Investigation on the effect of in-situ growth of PPy on structural, thermal and dielectric properties of PVA-CMC blend films

The intrinsic conducting polymer (ICP) Polypyrrole (PPy) was grown in situ in the matrix of polyvinyl alcohol (PVA)-Sodium carboxymethyl cellulose (CMC) using chemical oxidative polymerization method. The effect of in-situ growth of PPy on structural, morphological, thermal and dielectric properties of PVA-CMC blend films were investigated. Growth of PPy in the matrix of PVA-CMC was seen in SEM micrographs along with structural modifications which were confirmed by XRD and FT-IR analysis suggesting the amorphous nature of PVA-CMC-PPy blend films. Thermal analysis suggests good miscibility and compatibility of the polymers in the blend. The changes in the dielectric properties of in-situ-grown conducting polymer blend films of PVA-CMC-PPy were studied in detail at low frequency (100 Hz to 2 MHz) . Enhancement in the dielectric constant and ac conductivity values of PVA-CMC- PPy films were observed in this frequency range that is related to increased amorphousness and formation of conductive channels due to the presence of PPy. Further, the microwave absorption and dielectric behavior of PVA-CMC-PPy films in high-frequency region (200 MHz – 20 GHz) were specially studied to see the suitability of these films for EMI shielding application.