Thermally and electrically conductive, mechanically robust elastomer composites can be cost-effectively fabricated by melt-compounding with graphene, according to an international team of polymer experts. Heat-dissipating elastomers are highly desired in both domestic and military applications, and electrically conductive elastomers prevent the accumulation of static electricity and are of significance for underground mining safety.

The group, which includes researchers from the University of South Australia, Beijing University of Chemical Technology and Far East University, developed high structural integrity graphene platelets of 2–4 nm in thickness by combining the thermal expansion of a commercial graphite intercalation compound (Asbury 3494, 6–8 US$/kg) in a common furnace with a sonication process.

An industrial facility – two-roll mill – was employed to melt-compound graphene platelets (GnPs, estimated at 10–20 US$ per kg) with a commercial elastomer – ethylene-propylene-diene monomer rubber (EPDM), to fabricate electrically and thermally conducing elastomer-based composites of high mechanical performance.

A percolation threshold of electrical conductivity at 18 vol% GnPs was observed, and the thermal conductivity of the elastomer increased 417% at 45 vol%. The modulus and tensile strength increased 710% and 404% at 26.7 vol%, respectively. These highly improved functional and mechanical properties are due to the good dispersion of thin GnPs and the compatibility of the nanomaterial with polymer.

The reinforcing effect and cost advantage of GnPs appear to be generally superior to silicate layers and carbon nanotubes.

The researchers presented their results in the journal Nanotechnology.