May 28, 2013
Melt-compounding with graphene enhances elastomer composites
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.
About the author
The study was conducted by three research teams: Polymer Nanotechnology Research Group at University of South Australia (UniSA), Center for Advanced Elastomer Materials (CAME) at Beijing University of Chemical Technology, and Sustainable Material Research Center at Far East University, Taiwan. The teams focused on the development of novel nanomaterials and polymer-based nanocomposites, as well as the identification of structure–property relations of these materials, and their industrial applications. Dr Jun Ma is the group leader at UniSA and guided the project. Sherif Araby is a PhD student supported by International Postgraduate Research Scholarships, Dr Izzuddin Zaman is a Lecturer at University of Tun Hussein Onn, Malaysia, and Qingshi Meng is a PhD student supported by AutoCRC Scholarship. Dr Kawashima and Dr Michelmore performed the structural analysis. Prof Li-Qun Zhang is the director at CAME, and he has conducted extensive studies on elastomers. A/Prof Hsu-Chiang Kuan investigates the processing of polymer composites and their fundamental properties. Prof Peter Majewski works on the synthesis and engineering of surface functionalized and structured materials.