چكيده لاتين :
In view of their sensitivity to oxidation and to doping gases, it would seem natural to
use conducting polymers as chemical sensors. The first graft copolymer of polypyrrole
has been synthesized by chemical and electrochemical polymerization of pyrrole in
the presence of poly(para-chloromethylstyrene-co-styrene-co-pyrrolemethylstyrene),
which is abbreviated as PCMS-co-St-co-PMS. Electrochemical synthesis of PCMS-co-Stg-
PPy was carried out in conventional three-electrodes system with a SCE reference
electrode, platinum wire counter electrode, GC disk working electrode and tetrabutylammonium
hexafluorophosphate in acetonitrile as carrying electrolyte. The produced
copolymer exhibits an electrical conductivity comparable to that of polypyrrole. Then, prepared
films were exposed to hydrogen halides, hydrogen cyanide, halogens, 1,3,5trichloromethyl
benzene (TCMB), methylbenzyl bromide (MBB), bromoacetone (BA), and
cyanogen bromide (CB). Thermal stability of PCMS-co-St-g-PPy was investigated by
scanning thermal analysis (STA), differential scanning calorimetry (OSC) and thermal
gravimetrical analysis (TGA). TGA thermogram of copolymer showed multistep thermal
degradation behaviour. This measurement showed that copolymer has excellent thermal
stability. The response mechanism of this compound to sense a selection of gases and
vapours was investigated, by measuring its electrical conductivity by four-point probe
method. This gas sensor may have advantages over the other sensors in its ability to
operate at room temperature, lower gas and vapours sensing concentration, suitable solubility,
stability in air, sufficient diffusion, and selectivity.
