Enhanced ablative resistance of epoxy composites at low loadings of boron nitride nanotubes by the formation of near-graphitic structures

An effect of boron nitride nanotubes (BNNTs) with a low concentration on the ablative resistance of the epoxy matrix was evaluated. A linear ablation rate of a 0.3 wt% BNNT/epoxy composite was notably enhanced by 24.23% compared to neat epoxy. Field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD) and Raman spectroscopy revealed that it was ascribed to the formation of near-graphite rod structures with much larger diameters than BNNT particles in the non-graphitizable epoxy matrix during the ablation tests, similar to the reports on the MWCNT-containing polymer composites. The results indicate that non-carbon nanotube structures also act as the nucleation sites of graphitization in the polymeric matrix during pyrolysis in an ablation process.