1070-4272/01/7408-1418 $25.00 C 2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 8, 2001, pp. 1418!1421. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 8, 2001,
Original Russian Text Copyright + 2001 by Fakhrutdinov, Varnavskaya, Khvatova, Lebedev, Diyarov, Fakhrutdinov.
Activity of Nonionic Surfactants
B. R. Fakhrutdinov, O. A. Varnavskaya, L. K. Khvatova, N. A. Lebedev,
I. N. Diyarov, and R. Z. Fakhrutdinov
Kazan State Technological University, Kazan, Tatarstan, Russia
Received September 25, 2000; in final form, March 2001
Abstract-The surface activity of block copolymers of ethylene and propylene oxides, based on ethylene-
diamine, mono(ethylene glycol), and triethanolamine, was studied. Adsorption characteristics of the inves-
tigated compounds at the water3air interface are estimated.
At present, nonionic surfactants are widely used
as emulsifiers, stabilizers of dispersions, corrosion
inhibitors, antistatic agents, and demulsifiers [1, 2].
Both in Russia and abroad, studies of surfactants
as demulsifiers revealed that the highest demulsify-
ing effect is provided by nonionic surfactants. Fur-
thermore, it is known that high-molecular-weight com-
pounds of this type are more efficient than low-mo-
lecular-weight compounds . However, their adsorp-
tion characteristics at the water3air interface have
not been studied adequately. Therefore, we studied
in this work the surface activity of newly synthesized
nonionic surfactants, block copolymers of ethylene
oxide (EO) and propylene oxide (PO), based on ethyl-
enediamine (EDA), mono(ethylene glycol) (MEG),
and triethanolamine (TEA), and estimated the adsorp-
tion characteristics of the investigated compounds at
the water3air interface.
In the experiments, we used nonionic surfactants
based on EDA (sample nos. 139), MEG (sample nos.
10316), and TEA (sample nos. 17, 18), with differ-
ent molecular weights M and PO/EO ratios or having
the same M, but different degrees of oxyethylation.
All the surfactants were developed at the NIInefte-
promkhim Joint-Stock Company.
The surface tension of aqueous solutions of the
nonionic surfactants at the water3air interface was
determined by the anchor-ring method with a LAUDA
tensometer without displacement, using an inductive
Fig. 1. Surface tension isotherms of aqueous solutions of block copolymers of PO and EO, based on (a) EDA, (b) MEG, and (c)
TEA. (s) Surface tension and (C) concentration. The numbers 1315, 17, and 18 correspond to the sample numbers; and I, to MEG.