Zinc compounds thermal properties

New complex compounds of general formula Zn(4-ClC6H3-2-(0H)C00 2 L2 nH20 (where L=thiourea (tu), nicotinamide (nam), caffeine (caf), n=2,3), were prepared and characterized by Gyoryova and coworkers [230], vfho studied their thermal properties by TG/DTG and DTA methods. Thermal decomposition of the hydrated compounds starts with the release of water molecules. During the thermal decomposition of the anhydrous compounds, the release of organic ligands take place, followed by the decomposition of the salicylate anion. Zinc oxide was the final solid product of the thermal decomposition performed up to 650 C. TG, powder XRD, IR spectra and chemical analysis were used for the determination of the products of the thermal decomposition. 

Fluorosilicones can be compounded by the addition of mineral fillers and pigments. Fillers for such compounds are most commonly silicas (silicon dioxide), because they are compatible with the elastomeric silicon-oxygen backbone and thermally very stable. They range in surface areas from 0.54 to 400 m2/g and average particle size from 100 to 6 nm. Because of these properties, they offer a great deal of flexibility in reinforcement. Thus, cured compounds can have Durometer A hardness from 40 to 80. Other fillers commonly used in fluorosilicones are calcium carbonate, titanium dioxide, and zinc oxide. 

The use of transition metals or transition metal clusters to act as nodes for the modular self-assembly of diamondoid networks that are sustained by coordinate covalent bonds is also well established. Such architectures are of more than aesthetic appeal. Indeed, such structures have resulted in a class of compound with very interesting bulk and functional properties. Metal-organic diamondoid structures in which the spacer moiety has no center of inversion are predisposed to generate polar networks since there would not be any inherent center of inversion. Pyridine-4-carboxylic acid is such a ligand and bis(isonicotinato)zinc exists as a three-fold diamondoid structure that is thermally stable and inherently polar.33... 

A number of reports on phthalocyanines and porphyrins have been published. Spectral diffusion and thermal recovery of spectral holes burnt into phthalocyanine doped Shpol skii systems has been examined . An absorption, emission, and thermal lensing research on carboxylated zinc phthalocyanine shows the influence of dimerization on these properties. Fourier transformation of fluorescence and phosphorescence spectra of porphine in rare gas matrices has yielded much structural and electronic state data on this compound . Exciton splitting is an effect which is seen in the spectra of covalently linked porphyrins . A ps fluorescence study of the semirigid zinc porphyrin-viologen dyad has provided evidence for two dyad conformers . Spectral diffusion in organic glasses has been measured by observing the hole recovery kinetics over the time scale of 1 to 500 ms for zinc tetrabenzoporphyrin in PMMA . 

When a PA is to be used in applications requiring self-extinguishing characteristics and flame retardant properties, it is necessary to resort to the addition of a flame retardant. Flame retardant formulations, known in the field of poly(ester)s, can be widely adapted to PAs. Brominated poly(styr-ene) in combination with an antimony compound, such as sodium antimon-ate, can be used." The performance is improved when a minor amount of calcium oxide is added. The thermal stability of these compositions is much better in comparison to formulations with magnesium oxide or zinc oxide. 

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