Reinforcement of Polymer-Based Nanocomposites by Thermally-Conductive and Electrically-Insulating Boron Nitride Nanotubes

A detailed study has been undertaken of the mechanisms of stress transfer in a nanocomposite consisting of hexagonal boron nitride (hBN) nanotubes (BNNTs) in a poly(vinyl alcohol) (PVA) matrix based upon the use of non-resonance Raman spectroscopy. The structure of the BNNTs was characterized using transmission electron microscopy (TEM) where it was shown that the majority of the nanotubes had 2 - 5 walls with some having over 10 walls. The structure and mechanical properties of nanocomposites containing up to 1 wt% of both pristine and hydroxyl-functionalized nanotubes (OH-BNNTs) in PVA were investigated. The dispersion of the BNNTs in the nanocomposites was characterized using a combination of transmission electron microscopy and Raman mapping. The mechanical properties of the nanocomposites were evaluated by tensile testing and it was found that the Young’s modulus, yield strength and fracture stress all increased on the addition of the BNNTs. A further improvement in the mechanical properties was obta...