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

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 threecomponent 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 seaisland, 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.

Experimental and numerical analysis of conductive ternary polymer blend composites

“…The overall increase in conductivity of the PP/PMMA/(EAA‐CB) system compared to the single‐phase system in Figure is not due to the percolation of the CB, but is believed to be due to changes in the phase morphology and the formation of a completely connective EAA‐CB network. Previous experimental work showed that the morphology and resultant conductivity was found to be kinetically driven during the intensive compounding process and transitioned from kinetic to thermodynamic control after long annealing times . However in addition, we have found in a separate study that beyond a critical loading of conductive filler particles in the minor EAA phase, especially for high aspect ratio fillers such as the type of CB used in this work, phase separation is slowed significantly due to the aggregation of particles into a network formation within the EAA phase causing a significant increase in phase viscosity which can impact the overall morphology development.…”

“…Previous experimental work showed that the morphology and resultant conductivity was found to be kinetically driven during the intensive compounding process and transitioned from kinetic to thermodynamic control after long annealing times. 22 However in addition, we have found in a separate study that beyond a critical loading of conductive filler particles in the minor EAA phase, especially for high aspect ratio fillers such as the type of CB used in this work, phase separation is slowed significantly due to the aggregation of particles into a network formation within the EAA phase causing a significant increase in phase viscosity which can impact the overall morphology development. Chen et al 42 reported similar behavior in a PP/PMMA binary system where the coarsening process of the composites was significantly suppressed with the incorporation of carbon nanotubes.…”

“…An extension of the PP/PMMA/(EAA-CB) ternary polymer blend evaluated previously served as the basis for this study. 22 The polymers used in this work were PP (FF018F) from Braskem, PMMA (IF 850B) from LG Chemicals, and EAA copolymer (PRIMACOR TM 3004) with 9.7 wt % acrylic acid from The Dow Chemical Company. The conductive filler was a high surface area extra conductive CB (Ketjenblack EC-300J) from AkzoNobel.…”

“…Previous work showed that kinetic and thermodynamic parameters influenced the phase morphology and CB filler localization in CB‐filled polypropylene (PP)/poly(methyl methacrylate) (PMMA)/ethylene acrylic acid copolymer (EAA) ternary blends to increase electrical conductivity at significantly lower filler loading over a single polymer system as a function of annealing time . The PP/PMMA/(EAA‐CB) system was found to have an overall increase in conductivity upon thermal annealing as a result of changes in the phase morphology from a sea‐island to tri‐continuous structure.…”

Highly efficient electrically conductive networks in carbon‐black‐filled ternary blends through the formation of thermodynamically induced self‐assembled hierarchical structures

“…A suitable third polymer must fulfill two conditions: [27][28][29] (1) it must thermodynamically form the interphase of a tricontinuous blend, and (2) it must have the highest affinity for conductive particles among the three polymer components. For example, the addition of a styrene-butadiene-styrene triblock copolymer and an ethylene-acrylic acid copolymer can drive CB particles to the interfaces of polypropylene (PP)-polystyrene and poly (methyl methacrylate)-PP blends, 27,28,[30][31][32][33][34] respectively, and the precompounding of carbon nanotubes with maleic anhydride grafted acrylonitrile-butadiene-styrene and pyridine-modified poly(ethylene-co-methacrylic acid) can drive the carbon nanotubes to the interfaces of polycarbonate-acrylonitrile-butadiene-styrene and polyamide 12-PP blends, 29,35 respectively. So far, all of the studies on conductive particle-filled ternary polymer blends have dealt with driving conductive particles to the interface of the two major phases by the interfacial localization of the minor, third polymer component.…”