Abstract
Nanotubes (NTs), made of a wrapped graphitic sheet, exhibit diameters down to several nanometers. NTs were first discovered in C. Later on, it was realized that these nanostructures form in other layered compounds, e.g. BN, BCN, WS sub 2 etc. At present, NTs are considered to be unique structural and electronic materials. While C NTs are known to be metallic or semiconducting, depending on shell helicity and diameter, BN NTs are expected to be always insulating. This property creates the intriguing possibility of BN NT application as a nanoinsulating shield for any conducting material encapsulated within, i.e. metallic nanowires. Also, it is known that bulk BN is more stable to oxidation than C, which is important for applications. In addition, BN NTs are as tough as C NTs are. The measured Young's modulus of a BN NT exceeds approx =1 TPa, which is the highest value among all insulating fibres known to date. Clearly, the strength of tubular fibres may be further increased by assembling them into ropes. For instance, ropes made of singlewalled C NTs are assumed to be the hardest structural material. We note, however, that production of ropes made of BN NTs has never been reported. In this paper we present results on synthesis, structural and thermal analysis of ropes made of multiwalled BN NTs.