Morphology correlated free volume studies of multi-walled carbon nanotube plasticized poly (vinyl chloride) nanocomposites: Positronium probes and electrical properties

Abstract

Herein we present a new approach to develop nanocomposites based on plasticized poly (vinyl chloride)/multi-walled carbon nanotubes. The free volume is found to increase with increase in MWCNT content up to 1% CNT, but exceptional decrease was observed at higher loading. The increase in free volume is as a result of intercalation of carbon nanotubes between polymer chains, there by introducing slight disorder to nanocomposites. The decrease in free volume is as a result of bridging of polymer chains by carbon nanotubes, resulting in the decrease in free volume at the vicinity of carbon nanotubes. Structural studies via Raman spectra and Doppler Broadening reveals disorder and interfacial interactions in nanocomposites. A frequency up shift of G band is due to π electron transfer from MWCNT to chlorine in PPVC. Using Tao-Eldrup model, radius of free volume (R) and volume of free volume (Vf) are calculated for nanocomposites. Morphological studies via FESEM and TEM reveal uniform dispersion of MWCNT throughout the polymer matrix. Hence, nanocomposite with maximum MWCNT loading showed electrical conductivity of 4.2E-10 S/cm. Thus this is a new composite material for antistatic application.