International Appliance Manufacturing 2008 - (Page 62) The Iomega Corp. uses RTP’s carbonnanotube compounds in part because of its consistent electrical resistivity and its cleanliness standards. the charges, but if the charge is bled To date, work with nanooff to quickly there can be a corotubes has been limited by cost. na event, an electrical arcing. The In the past, prices have reached size and uniformity of the nanoabout $500 a pound, but prices are tubes, says Bryant, eliminates dropping. Bryant says some initial this problem. patents on nanotubes have expired The ESD properties was one and competition has increased. With of the compound’s selling points for the dropping prices, many experts believe the Iomega Corp., San Diego. The company, that nanotube technology is set to drap l a s t i c ’s which makes storage and network security matically increase. flexibility, lowers the solutions, uses the conductive material in its In May, RTP Company introduced Izod impact strengths, and changes REV Backup Drive and removable REV disk several new carbon-nanotube-based the shrinkage rate of the plastic. that secures critical data for easy recovery. compounds that are specifically engineered “With the low loading of nanoThe REV product family was initially introfor electrical applications, specifically for dealtubes, you still have easily moldduced in 2004 and a second-generation REV ing with electrostatic discharge (ESD) coned properties and can fill very thin drive was introduced in 2007. To date, Iomega cerns. Seven different resin systems are availhas sold approximately 300,000 REV drives able, including those for use with polycarbonsections, and now it can be either electrically and 1.5 million REV disks. The RTP Co. cusate (PC), polyether-ether-ketone (PEEK) and conductive or static dissipative,” Bryant says. tomized a high-impact RTP 300 Series PC polyetherimide (PEI). CNT compound for the original REV disk that Bryant describes the carbon nanotubes Eliminating residual voltage met difficult application challenges, includas resembling an extremely tiny steel wool Bryant says the uniformity of the carbon ing consistent electrical resistivity. Now, with pad that has been broken up. Measuring 10 nanotubes also helps to eliminate residual the new reformulated electrical grade comnanometers or less in diameter, these fibers voltage, or “hot spots” as Bryant calls these pounds, RTP Company was able to deliver a of conductive graphite, when properly disareas of extreme electrical conductivity. CNT product for the second generation REV persed, make up a fine network of wires inside Carbon fiber residing on the surface of the drive that was optimized to meet Iomega’s the plastic to carry the electrical charges away plastic can be conductive, almost metal like. strict high purity cleanliness standards for low from the part and keep it neutral. They can build up charges and also bleed off particle generation while simultaneAnd, like other nanocomposously offering cost improvements. ites, the loadings are small. In a typical, carbon-fiber material, the Novel nano filler loading is often in the 10 percent to 20 percent weight range in Research and development of order to get the electrical propernanotubes is ongoing at many other ties needed. With nanotubes, the companies and research facilities. same properties can be achieved NaturalNano, Rochester, N.Y., is at greatly reduced loadings. The moving forward with its own nanoactual weight percentages are protube recipe. In June, the company prietary, says Bryant, adding that says it successfully tested its Pleximer they are under 5 percent by weight product using high loadings of haland most of them are signifiloysite nanotubes in a variety of cantly less. (See chart, Percolation polymers. At HNT concentrations Curve.) as high as 20 percent, the mateAt these loads, the nanotubes rial showed a storage modulus that do not affect the plastics’ desired was 10 times higher than that of the properties. By contrast, the adding polymer alone, says Cathy Fleischer, of carbon fiber typically reduces A transmission-electron-microscope (TEM) image of SolVin president and CTO of NaturalNano. NanoVin material showing the dispersion of nanoclay particles around the larger PVC grains. 62 International Appliance Manufacturing 2008
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