ISSN 1070-4272, Russian Journal of Applied Chemistry, 2016, Vol. 89, No. 3, pp. 439−446. © Pleiades Publishing, Ltd., 2016.
Original Russian Text © M.N. Gorbunova, G.F. Krainova, D.M. Kisel’kov, V.O. Nebogatikov,
2016, published in Zhurnal Prikladnoi Khimii, 2016, Vol. 89, No. 3,
AND POLYMERIC MATERIALS
Copolymers of Betulin Esters and Silver
Nanocomposites Based on Them
M. N. Gorbunova*, G. F. Krainova, D. M. Kisel’kov, and V. O. Nebogatikov
Institute of Technical Chemistry, Ural Branch, Russian Academy of Sciences,
ul. Akademika Koroleva 3, Perm, 614013 Russia
Reseived February 16, 2016
Abstract—New biologically active silver nanocomposites based on the copolymer of lup-20(29)-ene-3,28-diol
28-O-vinylbenzoate with N-vinylpyrrolidone were prepared by the borohydride method. The formation of spherical
nanoparticles with a mean diameter of 67 nm was conﬁ rmed by scanning electron microscopy. The synthesized
copolymers and silver nanocomposites exhibit cytotoxic activity and show promise for the development of new
materials for medical purposes.
Polyfunctional macromolecular compounds exhibit
high performance as polymer matrices stabilizing
metal nanoparticles and preventing their aggregation.
The presence of functional groups of comonomers in
copolymers favors their efﬁ cient interaction with metal
nanoparticles in early steps of their formation, controlling
their growth, size, aggregation, and distribution in
the polymer matrix and ensuring synergism of unique
properties of the polymer matrix and metal nanoparticles.
It is known from the literature that the particle stabil-
ity is strongly inﬂ uenced by the nature of the nanosta-
bilizing matrix [1, 2]. Highly stable hydrosols with
isolated silver nanoparticles were prepared using the
following matrix materials: water-soluble poly-N-vinyl-
pyrrolidone [2–4] and its copolymer , 1-vinyl-1,2,4-
triazole homo- and copolymers [6, 7], and 2,2-diallyl-
1,1,3,3-tetraethylguanidinium chloride copolymers .
Natural monomers and polymers are also used as
nanostabilizing substances [9–11], and nanocomposites
prepared with them exhibit a broad spectrum of
This study was aimed at synthesis of copoly-
mers of betulin С-28 esters [lup-20(29)-ene-3,28-diol
28-О-vinylacetate (BVA) and 28-О-vinylbenzoate
(BVB)] with N-vinylpyrrolidone and acryloni-
trile in the bulk in the presence of a radical initiator,
azobis(isobutyronitrile) (AIBN), and at preparation of
new water-soluble composites with silver nanoparticles
stabilized with these triterpene-containing copolymers.
Betulin was prepared by the procedures described in
Vinylacetic (VAA) and vinylbenzoic (VBA) acids
(Lancaster) were used without additional puriﬁ cation.
N-Vinylpyrrolidone (VP) (Lancaster) was dried
over KОН and vacuum-distilled; the fraction with
bp 65°С/1.5 mmHg, n
1.5117, was used.
Vinyl acetate (VA) (Lancaster) was puriﬁ ed by
distillation; the fraction with bp 72°С, n
Acrylonitrile (AN) (Alfa Aesar) was puriﬁ ed by
distillation; the fraction with bp 78°С, n
BVA and BVB were prepared as described in
. A mixture of 0.5 g (0.11 mmol) of betulin, 1.8 g
(0.9 mmol) of dicyclohexylcarbodiimide (DCC), 0.28 g