Balancing Toughness and Antibacterial Activity of Polylactide Blends with Imidazolium-Based Polymers

Poly(lactic acid) (PLA) serves as a promising alternative to nondegradable conventional plastics, owing to its biobased origin, biodegradability, mechanical strength, and optical clarity. However, its inherent brittleness restricts its broader application. Incorporating rubber particles is an effective and practical approach to improving toughness by inducing matrix plastic deformation. Herein, we prepared a series of imidazolium-functionalized poly[oxy(chloromethyl)ethylene] (PDI#) as dual-functional agents that simultaneously enhance the toughness and antibacterial properties of PLA blends. The imidazolium groups promote strong interactions with PLA chains, significantly reducing the particle size within the PLA blends. Consequently, a PLA blend containing 20 wt % PDI51 achieved a toughness of 9.30 MJ m⁻³, representing more than a 15-fold increase compared to neat PLA (0.56 MJ m⁻³). Furthermore, 20 wt % PDI#-containing blends achieved potent antibacterial activity against E. coli, exceeding 3-log reduction.