Kinetic and thermodynamic control in conductive <scp>PP/PMMA/EAA</scp> carbon black composites

Abstract

ABSTRACT Multiphase polymer blends provide unique morphologies to reduce the percolation concentration and increase conductivity of carbon‐based polymer composites via selective distribution of the conductive filler. In this work, the kinetic and thermodynamic effects on a series of multiphase conductive polymer composites were investigated. The electrical conductivity of carbon black (CB)‐filled conductive polymer blend composites comprising polypropylene, poly(methyl methacrylate), and ethylene–acrylic acid were determined as a function of compounding sequence and annealing time. Kinetic and thermodynamic parameters were found to influence the conductivity. Phase morphology and conductivity at short annealing times were influenced by the compounding sequence where the CB was added after being premixed with one of the polymer components or directly added to the three‐component polymer melt. However, they were thermodynamically driven at longer annealing times; the resistivity was found to decrease by a statistically significant amount to similar levels for all the composite systems with increasing annealing time. The increase in conductivity at longer annealing times was determined to be the result of changes in the phase morphology from sea‐island, dispersed microstructure to a tri‐continuous morphology rather than change in localization of CB, given that the CB was found to be entirely located in the EAA phase even at short annealing times (and independent of compounding sequence), where the conductivity was not measurable. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42134.