ISSN 1070-4272, Russian Journal of Applied Chemistry, 2008, Vol. 81, No. 1, pp. 131!134. + Pleiades Publishing, Ltd., 2008.
Original Russian Text + N.S. Shaglaeva, R.T. Sultangareev, E.A. Zabanova, O.V. Lebedeva, K.S. Trofimova, 2008, published in Zhurnal Prikladnoi
Khimii, 2008, Vol. 81, No. 1, pp. 136 !139.
AND POLYMERIC MATERIALS
Nucleophilic Substitution of Chlorine Atoms
in Polyvinyl Chloride
N. S. Shaglaeva, R. T. Sultangareev, E. A. Zabanova,
O. V. Lebedeva, and K. S. Trofimova
Favorskii Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Irkutsk State Technical University, Irkutsk, Russia
Received May 15, 2007
Abstract-To modify properties of polyvinyl chloride, its chlorine atoms were substituted using sodium salts
of pyrazole, 3,5-dimethylpyrazole, and 2-mercaptobenzimidazole.
Polyvinyl chloride (PVC) is one of the most impor-
tant polymers produced on a large scale. High cost
efficiency of production and application of PVC in
different branches of industry caused fast growth
in its production in many countries, which is due to
availability and low cost of the initial raw material,
valuable physical and physicochemical properties of
materials and articles made of PVC, and advances
in stabilization of PVC and its processing.
However, PVC has a number of significant draw-
backs. The most serious drawback is that the straight
polymer cannot be processed. The presence of C3Cl
bonds determining many properties of PVC is the
main cause of its poor solubility in organic solvents,
very high viscosity of its melts, and low thermal
stability at temperatures required for its effective
The most widely used method for modifying PVC
properties is copolymerization of vinyl chloride (VC)
with one or several monomers. The PVC properties
can also be improved by nucleophilic substitution of
chlorine atoms in the polymer. Copolymerization of
VC was extensively studied [1, 2], whereas substitu-
tion of chlorine in PVC was given much less attention.
In this study we examined nucleophilic substitution
of chlorine atoms in PVC. For this purpose we used
sodium salts of pyrazole (pz), 3,5-dimethylpyrazole
(dpz), and 2-mercaptobenzimidazole (mbi).
Commercial pz, dpz, and mbi were recrystallized
Sodium and potassium salts of pz, dpz, and mbi
were prepared as follows. The initial pz, dpz, or mbi
(1 mol) were dissolved in ethanol (30 ml). To this
solution, an aqueous solution of NaOH or KOH
(1 mol) was added. The reaction mixture was kept for
3 h at room temperature. The solvent was removed
and the resulting salt was dried by azeotropic distilla-
tion with benzene. The purity of the salt was deter-
mined by potentiometric titration.
Substitution of chlorine atoms was performed in
solvents purified by known methods . To a 4%
PVC solution, Na or K salts of pz, dpz, and mbi were
added in portions at a definite temperature. The salts
were isolated by dialysis or precipitation into water.
The product was filtered off, washed with water, and
dried. The viscosity of polymer solutions was meas-
ured on an Ubbelohde viscometer at 25oC. Elemental
analysis of the reaction products was performed on
a Thermo Finnigan gas analyzer.
The IR spectra of the copolymers in the form of
KBr pellets or mulls in mineral oil were recorded on a
Specord IR-75 or Bruker IFS-25 spectrophotometer.
C NMR spectra of the copolymers were taken
on a Varian VXR-500S spectrometer operating at
125.5 MHz with relaxation delay of 2.5 s and 90o
pulse in DMSO-d
solutions. Chromium(III) acetyl-
acetonate (0.02 M) was used as a relaxation agent.
The relative integration error was 3%. The
spectra were recorded on a Bruker DPX-400 spec-
trometer operating at 400.13 MHz in C
. The concentration of the polymer solutions
The specific surface area of the composites was de-