ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 6, pp. 943−948. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © V.V. Tereshatov, A.I. Slobodinyuk, M.A. Makarova, Zh.A. Vnutskikh, A.V. Pinchuk, V.Yu. Senichev, 2016, published in Zhurnal Prikladnoi
Khimii, 2016, Vol. 89, No. 6, pp. 784−789.
AND POLYMERIC MATERIALS
Characteristics of Polyether Urethanes with Mixed Soft Segments,
Prepared by Two- and Three-Step Procedures
V. V. Tereshatov*, A. I. Slobodinyuk, M. A. Makarova, Zh. A. Vnutskikh,
A. V. Pinchuk, and V. Yu. Senichev
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences,
ul. Akademika Koroleva 3, Perm, 614013 Russia
Received June 3, 2016
Abstract—A three-step procedure for preparing polyurethanes with mixed polyether segments was suggested. It
involves preparation of the “inverse” prepolymer by the reaction of one of oligodiisocyanates with 1,4-butanediol
taken in a double excess, followed by the reaction with the other oligodiisocyanate. Polyurethanes with alternat-
ing poly(tetramethylene oxide) and poly(propylene oxide) soft segments were prepared by this procedure. Such
materials surpass polyurethanes prepared from a mixture of oligodiisocyanates in the strength and softening point
of the hard phase. In contrast to poly(tetramethylene oxide) urethane, elastomers with mixed polyether segments
do not crystallize.
Segmented urethane-containing elastomers (SUEs:
polyurethanes, polyurethane–ureas) are widely used in
various branches of industry, in building, and in medicine
[1–3]. The technological and physicomechanical
properties of polyurethane compounds can be controlled
by introducing inorganic ﬁ llers and plasticizers [4, 5].
Polymer chains of SUEs usually consist of alternating
identical soft (SS) and hard (HS) segments, (SSHS)
or of hard segments of equal composition but different
molecular mass (when using different ratios of oligodiol
and low-molecular-mass chain extender) .
The chemical structure of soft segments of SUEs
is set by the structure of the oligomers used in the
synthesis. Hard segments are formed by the reaction
of a diisocyanate with a low-molecular-mass diol or
diamine. In the two-step procedure, ﬁ rst an oligomeric
diisocyanate (prepolymer) is prepared from an oligodiol
and a low-molecular-mass diisocyanate at the NCO/OH
ratio no less than 2. In the second step, the prepolymer
reacts with low-molecular-mass diol or diamine.
The difference in the polarity of soft and hard
segments (blocks) leads to microphase segregation with
the formation of soft and nanodispersed hard phases .
Hydrogen bonds determine the structure and strength of
the structural formations in SUE . Domains of hard
blocks are cross-linking points of a peculiar physical
network, which is more resistant to elevated temperatures
, mechanical loads, and solvents  than the network
of labile physical bonds.
Urethane-containing tri- and tetrablock copolymers
were studied to a considerably lesser extent. However,
the available data demonstrate new possibilities for
controlling the properties of SUEs with polyether soft
segments and urethane or urethane–urea hard blocks.
The effect of mixed soft and different hard blocks on
the properties of block copolymers is not additive [11–14].
The dependence of the initial elastic modulus and secant
modulus on the composition of soft and hard segments of
a series of SUEs passes through an extremum . The
dependence of the strength of the block copolymer on the
composition of mixed urethane and urethane–urea blocks
upon curing of oligoether diisocyanate with a mixture of
a low-molecular-mass diol and an aromatic diamine also
passes through an extremum .