A Life-Cycle Based Integrated Framework for Assessing the Sustainability of Plastic Additives

Plastic additives are essential to modern polymer applications but raise growing concerns about environmental risks and circularity challenges with their rapidly increasing demand. Here, we present an integrated framework for assessing the multidimensional sustainability of plastic additives across their life cycle. By combining material flow, life-cycle environmental impacts, hazard, and recycling performance, the framework addresses key limitations of previous studies that focused on isolated stages or limited impact dimensions. A case study of two widely used additives─di(2-ethylhexyl) phthalate (DEHP) and bisphenol A (BPA)─demonstrates the applicability of the framework. Results show broadly similar flow patterns and distinct trade-offs between toxicity, environmental burdens, and compatibility with recycling technologies. The integrated dimensionless sustainability score of DEHP (4.81) establishes a reference for assessing plasticizers, while that of BPA (4.65) serves as a benchmark for evaluating flame retardants. These findings underscore the need for long-term considerations of additive behavior in circular systems and highlight the feasibility of additive comparison and substitution guided by the holistic, life-cycle-based assessment. The proposed framework is adaptable to additional indicators and socio-economic dimensions as data availability improves, offering a foundation for more comprehensive and policy-relevant evaluations of additive sustainability in support of circular economy transitions.