Research Summaries

Back Microscopy Investigation of Boron Nitride Nanotube Fillers in Carbon Fiber

Fiscal Year 2020
Division Graduate School of Engineering & Applied Science
Department Mechanical & Aerospace Engineering
Investigator(s) Ansell, Troy
Sponsor Naval Air Weapons Station-China Lake (Navy)
Summary Boron nitride nanotubes (BNNT), a polymorph of boron nitride, are structurally like the more well-known carbon nanotubes. Unlike its famous cousin; however, BNNT are excellent electrical insulators with higher decomposition temperatures and larger neutron absorption cross-sections. Despite these attractive properties, application of BNNT is currently limited. One solution is to use the BNNT as nanofillers in polymer-based composite materials. The problem with this approach is dispersion of the BNNT during casting of the polymer matrix.
To overcome the dispersion issue, a high g-load mixing method was used to generate polyacrylonitrile (PAN) solutions with homogenously dispersed boron nitride nanoparticles (BNP) and BNNT at different weight % (wt%) up to 20 wt%. Without additional chemical treatments, BNP and BNNT were found to influence the bulk properties of the composite. The evidence for this, so far, has been collected indirectly.
To collect direct evidence, e.g. microscopic images of the BNNT integrated in the composites, two pieces of instrumentation will be used. A dual-beam scanning scanning electron microscope/focused ion beam (SEM/FIB) and a transmission electron microscope (TEM). The SEM/FIB would be used to make micrometer sized cuts in bulk composites in order to find and image nanometer sized BNNTs and to determine the orientation of the BNNT. The TEM would add complimentary orientation information as well as provide higher resolution images of individual BNNT within the polymer.
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Data Publications, theses (not shown) and data repositories will be added to the portal record when information is available in FAIRS and brought back to the portal