Temperature effect on the viscoelastic properties of solutions of cylindrical mixed micelles of zwitterionic and anionic surfactants

The viscoelastic properties of semidilute mixed aqueous solutions of oleyl amidopropylbetaine and sodium dodecylbenzene sulfonate are studied in the temperature range of 20–40°C. It is shown that, at 20°C, the solution viscosity can be as high as 390 (Pa s), which is related to the formation of a network of entanglements of long cylindrical micelles of surfactants. It is revealed that, upon heating, the viscosity and relaxation time of the system decrease, while the contour length of cylindrical micelles decreases consider-ably. It is shown that this susceptibility of viscoelastic surfactant solutions to temperature is due to the low energy of break, which is much lower than the energy of covalent bonds.     

Sorbitol-Based Demulsifying Agents and Their Surfactant Properties

Sorbitol-based block copolymers of ethylene and propylene oxides were synthesized and characterized as surfactants and demulsifiers.__________Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 6, 2005, pp. 966–971.Original Russian Text Copyright © 2005 by Solodov, Varnavskaya, Khvatova, Fakhrutdinov, Lebedev, Diyarov.     

Activity of Nonionic Surfactants

The surface activity of block copolymers of ethylene and propylene oxides, based on ethylenediamine, mono(ethylene glycol), and triethanolamine, was studied. Adsorption characteristics of the investigated compounds at the water-air interface are estimated.     

Pentaerythritol-based demulsifying agents and their surfactant properties

Pentaerythritol-based block copolymers of ethylene and propylene oxides were synthesized and characterized as surfactants and demulsifiers.     

Preparation of adsorbed lipase and its properties

Summary 1. Under certain conditions, lipase immobilized on cellulose-based ion-exchange materials can be obtained. The best adsorbent is DEAE-cellulose.2. The optimum conditions for the immobilization of lipase on DEAE-cellulose are pH 8.0, time of contact with the support 15–20 min, temperature 10° C.3. The immobilized lipase (DEAE-cellulose-lipase) retains the main functional properties of the native enzyme.Department of Microbiology, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 267–271, March–April, 1977.