Enhanced thermal stability of carbamazepine obtained by fast heating, hydration and re-crystallization from organic solvent solutions: A DSC and HPLC study

Direct, efficient, organic solvent- and catalyst-free synthesis of a series of polyphosphates was accomplished. The reaction involved a gas-liquid interfacial polycondensation between arylphosphoric dichlorides and bisphenol A. The polyphosphates were characterized by IR, 1H NMR, 31P NMR, inherent viscosity, thermal analysis, and molar mass. Yields in the range 70-90 % and inherent viscosities in the range 0.30-0.40 dl/g were obtained. The thermal stability of the polyphosphates was investigated by using thermogravimetry.

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Synthesis, Characterization and Suspension Stability of Al2O3 Nanoparticles Functionalized by Polyurethane

Materials Science Forum ◽

10.4028/www.scientific.net/msf.852.480 ◽

2016 ◽

Vol 852 ◽

pp. 480-484

Author(s):

Yun Ran Zhang ◽

Ming Ding ◽

Zhi Shen Jiang ◽

Luo Lan Ke ◽

Ming Hua Li

Keyword(s):

Thermal Stability ◽

Organic Solvent ◽

Surface Properties ◽

Butyl Acetate ◽

Suspension Stability ◽

Structure Surface ◽

Ft Ir ◽

Thermal Stability Of

In this paper, we have synthesized new functionalized Al2O3 nanoparticles successfully via reaction, which was grafted polyurethane onto the surface of nanoparticles dispersed in n-butyl acetate. The structure, surface properties, and thermal stability of the functionalized Al2O3 nanoparticles were characterized by means of by FT-IR, TGA and SEM. The results showed that the surface of Al2O3 nanoparticles has been grafted with polyurethane (PU). Furthermore, Al2O3 nanoparticles was dispersed evenly in the organic solvent, which can show a long suspension stability near to 6 months without precipitation, indicating that this product is very useful to prepare stabilized coating nanocomposites.

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POLYMERIZATION OF 8-ACETOXYTETRACYCLO[4.4.12,5.17,10.01,6]DODEC-3-ENE AND ITS COPOLYMERIZATION WITH ACRYLIC ACIDS

Azerbaijan Chemical Journal ◽

10.32737/0005-2531-2021-3-31-37 ◽

2021 ◽

pp. 31-37

Author(s):

E.K. Makhmudova ◽

◽

R.A. Rasulova ◽

V.S. Kadyrly ◽

M.J. Ibrahimova ◽

...

Keyword(s):

Thermal Stability ◽

Reaction Time ◽

Ir Spectroscopy ◽

Organic Solvent ◽

Radical Polymerization ◽

Monomer Ratio ◽

Catalyst Temperature ◽

Acrylic Acids ◽

Thermal Stability Of

The reaction of radical polymerization of 8-acetoxytetracyclo[4.4.12,5.17,10.01,6]dodec-3-ene as well as its copolymerization with methacrylic acids in the presence of BF3·OEt2 in bulk and in the medium of organic solvent, particularly in benzene was investigated. The influence of various factors: the amount of catalyst, temperature and reaction time on the process of polymerization, as well as the influence of the monomer ratio on the copolymerization process was studied. The structure of the obtained homo- and copolymers was confirmed by IR spectroscopy and the thermal stability of the obtained polymers and their cured products was studied

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A Study of Thermal Stability of Hydroxyapatite

Minerals ◽

10.3390/min11121310 ◽

2021 ◽

Vol 11 (12) ◽

pp. 1310

Author(s):

Natalia V. Bulina ◽

Svetlana V. Makarova ◽

Sergey G. Baev ◽

Alexander A. Matvienko ◽

Konstantin B. Gerasimov ◽

...

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Structural Changes ◽

Slow Heating ◽

Hydroxyl Groups ◽

Congruent Melting ◽

Fast Heating ◽

Powder Sintering ◽

Ceramic Manufacturing ◽

Thermal Stability Of

High-temperature powder sintering is an integral part of the dense ceramic manufacturing process. In order to find the optimal conditions for producing a ceramic product, the information about its behavior at high temperatures is required. However, the data available in the literature are very contradictory. In this work, the thermal stability of hydroxyapatite prepared by a solid-state mechanochemical method and structural changes occurring during sintering were studied. Stoichiometric hydroxyapatite was found to remain as a single-phase apatite structure with the space group P63/m up to 1300 °C inclusively. A further increase in the sintering temperature leads to its partial decomposition, a decrease in the crystallite size of the apatite phase, and the appearance of significant structural strains. It was shown that small deviations from stoichiometry in the Ca/P ratio upward or downward during the hydroxyapatite synthesis lead to a significant decrease in the thermal stability of hydroxyapatite. An apatite containing almost no hydroxyl groups, which is close to the composition of oxyapatite, was prepared. It was shown that the congruent melting of stoichiometric hydroxyapatite upon slow heating in a high-temperature furnace does not occur. At the same time, the fast heating of hydroxyapatite by laser radiation allows, under certain conditions, its congruent melting with the formation of a recrystallized monolayer of oxyhydroxyapatite. The data obtained in this study can be used when choosing sintering conditions to produce hydroxyapatite-based ceramics.

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The Ordered Phase Formation in Ti-Al-Ga Alloys

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100069193 ◽

1970 ◽

Vol 28 ◽

pp. 440-441

Author(s):

Shiro Fujishiro ◽

Harold L. Gegel

Keyword(s):

Thermal Stability ◽

High Temperature ◽

Titanium Alloys ◽

Growth Kinetics ◽

Stoichiometric Composition ◽

Good Potential ◽

Alpha Titanium ◽

Cold Rolled ◽

Kinetics Of ◽

Thermal Stability Of

Ordered-alpha titanium alloys having a DO19 type structure have good potential for high temperature (600°C) applications, due to the thermal stability of the ordered phase and the inherent resistance to recrystallization of these alloys. Five different Ti-Al-Ga alloys consisting of equal atomic percents of aluminum and gallium solute additions up to the stoichiometric composition, Ti3(Al, Ga), were used to study the growth kinetics of the ordered phase and the nature of its interface.The alloys were homogenized in the beta region in a vacuum of about 5×10-7 torr, furnace cooled; reheated in air to 50°C below the alpha transus for hot working. The alloys were subsequently acid cleaned, annealed in vacuo, and cold rolled to about. 050 inch prior to additional homogenization

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Microstructure studies of tungsten silicide schottky contacts on Gaas

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126445 ◽

1987 ◽

Vol 45 ◽

pp. 328-329

Author(s):

Yih-Cheng Shih ◽

E. L. Wilkie

Keyword(s):

Thermal Stability ◽

Field Effect Transistors ◽

Schottky Contact ◽

Schottky Contacts ◽

Excellent Thermal Stability ◽

Barrier Heights ◽

Gaas Substrates ◽

Film Adhesion ◽

Threshold Voltages ◽

Thermal Stability Of

Tungsten silicides (WSix) have been successfully used as the gate materials in self-aligned GaAs metal-semiconductor-field- effect transistors (MESFET). Thermal stability of the WSix/GaAs Schottky contact is of major concern since the n+ implanted source/drain regions must be annealed at high temperatures (∼ 800°C). WSi0.6 was considered the best composition to achieve good device performance due to its low stress and excellent thermal stability of the WSix/GaAs interface. The film adhesion and the uniformity in barrier heights and ideality factors of the WSi0.6 films have been improved by depositing a thin layer of pure W as the first layer on GaAs prior to WSi0.6 deposition. Recently WSi0.1 has been used successfully as the gate material in 1x10 μm GaAs FET's on the GaAs substrates which were sputter-cleaned prior to deposition. These GaAs FET's exhibited uniform threshold voltages across a 51 mm wafer with good film adhesion after annealing at 800°C for 10 min.

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