UV ‐cured epoxy/graphene nanocomposite films: preparation, structure and electric heating performance

UV‐cured epoxy/graphene nanocomposite films with ca 100 µm thickness were manufactured by a facile cationic photopolymerization of 3,4‐epoxycyclohexylmethyl‐3′,4′‐epoxycyclohexane carboxylate mixtures including graphene sheets of 0.3 − 10.0 wt%, which was initiated by triarylsulfonium hexafluoroantimonate salts. The microstructure and thermal and electrical properties of the UV‐cured epoxy/graphene nanocomposite films were investigated as a function of the graphene content. X‐ray diffraction patterns and TEM images confirm that graphene sheets are well dispersed in the UV‐cured epoxy resin matrix even with a high graphene content of 10.0 wt%. The electrical resistance of the nanocomposite films decreased dramatically from ca 1012 Ω to ca 102 Ω with increasing graphene content, especially at a percolation threshold of 2.0 − 3.0 wt%. Accordingly, the UV‐cured nanocomposite films including 5.0 − 10.0 wt% graphene showed excellent electric heating performance in terms of temperature response as well as electric power efficiency at a given applied voltage. For a nanocomposite film with 10.0 wt% graphene, the maximum temperature of ca 138 °C was attained at an applied voltage of 15 V and a high electric power efficiency of ca 3.0 ± 0.3 mW °C−1 was achieved.