Polypropylene-based conducting nanocomposites: effect of aspect ratio of second conducting filler on the electrical percolation

TitlePolypropylene-based conducting nanocomposites: effect of aspect ratio of second conducting filler on the electrical percolation
Publication TypeJournal Article
Year of Publication2017
AuthorsRamanujam, BTS, Radhakrishnan, S, Deshpande, SD
JournalJournal of Thermoplastic Composite Materials
Volume30
Issue6
Pagination840-854
Date PublishedJUN
Type of ArticleArticle
ISSN0892-7057
Keywordscarbon nanofiber, Conducting polymer composites, Electrical properties, graphite nanosheets, hybrid composites, percolation, scanning, transmission electron microscopy
Abstract

Powder-mixed polypropylene (PP)-graphite binary composites exhibit an electrical percolation threshold at 10 wt% graphite signifying insulator-semiconductor transition. Three conducting fillers such as carbon black (CB), sonicated expanded graphite (s-ExGr), and carbon nanofiber (CNF) are mixed with PP-7 wt% graphite binary composites. The electrical percolation threshold has been found to have inverse relation to the aspect ratio of second conducting fillers in hybrid composites. The aspect ratio of second conducting fillers varies in the order CB < ExGr < CNF. The electrical percolation threshold is found to vary for the hybrid composites as 2.2 wt% for CB addition, 0.75 wt% for ExGr addition, and 0.2 wt% for CNF addition in the PP-7 wt% graphite binary composites. When the aspect ratio of second conducting fillers increases, they reduce the barrier for the charge transport. The second conducting fillers occupy the interspace of graphite and alternating current studies show that the effective dielectric constant increases with the concentration of second conducting filler in the hybrid composites. The composites are characterized by transmission electron microscopy and scanning electron microscopy. Melt-crystallized PP-7 wt% graphite-CNF composites exhibit higher percolation threshold due to decrease in the polymer viscosity which increases the interparticulate distance.

DOI10.1177/0892705715614063
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)0.912
Divison category: 
Polymer Science & Engineering

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