Facile preparation and properties of polybenzoxazine/graphene porous nanocomposites for electromagnetic wave absorption

Abstract Polybenzoxazine/graphene porous nanocomposites were prepared by sol–gel and subsequent thermal curing. The porous nanocomposites showed low densities ranging from 0.154 to 0.204 g/cm 3 . The chemical structures and microscopic morphology of the porous nanocomposites were studied using Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The electromagnetic wave absorbing ability of the porous nanocomposites was investigated, and the results showed that the minimum reflection loss for the porous nanocomposite with 15 wt% of graphene (PBG‐15) can reach −35.72 dB at a thickness of 2.6 mm with a 1.5 GHz frequency bandwidth. The excellent absorption ability was due to the conductivity loss in the porous nanocomposite. Also, PBG‐15 exhibited good heat resistance with a thermal deformation temperature near 220°C and a char yield of 56%. In addition, the addition of graphene could increase the compressive strength and compressive modulus of the porous nanocomposites by up to 126% and 364%, respectively. These polybenzoxazine/graphene porous nanocomposites have good potential application in light electromagnetic wave absorbing materials.