Polypyrrole/Natural Zeolite Composite Prepared by In Situ Oxidative Polymerization: Thermal and Humidity Sensing Properties

Composite of polypyrrole (PPy) and natural zeolite (NZ) was prepared by chemical polymerization of pyrrole in the presence of zeolite dispersed in aqueous medium. Results of elemental analysis showed that the percentage amount of dopant in the structure of composites was reached a value of as high as 35.5%. PPy content and conductivity of composites obtained under the tried polymerization conditions changed between 8% and 55% and 3.0 x 10(-3) and 17 x 10(-2) S/cm, respectively. The conductivity of composites prepared by chemical polymerization was higher than those prepared by physically mixing of the components of composite. Change in the resistivity of PPy/NZ composite monitored by heating-cooling cycles in the temperature range of 0-60 degrees C repeated five times, we noticed that the composite showed more repeatable results compared to that of its conductive component PPy. Size distribution analysis showed that particle size of NZ in the composite increased as a result of PPy coating and particle size of composite containing 43% PPy reached up to 30 mu m of d(0.9). FTIR, TGA, XRD and SEM techniques were also used for the characterization of PPy/NZ composite.