Engineering

Oxide

Epoxy

Metallurgy

Materials science

Graphene

Ultimate tensile strength

Chemical engineering

Polymer

Composite epoxy material

Nanotechnology

Izod impact strength test

Dynamic mechanical analysis

Glass transition

Fracture toughness

Composite material

Thermal stability

Flexural strength

Flexural modulus

Toughness

Journal of Colloid and Interface Science

Despite great efforts have been made on epoxy resins modification, development of additives that can be used to efficiently and universally modify epoxy composites remains a challenging task. Herein, graphene oxide (GO) sheets were covalently linked with hyperbranched epoxy resin (HBPEE-epoxy) to form HBPEE-epoxy functionalized GO (HPE-GO), which was then incorporated into epoxy resin (EP) matrix to achieve efficient and all-purpose enhancement of the properties of EPs. Compared with unmodified GO sheets, the functionalized HPE-GO sheets were better dispersed and exhibited better interfacial compatibility with the epoxy matrix, and consequently, the mechanical and thermal properties of HPE-GO/EP composites improved significantly compared to unmodified GO/EP composites. The tensile strength, flexural strength, impact strength, and fracture toughness (KIC) of EP composites containing 0.5 wt% HPE-GO increased by 65.0%, 36.2%, 259.1%, and 178.9%, respectively, compared with those for the neat EP. The storage modulus (E'), glass transition temperature (Tg), and thermal stability (T5%) also showed modest improvements. Furthermore, the HPE-GO/EP composites exhibited optimal thermal conductivities and thermal expansion properties, while maintaining higher volume resistivities compared with GO/EP composites. The results of this study support that HPE-GO is a promising, all-purpose modifier for EPs.

Hyperbranched epoxy resin-grafted graphene oxide for efficient and all-purpose epoxy resin modification