SBIR Phase I: Boron Nitride Nanotubes Manufacture

这个小企业创新研究（SBIR）第一阶段项目将通过连续热解方法合成氮化硼纳米管，该方法可以很容易地以合理的成本生产工业数量。 人们正在对单壁碳纳米管（C-SWNT）进行深入研究，以利用其在复合材料增强中的高比强度，以及其在纳米级电子器件中的不寻常的电子传输特性。 它们的特性和应用源于碳原子无缺陷排列成具有极高纵横比（长度/直径）的细丝，目前约为10，000。 然而，高纵横比，管状几何形状和原子完美性并不是碳所独有的;纳米管（NT）可以由许多其他层状材料形成，包括氮化硼。 基于BN和石墨之间的化学差异，BN-NT虽然也表现出高强度，但具有与C-SWNT互补的商业上有吸引力的性质。 BN-NTs最突出的特性是抗氧化性、光学透明性和均匀性。目前，BN-NT是在台式反应器中通过硼棒的电弧蒸发来制造的，这是一种低产量、不经济的批量工艺。 通过改进合成方法，氮化硼纳米管将可用于材料研究和应用，氮化硼纳米管将可用作高端复合材料的增强体。 BN纳米管的最佳用途是对C-SWNT的补充。 例如，BN-NT具有形成高强度、高温、形成金属碳化物的潜力。 作为另一个实例，聚合物基质的BN-NT增强将保持基质的电绝缘和光透射性质，而C-SWNT赋予聚合物基质导电性和不透明性。 此外，改进的耐化学性，特别是对氧侵蚀的耐化学性，将改进BN-NT在高温和其它苛刻的使用条件下的稳定性。

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 electrontransport 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 mostprominent 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.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,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.