Authors:P. Thomas, J. Šesták, K. Heide, E. Fueglein, and P. Šimon
The thermal properties are presented for a precious opal sourced from Coober Pedy, South Australia and a moldavite from Bohemia,
Czech Republic whose origins differ significantly as opal is derived from the slow isothermal diagenesis of silica, while
the tektites are specimens of vitreous silica formed from the terrestrial impact of asteroids. The differences between the
two glassy silicates are presented through measurement of the TG–DSC, TMA and high-vacuum-hot-extraction DEGAS analysis.
Authors:Zhaohe Yang, Qingcai Guan, Jingqian Wei, and Jiyang Wang
The thermal properties of KTN crystal were investigated at low temperatures by DSC and TM. The phase transition enthalpies
and the average specific heats of the crystal were measured. Results are analyzed and discussed.
Hydrazine derivatives of the monobasic nitrilotriacetate salts of zinc and alkaline earth metals have been prepared. IR absorption
frequencies and thermal properties of these metal-hydrazinium nitrilotriacetates, (N2H5)M[N(CH2COO)3]·xH2O have been defined. All the three -COOH appear to be dissociated in these salts. In thermal decomposition, these salts initially
undergo dehydration followed by dehydrazination and via acetate intermediate step to metal oxycarbonates.
Authors:H.-S. Kim, H.-S. Yang, H.-J. Kim, B.-J. Lee, and T.-S. Hwang
Summary In this study, the thermal properties of agro-flour-filled polybutylene succinate (PBS) bio-composites were investigated. PBS is one of the biodegradable polymers made from the condensation reaction of glycols and dicarboxylic acid and is naturally degraded by natural soil burial system. The thermal properties of the bio-composites were analyzed according to the agro-flour content and mesh size. On increasing agro-flour content, the thermal stability, degradation temperature and derivative thermogravimetric curve (DTGmax) temperature of the bio-composites decreased while the ash content increased. The thermal degradation of the bio-composites was not affected by agro-flour mesh size. The glass transition (Tg) and melting (Tm) temperatures of the bio-composites were not significantly changed. The storage modulus (E’) of the bio-composites was higher than that of neat PBS, because the incorporation of agro-flour increased the stiffness of the bio-composites. At higher temperatures, E’ of the bio-composites decreased due to the increasing viscosity and chain mobility of neat PBS. The thermal properties of bio-composites have an important effect on the manufacturing system and application methods.
Authors:P. Melnikov, R. Rolim, A. Delben, J. Delben, A. Souza, and A. Job
Xerogels were prepared from zirconium, barium, aluminum, lanthanum and lithium acetates, corresponding to a Li containing ZBLA composition. The study of their thermal properties (DSC, TG/DTG, FT-IR) showed that they might be used as chemically stable precursors in the preparation of fluoride glasses. Hydrofluoric acid in solution was chosen as a mild fluorinating agent. This newly proposed technique of fluorinating allowed to obtain high quality ZBLALi glass which presents the advantage of higher thermal stability and homogeneity in comparison with the glass obtained using individual commercial fluorides.
The new zinc ternary complexes [Zn(cyclen)NO3]ClO4 (I), [Zn2(cyclen)2(m-nic)](ClO4)3 (II), [Zn2(cyclen)2(m-pic)](ClO4)3 (III) (cyclen=1,4,7,10-tetraazacyclododecane; nic=nicotinic acid; pic=picolinic acid) were synthesized and their spectral and thermal properties were investigated. The compounds were characterized
by elemental analysis, IR spectroscopy and TG/DTG, DTA methods. Moreover, the way of coordination of pyridinecarboxylate anions
was proposed on the basis of the spectral data and consequently proved with results of X-ray structure analysis.
A series of PDPS/PDMS copolymers were synthesized through living anionic polymerization withn-butyllithium as an initiator. The changes of thermal property as a function of PDPS content were compared with respect to
different types of monomer sequence using differential scanning calorimetry and thermogravimtery. The results indicated that
the related variations of the thermal propertiesvs. the PDPS content and the monomer sequence provided independent operative control for preparing materials with desired thermal
properties. The thermal stability of these copolymers was dramatically improved with introducing PDPS segment. However, the
degree of these improvement pedended greatly on the monomer sequence in the copolymers.
Since some combustible, oxidative and reductive chemicals are used in the extracting process in the nuclear reprocessing plant
the process has potential hazards of a fire and explosion due to the undesired reaction.
In this study to obtain a better understanding of the thermal properties of hydrazine in nitric acid solution which is used
for preventing the oxidation of extracted plutonium, thermal analysis was carried out for the mixtures in various conditions.
From the results of DSC it was revealed that the vessel material has an influence on the thermal decomposition of hydrazine.
It was also found that hydrazine reacted with nitric acid in an autocatalytic manner, and concentration of nitric acid has
a strong influence on the thermal hazard of hydrazine and nitric acid mixtures.
The present paper discusses the results of assessing thermal properties of nitrile rubber, Perbunan NT 3945 and its peroxide
vulcanizates, before and after their swelling in solvents such as benzene, toluene and dimethylformamide. The measurements
were carried out by means of differential scanning calorimetry (DSC) and thermogravimetry (TG) under nitrogen. It has been
found that a slight rise in the glass transition temperature due to the elastomer cross-linking is clearly revealed under
the influence of its vulcanizates swelling in solvents whose solubility parameters considerably differ from the solubility
parameters of the polymer. The thermal curves of swollen samples reveal processes resulting from polymer-solvent interactions
and thermodesolvation processes, which accompany the initial stage of solvent evaporation.
DTA was used to study thermal properties and thermal stability of (50-x)Li2O-xTiO2-50P2O5 (x=0–10 mol%) and 45Li2Ot-yTiO2-(55-y)P2O5 (y=5–20 mol%) glasses. The addition of TiO2 to lithium phosphate glasses results in a non-linear increase of glass transition temperature. All prepared glasses crystallize
under heating within the temperature range of 400–540°C. The lowest tendency towards crystallization have the glasses with
x=7.5 and y=10 mol% TiO2. X-ray diffraction analysis showed that major compounds formed by annealing of the glasses were LiPO3, Li4 P2O7, TiP2O7 and NASICON-type LiTi2(PO4)3. DTA results also indicated that the maximum of nucleation rate for 45Li2O-5TiO2-50P2O5 glass is close to the glass transition temperature.