Existing material selection methods seem to offer limited support for addressing substance safety in practice, as the focus remains on intrinsic material properties and less on exposure risk. This hinders Safe and Sustainable by Design (SSbD) efforts that can prevent use and accumulation of substances of concern (SoCs) across product lifecycles in a circular economy. This study reviews 29 sustainable material selection methods to evaluate how they do support substance safety. Results show that substance safety is generally embedded within the broader sustainability realm without explicit risk or lifecycle-based assessment. Of the four steps that can be distinguished in material selection, most methods support the steps ‘Establishing a set of candidates’ and ‘Comparing candidates’ but the steps ‘Formulating selection criteria’ and ‘Choosing suitable candidates’ are often unsupported, leaving critical substance safety trade-offs unaddressed. The importance of mindsets such as systemic thinking and iterative reflection is recognized but underrepresented. The findings highlight the need to adapt existing methods with better guidance and risk integration to advance SSbD in material selection.

The short lifespans and rapid innovation cycles of electronic products result in the loss of valuable and critical resources (Bakker, Wang, Huisman, & den Hollander, 2014; Baldé et al., 2024). Strategies aimed at extending product lifetimes, such as design for repair, focus on improving the ease of manual disassembly (De Fazio, Bakker, Flipsen, & Balkenende, 2021). However, connections optimized for repairability can hinder the mechanical separation of materials during recycling. This highlights a critical trade-off: improving repairability can often conflict with recyclability, emphasizing the need for balanced design approaches that address both recovery goals. Navigating these trade-offs requires a deeper understanding of how materials and connection types in electronics affect circular strategies. This research aims to investigate tensions between repairability and recyclability by analyzing a diverse set of electronic products and relating the findings to their design architecture. This study seeks to inform design strategies that optimize for both repairability and recyclability, thus prolonging product lifetime while minimizing resource losses at end-of-life.

The increasing digitisation that we have witnessed in the past few years has resulted in increased information and communications technology (ICT) hardware manufacturing, which is not sustainable due to the growing demand for critical materials and the greenhouse emissions associated with it. A solution is transitioning to a circular economy (CE). To facilitate this, boost the data economy and digital innovation, the European Union has introduced digital product passports (DPPs), which should provide information about a product’s lifetime to bring more transparency into supply chains. However, several challenges, namely the lack of findable, accessible, interoperable, reusable ICT and materials data and tools to support its interpretation for decision-making, are present. Utilising ontologies and knowledge graphs is a possible solution. Although the ontology work in the ICT and materials domains has been on the rise, there is a lack of a unified semantic model that can capture the complex, heterogeneous cross-domain data needed for building DPPs of ICT devices such as laptops and data servers. Motivated by this, we present the RePlanIT ontology for ICT DPPs, which captures knowledge on several levels – ICT device, hardware components, materials and the CE itself. RePlanIT’s specification is based on a literature survey, interviews and inputs from domain experts from both industry and academia. The ontology, its utilisation for building a knowledge graph of DPPs of laptops and data servers and its application have been successfully validated in a real-world case focusing on supporting more sustainable ICT procurement in government.

Nowadays, the circular economy represents a promising strategy for achieving sustainable development through optimising resource efficiency, extending product lifespans, and reducing environmental impacts. Despite the growing interest in circular design practices, companies often face difficulties integrating these principles into their established New Product Development (NPD) processes. This is mainly due to the overwhelming number of available design tools and methods, which are fragmented, challenging to navigate, overlap in functionality, and lack standardisation. This study provides a comprehensive mapping, classification, and analysis of 77 existing circular design tools identified through a systematic literature review and supplementary online searches. The tools were systematically categorised according to format, data type, industry sector, circular strategies, innovation focus, aims, and applicability across the NPD stages. The results indicate a predominance of physical, qualitative, and sector-agnostic tools, emphasising circularity integration within the Discover, Define, and Develop phases of the design process. This structured classification facilitates stakeholder navigation of existing resources, highlighting opportunities for more targeted, industry-specific tool development, consumer-oriented approaches, and the importance of considering Industry 4.0 technologies in circular design practice. Future research could address these gaps by developing customised frameworks, validating tool effectiveness through real industrial applications, and promoting deeper integration of circular design tools within NPD practices and business objectives.

The validity and reliability of four prevalent reparability scoring systems has been investigated by comparing scores of ten smart phones and six vacuum cleaners versus empirically measured repair times, as well as comparing hypothetical ideal and problematic scenarios. Ease of disassembly methods was also assessed for five smart TVs, four washing machines and six vacuum cleaners. The scoring systems studied were the French Reparability Index (FRI), Joint Research Centre Scoring System (RSS/JRC), iFixit, and ONR19202. Overall scores of products across scoring systems were relatively well correlated, indicating a fair amount of overall reliability. However, the variability in scores for the best and worst case of the same product was often larger than the differences between products. Validity was good for products that are easily repairable, but scorecards often failed to score low when repair is infeasible or too expensive. Repair scores greatly depend on disassembly; since some scorecards count numbers of disassembly steps and other scorecards use proxy times, these two methods were compared against empirical disassembly times for five vacuum cleaners, five televisions, and four washing machines. The proxy time method was found to be highly accurate for all three product categories; the steps method was less so. It indicated the relative ease of disassembly well for washing machines, but not for televisions or vacuum cleaners. Finally, this study proposes improvements to scoring methods, including a limiting factor approach and the development of clearer protocols, to ensure the scoring systems are robust, reliable, and can effectively guide sustainable product design.

Product service systems (PSSs) are revenue models where customers pay the company for the service the product provides, not (only) for the physical product itself.
Designing the revenue model along with the product can align economic incentives with environmental impacts, so the company has an incentive to design products for longer lives.
Both the company and the customer can benefit financially from longer‑lived products billed as services.
Not all product service systems are sustainable environmentally or socially, but if properly designed, they can greatly enable the circular economy.

Wind turbine blades, though key to green energy, pose recycling challenges due to their material composition. This study explored reshaping thermoplastic composite blades—an emerging, more recyclable design—into useful applications without altering the material composition. First, key characteristics like material structure and thickness were defined after which sample material was produced. Reshaping experiments were conducted for both single and double curved geometries with different reshaping methods and parameters. The promising results were translated into a demonstrator re-use application, a lamppost, showcasing reshaping as an alternative to shredding in circular blade strategies.

Devulcanization has the potential to help meet circular economy goals by recovering end-of-life rubber. However, the adoption of devulcanized rubber by manufacturers remains low at the industry level. Devulcanization value chains are complex and involve multiple stakeholders, including waste collectors, sorters, recyclers, compounders, manufacturers and regulatory bodies. This study investigated the barriers compounders and manufacturers face when incorporating devulcanized rubber into new compounds and identified primary underlying causes. The research was conducted through in-depth interviews with compounders and manufacturers of tires and general rubber goods, focusing on the technical, market, institutional, and cultural factors related to incorporating recycled materials, specifically devulcanized rubber. From the results, we identified a number of barriers faced by the industry. A key barrier was the heterogeneity of devulcanized rubber, which made it more difficult to add to new rubber compounds with consistent quality. Other barriers included a lack of standardization and coordination, along with misaligned regulations that hamper the market adoption of devulcanized rubber. This implies that increasing the uptake of devulcanized rubber at the industry level will not be achieved through technological advancements alone or isolated market interventions; instead, it requires comprehensive, systemic solutions.