Amorphous Carbon Treatment

Sidel, a French company, has developed the Actis plasma process that coats the inside of PET bottles with a 0.15 micron thick layer of amorphous carbon to improve oxygen and carbon dioxide barrier. Actis stands for Amorphous Carbon Treatment on Internal Surface. The carbon is deposited from acetylene gas, using a microwave-assisted process to excite the gas into plasma. The bottles are clear, and the process is reported to increase the carbon dioxide barrier of beer bottles by up to seven times, while not interfering with recycling. Actis has been approved by FDA, and is reported to cost 20 to 25 percent less than multilayer PET bottles with comparable barrier properties [10], Sidel has also developed Actis Lite a lower level of treatment for carbonated soft drink bottles, sparkling waters, juices, teas, and sauces, which do not require as good a barrier as beers and ciders. 

The process is called ACTIS (Amorphous Carbon Treatment on Internal Surface). It consists of coating the internal surface of a standard single-layer PET bottle with a layer of highly hydrogenated amorphous carbon, obtained from food gas in its plasma state. The coating creates a thin (about 0.1 pm thick) barrier inside the bottle. The food safety quality has been approved by the Dutch standards authority (which is also accredited to the European Union), and the coated bottle is 100% recyclable. 

The Amorphous Carbon Treatment on Internal Surface (ACTIS) coating, developed by the French company Sidel, is a thin layer of hydrogen rich carbon deposited by plasma polymerization of acetylene on the inside wall of a PET hottle. This barrier solution is designed for small-size PET containers (less... 

Defects in arc-grown nanotubes place limitations on their utility. Since defects appear to arise predominantly due to sintering of adjacent nanotubes in the high temperature of the arc, it seemed sensible to try to reduce the extent of sintering by cooling the cathode better[2]. The most vivid assay for the extent of sintering is the oxidative heat purification treatment of Ebbesen and coworkers[7], in which amorphous carbon and shorter nanoparticles are etched away before nanotubes are substantially shortened. Since, as we proposed, most of the nanoparticle impurities orig-... 

There are more than a million known carbon compounds, of which thousands are vital to life processes. The carbon atom s unique and characteristic ability to form long stable chains makes carbon-based life possible. Elemental carbon is found free in nature in three allotropic forms amorphous carbon, graphite, and diamond. Graphite is a very soft material, whereas diamond is well known for its hardness. Curiosities in nature, the amounts of elemental carbon on Earth are insignificant in a treatment of the... 

Fig. 4 shows the SEM images of SWNTs purified by the thermal oxidation and acid-treated. Fig. 4(a) shows a SEM image of the raw soot. In addition to the bundle of SWNTs, carbonaceous particles are shown in the figure. These stractural features mi t be causal by various in the arcing process because of an inhomogeneous distribution of catalysts in the anodes [7]. It can be seen that the appearance of SWNTs was curled and quite different fiom that of MWNTs. Fig. 4(b) shows a decrease of amorphous carbons after oxidation. The basic idea of the selective etching is that amorphous carbons can be etched away more easily than SWNTs due to the faster oxidation reaction rate [2]. Since the CNTs are etched away at the same time, the yield is usually low. The transition metals can be etched away by an add treatment. Fig. 4(c) shows the SEM image of the acid-treated sample, where the annealed sample was immersed in 10 % HCl. 

A colorless gel formed which was isolated by vacuum evaporation of the volatiles. The resulting colorless glassy solid was pyrolyzed in vacuo at 900°C for 24 hours in a quartz tube and the evolved volatiles identified as NH3 and NH4CI. The remaining solid was briefly (2 hours) heated in air at 1200°C in order to remove minor carbon impurities and to improve crystallinity. This solid was then treated at room temperature with 40% aqueous HF to remove boric acid and silica formed in small quantities. The solid obtained at 900°C was identified as boron nitride however, the majority of the material was amorphous. After treatment at 1200°C, white crystalline boron-nitride was obtained in about 55% yield. 

A more gentle approach would be the oxidative treatment in humid air at elevated temperatures [92]. This method selectively removes the amorphous carbon, while keeping the corrosion of the carbon surface to a minimum. The degree of pu-... 

Tab. 1.2 Summary of typical purification techniques for CNTs. a Treatment can remove metal catalyst residues. b Carbon residues (e.g. amorphous or organic aromatic debris).c Purification introduces covalently bonded functional groups. d Only if not covered with carbon or encapsulated within CNT. e Only amorphous carbon around metal particles. From [39] with kind permission from ACS Publications.

OS3(CO)l2 Amorphous carbon black Adsorption from solution and thermal treatment under H2 Os particles active in methanation [71]... 

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