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

Abstract 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.