Circular economy of composites and especially recycling are gaining importance in science, politics and industry under the sustainability paradigm. Nevertheless, recycling of complex materials, such as glass fibre reinforced polymers (GFRP), requires life cycle assessment (LCA) to critically assess and verify the anticipated ecological benefit, and to analyse hotspots and identify optimization measures within the recycling value chain. The LightCycle project investigates various aspects of the circular economy of GFRP composites, such as i) the usage of mechanically recycled thermoplastic matrix material (polypropylene) and glass fibers, ii) technology optimization by a combined compounding and injection molding process (one-step process), iii) degradation behaviour and process control of the GFRP materials throughout multiple recycling cycles, and iv) the development of a demonstrator component for the identification of industrial substitution potentials.
This research presents different designs of LCA to evaluate the environmental performance and capture the impact of the project. Furthermore, it analyses the different LCA approaches’ in terms of scientific relevance, significance to project results, feasibility and data requirements. The identified approaches are i) comparison of virgin and recycled materials, ii) comparison of two-step compounding and injection molding with the one-step process, iii) benchmarking and substitution potential of the recycled demonstrator against industrial standards, iv) the determination of environmental and material performance of multiple recycling cycles, v) assessment of the role of additives, and vi) comparison of different GFRP composite recycling options, e.g. mechanical recycling, pyrolysis and solvolysis. Industrial benchmarking has the highest project and scientific relevance as previous research stresses out that there is a lack of examples for fields of application. From the project perspective, this approach combines material and process specific aspects to influence the environmental performance that can be captured per equivalent component. Difficulties arise from the high level of interdisciplinarity needed and feasibility of data collection.