JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
·
2018
·Vol. 134
·期 3
·2041-2048
·
IF 2.209
Wu Cheng-Jie,You Jin-Zong,Wang Xue-Jie
Piroxicam (PRX) is a nonsteroidal anti-inflammatory drug. The thermal decomposition process of PRX was investigated with thermogravimetry and differential scanning calorimetry. The gaseous products generated by thermal decomposition were characterized with thermogravimetric analysis coupled with Fourier transform infrared spectroscopy. The residues of the thermal decomposition at various temperatures were identified with infrared spectroscopy. The molecular bond orders were calculated using an ab initio method from the GAMESS program of quantum chemistry. The mechanism of thermal decomposition for PRX was discussed. The results indicated that the thermal decomposition of PRX is a two-stage process with the initial temperature of 198 °C either in nitrogen or air atmospheres. The thermal decompositions of the first stage in two atmospheres are the same process. The main part of the molecule, including sulfamide, amide, benzene ring and pyridine ring, decompose simultaneously and to form gasifiable small molecules and carbonaceous residue in the first stage. The second stage in nitrogen is a slow thermal pyrolysis process of carbonaceous residue. The forepart of the second stage in air is a slow thermal pyrolysis process as like as in nitrogen, and the later period of the second stage is an oxidation (combustion) reaction process of carbonaceous residue. PRX is stable under ambient temperature and air atmosphere, and it can be preserved for long-term storage under ambient temperature and in air atmosphere.
研究领域:
药物化学
·
热分析科学
✓ 已验证
产品关联
DOI
高影响因子
FUEL
·
2022
·
IF 8.035
Qi Zhao,Xianfeng Chen,Yi Li,Huaming Dai
To explore the suppression mechanisms of ammonium polyphosphate (APP) on methane/coal dust explosion flame, the experiment tests of methane/coal dust explosion flame propagation under different mass fraction of APP were conducted in a vertical pipe. Using Simultaneous Thermal Analysis and Py-GC/MS to analyze the effects of APP on the thermal decomposition process and thermal pyrolysis products of coal dust. The chemical characterization of explosion residues was carried out by confocal Raman and Fourier transform infrared spectroscopy (FTIR). Based on the apparent suppression ways of APP such as absorption of heat, reduction concentration of combustibles and adsorbent of free radicals, APP also limited the thermal decomposition process of coal dust and leaded to the reduction or even disappearance of some organic matters at coal dust pyrolysis. Noticeably, the investigation of explosion residues found that the carbonization effect of APP pyrolysis products and the activity reduction of functional groups (–CH 3 /–CH 2 and –OH) which contribute to ignition of coal dust, these coupling effects made it difficult for coal dust to ignite, and thus the methane/coal dust compound explosion were suppressed significantly.
研究领域:
安全科学与工程
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Solar RRL
·
2023
·Vol. 7
·期 7
·2300022
·
IF 7.9
Mengqi Liu,Linrui Duan,T. Jesper Jacobsson,Jingshan Luo
Inorganic CsPbI 3 perovskite solar cells (CsPbI 3 PSCs) have attracted extensive attention because of their excellent thermal stability and appropriate bandgap for tandem solar cells. At present, intermediate phase engineering with organic additive, e.g., dimethyl amine iodide (DMAI), is the most common method to obtain high-efficiency CsPbI 3 PSCs. However, it remains controversial whether the intermediate phase is entirely converted into a pure CsPbI 3 phase. By exploring the effect of annealing temperature, herein, it is demonstrated that substantial organic residues remain in the produced films while using the current standard recipes of DMA + -assisted synthesis of Cs 1− x DMA x PbI 3 perovskites. Thermal gravimetric and nuclear magnetic resonance show that DMA + remains in films annealed at a standard annealing temperature of 190 °C. The DMA + does, however, disappear if the annealing temperature is increased to 340 °C, which leads to a larger grain size, a contraction of the lattice, a narrower bandgap, and a redshift of the absorption onset. Though both Cs 1− x DMA x PbI 3 and CsPbI 3 perovskite solar cells show decent efficiencies, the pure CsPbI 3 perovskite solar cells annealed at a higher temperature demonstrate higher operational stability.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Feng Ye,Shuanshi Fan,Xuemei Lang,Yanhong Wang,Gang Li
Silicalite-1 zeolite membranes were successfully activated at 300–350 °C in a hydrogen atmosphere. FTIR, TGA, and N 2 adsorption-desorption characterizations confirmed that the amount of the organic structure directing agent (OSDA) residue in silicalite-1 zeolite channels was tunable. The H 2 -calcined membrane showed a lower gas permeance than that of the air-calcined membrane due to the partial pore blockage by the OSDA residue. The permeance of H 2 and CO 2 increased with increasing temperature, showing an activated diffusion-like mechanism. The activation energies for the permeation of H 2 and CO 2 were in the range of 1.63–4.15 and 0.76–5.90 kJ mol −1 , respectively, which confirmed the reduced average membrane pore size and different pore surface chemistry due to the presence of the OSDA residue in the membrane. Significant interactions between CO 2 molecules and OSDA residues confined in the membrane resulted in a notably lower CO 2 permeance compared to N 2 and CH 4 , despite CO 2 having a smaller kinetic diameter. Enhanced H 2 /CO 2 selectivity in the silicalite-1 zeolite membrane, featuring confined OSDA residue, was attributed to the reduction in membrane pore size and the fine-tuning of pore surface chemistry.
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
BIORESOURCE TECHNOLOGY
·
2015
·
IF 4.494
Shuangquan Yao,Shuangxi Nie,Yue Yuan,Shuangfei Wang,Chengrong Qin
To reduce the degradation of cellulose and obtain high molecular weight of hemicellulose from the extracts, pH pre-corrected hot water pretreatment was developed by employing sodium hydroxide (3.9 mol/L). The response surface model was established to optimize the extraction process. The species composition and purity of hemicellulose extract was analyzed by High Performance Liquid Chromatography (HPLC). The obtained solid remainder was analyzed by FTIR and SEM. The results showed that the component of xylose in hemicellulose extract was similar with commercial xylan. FTIR and SEM were shown to be able to evaluate solid remainder composition and surface characterization of the bagasse. The biggest balance between solid remainder and dissolved solid was obtained. Not only the yield of dissolved solid was improved, but the structure of solid remainder was also proved, which was beneficial to pulping and papermaking.
研究领域:
化学工程
·
材料科学
·
生物化工
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2021
·
IF 4.43
Hafezeh Nabipour,Xin Wang,Sadia Batool,Lei Song,Yuan Hu
A phosphaphenanthrene-containing vanillin-derived compound (VDG) was synthesized by a one-pot nucleophilic addition reaction from vanillin , 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), and 3,5‐diamino‐1,2,4‐triazole. The molecular structure of VDG was characterized by Fourier transform infrared (FTIR), and 1 H, 13 C, and 31 P nuclear magnetic resonance (NMR) spectrometer. Various loadings of VDG were incorporated into diglycidyl ether of bisphenol A (DGEBA) as a co-curing agent together with 4, 4′-diaminodiphenylmethane (DDM) to produce an epoxy thermoset . The thermomechanical, thermal and fire-retardant properties of EP thermosets were evaluated by dynamic mechanical analyzer (DMA), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), limiting oxygen index (LOI), UL-94, and cone calorimetry . The results showed that a linear decrease in glass transition temperature with increasing loading of VDG owing to the declined cross-linking density. The cured DGEBA/DDM system with 2.0 wt% of VDG exhibited super anti-flammability in terms of a high LOI value of 37.0% and UL-94 V-0 rating, whereas the cured DGEBA/DDM and DGEBA/DDM with 2.0 wt% of DOPO systems showed no rating in UL-94 test. In addition, cone calorimetry test showed that the cured DGEBA/DDM system with 2.0 wt% of VDG exhibited a reduction of up to 47.5% and 34% for peak heat release rate and total heat release, respectively, compared to the cured DGEBA/DDM system. The enhanced flame-retardant property was attributed to the formation of the compact and continual structure of char layer residue with good thermo-oxidative stability. In addition to good anti-flammability, the cured DGEBA/DDM/VDG thermoset showed antibacterial property against E. coli , with an inhibition zone diameter of 10 mm. Thus, this bio-based co-curing agent could impart flame-retardant and antibacterial performance to epoxy for developing high performance functional thermosetting materials.
研究领域:
材料科学
·
化学
·
高分子科学
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消防安全工程
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生物技术
✓ 已验证
产品关联
DOI
高影响因子
ENERGY & FUELS
·
2018
·
IF 3.024
Yang Peng,Xiangjiang Liu,Xun Gong,Xiaomin Li,Yifu Liu,Erwei Leng,Yang Zhang
In this study, three kinds of monocarboxylic acids, formic, acetic, and propionic acids, are first applied to modified microalgae residuals (M1-RD, M2-RD, and M3-RD, respectively) after lipid extraction, aiming to enhance the adsorption capacity and selective binding ability for Hg(II) ions in simulated wastewater. The effect of pH, temperature, and initial Hg(II) concentration was investigated to identify the optimum adsorption conditions. Batch adsorption tests showed that the maximum adsorption efficiency obtained was 96.7% for M1-RD, 91.1% for M2-RD, and 84.4% for M3-RD at pH 4.05 compared to 48.5 and 57.6% for raw and residual microalgae at pH 5.01, respectively. The adsorption capacity of raw, residual, and modified microalgae increased with the increase of the temperature. Langmuir and Freundlich isotherm model tests showed that the maximum equilibrium adsorption capacity among three modified adsorbents reached 63 ± 3 mg/g for M1-RD, in contrast to 17 ± 1 and 25 ± 2 mg/g for raw and residual microalgae, respectively. The characterization of the modified sample by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller, and scanning electron microscopy showed that the fibrous structure of the algae was decomposed by carboxyl groups in organic acids involved in microalgae, resulting in a larger surface area and more binding sites. In consideration of ion interference in the actual process, a kind of actual desulfurization wastewater from a 1000 MW coal-fired power plant (Guangdong, China) was introduced in the simulated adsorption system. Verification tests in desulfurization wastewater showed that up to 96% of Hg(II) ions were removed, probably as a result of co-precipitation of mercury and other co-existing ions.
研究领域:
环境科学
·
化学工程
·
废水处理
·
材料科学
✓ 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）