scholarly journals A Promising Thermodynamic Study of Hole Transport Materials to Develop Solar Cells: 1,3-Bis(N-carbazolyl)benzene and 1,4-Bis(diphenylamino)benzene

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 381
Author(s):  
Juan Mentado-Morales ◽  
Arturo Ximello-Hernández ◽  
Javier Salinas-Luna ◽  
Vera L. S. Freitas ◽  
Maria D. M. C. Ribeiro da Silva
Keyword(s):  
Hole Transport ◽  
Enthalpies Of Formation ◽  
Thermochemical Study ◽  
Computational Studies ◽  
Scanning Calorimetry ◽  
Gaseous State ◽  
Melting Temperatures ◽  
Micro Combustion Calorimeter ◽  
Combustion Calorimeter ◽  
The Enthalpy Of Formation

The thermochemical study of the 1,3-bis(N-carbazolyl)benzene (NCB) and 1,4-bis(diphenylamino)benzene (DAB) involved the combination of combustion calorimetric (CC) and thermogravimetric techniques. The molar heat capacities over the temperature range of (274.15 to 332.15) K, as well as the melting temperatures and enthalpies of fusion were measured for both compounds by differential scanning calorimetry (DSC). The standard molar enthalpies of formation in the crystalline phase were calculated from the values of combustion energy, which in turn were measured using a semi-micro combustion calorimeter. From the thermogravimetric analysis (TGA), the rate of mass loss as a function of the temperature was measured, which was then correlated with Langmuir’s equation to derive the vaporization enthalpies for both compounds. From the combination of experimental thermodynamic parameters, it was possible to derive the enthalpy of formation in the gaseous state of each of the title compounds. This parameter was also estimated from computational studies using the G3MP2B3 composite method. To prove the identity of the compounds, the 1H and 13C spectra were determined by nuclear magnetic resonance (NMR), and the Raman spectra of the study compounds of this work were obtained.

scholarly journals Thermochemistry of Eight Membered Ring Hydrocarbons. The Enthalpy of Formation of Cyclooctane

2001 ◽  
Vol 71 (3) ◽  
pp. 507-515
Author(s):  
Daniela Gheorghe ◽  
Ana Neacsu ◽  
Stefan Perisanu
Keyword(s):  
Differential Scanning Calorimetry ◽  
Liquid Phase ◽  
Phase Change ◽  
Enthalpy Of Formation ◽  
Membered Ring ◽  
Heat Of Combustion ◽  
Enthalpies Of Formation ◽  
Scanning Calorimetry ◽  
Solid Liquid ◽  
The Enthalpy Of Formation

A new value of the enthalpy of formation of cyclooctane (-156.2�1.2 kJ mol-1) based on heat of combustion measurements is reported. Its solid - liquid phase change was investigated by differential scanning calorimetry in both directions revealing an overcooling effect of over 23 K. Our enthalpy of formation of cyclooctane was used together with literature values of heats of hydrogenation of 8 carbon atoms cycloolefins to calculate the enthalpies of formation of the later. The strain energies of the investigated molecules were calculated and discussed.

A low-temperature technique for measuring enthalpies of formation

1996 ◽  
Vol 11 (6) ◽  
pp. 1403-1409 ◽  
Author(s):  
T. P. Weihs ◽  
T. W. Barbee ◽  
M. A. Wall
Keyword(s):  
Low Temperature ◽  
Enthalpy Of Formation ◽  
Enthalpies Of Formation ◽  
Scanning Calorimetry ◽  
Free Standing ◽  
Metal Compounds ◽  
Si Substrates ◽  
Multilayer Foils ◽  
Formation Enthalpies ◽  
The Enthalpy Of Formation

A technique to accurately measure the formation enthalpies of transition metal compounds at relatively low temperatures using thick multilayer foils and differential scanning calorimetry is demonstrated. The enthalpy of formation of Cu51Zr14 was measured using 25 μm thick, free-standing Cu–Zr multilayer foils. The multilayers were deposited onto Si substrates using a planetary, magnetron source sputtering system. They were removed from their substrates, cut into 6 mm diameter specimens, and scanned in temperature from 50 °C to 725 °C in a differential scanning calorimeter. Three distinct exothermic reactions were systematically observed. The heats from the first two reactions were summed and then analyzed using a simple model that accounts for interfacial reactions and heat losses during deposition. The enthalpy of formation for Cu51Zr14 was measured to be 14.3 ± 0.3 kJ/mol. This quantity agrees with the single value of ΔHf = 14.07 ± 1.07 kJ/mol reported in the literature for this Cu–Zr compound. The advantages of measuring formation enthalpies using thick multilayer foils and low temperature calorimetry are discussed.

Thermodynamic properties of montechellite

2019 ◽  
Vol 64 (12) ◽  
pp. 1274-1280
Author(s):  
L. P. Ogorodova ◽  
Yu. D. Gritsenko ◽  
M. F. Vigasina ◽  
A. Yu. Bychkov ◽  
D. A. Ksenofontov ◽  
...  
Keyword(s):  
High Temperature ◽  
Gibbs Energy ◽  
Solution Calorimetry ◽  
Thermochemical Study ◽  
Gibbs Energy Of Formation ◽  
Calvet Microcalorimeter ◽  
Magnesium Orthosilicate ◽  
Calcium And Magnesium ◽  
The Enthalpy Of Formation ◽  
Energy Of Formation

A thermochemical study of natural calcium and magnesium orthosilicate ─ monticellite (Ca1.00Mg0.95)[SiO4] (Khabarovsk Territory, Russia) was carried out on the Tian-Calvet microcalorimeter. The enthalpy of formation from the elements fHоel(298.15 K) = -2238.4 4.5 kJ / mol was determined by the method of high-temperature melt solution calorimetry. The enthalpy and Gibbs energy of formation of monticellite of the theoretical composition of CaMg[SiO4] are calculated: fH0el(298.15 K) = -2248.4 4.5 kJ/mol and fG0el(298.15 K) = -2130.5 4.5 kJ/mol.

scholarly journals Synthesis of a novel aluminium salt of nitrogen-containing alkylphosphinate with high char formation to flame retard acrylonitrile–butadiene–styrene

2020 ◽  
Vol 7 (9) ◽  
pp. 200800
Author(s):  
Xue Yang ◽  
Hao Wang ◽  
Xueqing Liu ◽  
Jiyan Liu
Keyword(s):  
Acrylonitrile Butadiene Styrene ◽  
Infrared Spectrometry ◽  
X Ray ◽  
Ethyl Methyl ◽  
Flame Retardant Properties ◽  
The Fourier Transform ◽  
Micro Combustion Calorimeter ◽  
Combustion Calorimeter ◽  
Composition Of Products ◽  
Butadiene Styrene

A novel nitrogen-containing alkylphosphinate salt—aluminium β-(p-nitrobenzamide) ethyl methyl phosphinate (AlNP) was synthesized and used to flame retard acrylonitrile–butadiene–styrene copolymer (ABS). The Fourier transform infrared spectrometry, 1 H, 13 C and 31 P nuclear magnetic resonance and X-ray fluorescent spectroscopy (XRF) were applied to characterize the structure and composition of products. The flame retardancy performance, thermal properties and mechanical strength of the ABS/AlNP with respect to AlNP loading were investigated. AlNP was stable before 330°C and decomposed very slowly with residues high up to 56.1% at 700°C. Adding 25–30 wt% of AlNP alone can make ABS to pass V0 rating in the vertical burning tests (UL 94). The results according to the micro combustion calorimeter, thermogravimetric analysis showed that AlNP can depress the heating release and retard the thermal degradation of the ABS. Scanning electron microscopy observation of the residues from LOI test indicated that AlNP formed the condensed and tough residues layer during combustion; XRF analysis showed that the residues contained phosphorus and aluminium element and nitrogen element was not detected. The compact phosphorus/aluminium-rich substance acted as a barrier to enhance flame-retardant properties of the ABS.

scholarly journals Chemistry of collagen cross-links: glucose-mediated covalent cross-linking of type-IV collagen in lens capsules

1993 ◽  
Vol 296 (2) ◽  
pp. 489-496 ◽  
Author(s):  
A J Bailey ◽  
T J Sims ◽  
N C Avery ◽  
C A Miles
Keyword(s):  
Type Iv Collagen ◽  
Cross Linking ◽  
Mechanical And Thermal Properties ◽  
Maximum Strain ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Type Iv ◽  
Collagen Molecules ◽  
Cross Links

The incubation of lens capsules with glucose in vitro resulted in changes in the mechanical and thermal properties of type-IV collagen consistent with increased cross-linking. Differential scanning calorimetry (d.s.c.) of fresh lens capsules showed two major peaks at melting temperatures Tm 1 and Tm 2 at approx. 54 degrees C and 90 degrees C, which can be attributed to the denaturation of the triple helix and 7S domains respectively. Glycosylation of lens capsules in vitro for 24 weeks caused an increase in Tm 1 from 54 degrees C to 61 degrees C, while non-glycosylated, control incubated capsules increased to a Tm 1 of 57 degrees C. The higher temperature required to denature the type-IV collagen after incubation in vitro suggested increased intermolecular cross-linking. Glycosylated lens capsules were more brittle than fresh samples, breaking at a maximum strain of 36.8 +/- 1.8% compared with 75.6 +/- 6.3% for the fresh samples. The stress at maximum strain (or ‘strength’) was dramatically reduced from 12.0 to 4.7 N.mm.mg-1 after glycosylation in vitro. The increased constraints within the system leading to loss of strength and increased brittleness suggested not only the presence of more cross-links but a difference in the location of these cross-links compared with the natural lysyl-aldehyde-derived cross-links. The chemical nature of the fluorescent glucose-derived cross-link following glycosylation was determined as pentosidine, at a concentration of 1 pentosidine molecule per 600 collagen molecules after 24 weeks incubation. Pentosidine was also determined in the lens capsules obtained from uncontrolled diabetics at a level of about 1 per 100 collagen molecules. The concentration of these pentosidine cross-links is far too small to account for the observed changes in the thermal and mechanical properties following incubation in vitro, clearly indicating that another as yet undefined, but apparently more important cross-linking mechanism mediated by glucose is taking place.

Thermochemistry of Organic and Heteroorganic Species. Part IX. Photoionization Studies of Isomerization and Fragmentation of Polysubstituted Cyclopropenes: Phenyl-Substituted Cyclopropenes

2000 ◽  
Vol 6 (1) ◽  
pp. 53-64 ◽  
Author(s):  
V.V. Takhistov ◽  
I.N. Domnin ◽  
D.A. Ponomarev
Keyword(s):  
Mass Spectrometry ◽  
Enthalpy Of Formation ◽  
Good Alternative ◽  
Enthalpies Of Formation ◽  
Isodesmic Reactions ◽  
Ion Structure ◽  
Photoionization Mass Spectrometry ◽  
General Methodology ◽  
Fragment Ions ◽  
The Enthalpy Of Formation

Ionization and appearance energies of some fragment ions from 1,2,3-trimethy1-3-phenyl-, 3-methyl-1,2,3-triphenyl-, 1,2-diphenyl-3-methoxycarbonyl-, 1,2,3-triphenyl-3-methoxycarbonyl- and 1,3,3-triphenyl-2-methoxycarbonyl-cyclopropenes were measured by photoionization mass spectrometry. It was shown that in none of these compounds did the fragment ions possess the expected stable substituted cyclopropenium ion structure. Accordingly, possible schemes of molecular ion isomerization are given. The enthalpies of formation of nearly 50 substituted cyclopropenium ions, and ions of related structure, were estimated using series of isodesmic reactions. This publication, together with the previous works of the authors in this Journal, demonstrates the general methodology for estimation of the enthalpy of formation for even-electron ions. It is suggested that the present methodology can provide a good alternative to other estimation or computation procedures applied to the thermochemistry of ions.

Melting and Oxidation of Nanometer Size Aluminum Powders

2005 ◽  
Vol 896 ◽  
Author(s):  
Mikhaylo A Trunov ◽  
Swati Umbrakar ◽  
Mirko Schoenitz ◽  
Joseph T Mang ◽  
Edward L Dreizin
Keyword(s):  
Particle Size ◽  
Oxidation Behavior ◽  
Melting Behavior ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Scanning Calorimetry ◽  
Aluminum Powders ◽  
Melting Temperatures ◽  
X Ray Scattering ◽  
Powder Samples

AbstractRecently, nanometer-sized aluminum powders became available commercially and their use as potential additives to propellants, explosives, and pyrotechnics has attracted significant interest. It has been suggested that very low melting temperatures are expected for nano-sized aluminum powders and that such low melting temperatures could accelerate oxidation and trigger ignition much earlier than for regular, micron-sized aluminum powders. The objective of this work was to investigate experimentally the melting and oxidation behavior of nano-sized aluminum powders. Powder samples with three different nominal sizes of 44, 80, and 121 nm were provided by Nanotechnologies Inc. The particle size distributions were measured using small angle x-ray scattering. Melting was studied by differential scanning calorimetry where the powders were heated from room temperature to 750 °C in argon environment. Thermogravimetric analysis was used to measure the mass increase indicative of oxidation while the powders were heated in an oxygen-argon gas mixture. The measured melting curves were compared to those computed using the experimental particle size distributions and thermodynamic models describing the melting temperature and enthalpy as functions of the particle size. The melting behavior predicted by different models correlated with the experimental observations only qualitatively. Characteristic step-wise oxidation was observed for all studied nanopowders. The observed oxidation behavior was well interpreted considering the recently established kinetics of oxidation of micron-sized aluminum powders. No correlation was found between the melting and oxidation of aluminum nanopowders.

Thermodynamic properties of melts of Bi—Eu system

2021 ◽  
Vol 2021 (2) ◽  
pp. 90-100
Author(s):  
V. S. Sudavtsova ◽  
◽  
V,A, Shevchuk ◽  
L. O. Romanova ◽  
M. I. Ivanov ◽  
...  
Keyword(s):  
Enthalpy Of Mixing ◽  
Enthalpies Of Formation ◽  
Thermochemical Properties ◽  
Melting Temperatures ◽  
Large Size ◽  
Intermediate Phases ◽  
Ideal Solutions ◽  
First Time ◽  
Enthalpy Data ◽  
The Eu

The thermochemical properties of alloys were determined for the first time by calorimetry Bi—Eu system at a temperature of 1200 K in the range of 0 ≤ xBi ≤ 0,2 and 0,77 ≤ xBi ≤ 1,0. It is established that the minimum value of the enthalpy of mixing is equal to –61,7 ± 0,5 kJ / mol at xBi = 0,5. = –184,7 ± 16,7 kJ / mol, = = –206,9 ± 21,8 kJ / mol. The activities of the components were calculated according to the model of an of the ideal associated solution (IAR), using the thermochemical properties of the melts of the Bі—Eu. system. It has been established that the activities of the components show large negative deviations from ideal solutions. To predict the enthalpies of formation of LnBi compounds, the available literature data on these parameters are analyzed and the most reliable ones are presented as a dependence on ∆fH = f(ZLn). It is established that the enthalpies of formation LnBi change smoothly and monotonically with the exception of Bi—Eu and Bi—Yb systems. This is due to the large size factors for the last two systems. To combine all the enthalpy data of Ln—Bi intermetallic formation of Ln—Bi systems depending on the sequence number Ln, we need similar values for the Eu—Bi compound. But at present they are not known, so based on the above, it was assumed that the value of the minimum enthalpy of mixing will be close to the enthalpy of formation of this compound. This hypothesis is confirmed by data on the enthalpies formation of phase YbBi and equiatomic melts of binary of Yb—Bi system. To confirm the thermodynamic data, we compare the known melting temperatures of the formed intermediate phases, known from the diagrams state Bi—Ln system. The obtained dependences correlate with ∆fH = f(ZLn ) і ∆V = f(ZLn). This means that the predictions of thermochemical properties accurately reflect the nature of the considered melts of the Bi—Eu system. Keywords: thermochemical properties, melts, compounds, Bi, Eu.

Microstructural Features and Properties of Al-Cu-Mg Alloy Containing Silver and Cerium

2021 ◽  
Vol 316 ◽  
pp. 533-537
Author(s):  
Pavel L. Reznik ◽  
Boris V. Ovsyannikov
Keyword(s):  
Heat Treatment ◽  
Mechanical Characteristics ◽  
Dendritic Segregation ◽  
Scanning Calorimetry ◽  
Electron Probe Micro Analyzer ◽  
Melting Temperatures ◽  
Heat Treatment Mode ◽  
Cast Condition ◽  
Component Phase ◽  
Non Equilibrium

The article presents the results of an investigation of microstructural features and mechanical characteristics of Al-5.0Cu-0.5Mg alloy containing up to 0.4 wt. % Ag and up to 0.1 wt. % Ce. The experiment was conducted using optical microscopy, Scanning Electron Microscopy as well as an electron probe micro-analyzer and Differential Scanning Calorimetry. Samples in cast condition and after heat treatment were examined. The melting temperatures of non-equilibrium eutectics (non-equilibrium solidus), equilibrium solidus and liquidus were determined. The optimal temperature of the homogenizing heat treatment was determined, which was 500°C. Using this heat treatment mode resulted in the elimination of dendritic segregation and complete dissolution of silver in aluminum. Injection of cerium into the Al-Cu-Mg-Ag system during crystallization of the melt is accompanied by the formation of a coarse four-component phase, which has the morphology of polyhedrons, is on the grain boundaries. The estimation of the relation between microstructure characteristics and mechanical properties of the alloy has been made.

scholarly journals Impact of environmental agents on non-woven polylactide/natural rubber agrofiber

2021 ◽  
Vol 285 ◽  
pp. 07034
Author(s):  
Yulia Tertyshnaya ◽  
Maksim Zakharov ◽  
Alina Ivanitskikh ◽  
Anatoliy Popov
Keyword(s):  
Natural Rubber ◽  
Uv Irradiation ◽  
Thermal Characteristics ◽  
Degree Of Crystallinity ◽  
Distilled Water ◽  
Fibrous Materials ◽  
Scanning Calorimetry ◽  
Melting Temperatures ◽  
Environmental Agents ◽  
The Degree Of Crystallinity

In the work an eco-friendly non-woven fiber made of polylactide and natural rubber with a rubber content from 0 to 15 wt.% was obtained by electrospinning. The influence of distilled water and UV irradiation on the agrofibers has been investigated. The water sorption test showed that the addition of natural rubber into the polylactide matrix does not significantly affect the degree of water absorption of the fibrous materials, which is in the range of 49-50.6%. Thermal characteristics after 180 days of degradation in distilled water at 22±2 oC and UV irradiation at a wavelength of 365 nm during 100 hours were determined using the differential scanning calorimetry. Changes in the values for glass transition and melting temperatures, and the degree of crystallinity were determined.

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