Study on dielectric properties of synthesized exfoliated graphite reinforced epoxy composites for microwave processing

In this study, exfoliated graphite (EG) was used as filler to enhance the dielectric properties of composites, which are processed through microwave (MW) curing. EG was synthesized through MW irradiation technique. The detailed characterizations of as-synthesized EG were first carried out. Afterwards, the EG reinforced epoxy composites have been synthesized. The dielectric properties of composites as a function of EG content with and without MW heating were measured at a frequency of 2.45 GHz. The 3 wt% EG/epoxy composite shows an increase of about 43 and 81% in dielectric constant and loss factor, respectively. The dielectric properties are found to decrease after MW curing. Finally, the dynamical mechanical analysis was performed for MW cured samples including thermally cured samples. The glass transition temperature and storage modulus are found to improve by about 24 °C and 58%, respectively for MW cured 3 wt% EG/epoxy composite as compared to neat epoxy counterpart. •The exfoliated graphite (EG) is used as filler in epoxy resin for improving the dielectric properties at 2.45 ± 0.05 GHz.•The dielectric constant (εr') and loss factor (εr'') increase with increasing EG content.•Both the εr' and εr'' of synthesized composites decreases after microwave curing using microwave oven.•The glass transition temperature of MW cured 3wt% EG/epoxy is almost equal to its conventionally cured counterparts for 4 h.•For both conventional and microwave curing methods, the optimum loading of 3wt% EG in epoxy is obtained.