Without additives, bioplastics tend to undergo oxidative and light-induced decomposition, which limits technical applications. In addition to the lignocellulosic components, antioxidants in coffee by-products offer a recyclable potential for material utilization and completely bio-based bioplastics. Polyphenols and vitamins prevent or slow down radical-forming processes and thus the ageing of bioplastics if properly prepared. Four naturally processed coffee cherries from different varieties, two parchments, and a silverskin mix were investigated with respect to their composition, micronization, particle size, structure, thermal, and antioxidative properties. Compounded with bio-based poly(butylene succinate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in various concentrations, differences were found in extrudability and mechanical properties, next to successful thermo-oxidative stabilization.

Proceedings: Rennert, M. Utilizing the Antioxidant Properties of Coffee By-Products to Stabilize Bioplastics. Proceedings 2023, 89, 7. https://doi.org/10.3390/ICC2023-14847