Graphitic Nanofillers in PMMA Nanocomposites—An Investigation of Particle Size and Dispersion and Their Influence on Nanocomposite Properties

ABSTRACT: Mechanical, thermal, and electrical properties of graphite/PMMA compo-sites have been evaluated as functions of particle size and dispersion of the graphitic nanofiller components via the use of three different graphitic nanofillers: ‘‘as received graphite’ ’ (ARG), ‘‘expanded graphite,’ ’ (EG) and ‘‘graphite nanoplatelets’ ’ (GNPs) EG, a graphitic materials with much lower density than ARG, was prepared from ARG flakes via an acid intercalation and thermal expansion. Subsequent sonication of EG in a liquid yielded GNPs as thin stacks of graphitic platelets with thicknesses of 10 nm. Solution-based processing was used to prepare PMMA composites with these three fillers. Dynamic mechanical analysis, thermal analysis, and electrical imped-ance measurements were carried out on the resulting composites, demonstrating that reduced particle size, high surface area, and increased surface roughness can signifi-cantly alter the graphite/polymer interface and enhance the mechanical, thermal