A multi-criteria framework for the ecodesign of bio-based materials at early development stages

Ex-ante life cycle assessment (LCA) allows for a holistic environmental evaluation of novel products at research and development (R&D) stages when the potential for environmental improvement is higher. Multi-criteria decision analysis (MCDA) incorporates techno-economic attributes and considers decision-makers' (DMs) perspectives. Thus, integrating ex-ante LCA and MCDA is key for R&D ecodesign. This article proposes a framework combining ex-ante LCA with multi-attribute value theory and stochastic multi-acceptability analysis (SMAA) for novel bio-based materials in four steps: i) Problem structuring, ii) LCA scope, inventory, and scale-up, iii) Performance table, elicitation, and MCDA calculations, and iv) Interpretation and recommendations. The LCA-MCDA framework provides a structured way to model upscaled environmental impacts and encompass technical and economic performances in a global value while considering novel materials' potential application and functionality. The framework is applied to lab-scale starch films for food packaging, comparing them with commercial polymers for cost, environmental, and technical criteria according to three DMs' perspectives (biopolymer/sustainability researchers). Materials, formulations, and scenarios are assessed on a 1-kg basis with properties as technical criteria. The commercial films outperform the novel films, primarily due to technical performance. Scale-up and plasticizer scenarios show potential for reducing environmental impacts but do not alter the ranking of alternatives. SMAA shows that the ranking highly depends on the criterion weights; conversely, individual DM's perspectives lead to similar results. Materials are also compared for equivalent properties (stiffness, strength, and moisture barrier) by applying material substitution factors. The most favorable results for the starch films are achieved for equivalent stiffness, thus suggesting further investigation for rigid applications. Furthermore, suggestions for applying the framework to other cases are provided. The LCA-MCDA framework facilitates the communication of LCA results with cost and technical performance, supporting R&D in dealing with trade-offs and identifying pathways toward more sustainable and competitive production of bio-based materials.