Green Toughness Modifier from Downstream Corn Oil in Improving Poly(lactic acid) Performance

A green multifunctional toughness modifier for poly(lactic acid) (PLA) was successfully synthesized from the derivatives of downstream corn oil (a coproduct of bioethanol industry) and itaconic acid. The efficiency of the synthesized toughness modifier, monomethyl itaconated epoxidized downstream corn oil (MIECO), was evaluated with a different loading percentage of it (5-1S wt %) in the PLA matrix. A dynamic cross-linking strategy was taken to achieve toughened PLA by using multifunctional MIECO in the presence of a radical initiator. During melt blending, the multifunctional MIECO self-polymerized and reacted with functional groups of PLA to produce a rubbery part within the PLA matrix and compatibilized the blend. The fabricated PLA-MIECO blends demonstrated a remarkably enhanced elongation at break (18 times), tensile toughness (11 times), and notched Izod impact (131%) compared to those of pristine PLA. The scanning electron microscopic (SEM) images confirmed that cavities were generated by debonding of polymerized MIECO from PLA matrix, which provides a plastic deformation and excellent toughness in the PLA-MIECO blends. The synthesized multifunctional toughness modifier and the strategy will pave a way to other biopolymers for expanding their performances and applicability.