1070-4272/04/7704-0603 C 2004 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 77, No. 4, 2004, pp. 603!607. Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 4, 2004,
Original Russian Text Copyright + 2004 by Lavrov, Pisarev, Sivtsov.
AND POLYMERIC MATERIALS
Copolymerization of N-Vinylsuccinimide
with Butyl Methacrylate in Pyridine
N. A. Lavrov, A. G. Pisarev, and E. V. Sivtsov
St. Petersburg State Technological Institute, St. Petersburg, Russia
Received January 23, 2004
Abstract-The kinetics of radical copolymerization of N-vinylsuccinimide with n-butyl methacrylate in
pyridine was studied, and the previously unknown copolymerization constants of the monomers were de-
termined. The calculations were performed using appropriate software and a new procedure for approxima-
tion of the experimental data, which allow determination of the kinetic parameters at high conversions with
the minimum error. The copolymerization kinetics were compared for the reaction systems constituted by
N-vinylsuccinimide and n-butyl methacrylate and by N-vinylsuccinimide and n-butyl acrylate.
Copolymers of N-vinylsuccinimide (VSI) with
n-butyl acrylate (BA) were suggested as materials for
preparing films for medicobiological purposes .
The acrylic comonomer acting as internal plasticizer
makes it possible to prepare elastic films recom-
mended for protection and treatment of skin wounds.
However, copolymers containing more than 80390%
BA are sticky liquids incapable of film formation.
This drawback can be eliminated by introducing one
more comonomer, i.e., by partially replacing BA with
n-butyl methacrylate (BMA). Papers on preparation of
VSI polymers and copolymers, published in the last
50 years , contain no data on binary copolymeriza-
tion of VSI with BMA. In this study, we examined
the copolymerization of VSI with BMA in pyridine.
The monomers and initiator, azobis(isobutyroni-
trile) (AIBN), were purified as described in . Ana-
lytically pure pyridine was double-distilled. The co-
polymerization of the monomers was performed in
glass ampules under Ar at 60oC. The total concentra-
tion of the monomers in pyridine was 0.7, and that of
AIBN, 0.0165 M. The reaction kinetics was studied
gravimetrically, as in . After the copolymerization
was complete, the ampule contents were poured into
distilled water. The precipitated copolymer was filtered
off and dried to constant weight at 20oC (660 Pa).
The copolymer compositions (Table 1) were deter-
mined by IR spectroscopy from the ratio of the optical
density at 1700 cm
, to that at 1725 cm
, using a calibration plot constructed according
to . The IR spectra of copolymers were recorded on
a Perkin3Elmer spectrophotometer. Samples were pre-
pared as films cast on KBr plates or as free films.
Copolymerization of VSI with both BMA and BA
 in pyridine is relatively fast, which does not al-
ways allow isolation of the copolymers at low conver-
sions. With increasing conversion, the viscosity of
the reaction mixture grows, thus complicating a quan-
titative isolation of the product. Copolymerization
occurs under homogeneous conditions and yields co-
polymers soluble in organic solvents, which allows
preparation of films by casting.
Comparison of the kinetics of VSI3BMA copoly-
merization with that of VSI3BA copolymerization and
with the results given in  shows that the initial rate
of VSI3BMA copolymerization is higher as compared
to the VSI3BA system (Table 1). This is due to the
higher activity of BMA, compared to BA. However,
the rate of copolymerization of VIS with BMA de-
creases with increasing conversion (Table 1). This
may be due to changes in the solution viscosity and
in conformations of macromolecules in the course of
polymerization, and also to steric factors.
The high viscosity of the reaction system may be
responsible for the fact that the gravimetric method
used to monitor the copolymerization kinetics gives
a certain scatter of experimental points. As a result,
the error in calculation of the copolymerization con-
stants increases. Therefore, in studying the kinetics
of copolymerization of VSI with BMA, we used the
approximation procedure  allowing correction of