AND POLYMERIC MATERIALS
Russian Journal of Applied Chemistry, 2011, Vol. 84, No. 2, pp. 311−316.
Pleiades Publishing, Ltd., 2011.
Original Russian Text © I.A. Sviridov, V.S. Soldatov, O.L. Karpova, V.P. Sokol, 2011, published in Zhurnal Prikladnoi Khimii, 2011, Vol. 84, No. 2, pp. 315−320.
Synthesis and Properties of an Aminocarboxylic Polyampholyte
Based on Polyacrylonitrile Fiber
I. A. Sviridov, V. S. Soldatov, O. L. Karpova, and V. P. Sokol
Institute of Physical Organic Chemistry, National Academy of Sciences of Belarus, Minsk, Belarus
Received April 27, 2010
Abstract—Aminocarboxylic ﬁ brous polyampholytes containing up to 2.5 mg-equiv g
weakly acidic groups and
up to 2.9 mg-equiv g
weakly basic groups were prepared from Nitron commercial polyacrylonitrile ﬁ ber by its
treatment with mixed aqueous solutions of diethylenetriamine and sodium silicate. The acid–base properties of
the polyampholyte were studied.
Aminocarboxylic ﬁ brous sorbents based on polyac-
rylonitrile (PAN) ﬁ bers are being actively studied be-
cause of their high performance in sorption of various
ionic compounds from aqueous media and air. Their
preparation and properties have been described in nu-
merous papers summarized in monographs and reviews
[1–4]. Fibrous sorbents of this type, commercially pro-
duced in small amounts, are usually characterized by the
prevalence of either anion-exchange (Vion AN-1, Fiban
AK-22) or cation-exchange (Vion KN-1, Fiban K-3 and
K-5) groups and are therefore named anion or cation ex-
The main principle of the preparation of
aminocarboxylic sorbents based on PAN is that the ﬁ ber
is treated with a reaction mixture containing amines
(di- or polyamines), a cross-linking agent (hydrazine
or polyamines), an alkali, and water. The reaction of
nitrile groups of the polymer with an amine leads to the
formation of various basic nitrogen-containing groups
linked to the polymer backbone ; with polyamines
or hydrazine , cross-links, also containing anion-
exchange groups, are formed; the reaction with alkali
yields ﬁ xed carboxy groups responsible for the cation-
exchange function of the sorbents.
Synthesis of aminocarboxylic ﬁ bers involves the
use of toxic, dangerously explosive, and expensive
reagents (amines, hydrazine, alkali), occurs at elevated
temperatures, and requires long time.
In this study we prepared an aminocarboxylic
polyampholyte containing acid and basic groups in
comparable amounts and examined its properties.
The synthesis procedure that we suggest differs from
the known procedures in that the aminating agent
consumption is considerably reduced, a low-toxic and
cheap alkaline agent is used, and the synthesis time is
As starting PAN ﬁ ber we used Nitron S (copolymer
of 92.5% acrylonitrile, 6% methyl acrylate, and
1.5% itaconic acid) with the effective diameter of
22 μm, produced by Polimir Production Association
(Novopolotsk, Vitebsk oblast, Belarus). For the
synthesis we used sodium metasilicate crystal
O (analytically pure grade) and
diethylenetriamine (DETA) NH
(100%, chemically pure grade). To study the chemical
properties, we used HCl, NaOH, KCl, and KOH.
A weight portion of Nitron ﬁ ber was placed in
a vessel that contained a reaction mixture consisting of
the amine, water, and sodium silicate. To determine the