| 초록 |
We fabricated graphene/polycarbonate nanocomposites by solution blending. In steady shear flow of the composite melt, we observed the contraction to the direction orthogonal to the shear direction. The Peclet number in graphene/polycarbonate composites is estimated to be 105~108, indicating the structural evolution of graphene sheets during shear flow may not be related with Brownian motion. The contraction results in the negative normal stress differences, which is due to the contraction of the composite induced by the deformation of gel-like structure during flow in melt. The linear viscoelasticity of graphene/PC composites was also characterized. The storage modulus approaches to a solid-like plateau in low frequency at concentration of graphene from 0.05 to 0.70 wt.%. The results presented here indicate that a small amount of graphene can be utilized as a flow modifier for PC in various applications such as polymer composites and a coating process. |
