Flame retardant investigations on carbon fibre-reinforced polyurethane resin parts for aircraft applications produced by wet compression moulding

Epoxy resins are widely used in composite materials for aircraft applications. However, they are difficult to recycle, thus posing an increasing challenge to the aviation sector. By contrast, polyurethane resins (PUR) can be easily chemically recycled by solvolysis, but structural parts made of carbon fibre-reinforced polyurethanes (CF-PURs) are currently not in use in aircraft applications. This is due to a lack of knowledge about the properties of CF-PURs, especially during exposure to higher temperatures and to fire. To increase the recyclability of aircraft parts, for example interior structures like seats, there is a need for CF-PUR components which are able to fulfil the flame retardant regulations as well as the quality and production cycle time requirements of the aviation industry. It was found that a CF-PUR formulation processed by wet compression moulding containing 9 wt% of a phosphorous polyol is able to fulfil these requirements for aviation interior applications.