Russian Journal of Applied Chemistry, 2010, Vol. 83, No. 8, pp. 1360−1366.
Pleiades Publishing, Ltd., 2010.
Original Russian Text
M.A. Makarova, V.V. Tereshatov, V.N. Strel’nikov, 2010, published in Zhurnal Prikladnoi Khimii, 2010, Vol. 83, No. 8, pp. 1254−1260.
Behavior in a Humid Medium of Segmented Polyurethane–Ureas
with Dissimilar Thermodynamically Compatible
and Incompatible Flexible Blocks
M. A. Makarova, V. V. Tereshatov, and V. N. Strel’nikov
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences, Perm, Russia
Received March 30, 2010
Abstract—Fundamental aspects of how moisture sorption affects physicomechanical properties of polyurethane–
ureas based on mixtures of oligoether and oligodiene diisocyanates were studied. Advantages of elastomers with
dissimilar ﬂ exible blocks in providing an enhanced strength of the material in a humid atmosphere and in contact
with water were revealed.
Depending on the destination, articles made of
block-structure polyurethanes, the so-called segmented
polyurethanes, can be used in media with various
relative humidities and, occasionally, in direct contact
with water (e.g., polyurethane coatings of nip rolls of
paper-making machines) . There is evidence that
moisture strongly affects physicomechanical properties
of materials with rigid urethane blocks, produced in
interaction of diisocyanate with 2,4-butanediol. At air
humidities φ exceeding 80%, the strength of materials
of this kind may decrease by a factor of 2.5–3 .
Moisture sorption markedly changes the strength
and elastic properties of segmented polyurethane–
ureas (SPUU) based on polyethers, especially those
with ﬂ exible poly(propylene oxide) segments. Their
moistening leads not only to a weaker interchain
interaction in the ﬂ exible phase of the polymer, but
also, possibly, to partial disintegration of domains of
rigid urethaneurea blocks. As a result, the strength of
the material becomes approximately two times lower at
atmosphere humidities φ = 90–100% .
A possibly promising way to improve the stability
of physicomechanical characteristics of SPUUs on their
exposure to moisture is to synthesize these compounds
from mixtures of oligoether diisocyanates with nonpolar
oligodiisocyanates, e.g., oligodiene diisocyanate,
instead of using individual oligoether diisocyanates.
This can improve not only the stability of SPUUs
against moisture, but also the frost resistance of the
materials. However, this area has been poorly developed
so far. The available single results obtained at close
molecular masses and equimolar ratios between polar
and nonpolar ﬂ exible blocks indicate that the stability of
strength properties of an elastomer with mixed polar and
nonpolar ﬂ exible blocks is higher. The absolute value
of the strength of this material in a humid medium does
not exceed that of poly(tetramethylene oxide) urethane–
The goal of this study was to examine the
fundamental aspects of the effects of dissimilar polar
and nonpolar ﬂ exible blocks on the moisture sorption
and physicomechanical properties of SPUUs and to ﬁ nd
the composition of ﬂ exible blocks that would provide
the highest strength of the material at high air humidities
and in contact with water.
To solve the problem, we used polyurethane–
ureas with polypropylene oxide ﬂ exible blocks
(SPUU-P), poly(tetramethylene oxide) (SPUU-T) and
polybutadiene (SPUU-B) ﬂ exible segments, mixed