Journal of Energetic Materials
·
2022
·
IF 2.421
Shu-Ji Wang,Di Wang,Ping Liu,Xiao-le Sun,Shi Yan,Xue-Yong Guo
TKX-50, as a representative of a new nitrogen-rich energetic compound, has attracted extensive interests due to its high energy and low sensitivity properties. As an important energetic material, combustible agent has great influence on improving the energy level of explosives and propellants. Boron powder has become the most potential combustible agent in energetic fields because of its unique performances. In this work, nano-boron-based microspheres containing TKX-50 are directly fabricated by electrospray deposition. The prepared microspheres showed high monodispersity with particle size ranging from ~1–3 μm. Thermal behavior results show that the mass gain of the electrostatically sprayed sample is 163.3%, which is much higher than that of pure boron and physically mixed samples. Combustion behavior tests show that electrosprayed microspheres exhibit outstanding performance in comparison to physical mixed sample, the peak pressure improved by 85%, the burning time decreased by 21% and the pressurization rate improved by 136%. These excellent properties are probably related to their uniform microstructure. Therefore, electrospray preparation of microspheres with controllable structure has a good application prospect in energetic materials.
研究领域:
化学
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材料科学
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能源科学
✓ 已验证
DOI
高影响因子
FIRE AND MATERIALS
·
2023
·Vol. 47
·期 8
·1082-1091
·
IF 1.9
Ke Shang,Gui-De Lin,Hui-Jing Jiang,Xing Jin,Jing Zhao,Dan Liu,Bi Zhao,Jin-Jun Yang,Teng Fu,Jun-Sheng Wang
Two types of ceramifiable flame-retardant room temperature vulcanized (RTV) silicone rubber foam containing mica power (MP) were prepared by using glass powder (GP) as fluxing agents and aluminum hydroxide (ATH) as flame-retardant agent, respectively. The flame retardant, combustion behavior, and thermal stability of ceramifiable flame-retardant RTV silicone rubber foams were investigated. The results show that GP is not conducive to the flame retardancy and thermal stability improvement of the foams. On the contrary, MP and ATH can significantly improve the flame retardancy and thermal stability at high temperatures of the foams. The foams with addition of MP and ATH can reach to a high limiting oxygen index value of 35.8 with V-0 rating in the vertical combustion test, and the total heat release and total smoke production of the foams are 21.0% and 61.7% lower than of the pure RTV silicone rubber foam, respectively. Furthermore, the structural and morphological changes of the foams under different pyrolysis conditions were studied, so as to reveal its ceramifiable mechanism under different fire scenarios. The results show that GP does not promote the formation of more char residue during pyrolysis, but it can greatly lower the ceramifiable temperature, resulting in a superior ceramic phase char residue. The foams including MP and ATH have a high char residue content; nevertheless, a comparatively higher temperature is necessary to create ceramic phase char residue.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Gels
·
2022
·Vol. 8
·期 10
·654
·
IF 4.432
Xiaowu Wang,Yang Wang,Mengtian Sun,Guichao Wang,Qiong Liu,Ming Li,Yury M. Shulga,Zhi Li
In this work, we reported that aramid pulps (AP) reinforced clay aerogel composites with improved mechanical strength, good thermal insulation and fire resistance based on the combination of AP, Poly(vinyl alcohol) (PVA) and sodium montmorillonite (MMT), which present a promising prospect in the thermal insulation application. The PVA-MMT-APx(x: denotes the mass content of AP) aerogel composites present an isotropic “lamella-honeycomb” porous structure, which endows them with excellent comprehensive performance. With the AP content increasing, the extremely low density is kept, ranging between 67–73 mg/cm3, and the low thermal conductivity is maintained within 40.9–47.9 mW·m−1·K−1. The mechanical strength is significantly improved with the maximum compressive modulus increasing from 2.95 to 5.96 MPa and the specific modulus rising from 44.03 to 81.64 MPa∙cm3/g. Their detailed heat transfer process has been analyzed, which provides a deep understanding to the low thermal conductivity of the PVA-MMT-APxaerogel composites. Based on the combination of thermogravimetric analysis and combustion behavior, the PVA-MMT-APxaerogel composites are demonstrated to possess improved thermal stability and fire resistance. This study puts forward a facile approach to utilizing AP to reinforce clay aerogel composites, which provides new insight into the development of thermal-insulating, fire-safe and high-strength thermal insulation materials.Keywords:aramid pulps;clay aerogel;mechanical properties;thermal properties;combustion behavior
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
·
IF 13.3
Ling Chen,Anning Sun,Jianwei Zhang,Derong Meng,Peichen Han,Feiyun Chen,Fengqiang Nan,Ping Du,Weidong He
High-energy propellant always encounters deficient mechanical properties and unstable combustion behavior under low temperature, leading to difficulties in subsequent use. Herein, the reinforcement filler carbon nanofibers (CNFs) were pioneered introduced into nitroguanidine propulsion, meanwhile, the molecular model and structure–function relationship of high-solid content propellant system was constructed. A sequence of characterizations manifested that CNFs were integrated well in propulsion system. The result of mechanical properties demonstrated that anti-impact strength increased with the increase content of CNFs in propellant, and a proper content range from 0.25 % to 1.0 % exerted better mechanical strength than that of high content under different temperature conditions. A “wire-tie” structure acting bridging effect that exhibit buffer exoenergic effect in terms of the enhancement mechanism was proposal as well, combing the theoretical calculated interaction of nitroguanidine (NQ) and nitrocellulose/nitroglycerin (NC/NG). Additionally, the analysis of thermal decomposition kinetic of propellant by conventional iso -conversional rate methods demonstrated that the addition of CNFs can could furtherly reduce the activation energy of NQ-GP, which is accord with the result of linear fitting methods. It also demonstrated that the thermal decomposition behavior of propellant was influenced by different high-pressure conditions and CNFs content, including T p and heat-release. Additionally, propellant integrated with CNFs burning steadily under different temperatures, and the burning rate coefficient and burning pressure exponent of propellant could be also flexible tuned with proper content of CNFs. Hence, the presented study highly broadens the application scope of reinforcement nanofiller, and will be potential of value to the community development in high-energy and high strength gun propulsion in aspect of combining experimental and theoretical calculation.
研究领域:
材料科学
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推进剂工程
·
分子动力学
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2021
·
IF 4.185
Shuai-Zhong Wang,Jie-Yao Lyu,Wei He,Pei-Jin Liu,Qi-Long Yan
Electrically controlled solid propellant (ECSP) is one promising solution for thrust adjustment and repeated ignition of conventional solid rocket motors (SRM). However, the widely studied ECSP based on hydroxylammonium nitrate (HAN) faces the problems of strong hygroscopicity and low thermal stability, which can lead to failure of ECSP. Inspired by polyethylene oxide-polyacrylonitrile (PEO-PAN) based solid polymer electrolyte , the new PEO-PAN based ion conductive energetic composites (ECs) have been designed and evaluated in this paper. The formulation was theoretically determined based on the energy content, and the samples were prepared by a conventional milling mixing method. The morphology, ionic conductivity , thermal reactivity, decomposition gaseous products and combustion behavior of these new ECs have been comprehensively studied. It has been shown that the initial decomposition temperature of PEO-PAN based ECs is around 243 °C with heat release of 1677.8–1873.9 J·g −1 depending on the oxidizer and polymer content. Meanwhile, the dependences of the ionic conductivity on the burning rate are evaluated. The results showed that the burning rate decreases as ionic conductivity increases. One of these ECs has a high ionic conductivity with a low burning rate under pressure, which is suitable for controllable ECSP.
研究领域:
材料科学
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航空航天工程
✓ 已验证
DOI
高影响因子
Materials
·
2018
·Vol. 11
·期 9
·1505
·
IF 2.467
Yan Song,Xu Zong,Nan Wang,Ning Yan,Xueying Shan,Jinchun Li
Lignin can be a candidate as a charring agent applied in halogen-free flame retardant polymers, and incorporation of silicon and nitrogen elements in lignin can benefit to enhancing its thermal stability and charring ability. In the present work, wheat straw alkali lignin (Lig) was modified to incorporate silicon and nitrogen elements by γ-divinyl-3-aminopropyltriethoxysilane, and the modified lignin (CLig) was combined with ammonium polyphosphate (APP) as intumescent flame retardant to be applied in poly(Lactic acid) (PLA). The flame retardancy, combustion behavior and thermal stability of PLA composites were studied by the limited oxygen index (LOI), vertical burning testing (UL-94), cone calorimetry testing (CCT) and thermogravimetric analysis (TGA), respectively. The results showed a significant synergistic effect between CLig and APP in flame retarded PLA (PLA/APP/CLig) occured, and the PLA/APP/CLig had better flame retardancy. CCT data analysis revealed that CLig and APP largely reduced the peak heat release rate (PHRR) and total heat release rate (THR) of PLA, indicating their effectiveness in decreasing the combustion of PLA. TGA results exhibited that APP and CLig improved the thermal stability of PLA at high temperature. The analysis of morphology and structure of residual char indicated that a continuous, compact and intumescent char layer on the material surface formed during firing, and had higher graphitization degree. Mechanical properties data showed that PLA/APP/CLig had higher tensile strength as well as elongation at break.Keywords:wheat straw soda lignin;silicon and nitrogen elements;poly(lactic acid);thermal stability;combustion behavior
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF APPLIED POLYMER SCIENCE
·
2016
·Vol. 133
·期 37
·
IF 1.866
Peng Wang,Fusheng Yang,Liang Li,Zaisheng Cai
Two phosphorus-containing phenolic amines, a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO)-based derivative (DAP) by covalently bonding DOPO and imine (SB) obtained from the condensation of p -phenylenediamine with salicylaldehyde, and its analog (AP) via the addition reaction between diethyl phosphite and SB, were used to prepare flame-retardant epoxy resins. The burning behaviors and dynamic mechanical properties of epoxy thermosets were studied by limited oxygen index (LOI) measurement, UL-94 test, and dynamic mechanical analysis. The flame-retardant mechanisms of modified thermosets were investigated by thermogravimetric analysis, Py-GC/MS, Fourier transform infrared, SEM, elemental analysis, and laser Raman spectroscopy. The results revealed that epoxy thermoset modified with DAP displayed the blowing-out effect during UL-94 test. With the incorporation of 10 wt % DAP, the modified thermoset showed an LOI value of 36.1% and V-0 rating in UL-94 test. The flame-retardant mechanism was ascribed to the quenching and diluting effect in the gas phase and the formation of phosphorus-rich char layers in the condensed phase. However, the thermoset modified with 10 wt % AP only showed an LOI value of 25.7% and no rating in UL-94 test, which was possibly ascribed to the mismatching of charring process with gas emission process during combustion. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133 , 43953.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2023
·
IF 4.4
Huiqing Mao,Xiandie Zhang,Rui Cui,Chun Zhang,Xiang Zhou
In this study, Si@PVDF composite microspheres are prepared by the electrostatic spraying method. The spheres are with average diameter of around 2 μm (when at ideal stoichiometry), within which Si nanopowder is uniformly distributed. The exothermic properties of samples are studied through simultaneous thermogravimetry and differential scanning calorimetry . Benefiting from the improved interfacial contact quality, Si@PVDF shows increased chemical reactivity in terms of reduced reaction onset temperature , peak temperature and apparent activation energy than those of physically mixed Si/PVDF counterpart. Si/PVDF cannot be ignited through Joule heating , either in the powder of pellet form, while self-sustained combustion propagation is observed for Si@PVDF pellets. The combustion behaviors of Si@PVDF pellets are systematically studied in open-air (where light signal is analyzed) and constant-volume (where pressure signal is analyzed) conditions. The results show that the combustion process is influenced by the equivalence ratio, porosity of the pellet and the accessibility of O 2 gas in the environment. Overall, the encapsulation of Si nanopowder into PVDF microspheres using electrostatic spraying shortens the mass and heat transfer distance and thus realizes enhanced energetic characteristics.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
高影响因子
INDUSTRIAL CROPS AND PRODUCTS
·
2022
·
IF 6.449
Xinyu Lu,Xiaoli Gu
Lignin, commonly treated as a waste from industrial or agricultural/forestry activities, can be used as a sustainable alternative of fossil phenol to fabricate lignin-based epoxy resins. In this study, the cured samples of lignin-based epoxy resins were prepared after curing process, and their combustion behaviors were investigated by thermogravimetric analysis coupled with Fourier transform infrared spectrometer (TG-FTIR) and cone calorimeter test. Results showed that these as-prepared epoxy thermosets (containing 0%, 5%, and 10% lignin) contained a higher LOI (limited oxygen index) value compared to others commercial resins reported in previous literature. Furthermore, they were all self-extinguishing materials during the first burning process, which was primarily contributed to their high-compactness crosslinking structure. Lignin addition would cause a negative effect on the thermomechanical properties of cured samples due to the decrease of crosslinking density, while better excellent gaseous inhibition and charring capacity can be obtained after lignin addition. This study presented an effective strategy to incorporate lignin into epoxy resin system via chemical crosslinking using glyoxal in place of formaldehyde as a green crosslinking agent to improve the combustion behaviors via reducing smoke releasing and increasing char formation, which was also beneficial for lignin valorization.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2024
·Vol. 149
·期 24
·14687-14698
·
IF 3
Zhang Yi,Wang Bingtao,Xia Yan,Zhang Li,Zhu Yingke,Guo Zhenghong,Li Juan
High flame retardancy and thermal conductivity are key performances for advanced electronic packaging materials. Herein, boron nitride (BN) and epoxy curing agent were chemically bonded with highly flame retardant DOPO moieties to obtain BN-DOPO thermal conductive filler and DOPO-PA curing agent with flame retardancy. The effect of BN-DOPO and DOPO-PA on the thermal stability, flame retardancy, combustion behavior and thermal conductive performance of EP composites were analyzed in detail. Compared with EP/Al(OH) 3 , up to 32.5% in LOI, V0 rating in UL-94, prolonged 125 s of TTI, 22% reduction of PHRR and 29% reduction of THR in cone test were observed when both BN-DOPO and DOPO-PA were incorporated into EP cross-linking network. According to the residual char morphology, the excellent flame retardancy of EP/Al(OH) 3 composite containing BN-DOPO and DOPO-PA was attributed to the formation of compact front char covered by fluffy porous carbon and thick continuous back char with tiny aluminum oxide particles. Moreover, the introduction of a small amount of BN-DOPO and DOPO-PA could also greatly improve the thermal conductivity of EP/Al(OH) 3 by 107% due to the better compatibility resulting in lower interface thermal resistance and more effective thermal transfer caused by the participation of BN-DOPO and DOPO-PA into epoxy curing reactions.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
COMBUSTION AND FLAME
·
2020
·
IF 4.57
Lirong Bao,Wei Zhang,Xiaojun Zhang,Yongyi Chen,Suhang Chen,Lizhi Wu,Ruiqi Shen,Yinghua Ye
In the controllable combustion field, hydroxyl ammonium nitrate (HAN)-based electrically controlled solid propellants (ECSPs) is of growing interest in green fuels with safety, throttle- ability and at-will on-off capability. However, the current research is confined to the ignition characteristics and ablation process of basic ECSP formulations (75 wt% HAN ionic liquid oxidizer , 5 wt% ammonium nitrate co-oxidizer and 20 wt% polyvinyl alcohol binder), rather than working in functional additives. Herein, multiwall carbon nanotubes (MWCNT) and nano/micro aluminum powders were introduced in ECSPs, facilitating electrical conductivity and energy release. It indicates that the homogeneous dispersed MWCNT in polyvinyl alcohol (PVA) microspheres , preparing by the micro-segmented flow method, results in a 9.8% increase in electrical conductivity of the ECSPs. At 0.5 MPa, ECSPs containing 1%, 3% and 5% 5 µm aluminum powder reinforce the burning rate by 38.0%, 186.3%, 214.7% and mass ablation by 10.7%, 95.2%, 175.6% at 200 V, yet the large heat release by excess aluminum powder shifts the non-self-sustaining combustion of ECSPs to self-sustaining combustion at high pressure (above 0.8 MPa). The mechanism of promoting ECSPs combustion by liberating aluminum-nitric acid (released by HAN ionization) reaction were proposed.
研究领域:
材料科学
·
燃烧学
✓ 已验证
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2023
·Vol. 136
·期 1
·13-22
·
IF 1.8
Tian Lu,He Jie-Xin,Huang Xin-Yang,Feng Yang,Lu Yue-Wen,Wang Rui-Hao,Wang Qian,Guo Chang-Ping
Herein, nano-Co 3 O 4 /C composite catalyst was successfully synthesized by calcination of cobalt alginate (CA) film, which was prepared by ion exchange method. The morphology and structure of the films and calcined samples were characterized. It was found that the thickness of the film produced by Co 2+ substituted Na + was 20 μm, and the surface and side of the film were smooth and uniform. After the calcination of CA film at 400 °C, Co 3 O 4 nanoparticles grown in situ were loaded onto the carbonized alginate skeleton. The results of the thermal analysis showed that the higher the content of catalyst, the more obvious the catalytic effect on AP. Compared with pure AP, the exothermic peak temperature with 3 wt% nano-Co 3 O 4 /C composite catalysts decreased by 103.1 °C, demonstrating the catalytic effect on the nano-Co 3 O 4 /C. The nanocomposite catalyst could be synthesized quickly and in large quantities in this way, which had certain theoretical and practical value for improving the combustion behavior of AP-based composite solid propellants. Graphical abstract Based on inspiring by biomaterial, we have designed and prepared a nano-Co 3 O 4 /C composite catalyst by a facile ionic crosslinking solidification method, which effectively enhanced the thermal decomposition of the ammonium perchlorate.
研究领域:
材料科学
·
推进剂化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）