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 chemistry of a host polymer matrix are considered.Due to its exciting electrical, thermal and mechanical properties, 1 the last few years have seen a surge of interest in the exfoliation of graphene. 2,3 More recently, attention has shifted to other layered compounds, notably hexagonal boron nitride (h-BN) and the transition metal dichalcogenides. [4][5][6]

Basal-Plane Functionalization of Chemically Exfoliated Molybdenum Disulfide by Diazonium Salts

“…Nonetheless, as has previously been shown for BN, aggressive reagents may indeed functionalize nanomaterials that are considered inert. 19,20 As we show within this manuscript, such a strategy can also be applied to functionalize MoS 2 . We expect that, once a synthetic protocol to achieve the functionalization and to characterize the material is established, the foundation will have been laid for a much broader and richer chemistry on the surface of TMDs.…”

“…1, 3 Significant progress has been made on the production of atomically thin, high quality TMDs by chemical vapor deposition (CVD) growth, 9,10 chemical exfoliation 3,11 and liquid phase exfoliation in suitable solvents 4,12 or by the aid of surfactants. 13,14 However, unlike the situation with graphene 15-17 or even boron nitride (BN), [18][19][20] there are very few reports on covalent functionalization of TMDs. Typically, functionalization of MoS 2 is achieved by ligand conjugation of thiols at sulfur vacancy sites that were either introduced by ion irradiation 21 or naturally occurring after chemical exfoliation.…”

Polymer reinforcement using liquid-exfoliated boron nitride nanosheets

“…While BN has long been thought too inert to functionalise, recent reports have shown that the basal plane of BNNS can be covalently functionalised with polymers. 37 Thus it may be possible to tailor the surface chemistry of BN to reinforce a wide range of polymers. Preliminary results suggest such strategies to be reasonably successful.…”

“…Preliminary results suggest such strategies to be reasonably successful. [37][38][39] In addition, it is worth noting that even if high s B values can be routinely achieved, because of the form of eqn (8), akes with relatively large lateral size will be required to achieve large values of ds B /dV f .…”

Mechanical, dielectric, and thermal properties of polyarylene ether nitrile and boron nitride nanosheets composites

“…Graphene, a two‐dimensional monolayer of sp2‐bonded carbon arranged in a honeycomb lattice , has received intensive attention due to its outstanding electrical, thermal, mechanical, and optical properties . Through the phonon transport, graphene shows extremely high thermal conductivity (∼5,300 W m −1 K −1 ).…”