Naeem, M.Kuan, H.C.Michelmore, A.Meng, Q.Qiu, A.Aakyiir, M.Losic, D.Zhu, S.Ma, J.2020-07-302020-07-302020Composites Part B: Engineering, 2020; 196:108096-1-108096-101359-83681879-1069http://hdl.handle.net/2440/126771Organic solvents are often used to prepare epoxy/graphene nanocomposites. In this study a graphene precursor is developed, which in epoxy at 200 °C is able to directly exfoliate into three classes of graphene platelets: large, single-layer sheets, medium sized sheets with 5.2 ± 1.95 nm in thickness, and smaller 0.5–1.0 nm thick sheets of 200–500 nm in lateral dimension, with a Raman ID/IG ratio of 0.177. The yield of single-layer graphene is 41.45%. Due to oxygen-containing groups on the surface, these sheets are named functionalized graphene platelets. Platelet films of ~10 μm in thickness have an electrical conductivity of 978.65 ± 79.44 S/cm. A percolation threshold of electrical conductivity is observed at 0.80 vol% for epoxy/graphene nanocomposites. The composites show highly improved mechanical and dynamic thermo-mechanical properties. At 1.03 vol%, the nanocomposite has a fracture energy release rate of 850.78 ± 58.00 J m−2 corresponding to an increase of 170.61% over neat epoxy.en© 2020 Elsevier Ltd. All rights reserved.Polymer-matrix composites (PMCs); fracture toughness; solventfree synthesis; multiscale graphene/epoxy nanocompositesJournal article100002154210.1016/j.compositesb.2020.1080960005402195000052-s2.0-85085146756533674Losic, D. [0000-0002-1930-072X]