Pyrolyzed cellulose/rGO aerogel composites via I2 treatment and silane surface functionalization with highly improved through-plane thermal conductivity and EMI shielding effectiveness

Abstract

Owing to the significant advancements in technology over the past few years, the importance of treating heat generated by electronic products is increasing. In addition, the importance of preventing electromagnetic interference (EMI) is increasing. In this work, we fabricated pyrolyzed cellulose (PC)/reduced graphene oxide (rGO) aerogel composites with thermally and electrically conductive properties. Cellulose and graphene oxide (GO) were subjected to iodine treatment before pyrolysis to maintain their morphology during pyrolysis. After that, iodine ions are adsorbed onto the surface of the composite. During pyrolysis, iodine ions preferentially generate HI to suppress the decomposition of carbon. After thermal reduction, the electrical conductivity of the composite was significantly improved. In addition, by attaching 3-aminopropyltriethoxysilane (APTES) to the surface of GO (APTES-GO), the dispersibility of GO to the cellulose matrix was improved. The thermal and electrical conductivity increased as the APTES-GO formed a path more easily on the matrix. So, PC nanofibers and rGO sheets form a double three-dimensional (3D) network structure that is thermally and electrically conductive. The fabricated composite shows high electrical conductivity of 85.3 S/cm, at a 50-wt percentage of APTES-GO, the composite exhibits an EMI shielding effectiveness (SE) of 72 dB and a through-plane thermal conductivity of 4.74 W/m·K.