Circular materials under analysis: A systematic literature review and a taxonomic analysis of Circular Materials, between theory and application

This contribution deepens the Circular Materials (CM) concept taxonomy aiming to highlight the complexity and multidisciplinary nature of this argument and outlining its broader implications. The present study adopts the PRISMA model to conduct a systematic literature review inquiring about the significant overlaps and divergences in CM definitions across disciplines, on a sample of 41 interdisciplinary works. Through a qualitative content analysis to systematically collect data for each work, the article delves into a taxonomy analysis of issues related to the CM development, concerning concepts, terms and key relationships around four complementary areas of interest. The taxonomy analysis is based on a holistic approach that intertwines various aspects (technical, economic, social) and it serves as reference point for academics, policymakers, and professionals working to enhance and improve CM across various sectors and disciplines. This taxonomy provides a structured framework to 1) identify opportunities to improve recovery and reuse practices, 2) understand the interactions between the CM system features and 3) support the design and planning of circular economy strategies in experimental settings as well as at industrial and policy levels. As main findings, the CM material category proposal is established, underscoring importance of a holistic approach to enhance the scalability and implementation of such materials across diverse contexts. Further studies can try to deepen the spectrum of references adopted in both academic and applicative fields identifying, for example, metrics to align the priorities of the different disciplines or between industrial sectors to be more easily standardized in circular manufacturing processes.