Showing papers on "Miscibility published in 1981"

Critical Phenomena in a Surfactant/Water/Oil System. Basic Study on the Correlation between Solubilization, Microemulsion, and Ultralow Interfacial Tensions

Abstract: The phase equilibrium in C8H17(OCH2CH2)3OH/water/decane system was studied at 13.6, 15.8, 21.5, 26.0, and 30.0 °C. An upper critical solution point for the surfactant and oil phases, and a lower critical solution point for the surfactant and water phases were found. Strong critical opalescence was observed in the vicinity of the critical points. In a temperature range between two critical points, a three-phase region appeared due to the superposition of three miscibility gaps, i.e., 1) surfactant+water; 2) surfactant+oil, and 3) oil+water phases. The correlations between the phase equilibria and the ultralow interfacial tensions were straightforward. An ionic surfactant/cosurfactant/brine/oil system gave similar phase equilibria as the nonionic surfactant system, but the effect of temperature was the reverse.

Multicomponent Oxides in Oxygen Potential Gradients

Abstract: The steady-state demixing of initially homogeneous oxides in an oxygen potential gradient is studied theoretically and experimentally. In ternary oxides which are stable (i.e., not oxidized or reduced) in the oxygen potential range in question, the crystal between two different oxygen potentials is shifted with respect to the oxygen lattice system. If DA> DB≫ DO, the crystal is normally enriched in AO at the side of the higher oxygen potential. Solutions of the transport problem are presented and the predicted effects are verified experimentally. The following systems are studied: Complete oxide solid solutions (A, B)O; A-B-O systems with limited solid solution ranges and miscibility gaps; A-B-O systems with compound (e.g., spinel) formation.

Liquid Immiscibility in the System Na2O-ZnO-B2O3-SiO2

Abstract: The limits of miscibility within a portion of the system Na2O-ZnO-B2O3-SiO2 were determined at 650°, 800°, and 950°C. The miscibility gap at 800° and 950°C is a low dome, adjoining the zinc borosilicate miscibility gap. Below 755°C the dome intersects the Na2O-B2O3-SiO2 face of the phase diagram. The locus of this intersection is in agreement with literature data on the sodium borosilicate system. Estimated tie-line placement in the ZnO-B2O3-SiO2 miscibility gap at 1300°C resembles those reported for the corresponding CaO and SrO systems. The microscopic morphology of glasses with the weight composition xNa2O-18ZnO-18B2O3-64SiO2 with 0≤×≤12 is described in detail.

Polymerization of diacetylenes in mixed multilayers

Abstract: Mixed multilayers of the Cd salts of pentacosa-10,12-diynoic acid and arachidic acid (mixture I) and tricosa-10,12-diynoic acid and tricosa-4,6-diynoic acid (mixture II) have been investigated with regard to their structure, miscibility, and polymerizability by the use of spectroscopic methods, X-ray and electron diffraction. In mixture I a phase separation into domains of the pure compounds is observed. Influences of the composition on the domain size and the maximum conversion to polymer are discussed. In mixture II a phase separation into domains of a 1: 1 mixture of both the compounds and into domains of the excess compound is observed. A structure model of the 1:1 complex phase is proposed.

Interpretations of Polymer-Polymer Miscibility.

Abstract: This paper concerns itself with with polymeric mixtures; mixtures of structurally different homopolymers, copolymers, terpolymers and or mixtures thereof.

Pressure dependence of the demixing of polymer solutions determined by viscometry

Abstract: From the break-down in the viscosity of a polymer solution, associated with the entrance into the two phase region, the pressure dependence of the demixing temperatures of solutions of polystyrene (M = 600.000) in cyclohexane, cyclopentane, diethylmalonate and 1-phenyldecane was measured up to 1000 bar. The application of pressure increases the solubility of polystyrene in cyclopentane and diethylmalonate, but decreases that in 1-phenyldecane; in the case of cyclohexane, a pressure of optimum miscibility is observed at ca. 120 bar.

Oligomer‐oligomer incompatibility, 3. End‐group effects

Abstract: In order to investigate the influences of different end-groups on oligomer miscibility with other substances, oligo(propylene glycol)s bearing OH groups (OPG-OH) studied in the previous paper2, were acetylated at both ends (OPG-AC). The limits of miscibility of OPG-AC with oligo(dimethylsiloxane) (ODMS) were measured turbidimetrically. A simple and reliable method for the determination of the critical points from turbidity data is presented. The observed upper critical temperatures (Tc) increase with degree of oligomerization of ODMS (ranging from 1 to 5), whereas Tc shows a minimum when the degree of oligomerization of the OPG-AC is raised (from 1 to 57,5). For lower mol. wt. oligoglycols, the Tc-values of ODMS/OPG-AC are lower by ca. 50 K as compared with those of ODMS/OPG-OH. The different end-groups play a minor role with respect to the pressure influences (up to 1 500 bar the miscibility increases in all cases). For OPG-AC the chain length of optimum miscibility with a given ODMS is found at considerably lower values than for OPG-OH. The theoretical evaluation of the experimental material on the basis of the lattice theory yields a reduction in the enthalpies of mixing up to 10% and an increase in the volumes of mixing (<0) up to 50% when OH is replaced by AC. For the treatment of end-group effects, the solubility parameter theory, when combined with the concept of molar attraction constants, presents several advantages: In particular it is possible to describe the phase separation behaviour of the different oligomer mixtures simply by means of solubility parameters and molar volumes of the different segments and end-groups and to forecast the presence or absence of a chain-length of optimum miscibility.

Phase boundary curves in toluene, 1-butanol, and aqueous sodium alkylbenzenesulfonate systems

Abstract: Miscibility relationships in systems containing toluene, 1-butanol, water, and sodium alkylbenzenesulfonates are reported. The sulfonates studied included benzene, p-toluene, p-ethylbenzene, 2,4,6-trimethylbenzene, p-cymene, and 2,5-diisopropylbenzene. In a triangular representation with a constant ratio of 1 mol of sulfonate/kg of water as one component, the phase boundary curves are fairly symmetrical with respect to the alcohol apex for S/sub AC/ (number of alkyl carbons on benzene ring of benzene sulfonate) less than 3, but highly asymmetrical for S/sub AC/ greater than 3. The amount of 1-butanol required to produce miscibility decreases with the increasing S/sub AC/ in the aqueous-rich region (> 40% aqueous solution) but increases in the toluene-rich region (> 80% toluene) when S/sub AC/ = 4 and 6. One system, containing sodium 2,5-diisopropylbenzenesulfonate, was studied at eight aqueous solution concentrations at 25/sup 0/C from 0.25 to 3.0 mol of sulfonate/kg of water. Phase relationships for limiting three-component systems were also determined. Under the boundary curves of the system containing 0.50, 1.0, and 1.5 m aqueous solutions, regions with three liquid phases in equilibrium were observed at 25/sup 0/C. The regions of the three coexisting liquid phases varied with changing temperature and composition. Opalescence can be seen at several compositions, especiallymore » near the S-shape sector of the phase boundary curves, an observation which, along with low interfacial tension between phases, suggests proximity of critical end points.« less

The location of both upper and lower critical phase boundaries in a polystyrene-poly(vinyl methyl ether) blend

Abstract: A method has been developed for the location of both upper and lower critical cloudpoint curves in miscible polymer blends. Ternary, solvent (1)/polymer (2)/ polymer (3) systems have been used and the phase separation temperatures have been measured in solutions containing a fixed ratio of the two polymers. Extrapolation to zero solvent then gives the critical temperatures for the blend. By measuring these for several blend compositions a miscibility range can be established for a quasi-binary blend of components with specific molecular weights. Using this method, both upper and lower critical temperatures have been established for a polystyrene-poly(vinyl methyl ether) mixture.

Porose, pulverformige polymerteilchen

Abstract: The invention relates to a process producing porous powdery polymer particles. A homogeneous mixture having two components minimum, one a meltable polymer, the other fluid inert to the polymer, both forming a system having a range of complete miscibility and a miscibility gap are introduced to a bed of solid-substance particles, then cooling the mixture to below solidification of the polymer and comminuting the obtained cake-like mass. The polymer is separated then from the inert fluid and solid-like substance particles.

Miscibility Studies Indicating a Low Temperature Smectic A Phase in Biaromatic Liquid Crystals with Re-entrant Behaviour

Abstract: Recent reports [1] have shown that compounds of the homologous series of the 4(4-n-alkyloxy- benzoyloxy)-4′-cyanoazobenzenes (Cn; n = 1 - 12), all have a low temperature smectic A phase (SA″). The homologues with alkyl chain length n≧9 exhibit in addition a high temperature smectic A phase (SA′), separated from the first one by a re-entrant nematic phase (N(re)). Homologues of this series were used for miscibility studies with some compounds of the biaromatic liquid crystal series of the 4-cyano-4′-n-alkyloxybiphenyls (n̄ CBP) and of the 4-cyanobenzylidene- 4′-n-alkyloxyanilines (CN · n̄). The phase diagrams studied show that the smectic A phases of biaromatic liquid crystalline nitrile compounds correspond to the high temperature smectic SA′ type and are not miscible with the low temperature SA″ phase. Moreover, the shapes of the transition temperature curves to the SA″ phase indicate a low temperature smectic A phase (SA″) for the biaromatic compounds. This suggests that for biaromatic compounds with re-entrant behaviour, the dependence of liquid crystalline phase sequences on the alkyl chain length is very similar to that of triaromatic compounds.

Studies in partial miscibility: the systems triethylamine–dimethylsulfoxide–methylethylketone and triethylamine–formamide–methylethylketone

Abstract: The systems triethylamine–methylethylketone–dimethylsulfoxide and triethylamine–methylethylketone–formamide have been studied by the methods of isothermal equilibrium and thermal analysis. At least...

Aqueous emulsion adhesive for stable decoration of excellent miscibility with wheat flour

Abstract: PURPOSE:To obtain aqueous emulsion adhesive of excellent miscibility with wheat flour which is free of the exudation of adhesive and also of cracking and is suitable for decorated veneer by the reaction of an ethylene-vinyl acetate emulsion aqeuous solution containing PVA and a specific synthetic rubber latex with vinyl acetate monomer. CONSTITUTION:An ethylene-vinyl acetate emulsion aqueous solution (referred to as EVA emulsion hereinafter) is added to a PVA aqueous solution with uniform stirring, and then the solution is further mixed with a carboxyl-modified stryene- butadiene synthetic rubber latex (C-SBR latex) in a proportion of 9:1-1:1 C-SBR latex: EVA emulsion by weight. Then, the mixture is reacted with vinyl acetate monomer by heating in the presence of a catalyst (e.g., sodium persulfate) to obtain a aqueous emulsion adhesive of excellent miscibility with wheat flour. Also, the adhesive may be mixed with an amino resin adhesive when being used.

The Miscibility of Water and Non-polar Substances at High Temperatures

Abstract: Data on the phase equilibria in water–non-polar substance systems at high temperatures and on the relations between the volume, pressure, and composition of the phases involved in these equilibria are considered. The characteristics of the phase equilibria are analysed. The bibliography includes 66 references.

Phase boundary curves in toluene, 1-butanol, and aqueous sodium alkylbenzenesulfonate systems

Abstract: Miscibility relationships in systems containing toluene, 1-butanol, water, and sodium alkylbenzenesulfonates are reported. The sulfonates studied included benzene, p-toluene, p-ethylbenzene, 2,4,6-trimethylbenzene, p-cymene, and 2,5-diisopropylbenzene. In a triangular representation with a constant ratio of 1 mol of sulfonate/kg of water as one component, the phase boundary curves are fairly symmetrical with respect to the alcohol apex for S/sub AC/ (number of alkyl carbons on benzene ring of benzene sulfonate) less than 3, but highly asymmetrical for S/sub AC/ greater than 3. The amount of 1-butanol required to produce miscibility decreases with the increasing S/sub AC/ in the aqueous-rich region (> 40% aqueous solution) but increases in the toluene-rich region (> 80% toluene) when S/sub AC/ = 4 and 6. One system, containing sodium 2,5-diisopropylbenzenesulfonate, was studied at eight aqueous solution concentrations at 25/sup 0/C from 0.25 to 3.0 mol of sulfonate/kg of water. Phase relationships for limiting three-component systems were also determined. Under the boundary curves of the system containing 0.50, 1.0, and 1.5 m aqueous solutions, regions with three liquid phases in equilibrium were observed at 25/sup 0/C. The regions of the three coexisting liquid phases varied with changing temperature and composition. Opalescence can be seen at several compositions, especiallymore » near the S-shape sector of the phase boundary curves, an observation which, along with low interfacial tension between phases, suggests proximity of critical end points.« less