Polybenzoxazine/graphene composites with concurrently improved thermal conductivity and mechanical strength via network microstructure control

Multifunctional polymer-based composites with enhanced thermal conductivity are indispensable for achieving advancements in both scientific research and technological innovation. This paper reports a new type of polybenzoxazine/graphene (PBZ/GN) thermal conductive composite. Specifically, GN forms a continuous thermal conductive network by coating resin monomer powder and then undergoing hot-pressing curing. Upon incorporating 10 wt% GN, the PBZ composite exhibited distinct anisotropic thermal conductivities of 0.82 W/m K in the through-plane direction and 1.96 W/m K along the in-plane orientation. Compared with pure PBZ, these values represent increases of 1.6- and 5.3-fold, respectively. The composite material exhibits enhanced thermal stability as GN content increases. However, the mechanical properties exhibit an initial increase followed by a decrease. Notably, with the addition of 2 wt% GN, the tensile strength and flexural strength increase by 75.4% and 41%, respectively. This composite material can be prepared in a simple and highly efficient manner. Consequently, this advancement broadens the applicability of benzoxazine resins, especially in fields requiring high thermal stability and heat dissipation. Highlights A graphene network was designed to enhance composite properties. Enhanced thermomechanical properties achieved through graphene-induced thermal conduction networks. Peak strength gains (75.4% tensile/41% flexural) achieved with adding 2 wt.% graphene.