Eco-friendly produced lightweight structural graphene/polyamide 12 nanocomposite: Mechanical performance and the controlling microstructural mechanisms

The present study explores the potential use of graphene nanoplatelets (GL-GNPs), synthesized from glucose through a new chemical approach that is facile, economical, and eco-friendly alternative to the conventional Hummer's method, as a nanoreinforcement in polymers for the production of light-weight structural polymer nanocomposites. Understanding the interface character of GL-GNPs/Polyamide 12 (PA12) nanocomposites with various nanofiller loadings and how this affects their tensile behavior, are focal points of interest. Results reveal that enhancements in polymer stiffness and strength are superior at low GL-GNPs content than higher contents. This is attributed to higher degree of GL-GNPs exfoliation and increased polymer phase crystallinity. Interestingly, abundant small/imperfect PA12 crystallites have grown on the GL-GNPs surface, strongly interlinking thus the polymer and graphene phases within nanocomposites. The intensity of such crystallites in interface region is the determinant of the nanocomposites' Young's modulus, assessed at small applied tensile stress. While the GL-GNPs-PA12 interfacial bonding is the determinant of yield and ultimate strengths, estimated at medium and high stress levels. Overall, the 1 wt% GL-GNPs/PA12 nanocomposite is considered the optimum. Its low density and good mechanical performance among the previously developed graphene/Polyamide nanocomposites, propose promising future for GL-GNPs-based nanocomposites as ecofriendly and cost-effective lightweight structural material. POLYM. ENG. SCI., 58:1201-1212, 2018. (c) 2017 Society of Plastics Engineers