Ethylene brassylate as a biobased plasticizer for poly(lactic acid): Evaluation of mechanical, thermal, and biodegradation properties

Poly(lactic acid) (PLA) is a bio-based polymer with high potential; however, its inherent brittleness restricts its practical applications. This work evaluates ethylene brassylate (EB), a macrocyclic diester of natural origin, as a plasticizer for PLA at 5-20 wt%. Thermal analysis confirmed a plasticizing effect, with the glass transition temperature decreasing from 59.9 °C in neat PLA to 38.0 °C in PLA-20 EB. Mechanical tests showed that 20 wt% EB increased elongation at break from 10 % (neat PLA) to over 460 % and improved impact resistance by ∼70 %. Furthermore, moisture resistance was preserved, and microscopy confirmed good miscibility with no phase separation. Under composting, degradation occurs more rapidly in proportion to EB content, reaching ∼90 % mass loss after four weeks. Migration tests revealed values below 40 mg kg^-1 for PLA-EB < 10 wt% EB, whereas PLA-15 EB reached the regulatory limit. EB is therefore an efficient bio-based plasticizer for PLA, offering enhanced ductility, toughness, and biodegradation, with promising applications in sustainable packaging, especially for refrigerated and cold-chain storage.