ISSN 1070-4272, Russian Journal of Applied Chemistry, 2014, Vol. 87, No. 8, pp. 1156−1160. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © M.S. Dashitsyrenova, D.M. Mognonov, S.L. Buyantuev, S.A. Bal’zhinov, 2014, published in Zhurnal Prikladnoi Khimii, 2014, Vol. 87,
No. 8, pp. 1178−1182.
AND POLYMERIC MATERIALS
Synthesis and Properties of Sulfonated
M. S. Dashitsyrenova
, D. M. Mognonov
, S. L. Buyantuev
, and S. A. Bal’zhinov
Baikal Institute of Nature Management, Siberian Branch, Russian Academy of Sciences,
ul. Sakh’yanovoi 8, Ulan-Ude, Buryatia, 670047 Russia
Buryat State University, ul Smolina 24, Ulan-Ude, Buryatia, 670000 Russia
East Siberia State University of Technologies and Management,
ul. Kalandarishvili 16, Ulan-Ude, Buryatia, 670013 Russia
Received August 29, 2014
Abstract—New polyamidobenzimidazoles derived from sulfonated diamine were synthesized, and strong
ﬁ lms based on them were prepared. The synthesized polymers were characterized by Fourier IR spectroscopy,
thermogravimetric analysis, and dynamic mechanical analysis, and their proton conductivity was measured.
Among a wide range of the existing polyhetero-
arylenes, polybenzimidazoles (PBIs) form a particular
group. They exhibit unique properties such as chemical,
flame, and heat resistance and mechanical strength
. Polyamidobenzimidazoles (PABIs) are PBIs
containing in the macrochain amide bonds alongside with
benzimidazole fragments. This combination improves
the solubility in available solvents and makes it possible
to make ﬁ bers and ﬁ lms based on these materials [2–4],
capable of operating as proton-conducting membranes of
medium-temperature fuel cells.
Despite the fact that numerous kinds of polymeric
membranes with high proton conductivity (PC)
characteristics have been developed, their wide practical
use is prevented by complex synthesis procedures and
high cost of the starting substances.
This paper deals with the synthesis and study
of sulfonated polyamidobenzimidazoles (SPABIs),
which are prepared by activated polycondensation
of 3,3',4,4'-tetraaminodiphenyl oxide (TADPO),
4,4'-diaminostilbene-2,2'-disulfonic acid (DASA),
and dinitrodiphenyl esters of dicarboxylic acids:
4,4'-dinitrodiphenyl adipate (DNDPA) and
4,4'-dinitrodiphenyl sebacate (DNDPS).
All the monomers and solvents were preliminarily
purified by standard procedures . The activated
polycondensation was performed as follows: Equimolar
amount of the monomers was dissolved in m-cresol in an
argon stream while stirring, after which the temperature
was raised to 140°С, and the synthesis was performed
for 3 h with continuous mixing to obtain the prepolymer,
sulfonated polyamino amide (SPAA), which was isolated
by precipitation into ethyl acetate. The SPAA obtained
was subjected to cyclization in a mufﬂ e furnace at 200°C
for 2 h (the cyclization process was studied in detail
previously ). The SPABIs obtained are soluble on
heating in amide solvents and in concentrated sulfuric
and formic acids. The reduced viscosities of SPABIs vary
insigniﬁ cantly relative to the prepolymers' ones.
The IR spectra were recorded with an Excalibur FTS
3000NX spectrophotometer (Varian) in the wavenumber
range 4000–400 cm
using an ATR attachment.
Thermomechanical studies were performed on a DMA
242 C device for dynamic mechanical analysis (Netzsch)
at a heating rate of 5 deg min
in a He atmosphere
(gas ﬂ ow rate 80 mL min
) at a frequency of 1 Hz.