  Graphene is one of the stiffest known materials, with a Young's modulus of 1
TPa, making it an ideal candidate for use as a reinforcement in
high-performance composites. However, being a one-atom thick crystalline
material, graphene poses several fundamental questions: (1) can decades of
research on carbon-based composites be applied to such an ultimately-thin
crystalline material? (2) is continuum mechanics used traditionally with
composites still valid at the atomic level? (3) how does the matrix interact
with the graphene crystals and what kind of theoretical description is
appropriate? We have demonstrated unambiguously that stress transfer takes
place from the polymer matrix to monolayer graphene, showing that the graphene
acts as a reinforcing phase. We have also modeled the behavior using shear-lag
theory, showing that graphene monolayer nanocomposites can be analyzed using
continuum mechanics. Additionally, we have been able to monitor stress transfer
efficiency and breakdown of the graphene/polymer interface.
