Russian Journal of Applied Chemistry, 2013, Vol. 86, No. 10, pp. 1594−1599.
Pleiades Publishing, Ltd., 2013.
Original Russian Text © O.N. Tretinnikov, L.K. Prikhodchenko, L.V. Shkrabatovskaya, 2013, published in Zhurnal Prikladnoi Khimii, 2013, Vol. 86, No. 10,
AND POLYMERIC MATERIALS
Photoinduced Graft Polymerization of Acrylic Acid
on the Surface of Polypropylene Films from a Thin Layer
of Nondeaerated Aqueous Solution of the Monomer
O. N. Tretinnikov, L. K. Prikhodchenko, and L. V. Shkrabatovskaya
Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk, Belarus
Received August 31, 2013
Abstract—Photoinduced graft polymerization of acrylic acid on the polypropylene ﬁ lm surface containing a
preliminarily adsorbed photoinitiator (benzophenone) from a thin layer of a nondeaerated aqueous solution of
the monomer, isolated from the contact with atmospheric oxygen, was studied. Data were obtained on how the
amount of the grafted polymer and the wetting angle for water on the ﬁ lm surface depends on the duration of the
UV irradiation and on the monomer solution layer thickness. These data are compared with the results previously
obtained for the photoinduced grafting of polyacrylic acid on polyethylene ﬁ lms.
In recent years, a considerable attention has been
given in the ﬁ eld of modiﬁ cation of polymeric materials
with surface-grafted functional polymers  to the
photoinduced graft polymerization . The method
consists in that molecules of the photoinitiating agent
become excited under the UV irradiation and, interacting
with the surface of the substrate polymer, split-off
from it hydrogen atoms and thereby create surface
macroradicals from which surface-grafted chains start
to grow in the presence of monomer molecules by the
radical polymerization mechanism [3, 4]. The method
is favorably distinguished from the radiation-induced
grafting methods with gamma radiation or electron
beams in simplicity, economic efﬁ ciency, high rate, and
no chemical destruction or deterioration of properties in
the bulk of the substrate polymer.
Benzophenone (BP) is an efﬁ cient, inexpensive, and,
accordingly, most widely used photoinitiating agent.
Most of photoinitiators, including BP, are insoluble
in water. Therefore, the grafting has been performed
until recently from joint solutions of monomers and
photoinitiators in organic solvents, although numerous
functional monomers are water soluble.
In 1996, Ulbricht suggested a method in which the
water-insoluble photoinitiator (BP) s deposited onto
the surface being modiﬁ ed from a solution in a volatile
organic solvent and then the graft polymerization is
performed from a solution of monomer in water .
In this case, as also in earlier techniques, the solution
is preliminarily deaerated to remove molecular
oxygen because it inhibits the photoinduced radical
polymerization. Previously, it has been shown, with
this method employed to graft polyacrylic acid (PAA)
on the surface of polyethylene (PE) ﬁ lms, that a
grafted polymer can be successfully obtained from a
nondeaerated (oxygen-containing) monomer solution.
For this purpose, a monomer solution is deposited onto
the ﬁ lm surface as a thin (~10 μm) layer and is isolated
from contact with the ambient air with a UV-radiation-
transparent plate or ﬁ lm . It seems to be important to
examine the applicability of this approach not only to
polyethylene, but also to other polyoleﬁ ns.
The goal of our study was to examine the
photoinduced graft polymerization of acrylic acid from
a thin layer of a nondeaerated aqueous solution of
the monomer on the polypropylene (PP) ﬁ lm surface