Optimized Interface Structure of Degradable Epoxy Composites Based on the Self-Assembly of Lignin-Graphite for Thermal Management Application

Enhancing the interface compatibility between the polymer matrix and filler is still a hotspot issue for the fabrication of thermal management materials. In this work, biomass lignin was used innovatively as coupling reagents to optimize the interface microstructure of the matrix/filler. The as-prepared lignin-graphite (AL@GP) and epoxy resin with a Schiff base structure (PBD-EP) were employed as functionalized filler and polymer matrix, respectively. And a degradable and thermally conductive epoxy composite was prepared through the hot-press technique. Experimental and theoretical calculations results based on the first principles demonstrated enhanced interface bonding between GP and PBD-EP. Besides, the developed polymeric composites exhibited excellent thermal conductivity (2.852 W m–1 K–1) when loaded with 50 wt % AL@GP, increasing by 26.1% compared with the PBD-EP/GP system. Moreover, it presented a reduced interface thermal resistance (0.10745 m2 K W–1) and superior solvent-free green degradability. LED heat dissipation experiments indicated the potential of as-prepared composites for thermal management applications. This work not only provides a novel and facile filler functionalization strategy for improving the interfacial interaction of the matrix/filler but also promotes the high-value applications of biomass lignin.