scholarly journals Effects of Ultrasound Pretreatment on Eucalyptus Thermal Decomposition Characteristics As Determined by Thermogravimetric, Differential Scanning Calorimetry, and Fourier Transform Infrared Analysis

ACS Omega ◽  
2018 ◽  
Vol 3 (6) ◽  
pp. 6611-6616 ◽  
Author(s):  
Zhengbin He ◽  
Jing Qian ◽  
Zhenyu Wang ◽  
Songlin Yi ◽  
Jun Mu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Fourier Transform ◽  
Fourier Transform Infrared ◽  
Infrared Analysis ◽  
Scanning Calorimetry ◽  
Ultrasound Pretreatment

scholarly journals Comparative thermal research on tetraazapentalene-derived heat-resistant energetic structures

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jing Zhou ◽  
Li Ding ◽  
Yong Zhu ◽  
Bozhou Wang ◽  
Xiangzhi Li ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Fourier Transform ◽  
Energetic Materials ◽  
Great Influence ◽  
Fourier Transform Infrared ◽  
Thermal Decomposition Mechanism ◽  
Scanning Calorimetry ◽  
In Situ Ftir Spectroscopy ◽  
Heat Resistant

AbstractOrganic inner salt structures are ideal backbones for heat-resistant energetic materials and systematic studies towards the thermal properties of energetic organic inner salt structures are crucial to their applications. Herein, we report a comparative thermal research of two energetic organic inner salts with different tetraazapentalene backbones. Detailed thermal decomposition behaviors and kinetics were investigated through differential scanning calorimetry and thermogravimetric analysis (DSC-TG) methods, showing that the thermal stability of the inner salts is higher than most of the traditional heat-resistant energetic materials. Further studies towards the thermal decomposition mechanism were carried out through condensed-phase thermolysis/Fourier-transform infrared (in-situ FTIR) spectroscopy and the combination of differential scanning calorimetry-thermogravimetry-mass spectrometry-Fourier-transform infrared spectroscopy (DSC-TG-MS-FTIR) techniques. The experiment and calculation results prove that the arrangement of the inner salt backbones has great influence on the thermal decompositions of the corresponding energetic materials. The weak N4-N5 bond in “y-” pattern tetraazapentalene backbone lead to early decomposition process and the “z-” pattern tetraazapentalene backbone exhibits more concentrated decomposition behaviors.

Curing behaviors of cyanate ester/epoxy copolymers and their dielectric properties

2016 ◽  
Vol 29 (10) ◽  
pp. 1175-1184 ◽  
Author(s):  
Yangxue Lei ◽  
Mingzhen Xu ◽  
Mingli Jiang ◽  
Yumin Huang ◽  
Xiaobo Liu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Thermal Decomposition ◽  
Fourier Transform ◽  
Dielectric Properties ◽  
Small Extent ◽  
Dielectric Constants ◽  
Cyanate Ester ◽  
Scanning Calorimetry ◽  
Peak Fitting ◽  
Curing Kinetic

The curing behavior and dielectric properties of cyanate ester/epoxy (EP) with a latent initiator imidazole was investigated as a function of blend composition. Differential scanning calorimetry (DSC) was used to investigate the dynamic cure behavior of the blends. Multiheating rate DSC, peak fitting, and iso-conversion method were applied to analyze the curing kinetic parameters. Two distinct peaks were fitted from the dynamic DSC curve and the activation energies of each reaction varied with the increase of curing degrees. Fourier transform infrared spectra revealed that several reactions coexisted during the curing processes of cyanate and EP, resulting in the coexistence of the polymers and copolymers in the final composites. The dielectric properties of the composites were studied and the phenomenon that the dielectric constants for all of the composites are independent of frequency was observed. The thermal decomposition characteristics of the blends were investigated using thermogravimetric analysis. By increasing the content of EP, the thermal properties of the cured blends were improved to a small extent, while the char yield markedly decreased.

scholarly journals New insight into single phase formation of capric acid/menthol eutectic mixtures by Fourier-transform infrared spectroscopy and differential scanning calorimetry

2020 ◽  
Vol 19 (2) ◽  
pp. 361-369 ◽  
Author(s):  
Hiba H. Ali ◽  
Mowafaq M. Ghareeb ◽  
Mayyas Al-Remawi ◽  
Faisal T. Al-Akayleh
Keyword(s):  
Differential Scanning Calorimetry ◽  
Hydrogen Bond ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Bond Formation ◽  
Capric Acid ◽  
Fourier Transform Infrared ◽  
Scanning Calorimetry ◽  
Hydrogen Bond Formation

Purpose: To examine the structural changes of a eutectic mixture comprising capric acid and menthol which are commonly used in pharmaceutical applications. Methods: A phase diagram was constructed by quantitative mixing of capric acid and menthol under controlled conditions until a single liquid phase was formed. Eutectic mixtures of capric acid: menthol at the ratios of 3:2, 1:4, 1:1, 2:3, and 1:4 were prepared. Hydrogen bond formation and conformational changes were analyzed using Fourier-transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC). Microscopic imaging was carried out to capture phase change events upon increasing temperature. Results: Menthol confirmed the intact structure of a hexagonal ring. The high degree of broadening of the menthol O-H groups indicates hydrogen bond formation. FTIR band changes related to capric acid suggest a break-up of the methylene arrangement structure due to changes in the C-H band frequencies. The red shift encountered in C=O stretching band emphasizes hydrogen bond formation taking place between the oxygen atom of the hydroxyl group comprising the carboxylic moiety of capric acid and the hydrogen atom of menthol hydroxyl group. DSC results indicate the presence of two polymorphs of the capric acid/ menthol complex. Both exhibited crystallization and conformational change exotherms in addition to two melting endotherms as result of transformation of crystalline components to become partially crystalline due to hydrogen bond formation. Conclusion: The interaction between capric acid and menthol results in a typical preparation of deep eutectic systems that can act as natural-based solvents in numerous pharmaceutical applications. Keywords: Eutectic system, Capric acid, Menthol, Differential scanning calorimetry, DSC, Fourier transform infrared spectroscopy, FTIR

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