Spent-coffee grounds as a zero-burden material blended with bio-based poly(butylene succinate) for production of bio-composites: Findings from a Life Cycle Assessment application experience

Abstract

This paper was conceived in consideration of the emerging trend of the composite industry's transition into organic filler application in materials and exploitation of organic wastes, to draw attention to the case of spent coffee grounds (SCG), namely the solid waste resulting from the popular beverage coffee. Life Cycle Assessment (LCA) analysis of SCG has been mainly focussed on oil extraction, which fails to address the value-added potential of solid waste and does not address the full life cycle of coffee. The study discussed in this paper aims at exploring the Carbon Footprint (CF) and the Cumulative Energy Demand (CED) of a set of composites through the application of LCA on a lab-scale dimension, which is comparable to small start-up production levels. Using the previously proven concept of the melt-blended SCG and bio-based poly (butylene succinate) (PBS) composites, the authors assessed a range from 20 to 60 wt% filler content suitable for a large variety of applications. Results from the study proved that the SCG/PBS ratio increased from 0.25 to 1.5 and reduced the whole-system related CED and CF by 7.4–8.4%. Overall, the study allowed to understand that, already in the phases of lab-scale design, testing, and assessment, it is possible to find material recovery paths that have the potential to lead to implementing sustainable circular models of the economy.