THERMOCHIMICA ACTA
·
2013
·
IF 1.989
Haisu Gao,Liping Chen,Wanghua Chen,Shilong Bao
The thermal stability of β-artemether under dynamic, isothermal and adiabatic conditions were investigated by differential scanning calorimeter (DSC) and accelerating rate calorimeter (ARC), respectively. The dynamic DSC measurements at various heating rates (1, 2, 4 and 8 °C min −1 ) displayed that β-artemether experienced polymorph transformation in the melting process. According to the isothermal DSC results at different temperatures 86, 88, 90 and 92 °C, β-artemether decomposed after the completion of the melting and the polymorph transformation, and the thermal decomposition of β-artemether is hazardous for its characteristic of autocatalytic decomposition. The kinetics analysis dynamically and isothermally described by Friedman method indicated the thermal decomposition of β-artemether did not comply with a single mechanism. The ARC results showed that the pressure increased with the increase of temperature, and indicated obvious linear relationship. Based on the ARC data, the value of SADT of β-artemether in 50 kg package was obtained.
研究领域:
药学
·
化学
✓ 已验证
DOI
高影响因子
THERMOCHIMICA ACTA
·
2016
·
IF 1.938
Jianhua Hu,Jiye Shan,Jianqing Zhao,Zhen Tong
The isothermal curing kinetics of a flame-retardant epoxy resin containing DOPO (1.5 wt% of phosphorus) with hardener DICY was investigated using differential scanning calorimetry and oscillatory shear rheometry. The glass transition temperature T g increased with conversion α measured by DSC. When the curing temperature is lower than T g ∞ of the completely cured epoxy, the curing kinetics at high α became diffusion-control due to that cured epoxy restricted the diffusion of the reactants to decelerate curing. The modified Kamal model including the diffusion factor described curing conversion rate curves quite well. The curing degree θ was established with relative storage modulus, which was measured by the cyclic frequency sweep, and revealed that the transition from liquid to solid during curing appeared later with a slower rate than that for the conversion change, because the network began to form after formation of branched polymer chains. At the modulus transition time, the epoxy samples cured at different temperatures had the same conversion of 0.409, indicating that above this conversion of reactants the effective network was formed to bear the stress.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF ANALYTICAL AND APPLIED PYROLYSIS
·
2022
·
IF 6.437
Jianwei Zhang,Ling Chen,Liangyou Zhao,Guorui Jin,Weidong He
Nitrogen heterocycles as Nitrogen-rich energetic material has been widely popularized due to their desirable properties like low sensitivities, excellent stability, and lower environmental impact, less erosive and less toxic combustion gases , especially in gun propellant application areas. The focus of this study is on investigating interaction mechanism of 1 H-tetrazole (1 H-TZ) and nitrocellulose (NC) by kinetics methods and TG-DSC-FTIR analysis. The mixture (NC-TZ) between 1 H-TZ and NC was prepared by means of physical blending. DSC experiments indicated that the open and closed environment can generate different and important influence on the chemical reaction between 1 H-TZ and NC. Combined with the change of activation energy , it illustrated that the gas 2 H-tetrazole, the isomer of 1 H-TZ, had a significant influence on the thermal decomposition of NC. In comparison with kinetic models of NC and NC-TZ, it can be found that the addition of 1 H-TZ mainly affected the contribution factor and m value in the first stage. The value of m decreased from 1.00 to 0.15, meanwhile, the contribution factor was decreased from 0.50 to 0.12. It showed that NO 2 , the initial decomposition product of NC, had taken part in the thermal decomposition process of 1 H-TZ. TG-DSC-FTIR experiments indicated that there was a chemical reaction between 2 H-tetrazole and the initial decomposition product of NC, NO 2 , to form CO, N 2 O and HN 3 .
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
RENEWABLE ENERGY
·
2022
·
IF 8.634
Lu Liu,Xuelai Zhang,Xiangwei Lin
Benefitting from high storage density, phase change material (PCM) has been widely utilized in cold chain logistics. However, the phase change process of composites is normally non-isothermal, which will lead to phase change hysteresis (PCH). The exploration of the mechanism and influence factors of PCH remains a huge challenge. In this paper, a nanocomposite PCM (NCPCM) based on paraffin (PA) was prepared to address this issue via the two-step method. Here, the applications of multi-walled carbon nanotubes (MWCNTs) and sodium dodecylbenzene sulfonate (SDBS) were contributed to the enhancement of thermal conductivity and suspension stability. Subsequently, after various characterization techniques, the results showed that thermal conductivity of the NCPCM with 1.0 wt% MWCNTs and a 2:1 mass ratio of MWCNTs and SDBS increased by 1.86 times. Moreover, the NCPCM exhibited high thermal charging-discharging efficiency, thermal stability, and cyclic stability. More importantly, the PCH has been studied via the dynamic differential scanning calorimetry (DSC) method. The effects of temperature range, temperature changing rate, and sample mass on the hysteresis degree were investigated. Furthermore, the PCH was interpreted in terms of energy storage, temperature delay, internal thermal resistance , crystallinity , and interfacial free energy . It was proved that the NCPCM possesses a smaller hysteresis degree when the temperature range was −40–50 °C, temperature changing rate was 10 K min −1 , and sample mass was within 10 mg.
研究领域:
材料科学
·
热能工程
✓ 已验证
产品关联
DOI
高影响因子
BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Yuan Zhang,Liping Kang,Hongmei Li,Xianzhang Huang,Xiaoyu Liu,Lanping Guo,Luqi Huang
The combustion of moxa floss was investigated by thermogravimetric/differential scanning calorimeter (TG/DSC), thermogravimetric/Fourier transform infrared spectroscopy (TG-FTIR) and an infrared radiation spectrum-detecting system. The average mass loss rate at the major stage of combustion was 1.08%/min with a peak at 7.86%/min. Moxa floss burning released the integral heat of 9188 mJ/mg from the temperature of 200 °C to 500 °C. The peak heat flow during char combustion stage was higher than those of other stages. The results indicated the combustion of moxa floss was a mild and slow process, releasing heat continuously and steadily. The infrared radiation spectra of burning moxa stick were in a range of 2.5–13.0 µm and showed double peaks at 3.75 µm and 8.75 µm. Thus, this study provided insight into why moxa floss biomass is the optimal material for thermal therapy and is beneficial for the development of electric thermal stimulation alternative.
研究领域:
热疗研究
·
生物医学工程
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
POLYMER
·
2024
·
IF 4.1
Biao Yang,Baomin Fan,Huifang Wang,Yuhong Ma
The isothermal crystallization behavior and kinetics of poly( l -lactic acid) (PLLA) melt-blended small amounts (0.7%–1%) of polyols (D-mannitol, D-sorbitol, and xylitol) were investigated by differential scanning calorimetry (DSC), and the interaction between polyols and PLLA was clarified via multiscale theoretical simulations. The decreased peak crystallization time and full width at half peak maximum ( FWHM ) of polyol-modified PLLA indicates that the crystallization capability of PLLA was improved, and the process was accelerated. The crystallinity remains unchanged before and after modification at the same temperature. The Avrami exponent ( n ) is largely unaffected, indicating that polyols as nucleation accelerants hardly alter the nucleation and growth mechanisms of PLLA crystallization. The outputs of long-term molecular dynamics simulations were fulfilled toward large-scale periodic models for three polyol-PLLA models that involved over 20,000 atoms. Therein, the interaction energies and the derived radial distribution function (RDF) implied the hydrogen bonding occurred between polyol and PLLA. To visualize the interaction sites between the polyol and PLLA, the frontier orbital distributions of the polyols were further calculated according to density functional theory (DFT). Theoretical evidence suggests that polyols improve the crystallization capability of PLLA by hydrogen bonding between the terminal hydroxyl group and the carbonyl oxygen of PLLA.
研究领域:
材料科学
·
高分子科学
·
物理化学
·
计算化学
✓ 已验证
产品关联
DOI
高影响因子
THERMOCHIMICA ACTA
·
2026
·
IF 3.6
Yongxuan Chen,Wenbing Hu
Anisotropic thermal conductivities of thin films of thermal conductive composites are important properties in thermal management of micro-electronic devices. In Flash DSC measurements, we positioned the specimens in edge-on and flat-on configurations on the chip sensor, and characterized the corresponding in-plane and cross-plane thermal conductivities of epoxy composite hot-pressed films with 5 wt% and 10 wt% carbon fiber loadings. The results demonstrated that increasing the fiber content up to 10 wt% significantly enhances the thermal conductivity from the pure epoxy (0.21 ± 0.01) to the in-plane composite (1.7 ± 0.1) W·m -1 ·K -1 with an in-plane to cross-plane conductivity ratio of approximately 2.0. The results indicated that the hot-pressing processing makes the preferential alignment of carbon fibers along the in-plane direction to enhance the anisotropic thermal conductivity. This work extends the application of Flash DSC measurement to the anisotropic thermal conductivity characterization of microscale-thick composite films.
✓ 已验证
DOI
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2024
·
IF 5.9
Yinhai Pan,Du Wei,Shuo Yao,Haijun Zhang,Quanzhi Tian
Coal gasification slag (CGS) is rich in Li and Ga. However, few studies have focused on the extraction of Li and Ga from CGS. In the present study, the leaching of Li and Ga from CGS calcined with the alkali reagents including NaOH, KOH, Na 2 O 2 , Na 2 CO 3 and K 2 CO 3 were studied through water leaching and solid characterizations including XRD, TG-DSC and NMR. The best leaching percentages of Li and Ga from NaOH-, KOH-, Na 2 O 2 -, Na 2 CO 3 - and K 2 CO 3 -roasted products were 40.81% and 47.89%, 41.19% and 31.60%, 28.04% and 52.40%, 28.21% and 48.58%, and 34.29% and 38.61%, respectively, showing Li and Ga are difficult to be leached out. It has been proven that the formation of insoluble crystal substances (such as NaAlSiO 4 ) in alkali fusion products inhibits the leaching of Li and Ga. In addition, Li and Ga can be released from the insoluble crystal substances due to Na 2 SiO 3 in alkali fusion products can promote the dissolution of insoluble crystal substances into SiO 4 and AlO 4 species, which can improve the leaching of Li and Ga. However, part of the released Li and Ga are stabled in the structure of amorphous substances generated by SiO 4 and AlO 4 species in the form of isomorphism, reducing the leaching of Li and Ga. Thus, this work would provide guidance for the leaching of Li and Ga from CGS.
研究领域:
化学工程
·
材料科学
·
环境科学
✓ 已验证
DOI
高影响因子
IRONMAKING & STEELMAKING
·
2026
·
IF 2.1
Jiawen Chen,Liang Yu,Shipeng Xu,Yu Wan
As a crucial functional material in the continuous casting process, mould fluxes play a significant role in ensuring smooth operation and improving the quality of cast billets. To mitigate the environmental impact of fluorides in mould fluxes, TiO2 has been introduced as a network former to reduce viscosity and melting temperature. The formation of perovskite instead of cuspidine also contributes to controlled heat transfer. However, preventing the formation of titanium carbide (TiC) under high-temperature conditions remains challenging. Experimental results indicate that during heating, both CaO–SiO2–TiO2 and CaO–SiO2–CaF2–TiO2 slag systems react to form perovskite. TiO2 participates more readily in solid-state reactions with CaO than CaF2 does, thereby inhibiting the formation of cuspidine. Furthermore, in carbon-containing CaO–SiO2–TiO2 systems, TiC forms along with CO at elevated temperatures. It is revealed that TiC formation does not result from the direct reaction between TiO2 and C, but rather from the reaction between CaTiO3 and C. Under high-temperature carbon-rich conditions, carbon reduces perovskite to form TiC. Consequently, in contrast to fluorine-based fluxes, titanium-bearing mould fluxes require careful optimisation of carbon content to prevent TiC precipitation.
✓ 已验证
DOI
高影响因子
Applied Sciences-Basel
·
2026
·Vol. 16
·期 9
·4152
·
IF 2.9
Jianyi Liu,Yang Cao
In the process of extracting and transporting waxy crude oil, pipeline blockages resulting from wax deposition significantly impede production efficiency and lead to substantial economic losses. Ethylene vinyl acetate copolymer (EVA) is a widely used chemical wax inhibitor; however, its performance is influenced by multiple factors, including its molecular structure, concentration, and the carbon number distribution of the wax system. A systematic elucidation of its mechanism of action and associated phase changes is therefore necessary. In this study, differential scanning calorimetry (DSC) was employed to systematically investigate the thermal behavior of a wax system with a broad carbon number distribution (C5–C50). The objectives were to analyze the influence of EVA concentration, vinyl acetate (VA) content, and molecular weight on the phase transition parameters, to elucidate the wax inhibition mechanism, and to construct a phase prediction model based on the Flory–Huggins theory. The results demonstrate that the wax appearance temperature (WAT), phase transition temperature, and phase transition enthalpy of the wax systems increase monotonically with carbon number. Furthermore, the addition of EVA was found to significantly reduce both the WAT and the amount of wax precipitated. The optimal structural parameters were identified as a VA content of 10%, a number average molecular weight of 20,000, and an optimal concentration of 800 ppm. The medium-carbon wax system (C16–C30) was found to be the most sensitive to the EVA response. The established phase model exhibited high predictive accuracy, with a mean relative error of less than 4%, a root mean square error (RMSE) of 0.32%, and a coefficient of determination (R2) of 0.987, thereby providing preliminary insights and a practical tool for optimizing EVA wax inhibitor formulations under simplified conditions and guiding their potential engineering applications.
Keywords: EVA wax inhibitor; differential scanning calorimetry; wax deposition; N-alkanes; phase transition behavior; phase model
✓ 已验证
DOI
高影响因子
THERMOCHIMICA ACTA
·
2018
·
IF 2.189
Jun-Cheng Jiang,Li Li,Jia-Jia Jiang,Yan Wang,Siu-Ming Lo,Yong Pan,Xu-Hai Pan,Lei Ni
Tert-butyl peroxybenzoate (TBPB) is thermally unstable organic peroxide, which may cause disasters such as fire or explosion when excessive heat released due to thermal decomposition. Ionic liquid is often used as a catalyst and inhibitor in engineering applications recently. This study investigated the thermal decomposition characteristics of TBPB when added two different ionic liquids which are 1-Propyl-3-methylimidazolium iodide ([PMIM][I]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) respectively with different mass ratio under DSC tests. Characteristic parameters such as the onset exothermic temperature (T 0 ) and heat of decomposition (ΔH d ) of samples were compared. Kinetic parameters such as activation energy E a were computed using two isoconversional methods which were Ozawa method and Friedman method respectively. The model based (zeroth order reaction) estimation method was used to estimate TMR ad at T 0 from non-isothermal DSC measurements to assess the thermal hazard of five samples. The paper aims to study the effect of ionic liquids (ILs) on the thermal decomposition of TBPB and analysis the influence of two ionic liquids on the decomposition mechanism of TBPB.
研究领域:
化学工程
·
安全科学
✓ 已验证
DOI
高影响因子
SEPARATION SCIENCE AND TECHNOLOGY
·
2022
·
IF 2.799
Qingxia Ye,Zhen Li,Jin Liu,Di Wang,Ping Wang,Xianbiao Wang,Xianhai Hu
In this paper, the application of zone smelting to remove the trace heavy metal lead from waste acrylonitrile-butadiene-styrene (wABS) plastics was investigated. ABS standard samples with uniform and stable lead content were prepared by the method of lead stearate coupling agent. The structure, thermal stability, morphology and lead content of the standard ABS samples before and after zone smelting were characterized by FTIR, DSC, SEM and ICP-AES. The results showed that the lead content in the front and middle sections of the ABS sample decreased obviously after zone smelting, while the lead content in the tail increased significantly, and the structure, thermal stability and morphology remained basically unchanged.
研究领域:
材料科学
·
环境工程
·
分析化学
✓ 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）