Comparison of the stabilization efficiency of a conventional antioxidant, biobased alternatives derived from wine by-products, and their extracts in poly(butylene succinate) (PBS) and poly(lactic acid) (PLA)

• Bio-additives as sustainable alternatives to conventional stabilizers. • Wine by-product bio-additives improve thermo-oxidative stability of biopolyesters. • Use of bio-additives maintains the main characteristics of biopolyesters. • Small performance gap in stabilization between synthetic and biobased antioxidants. • Increased stabilization efficiency through extraction. When researching sustainable materials, additives are often neglected. The use of stabilizers requires closer examination, as conventional antioxidants can be harmful to the environment and human health. Recent studies have shown that synthetic additives such as Irganox® 1010 (I-1010) could be replaced by by-products from winemaking such as wine grape pomace (WP) and its extracts (WP-Ex) to improve the thermo-oxidative stability of plastics. However, extraction is laborious and little comparison between polymer stabilization by WP-based bio-additives and conventional antioxidants in biopolymers has been made. This study investigates I-1010, WP and WP-Ex prepared by an environmentally-friendly procedure to analyze whether there is a performance gap between biobased and conventional antioxidants in stabilizing poly(butylene succinate) (PBS) and poly(lactic acid) (PLA) and whether the effort of extraction is worthwhile. Biocompounds with additive concentrations of 0.3–2.0% by weight were produced with a material-efficient miniaturized single-screw extruder followed by investigations with a lab-scale twin-screw extruder. The resulting biocompounds were analyzed regarding their thermal and mechanical properties and thermo-oxidative stability. A moderate performance gap between WP and I-1010 was found, which can be largely closed by extraction, demonstrating that both WP and WP-Ex can be used as biobased alternatives to I-1010. Compared to WP, lower concentrations of I-1010 and WP-Ex were required to achieve comparable stabilization. Thus, extraction might not be mandatory but could be beneficial to avoid affecting other material properties.