The concentration of multi-walled carbon nanotubes (MWNTs) and metal nanoparticles can be easily varied within the shaped carbonaceous solid. Carbon nanotube containing fibers and films have also been formulated from the precursor compositions. The potential range of applications is huge, including structure, energy, sensors, separation/filtration, battery, electronic displays, and nanoelectronic devices.
Using this method, carbon nanotubes (CNTs) are formed in a bulk carbonaceous solid from thermal decomposition of melt-processable precursor compositions formulated from organometallic compounds or metal salts in the presence of an excess amount of selected highly aromatic compounds.
The CNTs obtained by this patented method are not formed from gaseous components, as is common with the current CNT production based on chemical vapor deposition (CVD) methods, but rather evolve from metal and carbon nanoparticles that form within the carbonaceous solid during the carbonization process above 500°C. Only a small amount of the organometallic compound or metal salt is needed to achieve the formation of CNTs in high yield, but large quantities of the metal source can be used, depending on the application, if desired.
The solid-state method enables the large-scale production of MWNTs in moldable solid forms, films, and fibers using low-cost precursors and equipment, thereby reducing economic barriers that are inherent with carbon nanotube materials produced by more conventional methods, such as CVD. Following carbonization, the shaped carbon solids are composed of varying amounts of nanotubes and amorphous carbon, depending on such synthetic parameters as the metal catalyst concentration, carbonization temperature, and the specific organic precursors used. The amorphous carbon phase is readily removed via selective combustion at temperatures from 300–500 °C, producing highly porous, purified CNT solids with specific surface areas up to 500 m2 g-1. This highly flexible synthetic method also offers the ability to incorporate heteroatoms, for example nitrogen, oxygen, and/or boron, into the carbon nanotube solid via the initial carbon precursors.
The NRL scientists use standard resin melt processing techniques to produce various shaped CNT-containing carbonaceous configurations. Their research is the first example of using high temperature thermosetting resins as a carbon source for the formation of CNTs. Any commercially available resins, including phthalonitriles resins, polyimides, epoxy resins, phenolics, and petroleum pitches, that have good thermal properties and show superior structural integrity, are attractive sources of carbon for CNT formation by the novel method.
The use of commercially available resins is a potentially inexpensive route to CNTs. Using this simple, potentially cost-effective method could result in the production of CNTs in large quantities and various shapes. Scientists are evaluating them for possible use in numerous aerospace, marine, and electronic applications.
Donna McKinney | EurekAlert!
What happens when we heat the atomic lattice of a magnet all of a sudden?
17.07.2018 | Forschungsverbund Berlin
Subaru Telescope helps pinpoint origin of ultra-high energy neutrino
16.07.2018 | National Institutes of Natural Sciences
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering