Simplification of requalification procedure of outdated carbon/epoxy prepregs and scenarios of reuse

Abstract

Abstract As a result of their combined high mechanical performances and easy processability, carbon/epoxy prepregs are widely used in the manufacture of aerostructures. The resin of these materials is in an intermediate state of polymerisation which makes these materials perishable. Drastic manufacture conditions lead continuously to the generation of expired prepregs that, today, can no more be used in the aeronautic industry nor in other industries. Although requalification procedure can be carried out, its high cost does not always justify such a procedure. This is why large quantities of expired prepregs are send to landfill. The objective of the Cleansky project MANIFICA is to set up a complete recycling chain of carbon fibre composites “from aeronautic waste to innovative composite parts”. The aim of this work is to propose a simplified requalification procedure by avoiding unnecessary tests. These studies are illustrated by property measures on compliant and expired prepregs. The main results were that in most cases, aging induces processing difficulties while mechanical performance remains unaffected. It was also shown that a simpler requalification procedure was possible and that expired prepregs can be reused without loss of performance outside the aeronautical field. Rather than considering expired material as waste, MANIFICA offers several new reuse scenarios.