ISSN 1070-4272, Russian Journal of Applied Chemistry, 2015, Vol. 88, No. 9, pp. 1472−1480. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © L.A. Pavlova, S.E. Lyubimov, M.M. Il’in Jr., Z.K. Blinnikova, V.A. Davankov, Dm.S. Fokin, D.S. Fokin, S.M. Kishilov, 2015, published
in Zhurnal Prikladnoi Khimii, 2015, Vol. 88, No. 9, pp. 1329−1338.
Use of Hypercrosslinked Polystyrenes for Removing Iron
Complex Salts and Organic Impurities from Sodium Thiocyanate
Solution in Production of Polyacrylonitrile Fiber
L. A. Pavlova
, S. E. Lyubimov
, M. M. Il’in Jr.
, Z. K. Blinnikova
, V. A. Davankov
Dm. S. Fokin
, D. S. Fokin
, and S. M. Kishilov
Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences,
ul. Vavilova 28, Moscow, 119334 Russia
Khimprominzhiniring Research and Production Company, Volgogradskii pr. 43, Moscow, 109316 Russia
Kompozit Holding Company, Volgogradskii pr. 43, Moscow, 109316 Russia
Received May 14, 2015
Abstract—The main organic impurities in concentrated solutions of sodium thiocyanate in different steps of
production of polyacrylonitrile ﬁ ber were identiﬁ ed, and the possibility of their efﬁ cient removal simultaneously
with iron salts by commercial sorbents of neutral hypercrosslinked polystyrene type was demonstrated.
Polyacrylonitrile (PAN) ﬁ ber is widely used in textile
industry, and the high-strength or high-modulus carbon
ﬁ bers prepared by heat treatment of PAN ﬁ ber bundles
ﬁ nd diverse applications in modern high-tech products.
Setting up large-scale production of high-strength carbon
ﬁ bers is an essential step in updating many steps of
modern industry and the task of strategic importance
[1, 2]. Therefore, the optimization of the production of
the initial PAN bundles in all the steps, including the
system for puriﬁ cation of the polymerization medium,
concentrated solution of sodium thiocyanate (STC), is a
Any structural distortions of the polyacrylonitrile
chain of the polymer, caused by impurities accumulating
in the reaction medium, lead to less regular ﬁ nal carbon
structure and to lower strength parameters of the carbon
ﬁ ber. Therefore, the requirements to the quality of the
initial PAN polymer become more and more stringent.
The goal of this study was analysis of impurities in
the reaction medium of the industrial synthesis of the
acrylonitrile copolymer, the material for forming PAN
ﬁ ber and PAN bundles, and evaluation of advantages
of sorption methods for purification of sodium
thiocyanate solutions using the most effective sorbents,
Copolymerization of acrylonitrile, methyl meth-
acrylate, and itaconic acid is performed in a highly
concentrated (51.5 ± 0.5%) aqueous solution of sodium
thiocyanate, from which the PAN ﬁ ber is subsequently
spun. This reaction medium is used in a closed cycle and
accumulates all the impurities, both those present in the
starting components and the polymerization by-products.
Changes in the composition of the reaction medium can-
not but affect the polymerization and the quality of the
ﬁ ber formed and of items made of it.
The existing method for STC puriﬁ cation (conversion
of STC into hydrogen thiocyanate, its extraction with
diisopropyl ether, and back extraction into aqueous alkali)
involves consumption of large amounts of sulfuric acid
and sodium hydroxide with the formation of mineralized
wastewaters. The process is characterized by strong ﬁ re
hazard associated with the use of the ether; it is also
environmentally unfriendly, because it is based on the
recovery of strongly toxic HCNS. Additional step of