On the Composites Based on Epoxy Resin - Progress in Organic and Physical Chemistry: Structures and Mechanisms - page 174

The silanization reaction of diatomite surface with TEOS was carried out by
means of three-necked À ask supplied with mechanical mixer, thermometer, and drop-
ping funnel. For obtaining of modi¿ ed by three mass % diatomite to a solution of 50 g
grind ¿ nely diatomite in 80 ml anhydrous toluene the toluene solution of 1.5 g (0.0072
mole) TEOS in 5 ml toluene was added. The reaction mixture was heated at the boil-
ing temperature of used solvent toluene. Than the solid reaction product was ¿ ltrated,
the solvents (toluene and ethyl alcohol) were eliminated, and the reaction product was
dried up to constant mass in vacuum. Other product modi¿ ed by 5% tetraethoxysilane
was produced via the same method.
Following parameters were de¿ ned for obtained composites: ultimate strength (on
the stretching apparatus of type “Instron”), softening temperature (Vica method), den-
sity, and water absorption (at saving of the corresponding standards).
15.3 DISCUSSION AND RESULTS
The high temperature condensation reaction between diatomite and TEOS from the
one side, and between andesite and same modifier from the other one was carried out
in toluene solution (~38%). The masses of TEOS were 3 and 5% from the mass of
filler. The reaction systems were heated at the solvent boiling temperature (~110 o C)
during 5-6 hr by stirring. The reaction proceeds according to the following scheme:
The direction of reaction defined by FTIR spectra analysis shown that after reaction
between mineral surface hydroxyl, OSi(OEt) 3 and the OSi(OEt) 2 O- groups are formed
on the mineral particles surface.
In the FTIR spectra of modi¿ ed diatomite one can observe absorption bands char-
acteristic for asymmetric valence oscillation for linear Ł Si-O-Si Ł bonds at 1030 cm -1 .
In the spectra one can see absorption bands characteristic for valence oscillation of
Ł Si-O-C Ł bonds at 1150 cm -1 and for º C-H bonds at 2,950-3,000 cm -1 . One can see
also broadened absorption bands characteristic for unassociated hydroxyl groups.
On the basis of modi¿ ed diatomite and epoxy resin (of type ED-20) the poly-
mer composites with different content of ¿ ller were obtained after careful wet mixing
of components in mixer. After the blends with hardening agent, (polyethylene-poly-
amine) were placed to the cylindrical forms (in accordance with standards ISO) for
hardening at room temperature during 24 hr. The samples hardened later were exposed
to temperature treatment at 120 o C during 4 hr. The concentration of powder diatomite
(average diameter up to 50 micron) was changed in the range 10-60 mass %.