Nearly stoichiometric BN fiber with low dielectric constant derived from poly[(alkylamino)borazine]

Abstract Nearly stoichiometric boron nitride (BN) fiber with low dielectric constant was prepared by curing, pyrolysis of a novel poly[(alkylamino)borazine] (PAAB) under NH3 up to 1200 °C in a ceramic yield of 60 wt.%. Based on IR, XRD, XPS and elemental analysis (EA), the fiber with a composition of BN1.09 shows a characteristic of turbostratic BN (t-BN). The tensile strength is approximately 0.6 GPa with 13 μm in diameter. Moreover, the fiber possesses very low real part (e′) of 2.66 and loss tangent (tan δ) of 0.0012 at 10 GHz, respectively, making it possible to be used in microwave-transparent material.