Dr. Jun MA
Research Group: University of South Australia - Mawson Institute|
Current Research ActivitiesFunctional polymer nanocomposites of high mechanical performance. Polymers are of high specific strength and low manufacturing cost, but they inherently lack for functional properties, i.e. electrical/thermal conductivity and radiation shielding, and most polymers need either reinforcing or toughening. Graphene is hailed as the most promising material in engineering and science, because it is the stiffest and strongest material measure to-date and able to elongate 25 % upon loading, with electrical and thermal conductivities higher than copper.
My group has recently synthesized thin graphene platelets, which possess a low ID/IG ratio of 0.06 in Raman spectra, implying high structural integrity and thus retaining maximum of the striking function and mechanical performance of graphene.
Our graphene platelets show a thickness of 3.57±0.50 nm when dispersed in tetrahydrofuran. By compounding with epoxy, the platelets provide a low percolation threshold 0.612 vol% for electrical conductivity; at 0.984 vol%, we have observed a 573 % increase in fracture energy release rate. Please see our publication for details at http://pubs.rsc.org/en/content/articlelanding/2012/nr/c2nr30837a
The thickness of graphene platelets was measured as 2.51±0.39 nm by AFM, when they were suspended in N-methyl-2-pyrrolidone. My group is the first to explore the reaction between the platelets’ epoxide groups and the surfactant end amine groups, which is vital to produce stable graphene colloid. This reaction ha been employed to improve the interface of a polymer nanocomposite. The resulting epoxy nanocomposites demonstrate a lower percolation threshold 0.244 vol% for electrical conductivity; 0.489 vol% platelets have improved the fracture energy release rate from 140.7 to 557.3 kJ/m. Details are available at http://dx.doi.org/10.1002/adfm.201103041