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

This chapter addresses the environmental and energy challenges posed by the increasing production of composite materials, particularly those reinforced with carbon and glass fibres. Current recycling technologies focused on fibre recovery, such as thermal and chemical methods, now enable the production of fibres suitable for reintegration into the value chain. The chapter details adapted textile technologies for processing these recycled fibres, covering methods from non-woven fabric production to the newest manufacturing technology of yarns and unidirectional tapes. Technologies such as carding and yarn formation are analyzed, highlighting the need for hybridization with virgin materials to enhance the mechanical properties of the final products. While current advances do not yet match the performance of virgin materials, ongoing research continues to optimize these processes, paving the way for the industrialization of more sustainable composites, with applications ranging from lightweight structures to sectors with higher mechanical requirements.

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

This PART 2 is the continuation of the project: “PART 1: recyclability and revalorisation of railway components made of composite materials”. Following the successful development of the recycling process for the Lightweight Running Gear Frame prototype and the formulation of a 3R epoxy resin suitable for use in the railway sector, the project advances with the following challenges:

1. Revalorisation of Recycled Carbon Fibre (rCF) into new fabrics, by obtaining hybrid rCF and polyamide 6 (PA 6) yarns by adapting and optimising textile processes to incorporate recycled fibres into new intermediate products.
2. Production of a new prepreg and its laminates. The new prepreg and its laminates will be produced using the dry fabric obtained in the previous objective and the 3R epoxy resin, developed in PART 1 of the project.

The overall conclusions of the project are that: the recycling process is suitable for post-consumer components, the spinning and weaving methods are effective for dealing with this type of fibres and the 3R laminates manufactured are of high quality and ready to be evaluated in terms of their properties.

Abstract

Under the coordination of AITEX and in collaboration with the partners of the r-LightBioCom project, intensive research, selection, and validation of sustainable reinforcement fibers (natural, recyclable or recycled, and with low environmental impact) have been carried out for use in composites that will be validated in automotive demonstrators (spoiler and trunk floor), infrastructure (tunnel lining), and aeronautics (wing leading edge). In this area, the following achievements stand out:

1. Validation procedure regarding processability and mechanical characteristics of various sustainable reinforcement fibers (recycled carbon and glass fibers, natural fibers, basalt fiber, and recycled aramid fiber).
2. Development of sustainable textile intermediates (fabrics, mats, pre-pregs, honeycombs, and rovings) through the adaptation of textile technologies for processing the selected reinforcement fibers and compatible with bio-based resins.
3. Hybridization of sustainable reinforcement fibers with virgin filaments to improve mechanical properties while maintaining low environmental impact. The results obtained indicate that the selection of alternative and more sustainable fibers than those usually used in the production of composites are suitable for the development of the aforementioned demonstrators in terms of processability and resistance.​

The results obtained indicate that the selection of alternative and more sustanaible fibers than those usually used in the production of composites are suitable for the develpment of the aforementioned demonstrators in terms of processability and resistance.

Abstract

In the railway sector, represented by TALGO, there is growing concern about the recyclability and reusability of composite parts at the end of their useful life. To address this concern and comply with Spanish and European directives and legislation, an innovation project (divided into "PART 1" and "PART 2") has been carried out in which AITEX, CIDETEC, iTREE, and TALGO have collaborated. The main results of the first part are as follows:

1. Recycling process of the composite material of the first prototype of the Lightweight Running Gear Frame: This process focuses on recovering the carbon fiber contained in the material by combining several chemical-physical steps.
2. Development of a 3R (recyclable) epoxy resin formulation: This resin meets the thermal, mechanical, and FST (Fire, Smoke, and Toxicity) requirements of the railway sector and is suitable for use with prepreg technology.

The results indicate that the recycling process is suitable for producing post-consumer parts and that the formulated resin meets the required standards. The overall conclusions of the project will be revealed in PART 2 of this study.

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.