268990 Does Graphene Increase Tg of Polymer Nanocomposites?
Does Graphene Increase Tg of Polymer Nanocomposites?
Ken-Hsuan Liao1, Steven Maslo1, Shingo Kobayashi1, Hyunwoo Kim2, Ahmed Abdala3, Chris Macosko1
1Chemical Engineering & Materials Sciences, University of Minnesota, Minneapolis MN; 2The Dow Chemical Co., Midland MI; 3Chemical Engineering, The Petroleum Institute, Abu Dhabi UAE
Graphene recently has attracted large interest because of its 2-D structure, outstanding electrical and mechanical properties. Due to the high surface area and aspect ratio, graphene is capable to improve polymers' mechanical properties, gas impermeability and electrical conductivities. However, there is considerable disagreement as to whether the glass transition temperature (Tg) changes with incorporation of graphene in polymers. We review the literature and find that solvent or melt blending of graphene with typical thermoplastics does not result in a change in polymer Tg. However, aqueous-soluble polymer which can form strong hydrogen bonds with graphene derived from graphene oxide (GO) can show a significant Tg increase. Also blending polymers with chemically modified graphene or in situ polymerization of monomers in the presence of GO derived graphene, are capable to provide strong covalent bonds between matrix polymers and fillers, which cause Tg increase. We illustrate this with new experiments on PMMA.