Mechanical properties of graphene reinforced high-density polyethylene nanocomposites: a comprehensive review

Graphene-based high-density polyethylene (HDPE) nanocomposites have lately emerged as a promising route to enhance the mechanical properties of HDPE for high-performance engineering applications. This review critically examines the mechanical properties of HDPE/graphene nanocomposites, with emphasis on the influence of graphene size, type, concentration, and surface modification. Results indicate that the addition of graphene, even at very low concentrations, can enhance HDPE mechanical properties, including tensile and flexural moduli, and to a lesser extent the tensile and flexural strength. However, these enhancements depend on uniform dispersion and strong interfacial interactions within the polymer, where agglomeration can lead to significant reductions in mechanical properties. While ductility and impact resistance generally decrease with graphene addition, strategies such as graphene functionalization and compatibilizers can mitigate these drawbacks. Results also show that although larger graphene flake sizes better enhance the mechanical properties at lower concentrations, they lead to reductions in properties at higher concentrations due to increased agglomeration of graphene. Contrarily, impact resistance is higher with smaller graphene flake sizes. Finally, current challenges, including scalable dispersion methods, property trade-offs, and industrial processing compatibility, are discussed, and future research directions are outlined to facilitate their broader adoption in commercial applications, such as packaging and pipes.