TECHNOLOGY OF POLYMERIC
SYSTEMS AND COMPOSITIONS
Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 7, pp. 1056−1063.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © I.A. Novakov, D.V. Pyl’nov, M.A. Vaniev, V.P. Medvedev, A.V. Nistratov, E.V. Petrosyan, E.A. Korchagina, 2013, published in
Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 7, pp. 1122−1130.
Speciﬁ c Features of Curing of Oligodieneurethane
Isocyanate Prepolymer with Glycerol
in the Presence of an Organotin Catalyst
at Twofold Excess of Isocyanate Groups
I. A. Novakov
, D. V. Pyl’nov
, M. A. Vaniev
, V. P. Medvedev
, A. V. Nistratov
E. V. Petrosyan
, and E. A. Korchagina
Volgograd State Technical University, Volgograd, Russia
LKM-Grupp Limited Liability Company, Lipetsk, Russia
Received May 18, 2013
Abstract—The results of rheokinetic studies of catalytic curing of oligo dieneurethane prepolymer with glycerol at
double excess of isocyanate groups are presented. The curing is described in the initial step by the polymerization
equation with varying number of active sites (up to conversion х ≈ 20%); then, by an equation of an autocatalytic
reaction with adiabatic self-acceleration (up to х ≈ 40%); and in the ﬁ nal step (х > 40%), by a second-order equa-
tion with self-acceleration effect.
Curing of reactive oligomers, including isocyanate-
containing prepolymers, accompanied by the formation
of a 3D structure, is a complex multistep process .
The features of the reaction of isocyanate and hydroxy
groups at their equimolar ratio have been well studied and
described [2–6]. At the same time, systems with nonstoi-
chiometric ratio of these groups are also of much interest
for theory and practice. The rheokinetic method is one of
the most convenient and feasible methods for studying the
kinetics of urethane formation and concomitant reactions
and for determining the features of structural transforma-
tions (especially in the initial step) [7–9].
Previously [10, 11] we studied the rheokinetics of
the curing of oligodieneurethane isocyanate prepolymer
(OIP) with glycerol in the presence of an organotin
catalyst and determined the kinetic parameters of the
formation of the 3D network in the initial and ﬁ nal steps
of curing at stoichiometric ratio and 1.5-fold excess of
isocyanate groups. Of no less interest are formulations
with double excess of NCO groups relative to hydroxy
groups. In this case, the speciﬁ c feature of curing is that
the chain propagation can involve, along with the forma-
tion of urethane groups, also branching and formation of
allophanate and biuret groups, and also of trimerization
cross-linking nodes. This diversity of reactions occurring
both concurrently and successively is very important,
because it is reﬂ ected in the structure and properties of
the cured material [12, 13].
In this work we performed a rheokinetic study of cur-
ing of oligodieneurethane isocyanate prepolymer with
glycerol in the presence of an organotin catalyst at double
excess of the isocyanate component.
Oligobutadiene prepolymer with terminal isocyanate
groups (content 4.5 wt %), Krasol NN23 trade name ,
was used as OIP.
Glycerol [TU (Techincal Speciﬁ cation) 6-09-05-816–