摘要:

The homogeneity ranges of the systems consisting of the monomer (vinyl acetate or vinyl acetate + di-2-ethyl hexil maleate), cosurfactant (ethanol, n-propanol, n-butanol), surfactant (nonylphenol ethoxylate with 25 moles of ethylene oxide) and water were studied. Addition of the more hydrophobic comonomer requires utilization of a more hydrophobic cosurfactant. The increase of surfactant concentration entails the widening of the homogeneity range. The effect of the cosurfactants mentioned is accounted for by the modification of the cluster structure of water. Therefore the refractive indexes and the signals of protons in NMR spectra vary non-linearly with the composition of homogeneous systems. DSC analysis of the systems obtained has come out with two crystallization temperatures of water undercooled to −60°C in systems of concentrations close to those of organic and aqueous phases. The results plead for the existence of a structure which differs from that of the ideal solutions of the systems studied.

ISSN:0193-2691    

DOI:10.1080/01932699608943534

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The influence of twenty five different alcohols on the formation of warm oil-in-water (O/W) microemulsions was investigated. Selected concentrations of each alcohol were added to fixed amounts of stearic acid, Tween 20 and water at 65 ° C. Fifteen alcohols formed microemulsions, at least at one of the concentrations. A pattern recognition study was performed to elucidate the activities of the alcohols by Principal Component Analysis (PCA). Linear Discriminant Analysis (LDA) was used to classify them. Two classification functions, obtained for alcohols forming / not forming microemulsions, suggest that the formation of warm O/W microemulsion is linked to the nature and the dimension/lipophilicity of the alcohol.

ISSN:0193-2691    

DOI:10.1080/01932699608943535

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A potential rapid solid/liquid separation process of fine particles from dilute aqueous suspensions is introduced (tumbling method). This process involves the separation of one or two types of fine particles in aqueous suspension by heterocoagulation phenomena and is conducted by tumbling suspensions with a macroscopic collector such as glass beads which leads to the settling of particles with the collector. Particularly, it was found that silica (Si02: 0.12 μm) particles could effectively be collected by glass beads (80 μ.m) through a bridging effect of hematite (α-Fe203: 0.10 μm ) particles. The results were explained in terms of the DLVO theory and the efficient movement of the glass beads collector

ISSN:0193-2691    

DOI:10.1080/01932699608943536

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The detachment of fine particles of silica (0.12 μm) and hematite (0.10 μm) coattached on glass beads (80 μm) in aqueous solution were studied as a function of pH and electrolyte concentration. Detachment occurs at alkaline conditions wherein the surface potentials of the particles and collector are negative. The selective separation of silica particles being governed by the balance of short range forces, which are affected by increasing the pH and electrolyte concentration.

ISSN:0193-2691    

DOI:10.1080/01932699608943537

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The phase diagrams for tetramethyldioctyldisiloxane (TDDS), water and several organic components were determined using refractive index, polarizing microscopy and low angle x-ray diffraction. The solubility limits of the alcohols were established by quantitative analysis and compared to the refractive index of known single phase mixtures. The non-ionic surfactants systems contained isotropic liquids of varying concentrations. Two lyotropic liquid crystal regions were discovered, one of lamellar structure and one consisting of a hexagonal array of closed packed cylinders. The character of the amphiphiles components to solubilize the TDDS is reflected in Ihe phase equilibria.

ISSN:0193-2691    

DOI:10.1080/01932699608943538

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor