SBIR Phase I: Boron Nitride Nanotubes Manufacture

这个小型企业创新研究(SBIR)第一阶段项目将通过连续热解方法合成氮化硼纳米管，这种方法可以很容易地扩大规模，以合理的成本生产工业规模。人们正在对单壁碳纳米管(C-SWNTs)进行深入的研究，以利用它们在复合材料增强中令人难以置信的高比强度，以及它们在纳米电子设备中不同寻常的电子传输特性。它们的性能和应用源于碳原子无缺陷地排列成具有极高长径比(长径比)的灯丝，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独有的；纳米管(NTS)可以由许多其他层状材料形成，包括氮化硼。BN-NTs虽然也表现出高强度，但基于BN和石墨之间的化学差异，具有与C-SWNTs互补的商业吸引力。BN-NTS最突出的特点是抗氧化性、光学透明性和均匀性。目前，在台式反应堆中，BN-NTS是通过电弧蒸发硼棒来制造的，这是一种低产量、不经济的间歇工艺。通过开发一种改进的合成方法，BN-NTS将可用于材料研究和应用。氮化硼纳米管将在高端复合材料中作为增强体应用。氮化硼纳米管的最佳用途是对碳纳米管的补充。例如，BN-NTS具有形成高强度、高温、形成金属碳化物的潜力。作为另一个例子，聚合物基质的BN-NT增强将保持基质的电绝缘和光学传输特性，而C-SWNTs赋予聚合物基质导电性和不透明度。此外，提高的耐化学性，特别是对氧气的侵蚀，将改善BN-NT在高温和其他恶劣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.