Sustainable lignin-based carbon fibre reinforced polyamide composites: production, characterisation and life cycle analysis

This work presents the first production, characterisation and life cycle analysis of composite materials produced from injection moulded polyamide reinforced with short lignin-based carbon fibre (CF). To produce these composites many challenges associated with the production of lignin CF have been resolved through the utilisation of thermoplastic polyurethane blend with Alcell organosolv lignin. These CFs have been utilised to reinforce polyamide 66 (PA66) and their performance as a reinforcement have been compared with a textile grade PAN CF. Composites have been prepared using short CF and injection moulding with results compared in terms of interfacial interactions, and composite mechanical performance. It was found that lignin-based CF increases crystallinity in the PA66. The increased matrix affinity of the lignin-based CF may be attributed to increased oxygen on the lignin CF which has been retained from the lignin precursor fibre. When considering that the lignin CF reach equivalent diameter to the PAN CF, the mechanical properties of lignin based CF are comparable to that of PAN CF. Life cycle analysis modelling predicts that the replacement of PAN CF with lignin CF reduces the global warming potential by 54 % for these materials.