Boron Nitride Nanotubes (BNNTs) and BNNT Composites: A Review

This paper provides a summary of recent advances in boron nitride nanotubes (BNNTs) and their composites, including properties, purification, characterization techniques involved, fail-ure modes, and modeling methods. After the discovery of carbon nanotubes, BNNTs were first theoretically predicted and successfully synthesized in 1995 by an arc-discharge method. Following that, other techniques for BNNT synthesis were discovered; however, growing highly purified BNNTs remains difficult. The research on the physical properties of BNNTs shows that they have a stable broadband gap, excellent mechanical strength, high thermal conductivity, and high oxidation resistance. These properties make them a perfect candidate for future nanocomposites for high-temperature applications. Interesting effects of BNNT addition with the resultant mechanical behavior and thermal conductivity in a matrix are observed when BNNTs are applied to form nanocomposites with polymer, metal, and ceramic matrices. Modeling and simulation methods of nanotube composites are highly advantageous in devel-oping BNNT-based nanocomposites. Micromechanics, finite element analysis, and molecular dynamics are modeling techniques used to simulate nanotubes and are crucial for model -informed manufacturing and design. In summary, modeling, synthesis, purification, characteri-zation, and properties of BNNT composites are all reviewed in this paper.