Preparation of polystyrene-graphite conducting nanocomposites via intercalation polymerization

In situ polymerization of styrene was conducted in the presence of expanded graphite obtained by rapid heating of a graphite intercalation compound (GIC), to form a polystyrene-expanded graphite conducting composite. The composite showed excellent electrically conducting properties even though the graphite content was much lower than in normal composites. The transition of the composite from an electrical insulator to an electrical semiconductor occurred when the graphite content was 1.8wt%, which is much lower than that of conventional conducting polymer composites. TEM, SEM and other studies suggest that the graphite was dispersed in the form of nanosheets in a polymer matrix with a thickness of 10-30nm, without modification of the space between carbon layers and the structure of the graphite crystallites. The composite exhibited high electrical conductivity Of 10(-2)Scm(-1) when the graphite content was 2.8-3.0wt%. This great improvement of conductivity could be attributed to the high aspect ratio (width-to-thickness) of the graphite nanosheets. The rolling process strongly affected the conductivity and the mechanical properties of the composite. (C) 2001 Society of Chemical Industry.