NSF Award
0060326
This Small Business Innovation Research (SBIR) Phase I project will synthesize boron nitride nanotubes by a continuous pyrolysis method that can be readily scaled to produce industrial quantities at reasonable costs. Intensive research is being conducted on single-walled carbon nanotubes (C-SWNTs) to take advantage of their incredibly high specific strength in composite material reinforcements, and their unusual electron<br/>transport properties in nanoscale electronic devices. Their properties and applications stem from the defect-free arrangement of carbon atoms into a filament with extremely high aspect ratio (length/diameter), currently around 10,000. However, the high aspect ratio, tubular geometry, and atomic perfection are not unique to carbon; nanotubes (NTs) can be formed from many other layered materials, including boron nitride. BN-NTs, while also exhibiting high strength, have commercially attractive properties that are complementary to the C-SWNTs, based on the chemical differences between BN and graphite. The most<br/>prominent characteristics unique to BN-NTs are oxidation resistance, optical transparency, and uniformity. BN-NTs are currently made in benchtop reactors by arc evaporation of boron rods, a low-throughput, uneconomical batch process. By developing an improved synthetic method, BN-NTs will become available for materials research and applications.<br/><br/>Boron nitride nanotubes will have applications as reinforcements in high-end composite materials. The best uses of BN nanotubes are complementary to those of C-SWNTs. For example, the BN-NTs have the potential to form high strength, high temperature, form metal carbides. As another example, BN-NT reinforcement of a polymer matrix will maintain the electrically insulating and optical transmission properties of the matrix,<br/>whereas C-SWNTs impart electrical conductivity and opacity to the polymer matrix. Also, the improved chemical resistance, particularly to oxygen attack, will improve the BN-NT stability at elevated temperatures and other severe service conditions.
