Green interfacial engineering of wood fiber/MWCNTs/epoxy composites by ternary deep eutectic solvent-induced lignin regeneration

This study proposes a green interfacial modification strategy based on a ternary deep eutectic solvent (DES). The DES induced the in situ dissolution and redeposition of lignin. The treated fibers were then combined with multi-walled carbon nanotubes (MWCNTs) and epoxy resin (EP) to prepare thermally conductive composites. The results show that DES treatment formed a rough lignin-rich interfacial layer on the wood fiber surface, which significantly improved its interfacial bonding with MWCNTs and thereby effectively enhanced the mechanical properties of the composites. At an MWCNTs loading of 15 wt%, DWFC-15 exhibited tensile and flexural strengths that were 37.20% and 34.66% higher than those of the untreated NWFC-15, respectively, along with a 45.94% increase in thermal conductivity. With increasing MWCNTs loading, a denser thermal conduction network was formed within the composites, resulting in a maximum thermal conductivity of 0.69 W·m⁻¹ ·K⁻¹ , corresponding to an enhancement of 93.60%, as well as excellent Joule heating performance. This strategy, based on the synergistic construction of DES induced interfacial restructuring and MWCNTs thermal conduction networks, provides a feasible approach for expanding the application of wood fiber based composites in thermal management fields such as indoor heating and electronic heat dissipation, and also offers technical guidance for the development of low-carbon biomass-based thermal management composites.