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Novel type of highly swollen beads were prepared by grafting 2-hydroxyethylacrylate onto biodegradable Sodium alginate (SA) via free-radical polymerization using potassium persulphate as an initiator and Triprolidine hydrochloride as a model drug. Evidence of grafting was obtained by fourier transform infrared spectroscopic technique. Morphological properties of the beads were studied by SEM analysis. Thermal properties and crystallinity of the beads were characterized using differential scanning calorimetry and thermogravimetric analysis and X-ray diffraction techniques, respectively. Dissolution experiments were performed to study the release profiles at 37 °C in phosphate buffer solution (pH-7.4). Effect of monomer content, crosslinking agent and drug/polymer ratio on swelling properties and release profiles were also comparatively studied. A dissolution result concludes that drug release decreases with increasing crosslinker content. The highest release (96%) was obtained for the beads prepared with 0.5 mL crosslinking agent. Equilibrium swelling degree also supports the drug release profiles confirming SA-g-HEA beads showed better release profiles compare to plain SA beads. [ABSTRACT FROM AUTHOR]

Blends of Poly(ethylene terephthalate), (PET), and poly(ethylene naphthalene 2,6-dicarboxylate), (PEN), were prepared in a twin-screw extruder. Samples were investigated by differential scanning calorimetry (DSC) and proton nuclear magnetic resonance (H NMR) measurements to evaluate the extent of transesterification reaction. X-ray diffraction (XRD) test was performed to examine the effect of transesterification reactions on crystalline structure of the blends. Thermogravimetry analysis (TGA) was used to study thermal decomposition of the blends which could be explained by the level of transesterification reaction for various blend compositions. The kinetic of the decomposition reaction was analyzed by Freeman-Carroll and Chang models. It was found that these two methods were acceptable models for describing the thermal decomposition of the blends however, the Chang model showed better correlation with the experimental data as compared to the other model. Results revealed that progress of transesterification reaction in blends depends on temperature and mixing time, which have dominant role in thermal behavior and decomposition kinetic of the blends. Effect of nanoclay on transesterification reactions and degradation behavior was also investigated. It was found that the nanoclay inhibited the transesterification reactions and reduced the thermal stability of the blends. PET degraded much faster than PEN in O environment while, an opposite trend was observed in N atmosphere. [ABSTRACT FROM AUTHOR]

Abstract: The thermal behaviour of individual and mixed solids, with different molar ratios, of basic copper carbonate and ammonium metavanadate was reported. The pure and mixed solids were thermally treated at 300, 500, 750 and 1000°C. The thermal products at various calcination temperatures were characterized by means of thermal analyses (TG–DTG–DTA), X-ray diffraction (XRD) and electron spin resonance (ESR) techniques. The catalytic activity of all solids was measured using hydrogen peroxide decomposition at 30, 40 and 50°C. The results revealed that pure basic copper carbonate decomposed to CuO at 300°C and to Cu2O at temperature above 950°C, where as pure ammonium vanadate decomposed to (NH4)2V6O16 and NH4V4O10 as an intermediate compound at 250 and 350°C before the formation of V2O5 at 450°C. CuO enhanced the formation of V2O5 at 300°C. A series of copper vanadate phases were detected, Cu5V2O10, Cu2V2O7 and Cu3V5O4, for the mixtures 3Cu:1V, 1Cu:1V and 1Cu:3V preheated at 750°C, respectively. These phases were formed as a result of solid–solid interactions between copper and vanadium oxides. The calcination temperature and the composition of the Cu–V mixtures affect the degree of crystallinity and pattern intensities of different phases detected at treatment temperatures ranged between 300 and 1000°C. The catalytic activity of mixed CuO–V2O5 was found to be greater than that of single oxides obtained at the same calcination temperatures. This might be attributed to increase in the concentration of active sites by creation of new ion pairs. No measurable catalytic activity was observed for all solids calcined at 750 and 1000°C. This might be attributed to restriction of catalytically active constituents. [Copyright &y& Elsevier]

Hybrid materials were prepared by γ-irradiation of a mixture of polydimethylsiloxane (PDMS), with tetraethylorthosilicate (TEOS) and zirconium propoxide (PrZr), using a 60Co γ source, without any addition of solvents. Thermogravimetry, differential scanning calorimetry and X-ray diffraction measurements showed that the obtained hybrids are amorphous materials of the nanocomposite type. The results highlighted the different influence of each of the metallic alkoxides on the hybrid structure. The material rupture temperature, associated with the degradation of the organic component, depends mainly on the TEOS content, whereas the inorganic component structural stability depends on the relative PrZr content in the alkoxides mixture. [ABSTRACT FROM AUTHOR]

This work aims in studying the temperature dependence of the thermal properties (thermal diffusivity, k, specific heat, Cp and thermal conductivity, λ) of some basalt group samples, collected from different regions in the eastern desert of Egypt. The thermal properties of these samples were measured in the temperature range from r.t. to 900 K. The average values of the thermal conductivity of these investigated samples lie in the range from 0.4· 10-3 to 2.01 · 10-3 cal cm-1 s-1 K-1. This means that these samples are considered as thermal insulating materials. The thermogravimetric analysis (TG) confirmed that these investigated samples are dry rocks. X-ray fluorescence (XRF) and X-ray diffraction (XRD) confirmed that these rock samples have a crystalline phase, the peaks of XRD have a small change in their location as a result of heat treatment. This behaviour was attributed to the oxidation and firing of some minerals after the heat treatment. [ABSTRACT FROM AUTHOR]

A method for the synthesis of the Mo(acac) complex is proposed and its crystal structure is determined by single crystal X-ray diffraction. Space group P2/ c, a = 19.7538(5) Å, b = 7.4821(2) Å, c = 34.6190(8) Å, β = 96.8055(12)°, V = 5080.6(2) Å, Z = 12. The compound is studied by the thermogravimetric analysis, and MoO is shown to be the result of its decomposition. [ABSTRACT FROM AUTHOR]

The crystal structure, microstructure and thermal properties of the BaFe 11.1 In 0.9 O 19 sample have been investigated by SEM (Scanning Electron Microscope), X-ray diffraction, Raman spectroscopy, DSC (Differential Scanning Calorimetry), TGA (Thermogravimetric Analysis) and DTG (Differential Thermogravimetric Analysis) analytical methods. SEM investigations determined that, the average size of crystallites of the BaFe 11.1 In 0.9 O 19 sample is d ¯ = 5 μm. The X-ray diffraction investigations showed that, the structure of the sample corresponds to the hexagonal symmetry with P6 3 /mmc space group. An analysis of raman spectra at high temperatures determined that, there is no phase transition in the temperature range T = 20–450 °C. The lower boundary value is T ≥ 100 °C for starting thermal flux, the oxidation on mass kinetics and decomposition effects were determined from thermal analysis of the BaFe 11.1 In 0.9 O 19 sample. [ABSTRACT FROM AUTHOR]