Authors:I. Blanco, L. Oliveri, G. Cicala, and A. Recca
multifunctional epoxides: the monofunctional epoxides are primarily used as reactive diluents, viscosity modifiers, or adhesion promoters systems [ 2 ]. Epoxies are one of the most versatile classes of polymers with different applications such as metal can
The thermal reactivity of fossilized/petrified dinosaur eggshells excavated in China, Argentina and France has been studied
by means of thermal analysis/mass spectrometry (TG-MS), X-ray diffractometry (XRD) and analytical scanning electron microscopy
(SEM-EDX). The results provide more detailed information on the properties of these fossil materials and therefore allow an
improved typology of this most remarkable family of creatures.
The thermal reactivities of KHV6O16·3H2O and Cd(HV6O16)2·12H2O were investigated. By means of IR spectroscopy and X-ray phase analysis it was found that, after dehydration, both compounds decompose to vanadium pentoxide and the corresponding metavanadate. Potassium metavanadate and vanadium pentoxide react together to form bronzes of different compositions. In contrast, vanadium pentoxide and cadmium metavanadate are the predominant components of the reaction products obtained within the temperature range from 300° to 800°C.
Authors:P. Ubbrìaco, P. Bruno, A. Traini, and D. Calabrese
In this study the process of hydration of fly ash, produced by a municipal solid waste (MSW) incinerator, is examined in water
and in a solution enriched with Ca(OH)2. The examined fly ash samples are characterized by a high content of alkaline chlorides and anhydrite and by remarkable amounts
of heavy metals. Investigations using differential thermal analysis/thermogravimetry (DTA/TG) and X-ray diffractometry (XRD)show
particular kinetics of the formation of the ettringite phase. The development of such a hydrated phase is much more intense
in the presence of an excess of Ca(OH)2so as to consume the ‘free’ sulphate in the case of the more reactive fly ash. Experimental results from thermal analysis
and X-ray diffractometry show the presence of different hydrated phases during the interaction between fly ash and aqueous
solution. The analytical determinations, related to the aqueous solution, point out an interesting decrease in concentration
of metals Pb, Zn and Cr(VI), relating to the middle period of the interaction.
The thermal reactivity of the naturally occurring silicates jadeite, NaAl[Si2O6], and nephrite, a variety of actinolite, Ca2 (Mg,Fe)5[(OH,F)Si4O11]2, have been investigated by thermogravimetric and thermomechanical analysis as well as temperature-dependent X-ray diffraction
and analytical electron microscopy. TG shows that nephrite undergoes a weight loss at around 900°C. Mass spectrometry reveals
that this irreversible reaction corresponds to the evolution of H2O, and XRD shows that a phase related to diopside CaMg[Si2O6] is formed. Jadeite does not undergo and observable weight changes up to 1000°C. Thermomechanical analysis indicates a reversible
phase transition at about 950°C. Temperature-dependent X-ray diffraction shows that jadeite is again present on cooling (peak
temperature: 1000°C), but that this is accompared by an additional unidentified phase. The mechanism of this process is not
yet clear although it has been observed in several samples from different origins and with different metal impurities.
Authors:F. Cavani, G. Centi, F. Trifirò, and G. Poli
The contribution of thermal methods of analysis to the study of the structure and reactivity of vanadium-phosphorus oxides is examined. In particular, data are reported on the solid-state reaction VOHPO4·1/2H2O→(VO)2P2O7+2 H2O for VOHPO4·1/2H2O prepared in different ways, on the redox properties of oxidation and reduction of vanadium for catalysts prepared with different P∶V atomic ratios in the range 0.9–1.3, and on the surface properties determined by TPD of catalysts with different P∶V ratios. The relationship between these properties and the catalytic properties in the selective oxidation ofn-butane and but-1-ene is discussed.