LAUSR

Abstract Composites of polypyrrole with various cation exchanged forms of Zeolite A were successfully synthesized via chemical oxidative polymerization of Pyrrole (Py) in presence of a dispersion of A-zeolite (powder) in deionized water using anhydrous FeCl 3 as an oxidant. The composites were characterized spectroscopically by Fourier Transform-Infrared (FTIR), X-ray diffraction (XRD), Scanning electron microscopic (SEM) and Energy dispersive X-ray analysis (EDXA) for their nature, morphology and elemental analysis. Thermo-gravimetric analysis (TGA) was carried out for the thermal stability of the composites. Gas sensing studies were carried out for the carbon monoxide gas at the concentrations ranging from 5 ppm to 1000 ppm. The effects of cation type, zeolite content and CO concentration on the response of the composites were also investigated. The sensitivity of synthesized composites was found to obey the following order: Na-A/PPy > H-A/PPy > Fe-A/PPy > Cu-A/PPy > PPy depending upon the ionic radius of the cation present in the zeolite-polymer composites and the electronegativity. The response of the Na-A/PPy composite increases from 19.36% to 40.00% as the zeolite content was increased from 10% to 60% (w/w%). This increase in the sensitivity by increasing the zeolite content is due to the increase in the surface area of the composite.