The PG-NH and PG-CF nanocomposites exhibit a ~75% increase and ~50% decrease in filler modulus respectively, compared to PG-10 nanocomposites. The homogeneous dispersion of high aspect ratio PG-NH flakes enables an exceptional ~100% increase in tensile modulus to 5.01 GPa at 6.4 wt.% loading. Whereas the high density of particulates in the PG-CF nanocomposites, which are ineffective for stress transfer, increase the thermal conductivity of the epoxy by 120% to 0.50 W m -1 K -1 at 10 wt.% loading. While the loadings tested (≤ 10 wt.%) did not enable electrical percolative networks to form for any GNP.