Author(s): Skalnes Knudsen K.; Are Beukes J.; Hoang Dam A. 
| ISSN: 3005-2092
This study shows that the magnitude of improvement in the properties of composites with graphene depend on the structure of the graphene fillers (i.e., dimensions and number of graphene layers). The impacts of graphene flake size on the mechanical properties of epoxy resin and PU resin were different.
Citation:
ABSTRACT
In this work, a low-cost and scalable manufacturing technique was developed to incorporate highly dispersed graphene into epoxy and Polyurethane (PU), which are among the most widely used polymeric materials. The study covered the wide spectrum of graphene materials of different structures, both raw products of synthesis as well as a functionalized one, to be used as reinforced fillers of polymer resins. Additionally, a single-layeror few-layer graphene, as produced by a Plasma Enhanced Chemical Vapor Deposition (PECVD), and Graphene Nanoplatelets(GNPs), which are composed of a dozen or several dozen graphene layers produced from exfoliation of graphite, were also investigated. Furthermore, the properties of epoxy composites reinforced with hybrid graphene fillers and combinations of graphene materials with other fillers isalso discussed in this report.The influences of concentration and composition of hybrid graphene mixtures on tensile and flexural behaviour of epoxy resin were studied. Tensile and flexural properties of epoxy resin were improved significantly and reached maximum at low addition of graphene (i.e., below 0.1 wt%).In comparison with pure polyurethane, the graphene-based polyurethane composites exhibited higher tensile strength and modulus improvements, even with a very small amount graphene added. The impact of PECVD graphenes withdifferent flake sizes on tensile properties of PU were investigated. Unlike the graphene-enhanced epoxies, both the tensile strength and Young’s modulus of polyurethane improved greater with the addition of large flake-size graphene than with the presence of small flake-size one.Consequently, these graphene-based polymer resins have great potential in the preparation of various high-performance polymer composites for defence and military applications, such as marine, automotive, aerospace,protective equipment, and structures, by improving strength and ballistic performances, and reducing weight
