1070-4272/03/7607-1176$25.00C 2003 MAIK [Nauka/Interperiodica]
Russian Journal of Applied Chemistry, Vol. 76, No. 7, 2003, pp. 1176 !1178. Translated from Zhurnal Prikladnoi Khimii, Vol. 76, No. 7,
2003, pp. 1210!1212.
Original Russian Text Copyright + 2003 by Kabakova, Uspenskaya, Sirotinkin, Sanatin.
Behavior of Cross-Linked Copolymers of Acrylic Acid
and 5-Vinyltetrazole in Aqueous Media
M. M. Kabakova, M. V. Uspenskaya, N. V. Sirotinkin, and E. V. Sanatin
St. Petersburg State Technological Institute, St. Petersburg, Russia
St. Petersburg State Institute of Precision Mechanics and Optics, St. Petersburg, Russia
Received October 16, 2002; in final form, April 2003
Abstract-The equilibrium swelling of new hydrogels based on sodium acrylate and N, N-methylenebisacryl-
amide modified with 5-vinyltetrazole in water and aqueous solutions of nickel salts in the stage of radical
polymerization was studied. The influence of 5-vinyltetrazole concentration in the monomer mixture on the
characteristics of the resulting copolymers was studied.
The influence of various modifying copolymers on
the characteristics of acrylic hydrogels has been exten-
sively studied in the past ten years, since slight
changes in the copolymer composition can result in
significant changes in characteristics of the new poly-
meric materials. Progress in synthesis of tetrazole
derivatives gave opportunities for production of new
macromolecular compounds, which significantly
stimulated an interest in this class of (co)polymers,
since introduction of tetrazole-containing monomers
into copolymers expanded the application of acrylic
hydrogels [1, 2]. For example, copolymers based on
salts of acrylic acid (AA) and 2-methyl-5-vinylterazole
can be used as a medium for growth of plants at
elevated ambient temperature .
In this work we studied the behavior of cross-
linked copolymers based on salts of acrylic acid,
5-vinyltetrazole (VT), and N, N-methylenebisacryl-
amide (MBAA) in electrolyte solutions and also the
kinetics of swelling of the synthesized polymers in
Hydrogels based on sodium acrylate, VT, and
MBAA used as a cross-linking agent were prepared
by polymerization in aqueous solution at room tem-
perature; the initiating system was ammonium persul-
fate (APS)3tetramethylethylenediamine (TMEDA).
The degree of neutralization of AA with sodium hy-
droxide was 0.9. The concentration of acrylate mono-
mers in the reaction mixture was 30, VT, from 10 to
50, and APS, 0.8 wt %. The concentration of cross-
linking agent was varied from 0.1 to 0.7 wt % relative
to the sum of the monomers. 5-Vinyltetrazole was
recrystallized before polymerization.
istics and procedures of purification of the other
chemicals, and also the copolymerization procedure
were described previously .
The degree of equilibrium swelling was measured
by the standard gravimetric method and evaluated
by the equation
are the weights of swollen and dried
samples, respectively (g).
In calculations, the results obtained in measurement
of swelling of five similar samples were averaged.
The kinetic dependences of the degree of swelling
in distilled water with variation of the concentration
of the cross-linking agent and VT in the reaction mix-
ture are presented in Figs. 1a and 1b. The experiments
were carried out at 50oC. It is seen that, with increas-
ing content of MBAA cross-linking agent, the equi-
librium degree of swelling decreases. The results ob-
tained allow preparation of tetrazole3acrylic hydrogels
with preset characteristics in a definite time interval,
which is significant for specific applications. This
problem can be solved, e.g., by properly choosing
concentrations of the initial components in the reac-
Both hydrogen bonds involving tetrazole rings and
carboxy groups and hydrophobic interactions between
units affect conformation of macromolecules of N3H-
5-Vinyltetrazole was synthesized at the St. Petersburg State