Specific energy consumption of melt impregnated carbon fibre-reinforced polyamide 6 tape manufactured from sized or plasma surface treated fibres

The extent of carbon fibre (CF) surface treatment research highlights the importance of interfacial bonding in polymer composite manufacturing. An oversight in the surface treatment field has been the quantitative assessment of specific energy consumption (SEC) and specific greenhouse gas (GHG) emissions. Such data can highlight areas for improvement in novel approaches. One technology that has received attention for its versatility is atmospheric-pressure plasma surface treatment. Quantitative SEC comparisons between novel in-line atmospheric pressure plasma jet (APPJ) and current typical surface treatments (sizing) for CF-reinforced thermoplastic tape manufacturing have not been presented in the literature hitherto. The present work fills this gap by studying a CF/PA6 tape manufacturing process with (A) APPJ air, (B) APPJ nitrogen, (C) APPJ acrylonitrile, or (D) polyamide sizing as the CF treatment. A process-level partial life cycle analysis was used to provide a detailed breakdown of SEC and GHG emissions per kilogram of tape produced at a laboratory-scale. The current typical sizing process required a primary energy input of 24 . 4 MJ/kg compared to 37 . 4 MJ/kg for the laboratory-scale APPJ treatment using air working gas. The APPJ deposition of acrylonitrile required 173 . 8 MJ/kg due to greater plasma generator power consumption, input material embodied energy, and lower line speed to promote high-quality compatibilisation. A limitation of the process-level SEC comparison is that the various surface treatments may not be mechanically equivalent. Subject to this limitation, the SEC breakdown is relevant for plasma system selection and technology development, where generator input energy must be minimised while maximising treatment rapidity to reduce the SEC of working gases and precursors.