1070-4272/04/7701-0116C2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 1, 2004, pp. 116 !118. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 1,
2004, pp. 119!121.
Original Russian Text Copyright + 2004 by Airapetyan, Khachatryan.
AND POLYMERIC MATERIALS
Effect of Vinylchlorosilane on Polymerization Modification
of the Surface of Nonporous Microspheric Silica Gel
S. S. Airapetyan and A. G. Khachatryan
Khimtekh Research Institute, Yerevan, Armenia
Yerevan State University, Yerevan, Armenia
Received December 3, 2002; in final form, June 2003
Abstract-Formation of a polymeric coating in the course of preparation of polymer-containing silica gel as
influenced by preliminary activation of the surface of nonporous silica gel with vinylchlorosilane was studied.
Nonporous silica gel supports with various grafted
functional groups find expanding application in chro-
matography and immobilization of biopolymers [1, 2].
Before coating of the solid support or sorbent with
a polymeric layer, its surface is activated by various
procedures. Active centers formed by grafting of
organic compounds on the support surface containing
3OH groups allow their subsequent polymerization
modification with various functional groups. Such
active centers, which affect the kinetics of the initiator
degradation and monomer polymerization [3, 4], can
be prepared by grafting of compounds with unsatu-
rated bonds, e.g., vinylchlorosilanes (VCSs) and
vinyltrichlorosilanes, to the hydroxyl-containing sup-
port surface . Polymerization in these systems
is initiated by the agent occurring in the monomer
bulk or sorbed on the surface of modified solid sup-
Formation of a continuous polymeric coating pro-
tecting the support surface is urgent for preparing
packing materials for high-performance liquid chroma-
tography (HPLC). Uncontrolled cross-linking during
deposition of the polymeric coating can deteriorate the
chromatographic properties of the packing materials.
In this work we studied nonporous silica gel micro-
spheres to eliminate the effect of structural features of
the matrix (in particular, support porosity) on the
polymeric coating deposition.
As starting compounds for preparing packing ma-
terials with a polymeric coating we used nonporous
microspheric silica gel with a particle size of 2 mmand
residual pore volume of no more than 0.03 cm
it was prepared by the procedure given in . The sur-
face of this material was modified with VCS and
octadecylchlorosilane (ODCS) with additional silani-
zation with trimethylchlorosilane (TMCS) according
to published procedure .
Copolymer of octadecyl methacrylate (ODMA) and
methyl methacrylate (MMA) was used as polymeric
material. The ODMA3MMA copolymer was prepared
and deposited on the silica gel surface according to
 using dicumyl peroxide initiating agent.
The HPLC analysis was performed on a Gilson
device equipped with a double-beam UV detector
(l = 254 nm) using acetonitrile3water mobile phase
(3 : 7 volume ratio). The tests were performed with
4.6 050- and 4.6 033-mm columns.
We used chemically pure grade reagents and chro-
matographic grade acetonitrile, water, and uracil3
pyridine3phenol3toluene test mixture.
The sorption capacity factor of the material with
respect to toluene can be determined as
are the retention times of toluene and
uracil, respectively (min).
The chromatographic parameters of the columns
packed with nonporous supports (2 mm particle size)
and different content of the polymeric coating are
listed in the table. The particle surface was not pre-
liminarily modified with VCS. The chromatographic
properties of the columns packed with nonporous
silica gel microspheres modified with ODCS (C
given for comparison.
Let us consider the chromatographic properties of