Covalently functionalized hexagonal boron nitride nanosheets by nitrene addition

Abstract

Exfoliated h-BN nanosheets were covalently functionalized via a one-step nitrene addition using azide precursor molecules. Functionalized h-BN nanosheets were found to exhibit markedly enhanced dispersability relative to pristine h-BN in a range of organic solvents. Extension of the functionalization methodology allowed the covalent attachment of polymer chains to the surface of h-BN nanosheets. Polymer nanocomposites were prepared using the molecularly-functionalized h-BN nanosheets within a polycarbonate (PC) matrix, while h-BN nanosheets functionalized with poly(bisphenol A-co-epichlorohydrin) (PBCE) chains were employed within a PBCE matrix. In both cases the mechanical properties were studied. Significant increases in moduli, strength and ductility of the functionalized h-BN nanocomposites indicated enhanced reinforcement of the functionalized h-BN filler materials over pristine h-BN. The implications of tuning the surface chemistry of exfoliated nanosheets exactly to the chemis-try of a host polymer matrix are considered.