Abstract

Composite materials, such as those made from carbon and glass fibres, are now considered to be high value-added materials. However, a barrier to their full circularity is the difficulty of their recyclability and the serious environmental problems that these materials pose. Fibres can be recovered using techniques such as pyrolysis and solvolysis and disposed of as chopped fibre at the end of their life cycle. However, their use in industrial applications is limited to injection moulding, anisotropic mats, etc.

This work has focused on the research and adaptation of textile technologies for staple fibre processing, such as carding, spinning and weaving, with the aim of obtaining textile intermediates suitable for the production of thermoplastic composites. These technologies must improve the mechanical properties of currently available commercial solutions and adapt to these reinforcing fibres, which are fragile, extremely thin and in some cases electrically conductive.

This research has resulted in the production of intermediate textile products such as hybrid yarns (rCF-PA6 and rAramid-PA6), and nonwovens (rCF-PA6, rAramid-PA6 y rGF-PA6), both suitable for obtaining mainly thermoplastic composites.

Abstract

The implementation of composite materials within the industry is a trend that has been developing for many years. In the case of the aeronautical industry, the gradual replacement of metallic parts by composite elements is increasing with each new aircraft model developed. However, these composites imply a challenge towards their end of life, since their dismantling and processing is under development, and they are currently processed as waste, with no recycling or reuse opportunities. In this context, a robotic dismantling solution is proposed by means of abrasive water jet cut, guided by a digital twin system. This system allows operator-guided cutting of the composite part, permitting the selection of the specific area to be dismantled on the aircraft itself. Thanks to a portable abrasive water jet system, operated by a collaborative robot, the cutting operations can be carried out in situ. This dismantling system is placed on a portable platform, operated by an AGV (Automatic Guided Vehicle) system integrated in the dismantling system itself, capable of transporting it along the working area. In this way, new strategies for dismantling and reusing the composite material at its end of life are proposed. These new options include the extraction of complete parts selected by the operator for their reuse, the elimination and/or recovery of rivets and the adaptation of the parts to be dismantled for a subsequent recycling process.

Abstract

The use of carbon fiber (CF) has increased in the last decade, shifting from the aeronautical sector to the leisure and automotive sectors. CF production requires high energy consumption and emits large amounts of CO₂. This increase in consumption generates a greater amount of CF composite waste, which must be properly managed to give it a second life. Deremco project aims to transfer and increase the TRL of different recycling technologies for composite from the wind and aeronautical sectors. The companies IDEC, BIRZIPLASTIK, and TECNALIA have focused on the recovery of post-production waste from the aeronautical sector to obtain recycled CF (rCF) through a thermochemical process. IDEC proposed the horizontal stabilizer  of an aircraft's as a use case. This secondary structure requires a lower level of mechanical properties, so the introduction of rCF has proven feasible. BIRZIPLASTIK proposes developing a thermoplastic formulation with high technical requirements for automotive applications. Two formulations have been developed that meet these requirements, one of which is 100% recycled material. To carry out these success use cases, TECNALIA has worked on optimized the rCF sizing processes and integrating it into the compounding and Resin Transfer Molding (RTM) processes.