Chemically derived BN ceramics: Extensive B-11 and N-15 solid-state NMR study of a preceramic polyborazilene

Polyborazilene, a precursor for hexagonal boron nitride (h-BN) ceramics, ha s been extensively characterized by N-15 and B-11 MAS NMR. The various B an d N sites have been identified according to their first neighboring atoms a s well as to the second ones in the case of N-15 and have also been quantif ied. This study demonstrates that a suitable choice of NMR techniques toget her with the use of isotopic enrichment can lead to a large improvement in spectral resolution, which allows better understanding of such complex BN p receramic polymer structures.