Hengyu Feng,Qingshi Cui,Yu Zhou,Jinglong Dong,Ming Li,Linghan Xiao,Yuhui Ao
Understanding the mechanism of thermal degradation of a material may suggest a promising way for further improving its thermal properties. poly(melamine-co-phenolic resin) (P(M-co-PR)) has been widely used in flame resistant and fire-proof materials. Our characterization of the thermal degradation of P(M-co-PR) is described in this work. Fourier-transform infrared (FTIR) and X-ray photo-electron spectroscopy (XPS) analyses were used to investigate the structural evolution during the thermal degradation of the copolymer. The evolutions of C = N and C-N bonding in heteroaromatic rings were monitored during the degradation process by C1s and N1s XPS spectra. The degradation processes of P(M-co-PR) is divided into three stages. The degradation kinetics of P(M-co-PR) was researched by using the Ozawa and Kissinger activation energy equation methods. The conclusion is that the Kissinger equation applied to the first stage, and the Ozawa equation applied to the second and third stages.
Jinyi Liu,Yuxuan Zhang,Haojie Yu,Li Wang,Sergey Z. Vatsadze,Dingning Chen,Chenguang Ouyang
To enhance the combustion performance of composite solid propellants (CSPs), a series of ferrocene-based pyrazole energetic compounds were prepared and characterized systemically by spectroscopic techniques in this study. Moreover, their catalytic performance and mechanism as burning rate catalysts (BRCs) were investigated, and the related kinetic parameters were obtained via Flynn–Wall–Ozawa (FWO) and Kissinger–Akahira–Sunose (KAS) methods, respectively. Besides, their anti-migration performance and mechanism were studied via simulating the aging experiments of propellant samples at different times. The results showed that these compounds exhibited excellent catalytic effect on the thermal decomposition of ammonium perchlorate, which is a vital oxidizer in CSPs and determines its combustion performance. Among them, EMFc-1 showed the best catalytic performance because of the higher content of active component. The pyrolysis temperature of ammonium perchlorate was reduced by 56.2 °C and the heat release was increased by 248.2 J g −1 with 5 wt% EMFc-1 as catalyst. Moreover, their anti-migration performance was improved greatly compared with the commercial catocene ( Cat ) and ferrocene. The work indicates that these compounds can be applied as BRCs to enhance the combustion performance of propellants.
Ying Wu,Yong Liu,Shuai Hou,Qizhi Zhao,Han Gao,Xiao Yan
4,4’-Azo-1,2,4-triazole (atrz) is a new high nitrogen energetic material with high energy density, high gas yield and wide application prospects, but the low synthesis temperature and long time are the main reasons limiting its application. To achieve efficient synthesis of atrz, the double drop synthesis method was designed to solve the problem of unstable concentration of oxidant (HClO) due to batch feeding. The reaction temperature, reaction time, and molar ratio of reactants of n(4-amino-1,2,4-triazole):n(ClO−) were studied and optimized using the single factor variable method; Characterization and analysis of atrz using theoretical calculations with elemental analysis, infrared spectroscopy, crystal morphology, and nuclear magnetic resonance; The thermal properties and stability of atrz were tested and analyzed using TG-DTA. The results showed that the reaction time of the double drop synthesis method was shortened from 5 hours to 1.5 hours under the conditions of similar yield, and the efficiency was increased by 2.3 times. The optimized process was a reaction temperature of 5°C-10°C, reaction time of 1.5 hours, n(4-amino-1,2,4-triazole):n(ClO−) of 1:2, and the yield reached 73%. The product was white, needle-like crystals, which were determined to be atrz by means of characterization and theoretical calculations. Atrz’s decomposition peak temperature is 309.0°C, and when the temperature is below 271.7°C, atrz is thermally stable. The activation energies of atrz calculated by Kissinger and Flynn-Wall-Ozawa methods were 195.0 kJ·mol−1 and 194.6 kJ·mol−1.
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