Compatibilized polylactide/poly(pentamethylene furanoate) blends for fully bioderived packaging films with enhanced fracture toughness and UV- and O2-barrier properties

Polylactide (PLA) is a promising biopolymer from renewable resources but its brittleness and poor gas barrier properties limit flexible packaging applications. Therefore, in this work PLA was blended with a biobased rubbery poly(pentamethylene furanoate) (PPeF), acting as a toughening agent, and a commercial epoxy-functionalized compatibilizer (i.e., Joncryl® ADR-4468) was added to improve the interfacial interaction. The effect of PPeF loading (1–30 wt %) on phase morphology, mechanical properties, oxygen permeability, and degradability in compost was characterized. All blends displayed a sea-island morphology with refined PPeF domains upon compatibilization. Incorporating PPeF induced major tensile ductility enhancements from 5 % strain at break for neat PLA up to 200 % for the blend with 30 wt % PPeF, accompanied by progressive stiffness and strength declines. Through the application of the essential work of fracture (EWF) approach on the prepared films, the specific essential work of fracture (we) was seen climbing from 6.2 to 40.0 kJ/m2 with rising PPeF content, confirming its effectiveness as a toughness enhancer. PPeF contributed to increase the UV- and gas barrier properties of PLA. For example, the oxygen permeability dropped by 37 % for the blend with 30 wt % PPeF. Moreover, compost burial tests also revealed 26 % weight loss of PPeF after 60 days, proving its biodegradability. Hence, finely dispersed PPeF domains induced synergistic property improvements, making PLA/PPeF blends a promising sustainable option for flexible and biodegradable packaging.