scholarly journals Evolution Mechanism of Macromolecular Structure in Coal during Heat Treatment: Based on FTIR and XRD In Situ Analysis Techniques

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Dun Wu ◽  
Wenyong Zhang
Keyword(s):  
Heat Treatment ◽  
Infrared Spectroscopy ◽  
Infrared Spectrum ◽  
Functional Groups ◽  
Coal Sample ◽  
Diffraction Peak ◽  
Coal Rank ◽  
Coal Structure ◽  
Temperature Range

Owing to the complexity and heterogeneity of coal during pyrolysis, the ex situ analytical techniques cannot accurately reflect the real coal pyrolysis process. In this study, according to the joint investigation of Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD), the structural evolution characteristics of lignite-subbituminous coal-bituminous coal-anthracite series under heat treatment were discussed in depth. The results of the infrared spectrum of coal show that the different functional groups of coal show different changes with the increase of coal rank before pyrolysis experiment. Based on in situ infrared spectroscopy experiments, it was found that the infrared spectrum curves of the same coal sample have obvious changes at different pyrolysis temperatures. As a whole, when the pyrolysis temperature is between 400 and 500°C, the coal structure can be greatly changed. By fitting the infrared spectrum curve, the infrared spectrum parameters of coal were obtained. With the change of temperature, these parameters show regular changes in coal with different ranks. In the XRD study of coal, the absorption intensity of the diffraction peak (002) of coal increases with increasing coal rank. The XRD patterns of coal have different characteristics at different pyrolysis temperatures. Overall, the area of (002) diffraction peak of the same coal sample increases obviously with the increase of temperature. The XRD structural parameter of coal was obtained by using the curve fitting method. The changing process of two parameters (interlayer spacing (d002) and stacking height (Lc)) can be divided into two main stages, but the average lateral size (La) does not change significantly and remains at the 2.98 ± 0.09 nm. In summary, the above two technologies complement each other in the study of coal structure. The temperature range of both experiments is different, but the XRD parameters of coal with different ranks are reduced within the temperature range of less than 500°C, which reflects that the size of coal-heated aromatic ring lamellae is reduced and the distance between lamellae is also reduced, indicating that the degree of condensation of coal aromatic nuclei may be increased. Correspondingly, the FTIR parameters of coal also reflect that, with increasing temperature, the side chains of coal are constantly cracked, the oxygen-containing functional groups are reduced, and the degree of aromatization of coal may be increased.

Study of Ionic Liquids (AIL and PIL) Viscosity and its Functional Groups under Heat Treatment on Cutting Tool Surface Using Fourier-Transform Infrared Spectroscopy (FTIR)

2020 ◽  
Vol 981 ◽  
pp. 98-103
Author(s):  
Mona Alis Md. Yasser ◽  
Zaidi Embong ◽  
Erween Abdul Rahim ◽  
Amiril Sahab Abdullah Sani ◽  
Kamaruddin Kamdani
Keyword(s):  
Heat Treatment ◽  
Ionic Liquid ◽  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Fourier Transform Infrared Spectroscopy ◽  
Functional Groups ◽  
Cutting Tool ◽  
Fourier Transform Infrared ◽  
Nitrile Group ◽  
Tool Surface

This study was conducted to investigate the efficiency of Minimum Quantity Lubrication (MQL) technique by using Modified Jatropha Oil (MJO) bio-based lubricant with the presence of 10% Ammonium Ionic Liquid (MJO+AIL10%) and 1% Phosphonium Ionic Liquid (MJO+PIL1%) additives respectively at various temperature of 200 °C, 300 °C and 400 °C heat treatment to determine the ability to exhibit corrosion and wear throughout the process. Fourier-Transform Infrared Spectroscopy (FTIR) analysis revealed prominent peaks of functional groups in these bio-lubricants; esters (C-O) and (C=O), alkanes (C-H), hydroxide (O-H), and nitrile groups deposited on the cutting tool surface. Initially, nitrile group is detected on cutting tool surface without lubricants at 2200 to 2300 absorption band reduced to lower intensity and most likely concealed by MJO+AIL10% compared to MJO+PIL1% where the nitrile group remains reflected in FTIR spectrum. In this work, it is proved that MJO+AIL10% has higher viscosity as compared to MJO+PIL1%. in the context of functional groups and supported the previous study on MJO+AIL10% as corrosion inhibitor.

An Alternate Mechanism for Porous Si Photoluminescence: Recombination in SiHx Complexes

1991 ◽  
Vol 256 ◽  
Author(s):  
S. M. Prokes ◽  
O. J. Glembocki ◽  
V. M. Bermudez ◽  
R. Kaplan ◽  
L. E. Friedersdorf ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Porous Silicon ◽  
Hydrogen Content ◽  
Hydrogen Desorption ◽  
Porous Si ◽  
Temperature Range ◽  
Silicon Hydrides ◽  
Alternate Mechanism ◽  
Pl Intensity

ABSTRACTPorous silicon layers have been formed which exhibit photoluminescence (PL) peaks that do not blueshift with increasing porosity. Hydrogen desorption experiments have been performed in vacuum under anneals between 230°C–390°C. Simultaneous, in-situ PL measurements show that the PL intensity decreases and disappears with decreasing hydrogen content. Infrared spectroscopy (IR) measurements also show loss of hydride species in the same temperature range. These results indicate that hydrogen is important in the PL process. We suggest that silicon hydrides are the source of PL in porous SI.

scholarly journals Effects of Maceral Compositions of Coal on Methane Adsorption Heat

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Yingke Liu ◽  
Jianhong Kang ◽  
Fubao Zhou ◽  
Yanming Fan ◽  
Haijian Li
Keyword(s):  
Functional Groups ◽  
Pore Volume ◽  
Coal Sample ◽  
Methane Adsorption ◽  
Adsorption Heat ◽  
Coal Rank ◽  
Coal Ranks ◽  
Chinese Coal ◽  
Content Of Oxygen

The role of maceral compositions (vitrinite and inertinite) in the adsorption characteristics of coal has not been fully understood in terms of energy. In this study, using a microcalorimeter, the adsorption heat of maceral compositions for methane is directly measured for five groups of Chinese coal samples with different coal ranks. The results show that the adsorption heat of the maceral concentrates varies with increasing coal rank, but for the same coal sample, the vitrinite concentrates have a higher adsorption heat than the inertinite concentrates. Furthermore, the adsorption heat of both vitrinite and inertinite concentrates is highest at the long-flame coal stage. This finding indicates that the coalification and maceral compositions have significant effects on the adsorption heat of coal for methane. It is observed that although the inertinite concentrates have a larger pore volume, they are less microporous than their rank equivalent vitrinite concentrates, resulting in lower adsorption heat. Furthermore, it is revealed that the adsorption heat of both vitrinite and inertinite concentrates is primarily correlated to the content of oxygen-containing functional groups and aliphatic hydrocarbons.

scholarly journals THERMAL STABILITY AND POROSITY OF HYPER-CROSSLINKED AROMATIC POLYMERS

2020 ◽  
pp. 62-72
Author(s):  
Алексей Владимирович Быков ◽  
Галина Николаевна Демиденко
Keyword(s):  
Mass Spectrometry ◽  
Thermal Stability ◽  
Infrared Spectroscopy ◽  
Functional Groups ◽  
Polymer Matrix ◽  
Photoelectron Spectroscopy ◽  
Diffuse Reflection ◽  
Microporous Structure ◽  
X Ray ◽  
Temperature Range

В работе методами сопряженной с масс-спектрометрией термогравиметрии, физической адсорбции азота, инфракрасной спектроскопии диффузного отражения и рентгенофотоэлектронной спектроскопии проведено исследование изменений пористости и состава функциональных групп полимера MN270 в температурном диапазоне от 30 до 600С. В ходе исследования показано, что при разогреве ненаполненного металлами полимера его микропористая структура рушится при температурах ниже 300С, в то время как разрушение, связанное с деструкцией и деполимеризацией самой полимерной матрицы, происходит при температурах выше 350С. Thermogravimetry coupled with mass spectrometry, nitrogen physisorption, diffuse reflection infrared spectroscopy, and x-ray photoelectron spectroscopy were used to study changes in the porosity and composition of functional groups of the MN270 polymer in the temperature range from 30 to 600C. The study shows that when an unfilled with metals polymer is heated, its microporous structure collapses at temperatures below 300C, while the destruction associated with the destruction and depolymerization of the polymer matrix occurs at temperatures above 350C.

scholarly journals Исследование структуры бивня мамонта методом ИК спектроскопии

2022 ◽  
Vol 130 (3) ◽  
pp. 369
Author(s):  
В.В. Павлова ◽  
Е.С. Петухова ◽  
Т.А. Исакова ◽  
Е.С. Колесова ◽  
А.А. Чириков ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Infrared Spectroscopy ◽  
Functional Groups ◽  
Ir Spectrum ◽  
Absorption Bands ◽  
Organic Part ◽  
Characteristic Absorption ◽  
Carbonate Anion

The structure of mammoth tusk was investigated by infrared spectroscopy, including after heat treatment. The whole complex of functional groups of the tusk components - hydroxyapatite, collagen and water - was revealed. It was found that collagen in the IR spectrum is represented mainly by characteristic absorption bands of amide and aliphatic groups. After heat treatment at 600 °C, the organic part is completely removed from the sample. It was found that hydroxyapatite in mammoth tusk is presented in a carbonate-substituted form, however, heat treatment at 900 °C leads to the removal of carbonate anion and water from the sample, which is accompanied by the transition of hydroxyapatite from the nonstoichiometric state to the stoichiometric state.

Research of Interface of Carbon Fiber Reinforced PA6 by In-Situ Anionic Polymerization

2013 ◽  
Vol 634-638 ◽  
pp. 2028-2031
Author(s):  
Hong Kai Zhao ◽  
Li Guang Xiao ◽  
Jing Wu Gao
Keyword(s):  
Heat Treatment ◽  
Composite Material ◽  
Functional Groups ◽  
Carbon Fibers ◽  
Fiber Strength ◽  
Fiber Surface ◽  
Interface Layer ◽  
High Polymer ◽  
Activating Agent

High polymer active functional groups can be grafted on the surface of carbon fibers so as to adjust the interface effect between fibers in the composite material and resin and improve the performance of composite material, by controlling the structure of grafted high polymer, the interface layer with intended performance can be well designed. Heat treatment does not affect the fiber strength, the content of functional groups on the surface of the fibers reaches the max. value around 1h. There are no macromolecules polymerized and grafted on the surface of carbon fibers not subjected to isocyanate grafting treatment. Through isocyanate treatment after heat treatment, it can be obviously seen that the nylon molecules are grafted on the fiber surface. When no activating agent is added in the polymerized monomers, the resin grafting percent of fiber surface can reach 18.8%; when 0.003 activating agent (mole ratio of it to monomers) is added in the monomers, the grafting percent of PA6 on surface of carbon fibers is only 7.65%, this is the result of reactive competition on the interface between monomer matrix and fibers.

The reaction of amorphous Ni-Nb films with Si in the presence of a native SiO2 layer

1990 ◽  
Vol 48 (4) ◽  
pp. 664-665
Author(s):  
N. Rozhanski ◽  
A. Barg
Keyword(s):  
High Temperature ◽  
Crystallization Temperature ◽  
Diffusion Barriers ◽  
Sio2 Layer ◽  
Si Substrate ◽  
Cross Sectional ◽  
Plan View ◽  
Temperature Range ◽  
Sputter Deposited

Amorphous Ni-Nb alloys are of potential interest as diffusion barriers for high temperature metallization for VLSI. In the present work amorphous Ni-Nb films were sputter deposited on Si(100) and their interaction with a substrate was studied in the temperature range (200-700)°C. The crystallization of films was observed on the plan-view specimens heated in-situ in Philips-400ST microscope. Cross-sectional objects were prepared to study the structure of interfaces.The crystallization temperature of Ni5 0 Ni5 0 and Ni8 0 Nb2 0 films was found to be equal to 675°C and 525°C correspondingly. The crystallization of Ni5 0 Ni5 0 films is followed by the formation of Ni6Nb7 and Ni3Nb nucleus. Ni8 0Nb2 0 films crystallise with the formation of Ni and Ni3Nb crystals. No interaction of both films with Si substrate was observed on plan-view specimens up to 700°C, that is due to the barrier action of the native SiO2 layer.

Reductive Cleavage of Secondary Sulfonamides: Converting Terminal Functional Groups into Versatile Synthetic Handles

2019 ◽  
Author(s):  
Patrick Fier ◽  
Suhong Kim ◽  
Kevin M. Maloney
Keyword(s):  
Functional Groups ◽  
Late Stage ◽  
Reductive Cleavage ◽  
Bioactive Molecules ◽  
General Method

Sulfonamides are pervasive in drugs and agrochemicals, yet are typically considered as terminal functional groups rather than synthetic handles. To enable the general late-stage functionalization of secondary sulfonamides, we have developed a mild and general method to reductively cleave the N-S bonds of sulfonamides to generate sulfinates and amines, components which can further react <i>in-situ</i> to access a variety of other medicinally relevant functional groups. The utility of this platform is highlighted by the selective manipulation of several complex bioactive molecules.

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