Effect of graphene nanoplatelets on the properties of poly(propylene)-based nanocomposites for automotive applications

In this work, poly(propylene) (PP)-based nanocomposites containing three types of commercial graphene nanoplatelets (GnPs) were prepared through a melt blending technique. The influence of the GnPs fillers (1 wt.%) on the structural, thermal, mechanical, and rheological properties of the final PP-based GnPs nanocomposites was then evaluated. Overall, the results indicate that GnPs acted as a nucleating agent, promoting PP crystallisation due to increased crystallisation temperature (Tc) and degree of crystallinity (Xc) when compared with neat PP. The mechanical characterisation of the ensuing nanocomposites indicates an improved adhesion between components for fillers having the smaller average lateral size and highest specific surface area (SSA), which was confirmed by the respective morphological analysis. The rheological characterisation shows a decrease in the melt viscosity of PP due to the presence of GnPs, indicating that the GnPs do not hinder the injection moulding (IM) processing of PP-based GnPs nanocomposites. In summary, the most significant influence on the structural, thermal, mechanical, and rheological properties was higher as the smaller average lateral size and higher SSA were used as reinforcement. This study highlighted the capability of GnPs acting as nanofillers to improve the nanocomposites’ properties, incorporating much lower nanofiller percentages than traditional thermoplastic composites and reducing the weight of nanocomposites.