)binder.Due to the interfacial reinforcement among the components,the two HMX-based composites exhibited a remarkable increment of phase transition peak temperature by 10.2°C and 19.6°C with no more than 1.5%shell content,respectively.Furthermore,the impact and friction sensitivity of the composites decreased significantly as a result of the barrier produced by the grafted polymers.These findings will enhance the future prospects for the interface design of energetic composites aiming to solve the weak interface and safety concerns.展开更多
Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane ...Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane chain parts, and systematically investigate their structure-property relationships.Results show that DNPEPs have impact sensitivities all higher than 25.2 J, thermal decomposition temperatures all higher than 254 ℃, and glass transition temperatures(T_(g)) lower than-90 ℃.Furthermore, the effects of DNPEPs as plasticizer are studied on hydroxyl terminated polybutadiene(HTPB) in detail, including the viscosity, glass transition temperatures and others. It is noteworthy that 2,2-dinitropropyl nonanoate(DNPNc) among these DNPEPs exhibits the most expected simultaneous tuning effects on both viscosity and T_(g) of HTPB systems, providing favorable potentials to replace the conventional plastizers as dioctyl sebacate(DOS) in the HTPB based propellants and explosives.展开更多
An in-depth analysis on the cooperativity of intermolecular interactions including hydrogen bonding andπ-π stacking in 1,3,5-triamino-2,4,6-trinitrobenzene(TATB) crystal was studied. Two quantities, cooperativity ra...An in-depth analysis on the cooperativity of intermolecular interactions including hydrogen bonding andπ-π stacking in 1,3,5-triamino-2,4,6-trinitrobenzene(TATB) crystal was studied. Two quantities, cooperativity rate and energy, were defined to evaluate the nature and strength of cooperativity in a series of clusters diverging from 1D to 3D prototypes. The origin and mechanism of the cooperative effect were settled to demonstrate that the nature of cooperativity is determined by whether the non-covalent interactions compete or promote with each other, which is manifested by the changing trend of electron transfer. There exists obvious cooperative effect in intra-layer and inter-layer structures as they own the equivalent non-covalent interactions, while anti-cooperative effect is also observed if two interactions correlate with each other. On the whole, in the process of crystal formation, the apparent cooperativity is the check and balance of the two effects, which is capable to support a global interaction among all of molecules and contribute to the stabilization of system. Based on the results, one may get a new insight to understand the relationship between non-covalent interactions and low impact sensitivity.展开更多
Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE dr...Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE drop when the bladecoating and/or green-solvents toward large-scale printing are used instead,which hampers the practical development of OSCs.Here,a new series of N-alkyl-tailored small molecule acceptors named YR-SeNF with a same molecular main backbone are developed by combining selenium-fused central-core and naphthalene-fused endgroup.Thanks to the N-alkyl engineering,NIR-absorbing YR-SeNF series show different crystallinity,packing patterns,and miscibility with polymeric donor.The studies exhibit that the molecular packing,crystallinity,and vertical distribution of active layer morphologies are well optimized by introducing newly designed guest acceptor associated with tailored N-alkyl chains,providing the improved charge transfer dynamics and stability for the PM6:L8-BO:YRSeNF-based OSCs.As a result,a record-high PCE approaching 19%is achieved in the blade-coating OSCs fabricated from a greensolvent o-xylene with high-boiling point.Notably,ternary OSCs offer robust operating stability under maximum-power-point tracking and well-keep>80%of the initial PCEs for even over 400 h.Our alkyl-tailored guest acceptor strategy provides a unique approach to develop green-solvent and blade-coating processed high-efficiency and operating stable OSCs,which paves a way for industrial development.展开更多
Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strat...Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strategies.Herein,a class of low-cost and fully unfused polymer donors with precisely regulated backbone planarity via halogenation was designed and synthesized,namely PDTBTBz-2H,PDTBTBz-2F,and PDTBTBz-2Cl.These polymer donors possess a four-step synthesis route with over 80%yield from cheap raw chemicals comparable to existing low-cost polymer donors,such as PTQ10.Benefitting from the planar backbone via in-corporating the F…S non-covalent interactions,PDTBTBz-2F exhibits more robust J-type aggregation in solution and a long-ranged molecular stacking in film relative to PDTBTBz-2H and PDTBTBz-2Cl.Moreover,the systematical study of PDTBTBz-based organic so-lar cells(OSCs)reveals the close relationship between optimized molecular self-assembly and charge separation/transport regarding backbone halogenation when paired with the non-fullerene acceptor(Y6-BO-4F).As a result,the photovoltaic devices based on semicrystalline PDTBTBz-2F achieved a promising power conversion efficiency(PCE)of 12.37%.Our work highlighted the influence of backbone halogenation on the molecular self-assembly properties and a potential unfused backbone motif for further developing cost-effective OSCs.展开更多
Potassium 5,5'-azobis(1-nitraminotetrazolate),(K2ABNAT), a new green primary explosive, was synthesized via a safe and convenient synthetic procedure based on methylcarbazate and cyanogen azide. The compound was ...Potassium 5,5'-azobis(1-nitraminotetrazolate),(K2ABNAT), a new green primary explosive, was synthesized via a safe and convenient synthetic procedure based on methylcarbazate and cyanogen azide. The compound was characterized by single-crystal X-ray diffraction, IR spectroscopy, Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry(DSC). With the calculated(CBS-4M) heat of formation(617.0 kJ/mol) and the room temperature X-ray density(2.11 g/cm^3), impressive values for the detonation parameters such as detonation velocity(8367 m/s) and pressure(31.5 GPa) were computed using the EXPLO5 program. The superior calculated energetic performance show it could serve as a green replacement for the widely used primary explosive,lead(II) azide, which contains toxic ingredient.展开更多
Main observation and conclusion Important progress has been made in the development of energetic molecules with high performance by computer-aided molecular design in recent years,but structural novelty of organic sca...Main observation and conclusion Important progress has been made in the development of energetic molecules with high performance by computer-aided molecular design in recent years,but structural novelty of organic scaffolds is insufficient.In this work,we propose an intra-ring bridging strategy inspired by the known energetic nitramines to design novel polycyclic and cage energetic molecules.More than 100 energetic structures were designed by introducing the C—C bridges and increasing the ring size.The synthesis difficulty is considered besides the two most concerned properties of EMs,energy and safety.After a comprehensive estimation,a symmetric cage molecule labeled as 8U-30 was finally selected because of its relatively high detonation performance,and comparable impact sensitivity as well as synthetic accessibility with CL-20.Hopefully,the proposed strategy could be utilized in further molecular design to gain various scaffolds,especially cage structures,for different demands.展开更多
A novel energetic ionic salt,hydroxylammonium potassium 3,3?-dinitro-5,5?-bis-1,2,4-triazole-1,1?-diolate dihydrate[(NH3OH)2K(DNOBT)1.5?2H2O],was synthesized and structurally characterized by elemental analysis,IR spe...A novel energetic ionic salt,hydroxylammonium potassium 3,3?-dinitro-5,5?-bis-1,2,4-triazole-1,1?-diolate dihydrate[(NH3OH)2K(DNOBT)1.5?2H2O],was synthesized and structurally characterized by elemental analysis,IR spectra,13C NMR and single-crystal X-ray diffraction.(NH3OH)2K(DNOBT)1.5?2H2O crystallizes in triclinic system,space group P with a=7.9212(6),b=9.1924(7),c=14.2549(15)?,a=103.917(2)°,β=99.736(2)°,g=104.8110(10)°,V=944.16(14)?^3,Z=2,Dc=1.855 g/cm^3,F(000)=538,μ=0.386 mm^-1,S=1.070,the final R=0.0525 and wR(I>2s(I))=0.1593.Thermal decomposition of(NH3OH)2K(DNOBT)1.5?2H2O and its intermediate potassium 1?-hydroxy-3,3?-dinitro-5,5?-bis-1,2,4-triazole-1-olate monohydrate[K(HDNOBT)?H2O]was studied by using DSC and TG-DTG.It was found that(NH3OH)2K(DNOBT)1.5?2H2O,which has primarily one exothermic decomposition process at 248.2℃,has better thermal stability than K(HDNOBT)?H2O which is decomposed at 210.9℃.展开更多
基金the support for this work by National Natural Science Foundation of China(Grant Nos.22175139 and 22105156)。
文摘The weak interface interaction and solid-solid phase transition have long been a conundrum for 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane(HMX)-based polymer-bonded explosives(PBX).A two-step strategy that involves the pretreatment of HMX to endow—OH groups on the surface via polyalcohol bonding agent modification and in situ coating with nitrate ester-containing polymer,was proposed to address the problem.Two types of energetic polyether—glycidyl azide polymer(GAP)and nitrate modified GAP(GNP)were grafted onto HMX crystal based on isocyanate addition reaction bridged through neutral polymeric bonding agent(NPBA)layer.The morphology and structure of the HMX-based composites were characterized in detail and the core-shell structure was validated.The grafted polymers obviously enhanced the adhesion force between HMX crystals and fluoropolymer(F2314)binder.Due to the interfacial reinforcement among the components,the two HMX-based composites exhibited a remarkable increment of phase transition peak temperature by 10.2°C and 19.6°C with no more than 1.5%shell content,respectively.Furthermore,the impact and friction sensitivity of the composites decreased significantly as a result of the barrier produced by the grafted polymers.These findings will enhance the future prospects for the interface design of energetic composites aiming to solve the weak interface and safety concerns.
基金financial support of the National Natural Science Foundation of China (21875185)。
文摘Geminal dinitropropyl ester plasticizers(DNPEPs) possess excellent energetic performances which provide good potentials as insensitive plasticizer. In this study, we design and synthesize DNPEPs with different alkane chain parts, and systematically investigate their structure-property relationships.Results show that DNPEPs have impact sensitivities all higher than 25.2 J, thermal decomposition temperatures all higher than 254 ℃, and glass transition temperatures(T_(g)) lower than-90 ℃.Furthermore, the effects of DNPEPs as plasticizer are studied on hydroxyl terminated polybutadiene(HTPB) in detail, including the viscosity, glass transition temperatures and others. It is noteworthy that 2,2-dinitropropyl nonanoate(DNPNc) among these DNPEPs exhibits the most expected simultaneous tuning effects on both viscosity and T_(g) of HTPB systems, providing favorable potentials to replace the conventional plastizers as dioctyl sebacate(DOS) in the HTPB based propellants and explosives.
基金the support from the National Natural Science Foundation of China (No. 21875184)the Natural Science Foundation of Shaanxi Province (No. 2022JC-10)Youth Talent of Shaanxi “TeZhi” Program。
文摘An in-depth analysis on the cooperativity of intermolecular interactions including hydrogen bonding andπ-π stacking in 1,3,5-triamino-2,4,6-trinitrobenzene(TATB) crystal was studied. Two quantities, cooperativity rate and energy, were defined to evaluate the nature and strength of cooperativity in a series of clusters diverging from 1D to 3D prototypes. The origin and mechanism of the cooperative effect were settled to demonstrate that the nature of cooperativity is determined by whether the non-covalent interactions compete or promote with each other, which is manifested by the changing trend of electron transfer. There exists obvious cooperative effect in intra-layer and inter-layer structures as they own the equivalent non-covalent interactions, while anti-cooperative effect is also observed if two interactions correlate with each other. On the whole, in the process of crystal formation, the apparent cooperativity is the check and balance of the two effects, which is capable to support a global interaction among all of molecules and contribute to the stabilization of system. Based on the results, one may get a new insight to understand the relationship between non-covalent interactions and low impact sensitivity.
基金the support from the NSFC (22209131, 22005121, 21875182, and 52173023)National Key Research and Development Program of China (2022YFE0132400)+4 种基金Key Scientific and Technological Innovation Team Project of Shaanxi Province (2020TD-002)111 project 2.0 (BP0618008)Open Fund of Jiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and Applications (Changzhou University, GDRGCS2022002)Open Fund of Key Laboratory of Fluorine and Silicon for Energy Materials and Chemistry of Ministry of Education (Jiangxi Normal University, KFSEMC-202201)acquired at beamlines 7.3.3 and 11.0.1.2 at the Advanced Light Source, which is supported by the Director, Office of Science, Office of Basic Energy Sciences, of the U.S. Department of Energy under Contract No. DE-AC0205CH11231
文摘Power-conversion-efficiencies(PCEs)of organic solar cells(OSCs)in laboratory,normally processed by spin-coating technology with toxic halogenated solvents,have reached over 19%.However,there is usually a marked PCE drop when the bladecoating and/or green-solvents toward large-scale printing are used instead,which hampers the practical development of OSCs.Here,a new series of N-alkyl-tailored small molecule acceptors named YR-SeNF with a same molecular main backbone are developed by combining selenium-fused central-core and naphthalene-fused endgroup.Thanks to the N-alkyl engineering,NIR-absorbing YR-SeNF series show different crystallinity,packing patterns,and miscibility with polymeric donor.The studies exhibit that the molecular packing,crystallinity,and vertical distribution of active layer morphologies are well optimized by introducing newly designed guest acceptor associated with tailored N-alkyl chains,providing the improved charge transfer dynamics and stability for the PM6:L8-BO:YRSeNF-based OSCs.As a result,a record-high PCE approaching 19%is achieved in the blade-coating OSCs fabricated from a greensolvent o-xylene with high-boiling point.Notably,ternary OSCs offer robust operating stability under maximum-power-point tracking and well-keep>80%of the initial PCEs for even over 400 h.Our alkyl-tailored guest acceptor strategy provides a unique approach to develop green-solvent and blade-coating processed high-efficiency and operating stable OSCs,which paves a way for industrial development.
基金supported by the National Natural Science Foundation of China (52203241,21905225,22005121)the Science and Technology Program of Shaanxi Province (2022JM-229,2023-JC-QN-0448)+1 种基金Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow University (KJS2208)H.Y.W.acknowledges the financial support from the National Research Foundation of Korea (2019R1A6A1A11044070,2020M3H4A3081814).
文摘Developing novel unfused building blocks with simple synthesis and low cost is essential to advance and enrich cost-effective poly-mer donors;however,it remains a challenge due to the lack of efficient molecular strategies.Herein,a class of low-cost and fully unfused polymer donors with precisely regulated backbone planarity via halogenation was designed and synthesized,namely PDTBTBz-2H,PDTBTBz-2F,and PDTBTBz-2Cl.These polymer donors possess a four-step synthesis route with over 80%yield from cheap raw chemicals comparable to existing low-cost polymer donors,such as PTQ10.Benefitting from the planar backbone via in-corporating the F…S non-covalent interactions,PDTBTBz-2F exhibits more robust J-type aggregation in solution and a long-ranged molecular stacking in film relative to PDTBTBz-2H and PDTBTBz-2Cl.Moreover,the systematical study of PDTBTBz-based organic so-lar cells(OSCs)reveals the close relationship between optimized molecular self-assembly and charge separation/transport regarding backbone halogenation when paired with the non-fullerene acceptor(Y6-BO-4F).As a result,the photovoltaic devices based on semicrystalline PDTBTBz-2F achieved a promising power conversion efficiency(PCE)of 12.37%.Our work highlighted the influence of backbone halogenation on the molecular self-assembly properties and a potential unfused backbone motif for further developing cost-effective OSCs.
基金the National Natural Science Foundation of China (No. 21373157)
文摘Potassium 5,5'-azobis(1-nitraminotetrazolate),(K2ABNAT), a new green primary explosive, was synthesized via a safe and convenient synthetic procedure based on methylcarbazate and cyanogen azide. The compound was characterized by single-crystal X-ray diffraction, IR spectroscopy, Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, and differential scanning calorimetry(DSC). With the calculated(CBS-4M) heat of formation(617.0 kJ/mol) and the room temperature X-ray density(2.11 g/cm^3), impressive values for the detonation parameters such as detonation velocity(8367 m/s) and pressure(31.5 GPa) were computed using the EXPLO5 program. The superior calculated energetic performance show it could serve as a green replacement for the widely used primary explosive,lead(II) azide, which contains toxic ingredient.
基金support from the National Natural Science Foundation of China(Nos.21875184,21978311)the Youth Talent of Shaanxi"TeZhi"Programproject sponsored by Xi’an Modern Chemistry Research Institute(WDZCKYXM20190101).
文摘Main observation and conclusion Important progress has been made in the development of energetic molecules with high performance by computer-aided molecular design in recent years,but structural novelty of organic scaffolds is insufficient.In this work,we propose an intra-ring bridging strategy inspired by the known energetic nitramines to design novel polycyclic and cage energetic molecules.More than 100 energetic structures were designed by introducing the C—C bridges and increasing the ring size.The synthesis difficulty is considered besides the two most concerned properties of EMs,energy and safety.After a comprehensive estimation,a symmetric cage molecule labeled as 8U-30 was finally selected because of its relatively high detonation performance,and comparable impact sensitivity as well as synthetic accessibility with CL-20.Hopefully,the proposed strategy could be utilized in further molecular design to gain various scaffolds,especially cage structures,for different demands.
基金Financial support of this work by the National Natural Science Foundation of China(21805224)。
文摘A novel energetic ionic salt,hydroxylammonium potassium 3,3?-dinitro-5,5?-bis-1,2,4-triazole-1,1?-diolate dihydrate[(NH3OH)2K(DNOBT)1.5?2H2O],was synthesized and structurally characterized by elemental analysis,IR spectra,13C NMR and single-crystal X-ray diffraction.(NH3OH)2K(DNOBT)1.5?2H2O crystallizes in triclinic system,space group P with a=7.9212(6),b=9.1924(7),c=14.2549(15)?,a=103.917(2)°,β=99.736(2)°,g=104.8110(10)°,V=944.16(14)?^3,Z=2,Dc=1.855 g/cm^3,F(000)=538,μ=0.386 mm^-1,S=1.070,the final R=0.0525 and wR(I>2s(I))=0.1593.Thermal decomposition of(NH3OH)2K(DNOBT)1.5?2H2O and its intermediate potassium 1?-hydroxy-3,3?-dinitro-5,5?-bis-1,2,4-triazole-1-olate monohydrate[K(HDNOBT)?H2O]was studied by using DSC and TG-DTG.It was found that(NH3OH)2K(DNOBT)1.5?2H2O,which has primarily one exothermic decomposition process at 248.2℃,has better thermal stability than K(HDNOBT)?H2O which is decomposed at 210.9℃.