Extraction properties of organic salts of acidic phosphoryl podands and trioctylamine with respect to cesium

The extraction ability of the organic salt of acidic phosphoryl podand (1,5-bis(o-(hydroxyethoxyphosphoryl)phenoxy)-3-oxapentane) and trioctylamine with respect to cesium in nitric acid and carbonate media is investigated. The extraction ability of the organic salts of acidic phosphoryl podand and trioctylamine are compared to those of dibenzo-18-crown-6 and di-tert-butyldicyclohexano-18-crown-6. It is shown that organic salts of this type have a significant advantage in the extraction of cesium from nitric acid and carbonate solutions.     

Quantum chemical PM-3 study of the thermal stability of heterocyclic fragments of heteropolymers, 1. Five-membered heterocycles: Azoles and imides

Semiempirical PM-3 calculations of the mechanisms of the decomposition of oxazole and maleimide have been carried out. It has been shown that thermal decomposition of the considered heterocycles proceeds via a consecutive breaking of two ring bonds, the breaking of the second bond being the rate-determining step. Both an activation barrier of heterocycle decomposition and its dissociation energy (E_D) can be used as a measure of heterocycle thermal stability. The correlation between E_D values of azole and imide containing model compounds and the initial degradation temperatures of corresponding heteropolymers makes it possible to clarify some essential features of the thermal degradation of polyazoles, polybenzazoles and polyimides.     

Interplay of chemical and physical factors in reacting polymer blends. Theoretical considerations

Various effects produced by copolymers in polymer blends are discussed, with an emphasis on the role of interchain interactions. Simple theoretical models are considered to study the following problems: the interplay of diffusion and macromolecular reaction in compatible and incompatible blends, the stabilizing effect of premade diblock copolymer on the system of minor phase particles in incompatible blends, the kinetics of transesterification in a homogeneous blend. The effect of diblock copolymer on the Ostwald ripening in a polymer blend is stated in more details; the possibility of narrowing the size distribution of minor phase particles is predicted.