ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 6, pp. 1023!1026. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + N.I. Kurbanova, N.Ya. Ishchenko, A.M. Kuliev, 2008, published in Zhurnal Prikladnoi Khimii, 2008, Vol. 81, No. 6,
AND POLYMERIC MATERIALS
Preparation of Modified Polyisoprene
with a High Adhesion Strength
N. I. Kurbanova, N. Ya. Ishchenko, andA. M. Kuliev
Institute of Polymeric Materials, National Academy of Sciences of Azerbaijan, Sumgaiyt, Azerbaijan
Received November 2, 2007
Abstract-Modification of polyisoprene with trichloroacetic acid was studied, and the strength, adhesion,
and thermal properties of vulcanizates obtained from the modified polyisoprene were determined.
One of efficient methods for preparing polymers
with improved properties is chemical modification
usually consisting in treatment of an already formed
polymer molecule with a low-molecular-weight re-
agent. The most widely used modification route is
introduction of functional groups into a polymer
chain by addition or substitution reactions .
Introduction of functional groups into a polymer
macromolecule affects its properties. This can be
seen, e.g., from comparison of the properties of
commercial synthetic isoprene rubber SKI-3 with
those of semicommercial carboxylate isoprene rub-
ber SKI-3K . Rubber stocks based on SKI-3
exhibit decreased cohesion strength, and their vul-
canizates show poor adhesion to metal surfaces,
whereas SKI-3K is characterized by high strength
of rubber stocks and high adhesion of vulcanizates
A known method for improving the SKI prop-
erties is modification by introduction of functional
groups and, in particular, carboxy and hydroxy
groups or chlorine atoms .
Previously, we have examined the modification
of unsaturated elastomers with chloroacetic acids
and their derivatives. Their introduction into rub-
ber macromolecules noticeably improved the phys-
icomechanical parameters of vulcanizates, such as
the tensile, tear, and adhesion strength .
The goal of this study was to prepare modi-
fied SKI with improved physicomechanical proper-
ties, high adhesion, and high heat resistance by
modification of rubber with trichloroacetic acid
As object of study we used SKI-3 rubber with
96 mol % unsaturation and Mooney viscosity of
61 min (100oC); the modifier was TCAA (mp
58.7oC), and the initiator, benzoyl peroxide (BP).
To perform SKI modification, a 0.25-l flask
equipped with a stirrer, reflux condenser, and drop-
ping funnel was charged with a 2-g portion of rub-
ber. The rubber was dissolved in 125 ml of benzene,
and 5310 wt % of the modifier (relative to rubber)
was added. Then the initiator (0.131.0 wt % rel-
ative to rubber) was added, and the reaction was
performed at 60380oC for 1 h. In the process, 1-ml
samples were taken at 5-min intervals, the rubber
was precipitated with methanol, and the reaction
mixture was analyzed for the residual modifier con-
tent. The precipitated rubber was washed with
methanol and dried in a vacuum desiccator at room
The IR spectra were recorded on a UR-20 spec-
trophotometer. Samples were prepared as films on
NaCl plates by complete evaporation of the sol-
vent from 3% solutions of the rubber in benzene.
The chlorine content and unsaturation were deter-
mined using the procedure described in .
The modification kinetics was studied at 603
80oC on a pH-673 device equipped with an elec-
trode pair: a glass indicator electrode and an im-
mersed silver chloride reference electrode. The con-
tent of the unchanged modifier was determined
using a calibration plot.