ISSN 1070-4272, Russian Journal of Applied Chemistry, 2006, Vol. 79, No. 9, pp. 1500!1505. + Pleiades Publishing, Inc., 2006.
Original Russian Text + L.M. Kalyuzhnaya, L.I. Kutsenko, E.B. Karetnikova, E.N. Vlasova, A.M. Bochek, 2006, published in Zhurnal Prikladnoi Khimii,
2006, Vol. 79, No. 9, pp. 1516 !1521.
AND POLYMERIC MATERIALS
Sorption of Vapors of Organic Solvents with Cyanoethyl
L. M. Kalyuzhnaya, L. I. Kutsenko, E. B. Karetnikova,
E. N. Vlasova, and A. M. Bochek
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Received June 9, 2006
Abstract-The interaction of cyanoethyl hydroxyethyl cellulose with acetone, methylene chloride, and tri-
fluoroacetic acid in the temperature range 10350oC was studied by the solvent vapor sorption technique.
The temperature and concentration dependences of the Flory3Huggins parameter for polymer3solvent interac-
and the mechanism of the structural rearrangement in the systems were determined.
Growing attention is paid today to studying the
structure and physicochemical characteristics of poly-
mers having increased rigidity of macrochains and
able to form mesophase on dissolution in appropriate
solvents. It is well known  that cellulose ethers can
form both lyotropic and thermotropic liquid crystals
(LCs). Hydroxyethyl (HEC) and hydroxypropyl cellu-
lose (HPC) are typical representatives of such ethers.
It was shown  that HEC forms lyotropic cholesteric
LC and thermotropic LC only in the case of high
molar substitution (738 mol oxirane per glucose unit).
It is assumed that introduction of bulky substitutes
into anhydroglucose units of cellulose increases the
equilibrium rigidity of macrochains of the polymer
due to decreasing mobility of anhydroglucose units
(vibration amplitudes) relative to the b-glucoside
bond. Cyanoethylation of cellulose and HEC (intro-
duction of strongly polar groups into cellulose macro-
molecules and, in the case of HEC, at unsubstituted
hydroxy groups of anhydroglucose units and, prob-
ably, at terminal primary OH groups of hydroxyethyl
substituents) is an efficient way to increase the equi-
librium rigidity of macrochains and alter the inter-
molecular interaction between them.
Despite extensive experimental and calculated data
obtained on lyotropic polymeric LC systems ,
the thermodynamic features of the interaction of cellu-
lose ethers with solvents were not adequately studied.
Experimental determination of complete phase
diagrams for systems of this type using only one in-
strumental method is difficult. Additional problems
arise from the existence of higher and lower critical
solution temperatures in solutions of some cellulose
derivatives in a series of solvents. The structural fea-
tures of anisotropic solutions and ranges of phase
transitions are studied by polarization microscopy.
Sorption methods can also give information on the
structure and molecular dynamics of LC polymers .
It should be noted that any structural transitions in
a polymer sample are necessarily reflected in the
shape of absorption curves of a sorbate. Thus, study-
ing features of solvent vapor sorption is a necessary
link between studying the behavior of macromolecules
in solutions and the supramolecular structure and
physicomechanical characteristics of polymers in
In this study we examined the features of formation
of an ordered LC mesophase by cyanoethyl hydroxy-
ethyl cellulose in concentrated solutions in a series
of organic solvents. To elucidate the features of
mesophase formation and interaction of polymer with
the solvent, we evaluated various thermodynamic
parameters from the experimental data on sorption.
Cyanoethyl hydroxyethyl cellulose (CEHEC) sam-
ples were synthesized under laboratory conditions by
cyanoethylation of HEC with acrylonitrile according
to the procedure described previously . We used
commercial HEC with degree of polymerization DP =
900 and molar substitution MS = 2.0. On completion