Hybrid Thermosetting Polymer Nanocomposite Thin Films With Optimized Thermal Conductivity and Mechanical Reinforcement

ABSTRACT Epoxy‐based thin films reinforced with graphene oxide (GO), hexagonal boron nitride (h‐BN), and their hybrid combination (GO/h‐BN) at low filler contents (< 1 wt%) were developed to advance thermosetting nanocomposites for high‐performance thermal interface materials (TIMs). The incorporation of these 2D nanostructures led to marked and simultaneous increases in both the storage modulus ( E ′) and the glass transition temperature ( T g ) for the individual and hybrid systems. These enhancements indicated strong interfacial interactions between the nanofillers and the epoxy matrix, promoting a more efficient crosslinking density and reinforcing the overall rigidity of the polymer network. Uniform thin films, processed under controlled conditions, exhibited efficient phonon transport without compromising their dielectric integrity, as demonstrated by steady‐state and 3‐ω thermal analyses. The incorporation of 0.5 wt% GO/h‐BN resulted in up to a 56% enhancement in thermal conductivity at 90°C while preserving the intrinsic thermal stability of the epoxy system. These synergistic effects yielded multifunctional nanocomposites that combine high thermal conductivity, superior mechanical reinforcement, and electrical insulation, positioning them as promising candidates for next‐generation TIMs in advanced electronic and photonic applications.