Thermal Conductivity and Flame Retardancy of Nacre-like Cellulose-based Composite Films Reinforced with Flame-retardant Functionalized Graphene Nanoplatelets by One-Step Ball Milling

In the face of heat concentration during the operation of flexible electronic devices and possible fire hazards, effective thermal management materials need to synchronize high heat dissipation with low fire hazards. Graphene nanoplatelets (GNP) are widely used as an excellent thermal conductive and flame-retardant material, but the inertness of GNP and the insufficient flame-retardant efficiency limit its applications. In this paper, a high thermal conductivity and flame-retardant composite film was successfully prepared by combining flame-retardant functionalized graphene nanoplatelets (f-GNP) obtained by one-step ball milling with natural cellulose nanofibers (CNF). Introducing melamine cyanuric acid (MCA) enhances the interaction between f-GNP and CNF, reduces interfacial thermal resistance, and acts as a synergistic flame retardant. The prepared f-GNP/CNF-50 composite film exhibits a high in-plane thermal conductivity of 45.96 W/(m K) as well as a reduction of 81.2% in the heat release rate and 72.7% in the total heat release compared with pure CNF, respectively. At the same time, this composite film exhibits excellent flexibility, providing a new idea for thermal management of flexible electronic devices.