Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 9, pp. 1430−1434.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © R.N. Gadel’shin, A.D. Khusainov, Yu.N. Khakimullin, R.S. Davletbaev, O.Yu. Emelina, I.M. Davletbaeva, 2013, published in Zhurnal
Prikladnoi Khimii, 2013, Vol. 86, No. 9, pp. 1463−1467.
AND POLYMERIC MATERIALS
Modiﬁ cation of Siloxane Rubber
with Aminoethers of Boric Acid
R. N. Gadel’shin
, A. D. Khusainov
, Yu. N. Khakimullin
R. S. Davletbaev
, O. Yu. Emelina
, and I. M. Davletbaeva
Kazan National Research Technological University, Kazan, Russia
Kazan State Technical University, Kazan, Russia
Received February 12, 2013
Abstract—A modifying effect of amino esters of boric acid on polydimethyl/methylvinyl siloxane caoutchouc and
resin based on them was studied. It is shown that small amount of this type of modifying agent leads to a marked
increase in viscosity of the compositions, and improved mechanical and thermal properties of the vulcanizates.
With increasing the amount of the modifying agent they begin to show properties of a plasticizer.
At present, it is generally accepted that the possibility
of improving the properties of siloxane rubber due to the
synthesis of new silicone rubber has already been largely
exhausted. Therefore, an important role in the creation
of siloxane rubber with improved properties belongs to
modifying agents of chemical and physical type, ﬁ llers,
plasticizers, and other target additives.
For improving the mechanical and technological
properties of siloxane rubbers various white carbons,
ﬁ ne quartzite are used as ﬁ llers along with chemically
precipitated silica, and low molecular weight polydimeth-
ylsiloxanes and borsiloxane rubbers, as modifying agents
manifesting itself plasticizing properties. Introduction
of borsiloxane rubber in an amount of 5 wt % leads to
a substantial improvement of autohesion, adhesion, and
physico-mechanical properties of siloxane rubbers .
In this connection, the use of organic boron compounds
may be promising for improving the properties of silox-
Sterically hindered aminoethers of boric acid (AEBA)
were synthesized and investigated as modifying agents
for siloxane rubbers. In [2–4] possibility of the formation
in AEBA, which was synthesized using TEG, of intra-
and inter-molecular complexes, was demonstrated
(see the scheme). In these studies it was found that as
a result of the complexation spatially separated cations
of tertiary ammonium and borate anions were formed.
The average size of AEBA intermolecular complexes
determined by dynamic light scattering was 86 nm.
It is known that boric acid esters are of low hydrolytic
stability. It was revealed that the steric hindrances as
well as intermolecular and intramolecular complexation
result in the signiﬁ cant hydrolytic stability of the
It was assumed that AEBA representing branched
structure and containing along with the spatially
separated ion pairs terminal hydroxyl groups must
manifest itself as a physical modifying agent of
polydimethyl/methylvinyl siloxanes. As a result, in the
modiﬁ ed silicone rubber the formation of an additional
physical spatial polymer network may occur as well as
an increase in a strength of its vulcanizates.
For the synthesis of rubber compositions the
following components were used (wt %): polydi-
methyl/methylvinyl siloxane rubber SKTV-1 (resistant
vinyl synthetic rubber) 100, Aerosil (A-300) 40,
zinc oxide 5, an anti-structuring additive α,ω-