Investigation of Different Commercial Boron Nitride Grades and their Effect on Loss Spectra in Epoxy Resins and Silicone Rubbers

Literature on nanodielectrics has shown inconsistent behavior with nominally identical material systems (polymer/filler combinations), sometimes even from the same research groups. This paper compares four different commercial hexagonal boron nitride (hBN) products in two different polymer systems (epoxy resins and silicone rubbers) and compares their dielectric response. It is demonstrated that the dielectric properties of composites containing hBN are affected by the production steps, respectively the supplier of the nanofiller; notably, this effect varies depending on the host polymer, thus trends cannot be translated from material system to the next, even for the filler from the same supplier. Experimental evidence shows that equivalent types of fillers can lead to variations in dielectric losses, both in silicone-based and epoxy-based composites.