D. Lashmore, B. White, M. Schauer, R. Braden, Nanocomp Technologies, Concord, NH
The emphasis by Nanocomp on CVD synthesis of high strength carbon nanotubes has led to a unique process for continuous production of nanotube yarns, and to a new type of very strong non-woven CNT sheet. These materials may be single wall or dual wall. In this presentation an overview of the electronic, mechanical properties and some applications of these carbon nanotube wires and sheets will be presented. Sheet material is now being fabricated 3 foot by 10 foot panels, the largest CNT textiles ever made! Yarns over 1000 m have also been produced!
These products potentially enable a variety of applications which make use of their very high specific strength and electronic properties. For example yarns are over 1 N/Tex (2 GPa) and textiles over 0.5 N/Tex (1GPa) have been demonstrated. Prepregged composites of the textiles with strengths of about 2 GPa have been demonstrated. A unique process for post nanotube alignment not only dramatically increases strength but also reduces resistivity and increases the Seebeck Coefficient. Experiments on doping will be described that enable the stabilization of the p type yarns at high temperature in vacuum. Applications include: very light weight electrical conductors to replace copper wire in some applications, composites, sandwich structures, hybrid batteries, fire resistant coatings, and thermoelectric devices.
Summary: We have developed an automated CVD process based on gas phase pyrolysis for the synthesis of high strength carbon nanotubes. This has led to a unique process for continuous production of nanotube yarns whose strengths can exceed 1.5 N/Tex or ~3 GPa , and to a new type of very strong non-woven CNT sheet whose strengths can exceed 0.5 N/Tex or ~1 GPa.
These materials may be made of single wall or dual wall CNTs and can this can be selected by the system operator. In this presentation an overview of the electronic, mechanical properties and some applications of these carbon nanotube wires and sheets will be presented. Sheet material is now being fabricated 3 foot by 10 foot panels, the largest CNT textiles ever made! Yarns over 1000 m have also been produced!
Both materials can be used as deposited with the catalyst left in the structure or alternatively the catalyst can be removed chemically or by high temperature, 1550 C, followed by higher temperature annealing at ~1850 C.. These products potentially enable a variety of applications which make use of their very high specific strength and electronic properties. For example yarns are over 1 N/Tex (2 GPa) and textiles over 0.5 N/Tex (1GPa) have been demonstrated. Post processing of the yarns to improve uniformity and control pitch angle improve properties significantly.
Prepregged composites of the textiles with strengths of about 2 GPa have been demonstrated. The materials have a very low compression modulus so that they are best used as sandwich structures. Woven and braded textiles will also be shown and some properties given.
Applications include: very light weight electrical conductors to replace copper wire in some applications, composites, sandwich structures, hybrid batteries, fire resistant coatings, and thermoelectric devices
