Volatility studies of metal chelates. I. Thermal studies of vanadium β-diketonates

1976 ◽  
Vol 29 (11) ◽  
pp. 2369 ◽  
Author(s):  
S Dilli ◽  
E Patsalides
Keyword(s):  
Thermogravimetric Analysis ◽  
Chemical Stability ◽  
Thermal Studies ◽  
Metal Chelates ◽  
Temperature Range ◽  
Water Saturated ◽  
Thermal And Chemical Stability

The complexes of vanadium(111) and oxovanadium(1V) with pentane-2,4-dione; l,l,l-trifluoropentane-2,4-dione; 1,1,1,5,5,5-hexafluoropentane-2,4-dione; l,l,l-trifluoro-5-methylhexane-2,4-dione; l,l,l-trifluoro-5,5-dimethylhexane-2,4-dine 1,1,1,2,2-pentafluoro-6,6-dimethylheptane-3,5-dione and 1,1,1,2,2,3,3-heptafluoro-7,7-dimethyloctane-4,6-dione have been prepared. The volatility, thermal and chemical stability of the chelates have been examined by simultaneous differential thermal and thermogravimetric analysis in dynamic atmospheres of nitrogen, air and water-saturated nitrogen and air, in addition to heating under vacuum to temperatures approaching 360�C. The vanadium(111) chelates of the fluorinated β-diketones volatilized with little evidence of decomposition even in air and were stable in the absence of air to 280-320�C. In contrast, the oxovanadium(1V)chelates partly decomposed during volatilization at temperatures as low as 150�C, and completelydecomposed over the temperature range 180-240�C.

High-performance and thermostable wire supercapacitors using mesoporous activated graphene deposited on continuous multilayer graphene

2021 ◽  
Author(s):  
TaeGyeong Lim ◽  
Ba Trung Ho ◽  
Ji Won Suk
Keyword(s):  
Chemical Stability ◽  
High Performance ◽  
Multilayer Graphene ◽  
Cvd Graphene ◽  
Highly Porous ◽  
Thermal And Chemical Stability

Highly porous activated graphene coated on CVD-graphene/Cu wires enables high-performance wire supercapacitors with enhanced thermal and chemical stability.

Robust ionic liquid@MOF composite as a versatile superprotonic conductor

2021 ◽  
Author(s):  
Taksande Kiran ◽  
Effrosyni Gkaniatsou ◽  
Corine Simonnet-Jégat ◽  
Carine Livage ◽  
Guillaume Maurin ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Chemical Stability ◽  
Conducting Composite ◽  
Proton Conducting ◽  
Thermal And Chemical Stability

A highly performing proton conducting composite was prepared through the impregnation of EMIMCl ionic liquid in the mesoporous MIL-101(Cr)-SO3H MOF. The resulting EMIMCl@MIL-101(Cr)-SO3H composite displays high thermal and chemical stability,...

scholarly journals Chemical Stability of Ti3C2 MXene with Al in the Temperature Range 500–700 °C

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 1979 ◽  
Author(s):  
Jing Zhang ◽  
Shibo Li ◽  
Shujun Hu ◽  
Yang Zhou
Keyword(s):  
Electron Microscopy ◽  
Chemical Stability ◽  
Metal Matrix ◽  
Matrix Composites ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Range ◽  
Transmission Electron ◽  
Work First ◽  
Scanning Electron

Ti3C2Tx MXene, a new 2D nanosheet material, is expected to be an attractive reinforcement of metal matrix composites because its surfaces are terminated with Ti and/or functional groups of –OH, –O, and –F which improve its wettability with metals. Thus, new Ti3C2Tx/Al composites with strong interfaces and novel properties are desired. To prepare such composites, the chemical stability of Ti3C2Tx with Al at high temperatures should be investigated. This work first reports on the chemical stability of Ti3C2Tx MXene with Al in the temperature range 500–700 °C. Ti3C2Tx is thermally stable with Al at temperatures below 700 °C, but it reacts with Al to form Al3Ti and TiC at temperatures above 700 °C. The chemical stability and microstructure of the Ti3C2Tx/Al samples were investigated by differential scanning calorimeter, X-ray diffraction analysis, scanning electron microscopy, and transmission electron microscopy.

Influence of Temperature on Hydraulic Conductivity in Compacted Bentonite

1997 ◽  
Vol 506 ◽  
Author(s):  
W. J. Cho ◽  
J. O. Lee ◽  
K. S. Chun
Keyword(s):  
Hydraulic Conductivity ◽  
Influence Of Temperature ◽  
Temperature Range ◽  
Compacted Bentonite ◽  
Influence Of Temperature On ◽  
Water Saturated ◽  
Increasing Temperature ◽  
Good Agreement

ABSTRACTThe hydraulic conductivities in water saturated bentonites at different densities were measured within temperature range of 20 to 80 °C. The results show that the hydraulic conductivities increase with increasing temperature. The hydraulic conductivities of bentonites at the temperature of 80 °C increase up to about 3 times as high as those at 20 °C. The measured values are in good agreement with those predicted. The change in viscosity of water with temperature contributes greatly to increase of hydraulic conductivity.

Thermoanalytic interlaboratory experiment for identification of materials, substances and fire protection equipment

2020 ◽  
pp. 15-23
Author(s):  
Игорь Валентинович Архангельский ◽  
Юрий Кузьмич Нагановский ◽  
Игорь Андреевич Годунов ◽  
Николай Владимирович Яшин
Keyword(s):  
Thermogravimetric Analysis ◽  
Fire Protection ◽  
Dispersion Analysis ◽  
Statistical Characteristics ◽  
Single Measurement ◽  
Temperature Range ◽  
Conversion Rates ◽  
Polymer Dispersions ◽  
Parallel Measurements

Проведен межлабораторный термогравиметрический эксперимент по идентификации огнезащитных составов интумесцентного типа. Использование дисперсионного анализа позволило установить значимость/незначимость различий в поведении исследуемых материалов при нагревании, выявить лаборатории, обладающие необходимыми компетенциями для проведения идентификации. Найдено, что применение различных водно-полимерных дисперсий даже близкого строения в составе огнезащитных материалов приводит к неидентичности их свойств. Представленный подход позволил однозначно установить неидентичность исследованных огнезащитных составов. The article deals with the problem of identification of materials, substances and means of fire protection according to GOST R 53293-09 using one of the methods of thermal analysis, namely, thermogravimetric analysis. The long-term practice demonstrated that the methodology presented in the standard did not always give a clear result when identifying objects. Therefore, the evaluation experiment was conducted simultaneously in several testing laboratories with the appropriate equipment. The tests were conducted in the laboratories of the FGBU VNIIPO EMERCOM of Russia, ANO «CISIS FMT», and two CCPS of the Lomonosov Moscow State University. The most complex and controversial objects for identification were studied, namely, thermally expanding (intumescent) flame retardants based on water-polymer dispersions, which are used to protect building structures in closed premises. The purpose of the work consists in more correctly identifying the differences in the samples of the identifier and the analyzed object by using methods of dispersion analysis (GOST R ISO 5725-1, 2-202) when processing the joint interlaboratory experiment. Thermogravimetric analysis of objects was performed in platinum crucibles on samples in the form of disks with a thickness of 0,2-0,3 mm, weight 5-7 mg, at a heating rate of 20 °C/min in the air flow (50-70 ml/min). As a result of the experiment, the significance/insignificance of differences between samples should be displayed. The opinion about the competence of the laboratories participating in the experiment was made. In each laboratory there were conducted two series of thermogravimetric tests in 30-700 °C temperature range including five parallel measurements in each series. Each independent single measurement for further processing was represented by the data array formed within the temperature range of 140-650 °C with a 5° step, in total 103 points in each measurement. The results were processed using Excel spreadsheets. In the context of dispersion analysis there were evaluated both mean values of conversion rates for all laboratories, and the convergence (repeatability) variance for each laboratory using the Student's test, and the inter-laboratory variance (reproducibility variance) using the Cochran’s С test. This procedure revealed the nature of the quasi-samples and established the identity/non-identity of the samples. The results of calculations are represented by the graphical dependence of the generalized average degrees of transformation of destruction processes of objects under the temperature as well as the difference between these characteristics for laboratories I-IV. The presented identification procedure allows both to uniquely solve the problem of significance/insignificance of differences between the test object and the identifier, and to distinguish samples that have a similar composition. The statistical characteristics of a single measurement are calculated. The convergence of parallel measurements for determination of statistical outliers is identified. Determination of the overall average difference for a series of degrees of transformation allows to calculate the Student's test and accept or reject the null hypothesis. The performance of the joint evaluative (interlaboratory) experiment allows not only to establish the significance/insignificance of differences in the behavior of the materials during heating, but also to identify laboratories that have the necessary competencies for identification. The case considered in this paper revealed that the use of various water-polymer dispersions of even close structure in the composition of fire-resistant materials leads to non-identity of their properties.

ChemInform Abstract: ON THE THERMAL AND CHEMICAL STABILITY OF CARBAMOYL SULFOXIDES

1975 ◽  
Vol 6 (22) ◽  
pp. no-no
Author(s):  
F. GOTTO ◽  
M. MASOERO ◽  
R. SANTI ◽  
G. GALLUZZI ◽  
D. H. R. BARTON
Keyword(s):  
Chemical Stability ◽  
Thermal And Chemical Stability
Sign in / Sign up

Export Citation Format

Share Document