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Journal of Biotechnology and Phytochemistry
Volume 1 Issue 3
Chemistry World 2017
Page 62
November 13-15, 2017 Athens, Greece
7
th
World Congress on
Chemistry
Chemical ensuring subnanostructures
formation in densely crosslinked organic-
inorganic hybrid polymer networks
Alexander Fainleib
Institute of Macromolecular Chemistry- NASU, Ukraine
Cyanate Ester Resins are known to form polymer networks
through reaction of polycyclotrimerization of cyanate groups.
Cyanate groups are highly reactive towards active hydrogen
containing organic groups as well. The high crosslink
density organic-inorganic hybrid polymer networks have
been synthesized from the mixture of tetraethoxysilane
(TEOS), 3-aminopropyltrimethoxysilane (APTMS) and
1,1-Bis(4-cyanophenyl)ethane (DBCE). First, acid hydrolysis
of the silanes followed by polycondensation reaction of
the hydrolysis products was fulfilled in situ, and then
reaction of DBCE cyanate groups with amino and hydroxyl
groups of silica units formed was carried out under mild
conditions. As a result, some DCBE molecules appeared
to be chemically grafted to the silica network units. Then,
polycyclotrimerization of DCBE free and grafted (by one
side) molecules was performed at high temperatures. The
composites with silica contents from 0.01 to 10 wt. % were
prepared. The state of silica in the composites has been
characterized by means of FTIR, high-angle annular dark-
field scanning transmission electron microscope (STEM)
combined with Energy-dispersive X-ray spectroscopy
(EDXS). For the composites with ultralow silica contents (<<1
wt. %), the structures without nano- or microclusters but with
silica units distributed quasi-regularly within the amorphous
polymer matrix have been formed. The data obtained
imply the existence only in this case of subnanometer-sized
silica nodes connected covalently with the matrix, i.e., the
formation of the hybrid subnanocomposites. The Far-IR
spectroscopy, DMA (Dynamic Mechanical Analysis) and
DSC (Differential Scanning Calorimetry) data showed that
these subnanocomposites manifest the largest “constrained
dynamics” effect and superiority in thermal and mechanical
properties compared to those of the nanocomposites with
higher silica contents containing nanoclusters and their
aggregates.
fainleib@i.uaJ Biotech and Phyto 2017