Apply online to license this technology
Filamentary nanocarbon is a recently developed material having great commercial utility and promise for providing structural support or reinforcement, electrical and thermal conductivity, and for use in electronic devices including transistors and solar cells. Other uses of filamentary nanocarbon include composites, filled polymers, electron emitters, and flat panel displays.
The filamentary nanocarbon in its as-produced state is often very bulky, with the product occupying a large volume to mass ratio. It is frequently desirable to reduce this bulk for several reasons including ease of handling, shipping and packaging, as well as to lower propensity of the tiny fibers to become airborne.
A need exists therefore for an improved method for processing filamentary nanocarbon for purification, de-bulking, surface treatment, polymer pre-impregnation, and dispersion. Such a method would provide effective nanofiber processing, utilize commonly available apparatuses and equipment, and provide reduced processing costs.
In accordance with this Air Force invention, a quantity of filamentary nanocarbon is introduced into a pressure vessel. Near-supercritical CO2 is then introduced into the pressure vessel. Processes such as debulking, dispersing, purifying, surface treating, pre-impregnating and micronizing can then be performed within the pressure vessel. For example, if the mixture of CO2 and filamentary nanocarbon is agitated within the pressure vessel, de-agglomeration and disentangling is achieved. When the CO2 is released from the pressure vessel, the filamentary nanocarbon collected exhibits a dramatic reduction in volume. Other nanofiber processes can be performed such as surface treating and pre-impregnation by introduction of the desirable species into the near-supercritical CO2 prior to processing. Purification processing can additionally be performed by introducing a co-solvent into the near-supercritical CO2.
- Fast processing times on commonly available equipment
- Disentangled fibers are better conductors
- Dispersion is necessary to separate fibers by type such as semi-conducting or metallic
- Process does not break the fibers
- Process removes catalysts, hydrocarbons, soot, other nanoparticles
- Renders the fibers compatible for dispersion into polymers without incorporating a liquid process
- US patent 7,582,275 available for license