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Eco-Profiling of Bio-Epoxies via Life Cycle Assessment
Abstract:
Epoxies, synthesized from bisphenol-A (BPA) and epichlorohydrin (ECH), are predominantly used as coatings, adhesives, and matrix material in fiber-reinforced composites for body-in-white (BiW) applications in the automotive sector. However, given the production of conventional epoxies from nonrenewable petroleum resource and toxicity of BPA, several initiatives have been undertaken by researchers to synthesize alternative epoxies from various bio-sources that are free of BPA and exhibit similar mechanical performance. As a result, such bio-sourced epoxies are almost immediately termed as “ecofriendly,” despite the lack of comprehensive evaluation of their ecological performance that takes into account enhanced natural resource usage and associated impacts accompanying such epoxies. Hence, this work aims at addressing this gap by evaluating the environmental impacts of such bio-sourced epoxies via cradle-to-gate life cycle assessment (LCA) to determine the genuine credentials of their ecofriendliness.
Epoxies synthesized from three different bio-sources - namely, bark extractives, lignin, and triglyceride - were chosen so to evaluate their ecological performance. ReCiPe midpoint and endpoint methods were used to evaluate these epoxies in accordance with ISO 14040 and ISO 14044 standards. Among the three bio-epoxies, lignin-based epoxy exhibits poor eco-performance mainly due to the use of large amount of chemicals during extraction of lignin, involving delignification and valorization. On the contrary, bio-epoxy synthesized from triglycerides was found to be ecofriendly compared to other bio-epoxies. All bio-epoxies are observed to contribute significantly to toxicity-related categories, mainly due to higher electricity consumption during both epoxy synthesis and manufacturing processes. Overall, this work sheds light on various avenues for synthesizing truly sustainable epoxies that exhibit mechanical performance comparable to their conventional counterparts.