Use of Recycled Carbon Fibers for Lightweight Construction Applications with High Fire Protection Requirements

For the development and production of commercial aircraft appropriate materials, design and appropriate manufacturing technologies are important keys for the realization of fuel-saving and environmentally friendly aircrafts. In this context, the use of Carbon Fibre Reinforced Plastics (CFRP) is very auspicious. Nevertheless, the current production of carbon composites in aviation industry causes a high percentage of cutting scrap and production waste. As a result, such unusable carbon fibres and uncured prepreg waste have to be disposed as special waste in appropriate recycling plants. In this case long and short carbon fibres can be recovered from production waste or increasingly from end-of-life aircraft components by technologies such as the thermal-chemical pyrolysis process. One promising way to bring these carbon fibre recyclates back into aircraft cabin and cargo applications are compression technologies for chopped fibre materials with thermoset matrix systems such as Sheet Moulding Compounds (SMC). Hence, the ecological sustainability of modern aircraft along their whole life cycle can be increased. This paper deals with the development of new flame-retardant SMC materials reinforced by recycled carbon fibres for aircraft interior applications. Based on unsaturated polyester resins new SMC formulations with reactive flame retardant additives have been rebuilt. Aims are to optimize fibre impregnation, to lower the density and to increase the strength of the SMC in comparison to existing flame-retardant SMC fabrics with a high amount of aluminium hydroxide (ATH).