Low and high frequency shielding effectiveness of PVC-PPy films

Abstract

In the present communication, an attempt is made to study the structural, morphological, thermal, low (100 Hz–2 MHz) and high (12.4–18 GHz) frequency dielectric properties of PVC films doped with various weight percentage concentrations of PPy. RFI/EMI shielding effectiveness of these films is also evaluated form the dielectric data. The structural study of the films reveals their amorphous nature. Morphological analysis confirms the growth of conductive phase of PPy in PVC on increasing the PPy content. Thermogravimetric analysis of the films show that the thermal stability of films improves on loading PVC films with PPy. Low and high frequency dielectric characterization of the films show that on increasing weight percentage concentration of PPy in PVC values of dielectric constant, dielectric loss and ac conductivity increase. Study of radio frequency/electromagnetic shielding effectiveness of these films show that these films act as reflective medium in low frequency region and as an absorptive medium in high frequency region. Of all the compositions studied, PVC film with 40% weight concentration of PPy acts as the best reflective shield in radio frequency region and it acts as good absorptive shielding material in the microwave region offering highest and almost constant SET of around −19 dB. This suggests that this composition can be effectively utilized for shielding purposes in both low and high frequency regions.