Functionalization of Graphene Nanosheets-3D Printing Resins for Improvement of Mechanical Properties and Thermal Conductivity

In this study, a photocurable 3D printer was utilized to fabricate soft thermal interface materials (TIMs) with enhanced thermal conductivity and mechanical properties. Graphene oxide (GO) nanosheets were oxidized from graphite and subsequently grafted with poly(ethylene glycol) methacrylate (PEGMA) at the edges, resulting in a material named GO-MA. GO-MA was blended with the 4-hydroxybutyl acrylate (4-HBA) monomer and polymerized using a photoinitiator, phenylbis(2,4,6-trimethylbenzoyl) phosphine oxide, to form nanocomposites. The van der Waals force interaction between GO sheets makes it easy for GO to aggregate. The modification of GO with PEGMA can effectively disperse GO in the monomer, preventing aggregation. The modified GO-MA forms a highly interconnected network within the polymer matrix, facilitating heat dissipation by providing multiple pathways for heat transfer. Thermal conductivity and mechanical properties of the nanocomposites were investigated. A 3D-printed nanocomposite containing 40 wt % GO-MA in 4-HBA exhibited a thermal conductivity that was 5.8 times higher than that of pristine 4-HBA, along with a 4.2-fold enhancement in mechanical properties. These results demonstrate that the proposed method is a promising approach for fabricating soft TIMs with enhanced thermal conductivity and mechanical properties. The increased thermal conductivity is attributed to the high thermal conductivity of GO and the highly interconnected network formed by GO-MA. The improved mechanical properties result from the strong interfacial bonding between GO-MA and the polymer matrix.