1070-4272/01/7409-1546$25.00C2001 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 74, No. 9, 2001, pp. 1546 !1550. Translated from Zhurnal Prikladnoi Khimii, Vol. 74, No. 9,
2001, pp. 1500!1504.
Original Russian Text Copyright + 2001 by Borisova, Fazlieva, Fokkho, Promyshlennikova, Cherezova, Khusainov, Mukmeneva.
AND POLYMERIC MATERIALS
Development of Synergistic Stabilizing Compositions
for Polyolefins and Evaluation of Their Performance
M. V. Borisova, L. K. Fazlieva, Zh. Fokkho, M. A. Promyshlennikova, E. N. Cherezova,
A. D. Khusainov, and N. A. Mukmeneva
Kazan State Technological University, Kazan, Tatarstan, Russia
Received December 18, 2000; in final form, July, 2001
Abstract-A series of new synergistic polyfunctional stabilizing compositions phenol3phosphite for poly-
olefins were developed. Their performance as antioxidants, color stabilizers, and agents preventing thermo-
mechanical degradation was quantitatively evaluated.
Despite numerous papers published in the field of
polymer stabilization [1, 2], search for effective sta-
bilizers remains an urgent problem. Growing attention
is given to synergistic mixtures of stabilizers, i.e., to
mixtures whose performance under certain conditions
exceeds the additive value. Of particular importance
are papers aimed at search for synergist intermediates
of antioxidation processes, since specifically these
processes are most often responsible for preservation
of valuable physicochemical properties of polymers
According to the existing theory , the most ef-
fective compositions inhibiting polymer oxidation are
those in which one of the components terminates oxi-
dation chains be decomposing hydroperoxides and the
other reacts with peroxy radicals to form inactive
products. It is known that phenolic stabilizers inhibit
polymer oxidation by decomposing peroxy radicals,
and phosphites decompose hydroperoxides . Fur-
thermore, phosphite-containing stabilizing composi-
tions exhibit one more valuable property: they pre-
serve the polymer color in storage, processing, and
service, which is very important for production of
competitive items .
In this work we studied a series of new stabilizing
As phenolic oxidation inhibitors we tested Irganox
1010 (I, ester of pentaerythritol and 2,6-di-tert-butyl-
4-hydroxyphenylpropionic acid, mp 120oC), Agidol 2
mp 1283129oC], and Agidol 5 (III, 4,4`-dihydroxy-
3,3`,5,5`-tetra-tert-butyldiphenyl, mp 1803181oC).
As organophosphorus component we tested a new
stabilizer, Stafor 24 [IV, tris(2,4-di-tert-butylphenyl)
phosphite, mp 1753183oC) .
Tests were performed with high-density polyethyl-
ene (HDPE) of 289-73 grade [TU (Technical Specifi-
cations) 6-05-1870-804) and polypropylene (PP) (TU
The antioxidative performance of the stabilizers
was evaluated by the duration of the induction period
of oxidation in oxygen  under rigorous conditions:
165oC for PP and 195oC for HDPE.
The color stability of the polymers in the course of
oxidation in air (PP at 165oC and HDPE at 195oC)
was evaluated in a 10-point color scale (white, 1;
The efficiency of thermomechanical stabilization
was evaluated from variation of the torque M
The tensile strength of the polymers was evaluated
as described in . A polymer sample subjected to
thermomechanical degradation was subjected to single
sheeting with laboratory rollers (clearance 1.532 mm),
after which 20330-mm strips were cut. These strips
were subjected to extrusion on the extrusion machine
of a Brabender plasticorder with a stock worm diam-
eter of 20 mm and a length-to-diameter ratio of 22 : 1.
Samples were formed with a slit head 50 mm wide at
a rotation rate of 60 rpm and the following zone tem-
The commercial synthesis procedure was developed at the
Kazan State Technological University; the production was
mastered at the Kazan’orgsintez Joint-Stock Company.