▎ 摘　　要

We measured the negative normal stress differences in graphene (0.5 wt. %)/polycarbonate composites during shear flow. The Peclet number in graphene/PC melt is estimated to be 10(5) similar to 10(8), indicating the graphene sheets are non-Brownian. The negative normal stress is related with the deformations of gel-like structure of graphene sheets in PC. The storage modulus of graphene/PC composite melts approaches to a solid-like plateau in the terminal region at low concentration of 0.05 similar to 0.70 wt. % graphene. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4704929]