Nanocomposites
Less Hype, More Hard Work On Commercial Viability

From the May 2007 issue of Plastics Technology.
Published on the Vorbeck site with permission.
By Lilli Manolis Sherman, Senior Editor

Economical nano-carbons
Start-up company Vorbeck Materials Corp. has licensed a technology developed at Princeton University that reportedly enables economical commercial production of graphene, conductive functionalized single sheets of graphite, for use as multifunctional nano-fillers. They are said to provide electrical conductivity, barrier properties, and improved physical properties in a wide range of thermoplastics, thermosets, and rubbers.

Vorbeck’s Vor-x graphene nano-fillers reportedly offer a combination of mechanical and electrical properties superior to those of carbon nanotubes, plus barrier and thermal properties equivalent to nanoclays. Vor-x graphene fillers are functionalized through proprietary surface chemistry to ensure better compatibility and more complete dispersion in polar and non-polar matrices. These fillers have been successfully dispersed in PET, PEN, PMMA, and TPEs and reportedly have potential in a broad range of commodity and engineering thermoplastics, including PC and nylons as well as thermosets such as epoxy.

Pilot tests in twin-screw extruders and batch mixers reportedly show that Vor-x graphene is efficiently dispersed using melt mixing techniques, unlike most high-performance nano-fillers that must be mixed as solvent dispersions, according to Vorbeck president John Lettow. Evaluation samples are available in both powder and masterbatch forms, although the company plans to market Vor-x primarily in masterbatch form.

Recent trials show Vor-x polymer composites to have greater tensile yield and ultimate strengths, higher thermal degradation temperatures, and greater electrical conductivity than composites made with other fillers, according to Lettow. “Low fill levels of Vor-x can nearly double the modulus of rigid thermoplastics, and the electrical conductivity is improved by an order of magnitude over similar loadings of carbon nanotubes,” he says.

Vor-x composites can be molded and extruded. Potential uses are expected to include electronic components and electrostatic discharge (ESD) applications. Automotive uses could include under-hood components and thermoplastic body panels, where Vor-x can both stiffen the panel and make it electrically conductive so it can be painted by electrostatic spraying.

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