1070-4272/02/7506-1001 $27.00 C 2002 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 75, No. 6, 2002, pp. 1001!1005. Translated from Zhurnal Prikladnoi Khimii, Vol. 75, No. 6, 2002,
Original Russian Text Copyright C 2002 by Safiullina, Sergeeva, Sopin, Zenitova.
AND POLYMERIC MATERIALS
Filling of Castable Polyurethanes with Solid Wastes
from Petrochemical Production
T. R. Safiullina, E. A. Sergeeva, V. F. Sopin, and L. A. Zenitova
Kazan State Technological University, Kazan, Tatarstan, Russia
Received December 10, 2001; in final form, February 2002
Abstract-Physicochemical properties of castable polyurethanes based on polyethylene glycol adipate and
mixture of 2,4- and 2,6-toluylene diisocyanate (NCO : OH molar ratio 1.6) and filled to 10 wt % with silica
gel (waste from petrochemical production) were studied.
Solid wastes, including those from chemical pro-
duction, are the main sources of lithosphere pollution.
Their accumulation in various branches of industry
is determined by the existing level of processing of
raw materials and by their inexhaustive utilization.
Removal (transportation) of the wastes and their stor-
age (design and maintenance of slag-heaps and slurry
tanks) are rather expensive [1, 2].
Solid wastes from petrochemical production in-
clude rejected and spent gas-purifying filters based,
in particular, on silica gel and alumina. Hence, treat-
ment to recycle these compounds is an urgent problem.
It is known that materials of similar composi-
tion are used as fillers of various polymeric compos-
ites and rubbers . However, these fillers are rather
expensive and scarce. Hence, use of wastes containing
silicon as alternative fillers of polymeric materials
and, in particular, castable polyurethanes (PUs) is
a promising way of their safe utilization [4, 5].
In this work, we studied castable polyurethanes
prepared from polyethylene glycol adipate (PEGA,
M ; 2000) and a mixture of 2,4- and 2,6-toluylene
diisocyanate (TDI, 80/20) at a PEGA : TDI molar
ratio of 1.6 . Preliminarily ground to 10350 mm
spent gas-purifying filters based on silica gel [GOST
(State Standard) 3956376] and pearlite [GOST 108323
91] were used as fillers.
The properties of filled PUs at elevated tempera-
tures were studied by differential scanning calorime-
try on a DSC-111 device (Setaram) and thermogravi-
metric analysis on a TGS-2 automated recording unit
(Perkin3Elmer) in the 203500oC temperature range
with heating rate of 5 deg min
. The effective den-
sity of the network v
/V was determined from the axi-
al compression measured on a relaxometer according
to the Cluff-Glading method . The physicochemical
parameters were evaluated according to GOSTs.
As seen from Fig. 1c, the shape of the DSC curves
after filling of the polyurethanes with silica gel is re-
tained. The effect of the fillers on the sample proper-
ties can be analyzed using the TG curves (Fig. 1a).
At temperatures higher than 244oC, the samples
intensively lose weight. At lower temperatures, the
polymer loses about 1.031.5 wt %, which is prob-
ably due to liberation of adsorbed moisture and other
volatile products. In the 2443446oC range, the sample
Table 1. Thermal degradation of PU and amount of residue
in relation to content of silica gel and pearlite fillers
³ Temperature of intensive ³
Content, ³ weight loss, oC ³ Amount of
³ onset ³ end ³
0 ³ 330 ³ 415 ³ 8
1 ³ 335 ³ 420 ³ 10
3 ³ 345 ³ 425 ³ 11
5 ³ 350 ³ 425 ³ 12
10 ³ 355 ³ 430 ³ 14
0 ³ 324 ³ 439 ³ 8.0
1 ³ 328 ³ 440 ³ 8.6
3 ³ 335 ³ 447 ³ 9.0