A circular economy framework for plastics: A semi-systematic review

Plastic is an incredibly versatile and useful material, however with only a fraction of this material being collected for recycling, it thus creates a serious environmental issue. Much of the research on plastics that contributes to a circular economy emphasises end of life, whereas solutions may be present earlier in the supply chain. There is a need for an evidence-based framework that describes circular economy interventions that can occur throughout the plastics supply chain. This research is, to the best of the authors knowledge, the most comprehensive review of plastics focussed circular economy literature covering the previous 21 years and 391 articles. Using a semi-systematic approach, a coding framework was designed to assign articles to one of sixteen circular economy stages across the supply chain. Papers were also coded according to their polymer resin types, first author country and plastic use categories. The resulting coded database was interrogated for publication trends across these categories. Our results show that publications in this field are growing rapidly, with much of the published literature coming from Europe and America. We also noted that most of the articles appeared general in nature, not specifying a particular resin type or plastic use category. This may limit the translation of research into practical, implementable solutions. The data obtained was used to validate a comprehensive framework that describes and quantifies the full breadth of circular economy interventions for the plastics supply chain. This research takes the sixteen circular economy stages our research identified and divides them into six key areas: resources (n = 67, 17%), production (n = 31,8%), use (n = 37, 9%), recycling (n = 100, 26%), waste (n = 49.13%), and system analysis (n = 107, 27%). This shows that by far, there is a focus in the literature on system-based approaches and recycling interventions, constituting 53% of all articles examined. In contrast, early-stage interventions involving production and use appear as relative gaps, collectively making up only 17% of the articles examined. The most important contribution of this research is to develop and validate a conceptual framework for plastics in the circular economy. This framework can be applied to addressing and conceptualising a circular economy for plastics in research, industry and policy settings, thus serving to catalyse this transition.