Effect of multiwalled carbon nanotube and temperature on dielectric and impedance spectroscopy of chlorobutyl elastomer nanocomposites. (October 2015)

• Record Type: Journal Article
• Authors: Tiwari, Shashi Kant; Choudhary, Ram Naresh Prasad; Mahapatra, Shyama Prasad
• Is Part Of: Journal of elastomers and plastics. Volume 47:Number 6(2015)
• Page Start: 549
• Page End: 572
• Publication Date: 2015-10
• Subjects: Nanocomposite -- carbon nanotube -- dielectric -- temperature -- conductivity -- percolation; Plastics -- Periodicals; Elastomers -- Periodicals; 668.405
• DOI: 10.1177/0095244314526742
• Languages: English
• ISSNs: 0095-2443

Abstract

Dielectric relaxation characteristics of multiwalled carbon nanotube (MWCNT)-reinforced chlorobutyl (CIIR) nanocomposites have been studied as a function of frequency (100–10 6 Hz) at different filler loadings (0, 2, 4, 6 and 8 phr) over a wide range of temperatures (30–120°C). The effect of MWCNT loadings and temperature on the dielectric permittivity ( ∊ ′), dielectric loss tangent (tan δ ), complex impedance ( Z *) and electrical conductivity ( σ ) was studied. The variation of ∊ ′ with MWCNT loading has been explained based on the interfacial polarization of the fillers within a heterogeneous system. A significant effect of MWCNT loading on the real ( Z ′) and imaginary ( Z ′′) part of Z * was observed due to the relaxation dynamics of polymer chains at the CIIR-MWCNT interface. The non-linearity of CIIR nanocomposites has been studied from Nyquist plots. The dielectric modulus formalism has been utilized to further investigate the conductivity and relaxation phenomenon. The permittivity and conductivity of the nanocomposites have been analyzed based on scaling theory at increasing temperatures. The frequency dependency and percolation phenomenon in the composites have been discussed in terms of σ . The percolation threshold ( Φ crit ) occurred at around 6 phr of MWCNT loading irrespective of temperature. The dispersion of MWCNT in the CIIR matrix and agglomeration of the filler at higher loading have been studied using scanning electron microscopic photomicrographs.