摘要:

These words by one of Lottermoser's collaborators are of a kind usually reserved for the truly great scientists. Alfred Lottermoser's scientific contributions and his leadership in developing the Institute for Colloid Chemistry at the Technical University in Dresden, Germany, without significant state support and during a time, 1922, when runaway inflation made such support worthless, are each sufficient for his name to remain important in the history of colloid chemistry. Together, they guarantee a place among the true greats.

ISSN:0193-2691    

DOI:10.1080/01932699908943822

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper presents two experiment phenomena of nanocrystalline particles. One is the dispersion of rare earth element on the surface of transition metal particles by hydrogen arc plasma method, the other is that nanocrystalline metal particles were dispersed into the pores of alumina: The dispersion mechanism was discussed

ISSN:0193-2691    

DOI:10.1080/01932699908943823

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The present paper proposes the emulsification of weathered crude oils in water as a competitive and cost effective method for reducing their viscosities. Weathered crude oil samples were collected from major Kuwaiti oil lakes. Emulsion preparation involved using, either a nonionic surfactant or alkali, as well as both alkali and fatty acid. The obtained emulsions were characterized by measuring the droplet size distribution of the dispersed phase using optical microscopy. Emulsion stability was also examined in terms of the system breakdown. The rheological properties were measured using a concentric cylinder rotary rheometer. The emulsion rheological behavior has been studied as a function of composition, temperature, and shear rate. A constitutive model was developed to characterize the pseudoplastic behavior of the crude oil and the emulsion systems. The model fitted well the experimental results with a correlation coefficient higher than 95%. Associated with the pseudoplastic behavior, viscoelastic behavior has been observed with emulsions and some oils at high shear rates.

ISSN:0193-2691    

DOI:10.1080/01932699908943824

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Surfactant-oil-water systems in which the surface active substance is a mixture of carboxylic acid and its sodium salt (soap), exhibit emulsion property maps that are consistent with the phase behavior and the general emulsion phenomenology. However they present specific features such as an extended C+multiple emulsion region and a skinked A+W/O emulsion zone. In this case the aqueous phase pH drives the relative hydrophilicity of the acid/salt mixture at interface and plays the role of the most sensitive formulation variable. Studied systems contain C10 to C14 carboxylic acid, NaCl brine and a light distillation cut, as well as alcohols.

ISSN:0193-2691    

DOI:10.1080/01932699908943825

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Very fine emulsions with droplet size in the sub-micron range, often called miniemulsions, are prepared by the moderate (magnetic) stirring of a system undergoing a dynamic transitional inversion driven by a continuous change in physicochemical formulation (here temperature). Near optimum formulation for three-phase systems, the ultralow interfacial tension favors the drop breaking rate, and fine emulsions can be made. However, this region is also known for its rapid coalescence rate. Thus, a high enough stability can be attained only by shifting the formulation away from optimum as soon as the emulsion is made. Moreover, a rapid change in formulation through the three-phase region also results in a separation phenomenon that can be harnessed to produce ultra fine droplets.

ISSN:0193-2691    

DOI:10.1080/01932699908943826

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Poly(methyl methacrylate-co-N-isopropylacrylamide-co-N-acryloxysuccin-imide) (poly(MMA/NIPAAni/NAS)) latex particles were prepared by emulsifier-free emulsion polymerization. The latex particles could reversibly flocculate and disperse when the solution temperature was kept above and below the characteristic lower critical solution temperature (LCST). The LCST of the latex dispersion could be adjusted lower or higher by increasing or decreasing, respectively, the ionic strength of the solution.α-Amylase was immobilized onto the latex particles by reacting with the succinimide groups on NAS. It was demonstrated that the ct-amylase immobilized latex particles could be separated by thermoflocculation. After 5 repeated thermocycles, 83 % of the latex particles could be recovered, and the apparent enzymatic activity could be retained as high as 78percnt;.

ISSN:0193-2691    

DOI:10.1080/01932699908943827

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The authors have in previous contributions determined dielectric properties of W/O-emulsions by applying the Time Domain Dielectric Spectroscopy technique. The main findings are summarized here. The influence of droplet shape and flocculation on the dielectric parameters characteristic of the emulsions is discussed. A technique developed for a dielectric investigation of electrically induced coalescence is demonstrated, together with experimental results from surveys on emulsions stabilized both by commercial and natural surfactants.

ISSN:0193-2691    

DOI:10.1080/01932699908943828

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

ISSN:0193-2691    

DOI:10.1080/01932699908943829

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The solubilization of water in w/o microemulsions formed with mixed-surfactants containing one anionic and one cationic surfactant and alcohol was studied as a function of alkyl chain length of oil (C6 to C16), mixed-surfactant (sodium dodecyl sulfate, SDS, and cetyltrimethylammonium bromide, CTAB, or cetylpyridinium bromide CPB), and alcohol (1-butanol, 1-pentanol, 1-hexanol). The results show that the solubilization of water in microemulsion systems increases significantly with the mixed-surfactants due to the synergistic effect resulting from the strong Coulombic interactions between cationic and anionic surfactants and the solubilizing efficiency increases as the chain length or concentration of alcohol increases. With increasing the oil chain length the solubilization for water increases, decreases, and has the chain length compatibility effect when the systems contain 1-hexanol, 1-butanol, 1-pentanol, respectively. The total solubilizing capacity increases as the surfactant concentration (keep the ratio of SDS to butanol constant) increases.

ISSN:0193-2691    

DOI:10.1080/01932699908943830

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The micellar catalytic model (or the consecutive first order reaction has been proposed in this paper. It was applied to the alkaline hydrolysis of dimethyl phthalate in micellar solutions of surfactants (CTAB, SDS and Triton X-100), and the alkaline hydrolysis of bis (2,4-dinitrophenyl) posphate in CTAB micellar solution. Rate constants obtained in micellar phase indicate that the two steps of alkaline hydrolysis of dimethyl phthalate are both inhibited by all of the surfactants investigated. CTAB micelle exhibits a greater catalytic effect on the alkaline hydrolysis of bis (2, 4-dinitrophenyl) phosphate. this may be arised from the local concentration effect of hydroxide ion in CTAB micellar phase. Nevertheless. the second order rate constant of bis-(2, 4-dinitrophenyl) phosphate in the micellar phase is smaller than that in the bulk phase.

ISSN:0193-2691    

DOI:10.1080/01932699908943831

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor