Sustainable manufacturing of hexagonal-BN fibres through the rational design of molecular precursors

The scientific community is constantly seeking new materials that can aid in revolutionising industries, whilst also meeting the need of future generations. A candidate for this is boron nitride (BN), an attractive option due to its unique properties and potential wide-scale applications. Boron nitride is comprised of equal parts boron and nitrogen and can exist in several forms. Of particular interest is hexagonal-BN, which possesses a layered structure like graphite, with boron and nitrogen arranged in hexagonal rings. Hexagonal-BN has high thermal conductivity and electrical insulation, excellent chemical and thermal stability, and a range of lubricating properties. This unique combination makes hexagonal-BN ideal for an array of advanced applications within the aerospace, electronics, and biomedicine fields.
Typical approaches to the synthesis of hexagonal-BN involve extremely high temperature and pressure reactions with boron and nitrogen containing substituents. As well as being extremely energy intensive, these methods tend to incorporate impurities into the material, which can negatively affect the bulk properties. Instead, an attractive solution is to use molecular precursors, which allow for higher degrees of control during synthesis of the BN material. One solution is to use borazine, a chemical compound that takes the form of a singular hexagonal ring, comprised of three boron-hydrogen and three nitrogen-hydrogen groups. These borazine units can be linked together, forming long borazine chains which can then be processed into BN fibres.
This project aims to synthesise borazines, using efficient, scalable, and sustainable methods. A variety of functional groups will be incorporated into the borazines, and the resulting compounds characterised using a range of advanced techniques to elucidate their properties. The functionalised borazines will then be linked together through a polymerisation process, resulting in a chain of borazines that can then be transformed into BN fibres using specialist spinning techniques. The properties of these fibres will then be characterised using state-of-the-art analytical and structural techniques.
This project will involve external collaboration with Professor Andrew Weller at the University of York for the formation of the long chain polymeric borazine materials. Synthesis of the BN fibres from these borazine chains collaboration with Professor Nicole Grobert in the Department of Materials, as part of the Nanomaterials by Design group.
This research project falls within the ESPRC manufacturing the future research area.