Cradle-to-gate life cycle assessment of structural bio-adhesives derived from glycerol

Purpose Due to increasing environmental concerns about petroleum-based products, the replacement of petro-products has attracted much attention in recent years. The purpose of this paper was to evaluate the potential environmental impacts of glycerol-based structural bio-adhesive produced through the reversible addition-fragmentation chain transfer polymerization process. Methods In this study, two pathways of glycerol production were considered in this cradle-to-gate life cycle assessment: bio-glycerol produced from biodiesel production plant and petroleum-based glycerol derived from petroleum refineries. Several impact categories were analyzed including global warming potential, acidification potential, eutrophication potential, and human health effects (both cancer and non-cancer). The impact of different allocation methods (energy content, mass value, and economic value) was also explored in this study. Results Our results showed that bio-glycerol-based structural adhesive had a lower environmental impact in general compared to petro-glycerol-based structural adhesive. Higher environmental impacts throughout the structural bio-adhesive life cycle were observed by adopting the energy allocation method. The key factors that influence the global warming potential were electricity sources and the product yield. Conclusions This LCA study provides useful information for developing sustainable biomaterials and processes. It is recommended to further explore the potential approaches to reduce the carbon intensity and eutrophication potential in the RAFT polymerization process as it is identified as the hotspot in the structural bio-adhesive production process.