COMPOUNDS | ELECTRICALLY CONDUCTIVE


Right: Milled carbon fibre produced by Procotex from composite waste


industries are already leading to a tension between design parameters that a multifunctional material such as CarbonX has the potential to solve, Calderone says. Key material properties such as high crystallinity, strong pores and excellent processability is said to result in an unusual combination of reinforcement and conductivity features in the compound. “At the same time, processability is never compromised, so for example conductive films with a thickness down to 20 µm can be fabricated,” he adds. Calderone says that, together with its commer-


cial partners, CarbonX has recently developed some new applications in the field of EMI shielding. “For example, when mixed with CarbonX, PA6 compounds can achieve shielding effectiveness of 60dB in the range 1-10GHz, while reinforcement is 50% better than when using other conductive carbon fillers.”


Recycling ideas Hans Miltner is Senior Consultant and Business Development Manager with Procotex in Dottignies, Belgium, which specialises in processing recovered carbon fibres. “Today, conductive polymer com- pounds are believed to be on the verge of a much


PolyOne’s Surround family of conductive compounds are designed to shield sensitive electronics from both electromagnetic (EMI) and radio frequency interference (RFI), minimising the risk of “cross talk” between electronic components. The company says the compounds (formerly marketed under the ElectriPlast name) weigh up to 60% less than aluminium or copper and provide greater design freedom. They can be formulated with either stainless steel or nickel-coated carbon fibres. � www.polyone.com


46 COMPOUNDING WORLD | February 2020


wider global utilisation, with volume demand forecast from mainstream markets and applications in the near future,” he says. “Especially the automo- tive industry is now rapidly driving their adoption, as the ongoing electrification and the development of autonomous driving are putting new require- ments to the materials that are used.” Carbon fibre as a reinforcement offers unrivalled mechanical performance and durability with low weight for critical applications that include aero- space structures, he says, but the manufacturing of carbon fibre composites and parts also comes with a significant amount of production waste. Close to a third of all carbon fibre produced ends up as waste in the form of trim in composite production, and much of that ends up in landfill. Miltner says recycled carbon fibre will mainly


target markets other than aerospace where the favourable performance/cost ratio provides a better value proposition compared to incumbents, includ- ing virgin carbon fibre. “Compared to alternative conducting fillers, recycled carbon fibre can offer equivalent electrical and superior mechanical performance, up to competing with virgin carbon fibre at 30-50% lower cost. Its overall CO2


footprint is


lower than that of any of the virgin alternative solutions, including carbon black,” he says. Data for a PA66 compound with a recycled carbon fibre content as low as 10% shows property levels typical for a 30% glass-filled material but with a 15% lower density and additional antistatic or static-dissipative behaviour (depending on the type of fibre used). “Further increasing the carbon fibre content to 30% results in a 150% higher specific stiffness and a 65% higher specific strength than an equivalent glass-filled compound, but with conduc- tive or EMI-shielding behaviour,” Miltner says. Future developments at Procotex are dedicated to


improving handling of the recycled carbon fibre products, as well as maximising achievable perfor- mance levels in polymer compounds. “To comple-


IMAGE: POLYONE/THINKSTOCK


www.compoundingworld.com


IMAGE: PROCOTEX


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