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roughly 10,000 times thinner than a human hair and 1000 times thinner than standard carbon fiber. The second key difference is that, unlike powdered CNTs, which are produced as loose, individual fibrils, Miralon CNTs tend to entangle and intertwine with each other in the reactor; they also tend to stick together, forming an elaborate network (see photo above). This makes it easier to collect them out of the furnace and convert them inline to continuous fibers or sheets. Miralon comes out of the furnace in a cloud of entangled CNTs called a "sock." The sock can be wound around a drum, where it forms a felt and then can be densified into a nonwoven sheet, which can be slit into tape. Alternatively, the sock can be collected in a spinneret to form a continuous yarn made up of millions of entangled CNTs, each only a few millimeters long. Miralon yarn can be used in compos- ites and sheet can be made into prepregs or chopped into porous bundles of around 0.05 mm diam. × 1 mm long. Nanocomp offers the chopped "dispersed products" as either a "dry pulp" or as custom masterbatches on request. Chopped Miralon can be used in thermoplastic injection or compression molding, LSR injection molding, and compounding into 3D-printing filament. Nanocomp currently has 13 production lines—six for fiber and seven for sheets. The company says that multi-millimeter-long Miralon CNTs have been classified by the U.S. EPA as "articles," not "particles," unlike CNT powders or loose tubes. This means they are too large to be inhaled or absorbed by the skin, according to Nanocomp. Broad areas of potential applications in thermoplastics and thermo- sets—including liquid silicone rubber (LSR)—are envisioned for a new form of carbon nanotube (CNT) that's said to be highly compatible with polymers. Miralon CNT sheets, yarn, and dispersion grade come from Nanocomp Technologies Inc. in Merrimack, N.H. (nanocomptech. com). The firm started in 2004 and moved to a larger facility in a former paper mill in 2012. It is currently in the pilot production phase, with capacity for around 0.85 metric ton per year. It is raising capital for a planned expansion to 8 m.t. in 2018 and potentially to more than 20 m.t. by 2021. Nanocomp co-founder, president, and CEO Peter Antoinette foresees broader poten- tial for large-scale use of CNTs in existing plastics processes with his firm's new tech- nology. It uses ethanol and methanol as low-cost raw materials, which are vaporized in a furnace reactor at more than 800 C (1470 F) with an oxygen-free atmosphere of pure hydrogen gas and iron as a catalyst. In this furnace, chemical vapor deposition precipi- tates billions of CNTs that have two unique properties. First, Miralon CNTs are typically 1 to 10 mm long but only 3-5 nanometers wide, yielding an aspect ratio (length to diameter) of about 1 million to one. That compares with aspect ratios of 1000 to 10,000 to one for typical CNTs, which have similar thick- ness but lengths in the micron range (1/1000 of a millimeter). High aspect ratio is said to be an advantage over other CNTs, which are powder-like and reportedly tend to agglomerate when added to resins. Despite its greater L/D, Miralon is still invisibly small— By Matt Naitove Executive Editor High conductivity of compounds containing Miralon CNT is partly an effect of entanglement of the hair-like fibrils. New 'Long' Carbon Nanotubes Show Promise In Thermoplastics, LSR Novel hair-like nanotubes are said to "love thermoplastics" and to provide electrical conductivity at very low loadings. Long CNT fibrils won't clump, but entangle with each other to provide continuous conductive paths. 12 APRIL 2017 Plastics Technology PTonline.com C A R B O N N A N O T U B E S Close -Up On Technolog y