1070-4272/05/7809-1522C2005 Pleiades Publishing, Inc.
Russian Journal of Applied Chemistry, Vol. 78, No. 9, 2005, pp. 1522!1525. Translated from Zhurnal Prikladnoi Khimii, Vol. 78, No. 9,
2005, pp. 1547!1550.
Original Russian Text Copyright + 2005 by A. Tereshatov, Fedchenko, Tereshatova, Makarova, V. Tereshatov.
AND POLYMERIC MATERIALS
Influence of the Chemical Structure of Flexible Blocks
on the Mechanical Properties of Poly(Urethane!Ureas)
in a Humid Atmosphere
A. V. Tereshatov, V. V. Fedchenko, E. N. Tereshatova,
M. A. Makarova, and V. V. Tereshatov
Institute of Technical Chemistry, Ural Division, Russian Academy of Sciences, Perm, Russia
Received January 26, 2005
Abstract-Sorption of moisture on segmented poly(urethane3ureas) with flexible segments of various chem-
ical structures and the effect of a humid atmosphere on the mechanical properties of these materials were
studied. Poly(urethane3urea) prepared from mixtures of oligoethers shows advantages from the viewpoint of
preservation of high strength in a humid atmosphere.
Block polyurethane elastomers, so-called seg-
mented polyurethanes (SPUs), are widely used in
various branches of industry thanks to their high
strength, good deformation characteristics, and resist-
ance to a number of solvents . Depending on the
destination, polyurethane items can operate in air or
in direct contact with water (e.g., polyurethane coat-
ings of squeeze rolls in paper-making industry).
Published data on the behavior of SPUs in moist
media mainly concern the moisture transfer in these
materials  and changes in the structure [2, 5, 6]
and glass transition point [5, 6] of moistened polyure-
thanes. Experiments were performed with thin poly-
urethane films prepared from solution; in this case,
correct estimation of changes in mechanical properties
on moistening is complicated by intense moisture
exchange with the surrounding medium. Data on the
mechanical properties of the films are limited to the
results of their mechanical tests before moistening .
Therefore, it is unclear to what extent the mechanical
characteristics of various SPUs vary on moistening
and how the extent of their variation depends on the
Studies in this direction are necessary for under-
standing how the mechanical characteristics of poly-
urethanes change on moistening and for choosing
formulations of polyurethane materials suitable for
operation in moist media.
In this study we examined the influence of the
relative air humidity, varied in a wide range, on the
mechanical properties of SPUs with various flexible
segments. Our main goal was to reveal what structure
of flexible blocks would provide the highest strength
of the polyurethane material in a humid atmosphere.
We used segmented poly(urethane3ureas) with
poly(tetramethylene oxide) flexible blocks (SPUM-1),
poly(propylene oxide) segments (SPUM-2), mixed
polyether blocks (SPUM-3), and mixed polybutadi-
ene3poly(tetramethylene oxide) flexible segments
(SPUM-4). To prepare SPUMs, we took prepolymers
based on oligo(tetramethylene oxide)diol (M ~1700),
oligo(propylene oxide)diol Laprol 2102 (M ~1950),
and polybutadienediol (M ~2100, SKU-DF-2 prepoly-
mer). The molecular weight of the oligomeric diols
was estimated from the content of hydroxy groups.
The prepolymers were prepared by the reactions of
appropriate diols with toluylene-2,4-diisocyanate. The
prepolymers and their mixtures (in preparation of
SPUMs with mixed flexible segments) were cured
with 3,3`-dichloro-4,4`-diaminodiphenylmethane (Dia-
met Kh) by the procedure described in .
The molar ratio of the prepolymers (or their mix-
ture) to Diamet Kh was 1.03, and the molar ratio of
the NCO and OH groups in the synthesis of the pre-
The isotherms of the moisture sorption by SPUMs
were obtained using the kinetic curves of the weight
gain of the samples placed in atmospheres of different
relative humidities j (over appropriate solutions of