This work reports an improvement in the mechanical and thermo-mechanical properties of short carbon
fiber (SCF)/polypropylene (PP) composite, resulting from coating of the SCFs with exfoliated graphene
nanoplatelets (xGnPs). Firstly, the xGnPs were coated on the SCFs surface by a simple physical absorption
method, and then the composites were manufactured by melt blending and hot-press processing. The
amount of SCFs was kept constant at 15 wt% and the amount of xGnP was varied up to 3 wt%. Results of
tensile and impact measurements indicated that, for the xGnP–SCF/PP composite, maximum tensile
strength, tensile modulus and impact strength were 43.4 MPa, 1.052 GPa, and 38.1 J/m, respectively,
corresponding to 13.6%, 41.7%, and 7.3% enhancement compared to the untreated SCF/PP composite. In
addition, the results of dynamic mechanical thermal analyses indicated enhancement in storage
modulus and damping capacity for the treated samples; however, no significant difference was observed
in the glass transition temperature. The xGnP–SCF/PP interface adhesion enhancement was clearly
shown by scanning electron microscopy (SEM) images of the tensile failure surfaces. Finally, the optimal
xGnP content for effectively improving the overall composite mechanical and thermo-mechanical
performance was found to be 1 wt%.