JEC COMPOSITES MAGAZINE - Issue #44 - October 2008 - Special Asia - 25

Nanofibres Carbon nanofibres for low-cost engineered polymers Lightweight non-metallic composites exhibiting high thermal/electrical conductivity and high performance are favoured for a wide number of applications from high-volume commodity industrial applications to high-tech applications. Carbon nanofibres are one of several emerging nanomaterials available to boost the physical properties of composites and expand their applications and volume of use. PATRICK LAKE, PROJECT ENGINEER, AND CARLA LEER, RESEARCH SCIENTIST, APPLIED SCIENCES, INC. T he availability of nanocarbon materials, including single-walled nanotubes (SWNTs), multi-walled nanotubes (MWNTs), carbon nanofibres (CNF) and nanographene platelets (NGP), offer the promise of capturing the ultra-high mechanical and transport properties of the graphite bond in a new generation of carbon fibre reinforced polymers which are of great technological importance. Carbon nanofibres (CNF) (see Figure 1) – a form of vapour-grown carbon fibres – are similar to carbon nanotubes in structure, with comparable mechanical and transport properties but a diameter of approximately 100 nm, and lengths of tens to hundreds of microns. High-purity CNF is available in commercial volumes at affordable prices from several suppliers worldwide. The combination of these dimensions with low production costs and satisfactory availability allows CNF to bridge the gap between commercial continuous carbon fibre used widely for structural composites and single- or multi-wall nanotubes developed for sophisticated applications such as molecular electronics and sub-micron biomedical applications, both in terms of material processing and end applications. In the composite industry, the interest in carbon nanofibre stems from its Fig. 1: SEM potential to provide of carbon nanofibre. true multifunctional capabilities. CNF has been successfully used as an additive in polymer composites to modify several physical properties including thermal conductivity, coefficient of thermal expansion (CTE), absorption and scattering of electromagnetic radiation, electrical conductivity, flame retardancy, electron emission, and vibration damping. A recent review by Tibbetts et al. gives a useful overview of the achievements made thus far on CNF composite preparation and their properties [1]. Although much progress has been made, a bottleneck in Fig. 2: Carbon Nanofibre in Flexible Preform. achieving industrial applications for these composites is the homogeneous dispersion of the CNF into polymeric matrices. Ultimately, achieving superior transport properties in polymer composites comes down to a proper choice of fibre type, and geometry, and mastering the composite processing steps – more specifically the effective dispersion of the nanofillers in the continuous polymeric phase – or finding new product designs which overcome processing and dispersion difficulties. One example is the new CNF preforms Fig. 3: High(Figure 2), which are resolution TEM of easy to handle and PR-25 CNF surface overcome many of the showing orientation difficulties attending of graphene planes. to dispersion. (Courtesy of Applied Sciences, Inc. J. Howe, Oak Ridge National has recently Laboratory) No44 October 2008 / JEC Composites Magazine

JEC COMPOSITES MAGAZINE - Issue #44 - October 2008 - Special Asia

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #44 - October 2008 - Special Asia