Thermodynamic parameters of urethane formation reactions and concomitant processes

Thermodynamic parameters of reactions of methyl and phenyl isocyanates with a series of compounds were determined by quantum-chemical calculations. The products of these reactions model for various functional groups present in commercial polyurethanes. The thermodynamic stability series for compounds formed from aliphatic and aromatic isocyanates were constructed.     

Effect of the Structure of Oxypropylated Hydroxyl-Containing Molecules on Glycolysis of Foamed Polyurethane

The activity of a polyether derived from ethylene and propylene oxides (Laprol 5003) and of N,N,N',N'-tetra(hydroxypropyl)ethylenediamine (Lapramol 294) in glycolytic degradation of elastic foamed polyurethane was studied.     

Mechanism and Relationships of Chemical Degradation of Rigid Polyurethane Foam

The regular trends in chemical degradation of rigid polyurethane foam under the action of oxypropylated hydroxy compounds were studied. The molecular-weight characteristics, functionality with respect to 4,4′-diphenylmethane diisocyanate and OH groups, viscosity, and the content of terminal OH groups of alcoholysis products at temperatures from 150 to 220°C were determined. A mechanism of degradation of the network structure of rigid polyurethane foam was suggested.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 5, 2005, pp. 840–845.Original Russian Text Copyright © 2005 by Galimzyanova, Bakirova, Valuev, Zenitova.     

New macroporous electron ion-exchangers

Conclusions The condensation of the weakly basic anionite, Ional ANP, with chloranil gave some new oxidation-reduction ionites, which contain quinoid and weakly basic amino groups.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2607–2609, November, 1972.     

Oligoesters on the basis of hydroxyethylated derivatives of 4,4′-(propan-2,2-diyl)diphenol

Equilibrium melt polycondensation was used to synthesize a series of oligoethers containing end hydroxy groups, starting with hydroxyethylated derivatives of 4,4′-(propan-2,2-diyl)diphenol and saturated aliphatic dicarboxylic acids. The structure of the oligoethers was assigned, and their physicochemical characteristics and thermal stability were determined.     

Effect of organometallic catalysts on the synthesis process and properties of molded polyurethane

Application of organotin catalysts adversely affects the strength of polyurethane. Use of small amounts of metal acetylacetonates hardly affects the physicomechanical properties of the material, whereas their increased amounts improve the strength. It is shown that, in contrast to other catalysts, tin octoate does not accelerate the hydrolysis of the oligoester.     

Chemical degradation of elastic foamed polyurethanes under the action of thiodiglycol

Alcoholysis of elastic block foamed polyurethane under the action of thiodiglycol and its mixture with Laprol 3603 polyether was studied. The structure and physicochemical properties of alcoholysis products were determined.     

Conditions of Formation of Stable Polyelectrolyte Complexes Based on N-Succinyl Chitosan and Poly-N,N-diallyl-N,N-dimethylammonium Chloride

Russian Journal of Applied Chemistry - The influence of preparation conditions on the size characteristics and stability of particles of aqueous dispersions of positively and negatively charged...     

Simple two-sided anti-Lie-admissible algebras

For a Lie algebra L, a bilinear map is called a commutative cocycle if ψ(a, b) = ψ(b, a) and ψ([a, b], c) + ψ([b, a], c) + ψ([c, a], b) = 0 for any a, b, c ∈ L. We prove that any commutative cocycle of a simple Lie algebra of characteristic p ≠ 2, 3 is trivial if the rank of L is at least 2. In particular, any two-sided Alia algebra connected with a simple, finite-dimensional Lie algebra L is isomorphic to L, except for the case where L = sl ₂ . Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 60, Algebra, 2008.