ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 9, pp. 1622!1629. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + N.M. Zabivalova, A.M. Bochek, E.N. Vlasova, B.Z. Volchek, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81,
No. 9, pp. 1547!1554.
AND POLYMERIC MATERIALS
Preparation of Mixed Ethers by Reaction of Carboxymethyl
Cellulose with Urea and Their Physicochemical Properties
N. M. Zabivalova, A. M. Bochek, E. N. Vlasova, and B. Z. Volchek
Institute of Macromolecular Compounds, Russian Academy of Sciences, St. Petersburg, Russia
Received February 1, 2008
Abstract-The conditions of preparation of mixed cellulose ethers containing carboxymethyl and amide
groups by reaction with urea were examined with samples of commercial carboxymethyl cellulose and that
prepared from flax cellulose as examples. The water solubility of the resulting products and their sorption
activity toward copper ions were examined in relation to the amount of amide groups introduced.
Water-soluble cellulose compounds are widely
used in various branches of engineering and also
in food industry, perfumery manufacture, and
medicine. Sodium salt of carboxymethyl cellulose
(NaCMC)and methyl cellulose (MC)are the most
widely applied cellulose compounds. They are used
in oil extraction, paper, textile, and food industries,
as well as in manufacture of paints and varnishes,
dry building mixtures, adhesives, etc. These cellulose
ethers are utilized primarily as aqueous solutions.
The application field for carboxymethyl cellulose
(CMC)can be extended by its compounding with
other polymers or by chemical modification.
Chemical modification of partly substituted cellu-
lose ethers is effected either by introduction of new
functional groups at free hydroxy groups of the
polymer in anhydroglucose moieties or by selective
modification of the already existing substituents.
Carboxymethyl cellulose amides (CMCAs)are
prepared by reactions of amines with CMC chlorides
 or with CMC in the H form . We described
previously  the conditions of preparation of
amides of CMC based on flax and cotton cellulose
by the reaction with chloroacetamide.
Cellulose compounds are produced mostly from
wood and cotton cellulose. An alternative raw ma-
terial can be found in large-capacity waste from flax
production: short flax fibers and lignified part of
The physicochemical properties of new cellulose
compounds are affected by the following factors:
nature of the initial polymer, molecular weight,
chemical composition, presence of concomitant sub-
stances, structural uniformity, fiber morphology, etc.
This study was aimed to elucidate the conditions
of synthesis of cellulose ethers by the reaction of
CMC prepared from flax and cotton fibers with
urea. Vali et al.  and Goikhman et al.  described
the conditions of preparation of cellulose car-
bamates by reaction with urea. These conditions dif-
fer from those for other cellulose compounds.
Urea can be introduced into the reaction mixture
by various procedures : using ammonia (introduc-
tion of biuret and urea into liquid ammonia)and
without using ammonia: by impregnation of cellu-
lose with an alkaline solution of urea, by introduc-
tion of urea in a buffer high-boiling substance where
urea melts and gets uniformly spread over the sur-
face of cellulose fibers, or by impregnation of cellu-
lose with a solution of urea or biuret in water,
DMSO, DMAA, and DMF.
Depending on the conditions, the reaction bet-
ween CMC in the acid form (CMC)and amines
can yield cross-linked systems [8, 9] and mixed cellu-
lose ethers containing amide and catboxymethyl
groups . Polysaccharides (starches, CMC)and
urea can also be used to prepare composite materials
that can be processed as a melt . Such com-
posites are obtained using an oxidizing agent (hy-
drogen peroxide)and a catalyst (iron chloride).
We elucidated here the conditions of synthesis of
mixed cellulose ethers without oxidizing agents and