Showing papers on "Miscibility published in 1973"

Effect of Small Additions of Al2O3 and Ga2O3 on the Immiscibility Temperature of Na2O‐SiO2 Glasses

Abstract: Alumina and gallia were substituted separately for Na2O in amounts of 0.2, 0.5, 1.0, 1.5, 2.0, and 3.0 wt% in three Na2O-SiO2 glass compositions (82, 84, and 86 wt% SiO2) within the immiscibility region. The immiscibility regions for each system extend to ∼1.5 mol% of the added oxide. In general, the addition reduced the immiscibility temperature (Tm), but at the edge of the immiscibility region (82% SiO2) the Na2O loss effect initially increased Tm. A structural model of the miscibility of Al2O3 added to silicate glasses is presented.

Miscibility Gaps in Fused Salts. Note VII. Systems of LiF with Alkali Halides

Abstract: Twelve systems formed with lithium fluoride and alkali halides were studied in order to put into evidence possible demixing phenomena. Liquiddiquid equilibra were found in the seven mixtures containing KBr, KI, RbBr, Rbl, CsCl, CsBr, and Csl; however, the miscibility gaps could be fully detected only for LiF + CsCl, LiF + KBr and LiF + RbBr. The tendency to demix in these systems, formed by typically ionic components, agrees with the reciprocal Coulomb effect rule. On the basis of the solid liquid and liquiddiquid equilibria, the LiF excess potentials were evaluated and compared with those calculated according to current theories.

Preparation of a concentrated solution of an anionic azo dye containing a sulfonic acid group

Abstract: Process of preparing a concentrated solution of a water-soluble anionic azo dye containing 1 to 4 sulfonic acid groups by diazotization and coupling of a diazo and coupling component, respectively, in the solvent or solvent mixture required for the concentrated solution which should have as essential solvents water and/or water-soluble or water-miscible organic solvents other than carboxylic acids. Diazotization is carried out with a nitrous acid ester of a hydroxy-substituted aliphatic hydrocarbon, e.g., an alkyl nitrite. The process provides highly stable concentrated or stock solutions of unlimited miscibility with water for use in continuous dyeing methods.

The Critical Miscibility Composition of Styrene-Acrylonitrile-Methyl Methacrylate Terpolymers

Abstract: Ternary statistical copolymers composed of styrene, acrylo-nitrile, and methyl methacrylate were synthesized and frac-tionated by a precipitational method. For a given polymer concentration, the volume fraction of nonsolvent, i.e., methanol, at the precipitation point. γ, increases in the order: polystyrene > acrylonitrile-styrene and acrylonitrile-methyl methacrylate binary copolymers > ternary co-polymers. The γ values in methanol-dimethylformamide (DMF) mixture are larger than those in methanol-butanone, indicating that DMF is a better solvent for the terpolymer. A linear relation was obtained between the reciprocal limiting viscosity number and γ values of fractions. The dependence of γ on the terpolymer composition could not be established exactly in these systems. The temperature coefficient of γ, dγ/dT, increases with the MMA content and decreases with the styrene content in terpolymers both in butanone and in DMF mixtures.

A Study of Liquid Systems with Miscibility Gaps: Water-Ethylene Glycol Monobutyl Ether Mixtures

Abstract: Abstract In this paper we show that in binary liquid systems with miscibility gaps, the forces related to the formation of spatially ordered regions near the critical solution temperature, Tc, prevalently involve interactions of type AA and BB rather than interactions of type AB. A and B being the components of the mixture. For this purpose we have measured the viscosity and proton spin-lattice relaxation as a function of temperature and concentration in water-ethylene glycol monobutyl ether systems. With a method previously described, which allows to determine the contributions to the relaxation that arise from the coupling of protons belonging to molecules of different types, the mixed translational contributions near Tc due to interactions of type AB and the mixed translational contributions one would obtain if the same region were not critical, have been calculated. The knowledge of these quantities allowed us to evaluate the viscosity per cent deviation due to the critical phenomenon, considering this to be essentially related to interactions of type AB. Comparison with the per cent deviation of the measured viscosity shows that the two sets of values are quite different. The difference must be due to interactions of tpye AA and BB.

Effect of small additions of al2o3 and ga2o3 on the immiscibility temperature of na2o-sio2 glasses

Abstract: Alumina and gallia were substituted separately for Na2O in amounts of 0.2, 0.5, 1.0, 1.5, 2.0, and 3.0 wt% in three Na2O-SiO2 glass compositions (82, 84, and 86 wt% SiO2) within the immiscibility region. The immiscibility regions for each system extend to ∼1.5 mol% of the added oxide. In general, the addition reduced the immiscibility temperature (Tm), but at the edge of the immiscibility region (82% SiO2) the Na2O loss effect initially increased Tm. A structural model of the miscibility of Al2O3 added to silicate glasses is presented.