In March 2025, the r-LightBioCom project has reached its fourth milestone identifying sustainable High-Performance Composites (HPC) components ready for use case implementation. By reaching this milestone, the project has laid essential groundwork for the development of new high-performance composites for meeting the sustainability requirements of the project’s envisaged automotive, infrastructure and aeronautics use cases.
The r-LightBioCom project aims to develop new sustainable high-performance composites with inherent recyclability properties. In this context, the development and implementation of new raw materials that reduce weight and cost and introduce recyclability and sustainability to the resulting high-performance composites form the basis for all project results and the main advances in the state of the art. Therefore, the selection of sustainable components suitable for project implementation constitutes an essential building block of the project.
Use Case 1: Spoiler for automotive sector
The project aims to develop a sustainable spoiler as an alternative to conventional thermoset-based components and pristine fibres. By introducing bio-based resins and natural fibres, the project seeks to increase the green content of composite components. This approach not only enhances recyclability at the end of the product’s life but also provides an aesthetically pleasing natural appearance. The current system, made of epoxy resin and carbon fabric, ensures mechanical stability but lacks recyclability.
The project seeks to enhance its environmental performance and achieve a high-quality finish by selecting three more sustainable options for reinforcement fibres. Firstly, fabrics with various structures composed of flax fibres will be used. Secondly, basalt filament fabrics will be incorporated. Thirdly, a combination of both options will be explored.
For resins and manufacturing processes, the most viable options to meet the mechanical, aesthetic, and compatibility requirements with reinforcement fibres are bio-based epoxy resin and/or bio-based epoxy vitrimer resin, both functionalized with nano-lignin. These developments are focused on their application in hand lay-up technologies and autoclave processes with microwave-assisted curing, or RTM processes with frontal photopolymerization developed in the project.
Use Case 2: Trunk floor for automotive sector
The goal of this use case is to create a more sustainable trunk floor compared to traditional components made from thermoset materials and virgin fibres. The project aims to increase the green content of final components; currently, only the paper is considered green. After the project, the bio-based content of components can be increased through the application of bio-based resins and green fibres. Another objective is to develop a high-performance thermoplastic honeycomb structure. This component integrates a cardboard honeycomb wave structure with a PU/glass fibre skin and PET carpet. The challenge is to optimize impregnation for structural integrity while maintaining low weight with sustainable fibres.
For this case study, several textile material options have been proposed. On one hand, for the corrugated core of the honeycomb, the most sustainable textile intermediates are based on various nonwovens composed of natural fibres and thermoplastic fibres. The first option involves using recycled polypropylene combined with natural fibres (hemp and flax) and basalt fibres. Alternatively, a bio-based thermoplastic matrix such as PLA (polylactic acid) fibre, in combination with flax fibres, has also been considered.
For higher performance properties with lower weight, alternative options focus on nonwovens with polyamide fibre and high-performance recycled inorganic fibres such as recycled glass fibre and recycled carbon fibre.
Regarding the outer layers of the honeycombs, depending on the chosen core, fabrics composed of the same type of fibres as the core (flax) have been selected, or nonwovens composed of natural fibres (flax and hemp) with basalt and nonwovens of carbon fibre. These outer layers of the honeycomb will be processed in the form of prepreg using vitrimer bio-epoxy resin functionalized with nano-lignin to improve compatibility with the honeycomb cores.
Use Case 3: Tunnel lining for infrastructure sector
In this use case, the project explores bio-based resin alternatives to current non-bio-based resins and non-glass fibre reinforcements for fire and water-resistant tunnel panels. Currently, the Panel System has been developed via pultrusion using high-performance composites (HPC) with conventional thermoset resins and glass fibre, ensuring durability in harsh environments.
For this use case, the most sustainable textile intermediates suitable for pultrusion have been selected based on the use of rovings composed of recycled aramid fibre and basalt filament. To improve processability and mechanical properties, the use of individual rovings (basalt roving and recycled aramid roving) is being studied, as well as hybrid rovings composed of these two fibres. This is to determine the most feasible processing method in the pultrusion line.
Regarding the resins for adaptation to the pultrusion process, several types of bio-epoxy resins with modified viscosity and enhanced fire resistance are being explored. These resins incorporate special nano-fillers and nano-lignin additives.
Use Case 4: Detachable leading-edge panel for aerospace aircraft
The project focuses on composite materials made from bio-based resin and, if possible, recycled fibres for RTM or infusion processing in secondary aeronautical structures. The current Panel System consists of a CFRP-based cover for a small commercial aircraft rudder, leveraging a high strength-to-weight ratio (Aluminium: 2700 kg/m³ vs CFRP: 1600 kg/m³).
The proposed bio-resin alternatives include bio-benzoxazine, aromatic resins, and bio-polytriazine reinforced with pristine carbon fibres. After numerous tests and developments of textile intermediates based on recycled carbon fibres hybridized with virgin carbon filaments, the use of recycled reinforcement fibres (carbon fibres) has been ruled out due to the high mechanical requirements of the part.
To achieve the required semi-structural properties, using recycled carbon fibres would necessitate excessively increasing the weight of the composite, which is counterproductive for the aeronautical sector that demands lightweight components. However, research into the use of recycled carbon fibres hybridized with virgin fibres has opened new possibilities for non-structural aeronautical composites.
