Super Heat-Resistant Conductive Nanocomposites Based on Polysulfone–Carbon Nanofillers

Author: Nayak Lalatendu   Chaki Tapan K.   Khastgir Dipak  

Publisher: Taylor & Francis Ltd

E-ISSN: 1525-6111|54|3|315-323

ISSN: 0360-2559

Source: Polymer-Plastics Technology and Engineering, Vol.54, Iss.3, 2015-02, pp. : 315-323

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Abstract

The present article describes the morphology, mechanical, thermal, electrical, and dielectric properties of polysulfone (PSU) nanocomposites filled with different concentrations of multiwalled carbon nanotubes (MWCNT) and carbon nanofibers (CNF) [Only one carbon material per each]. The tensile strength and tensile modulus of both MWCNT- and CNF-filled nanocomposites increased with the increase in filler loading up to 3 wt.%. The addition of 3 wt.% CNF led to increase in tensile strength and modulus by 22% and 46%, respectively. Similarly at the same loading of MWCNT, the tensile strength and tensile modulus increased by 16% and 44%, respectively. Thermogravimetric analysis indicated continuous upgrade in thermal stability compared to pure PSU matrix up to 3 wt.% nanofiller loading. Electrical conductivity of both nanocomposites obeyed a power law model of the percolation theory having very low percolation threshold of 0.0079 (0.9 wt.%) for PSU/CNF nanocomposite and 0.014 (1.5 wt.%) for PSU/MWCNT nanocomposite. Dielectric properties of nanocomposites were enhanced significantly with increasing MWCNT/CNF concentration, but decreased with increasing frequency. The dielectric constant reached to 8.5 × 109 (100 Hz) at 5 wt.% MWCNT and 5.4 × 1010 at 5 wt.% CNF, respectively, from the neat PSU matrix (2.1 at 100 MHz). The current (I)–voltage (V) characteristics exhibited ohmic conduction at and above the percolation threshold for both MWCNT- and CNF-filled nanocomposites.