Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 9, pp. 1399−1403.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © I.N. Bakirova, A.S. Kirillova, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 9, pp. 1432−1436.
AND POLYMERIC MATERIALS
Effect of Organometallic Catalysts on the Synthesis
Process and Properties of Molded Polyurethane
I. N. Bakirova and A. S. Kirillova
Kazan National Research Technological University, Kazan, Tatarstan, Russia
Received May 18, 2013
Abstract—Application of organotin catalysts adversely affects the strength of polyurethane. Use of small amounts
of metal acetylacetonates hardly affects the physicomechanical properties of the material, whereas their increased
amounts improve the strength. It is shown that, in contrast to other catalysts, tin octoate does not accelerate the
hydrolysis of the oligoester.
Most of chemical industries require that technological
processes should be accelerated, which is successfully
achieved by use of catalysts. Catalysts are also widely
used in synthesis of polyurethane materials [1–4].
They can accelerate various transformations involving
isocyanates and set the required balance between these
compounds. In this case, the problem encountered
in accelerating the reaction consists in that not only a
catalyst is to be chosen but also the service parameters
of the polymer should not be impaired by this catalyst.
Organometallic compounds belong to catalysts
widely used in manufacture of polyurethanes (PUs) .
So far, the kinetic activity of these catalysts in reactions
with isocyanates, which simulate the chemistry of
PU formation, has been sufﬁ ciently well studied. At
the same time, issues associated with the effect of the
catalyst on the PU properties remain poorly studied.
Meanwhile, knowledge of this relationship enables a
better substantiated approach to the choice of a catalyst,
development of materials with a required combination
of properties, and prediction of their behavior in various
Our study is concerned with effect of the structure
and concentration of the organometallic catalyst on the
synthesis process, physicomechanical properties, and
performance of molded polyurethane.
We synthesized oligoethylene glycol adipate (OEGA)
by condensation of adipic acid with ethylene glycol at
their molar ratio of 1 : 1.3, respectively. The number-
average molecular mass of OEGA obtained was 1850.
A kinetic study of the urethane formation process
was performed with OEGA, 2,4-toluidenediisocyanate
(TDI) and the following catalysts: tin octoate (TO),
dibutyltin dilaurate (DBTDL), iron acetylacetonate
Fe], and copper acetylacetonate [(AcAc)
The reaction was carried out at a temperature of 60°C
and molar ratio of functional groups, NCO : OH = 2.0.
The reaction course was monitored chemically from the
disappearance of NCO groups by titration of a weighed
sample of the reaction mixture dissolved in a mixture
of diethylamine, with acetone and 0.1 n hydrochloric
acid . As the conditional reaction rate was taken the
content of NCO groups in the system in 20 min after the
reaction onset, c
The molded PU of SKU-6 brand was obtained by the
single-stage method. TDI was introduced in a mixture of
OEGA, 1,4-butanediol (BD), 1,1,1-trimethylolpropane
(TMP), an a catalyst, preliminarily dried in a vacuum,
at 55–60°C. The TDI : OEGA : BD : TMP molar ratio
was 2.0 : 1.0 : 0.32 : 0.24. Depending on the amount of
the catalyst, the reaction mass was vacuum-treated for