Mechanical and thermo-mechanical properties of short carbon fiber reinforced polypropylene composites using exfoliated graphene nanoplatelets coating

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%.