Enhancing Polylactic Acid Films With Polyethylene Glycol-Based Plasticizers: A Reactive Extrusion Approach

The enhancement of polylactic acid (PLA) films using polyethylene glycol (PEG)-based plasticizers through reactive extrusion, employing dicumyl peroxide (DCP) as a cross-linking agent is studied in this work. Incorporating PEG plasticizers into PLA substantially raises its elongation at break, from 12.0% in neat PLA to 61.3%, while preserving satisfactory tensile strength. This improvement broadens the industrial applicability of PLA; however, it should be noted that the plasticizers exhibit a tendency to migrate. The reactive extrusion process reduces plasticizer migration, lowering values from 140.3 mg kg^-1 in PLA-PEG films to 40.8 mg kg^-1 in films processed with reactive extrusion (PLA-PEG-R). This substantial reduction enables the safe use of these materials in food-contact applications. Thermal stability is also enhanced, with degradation temperatures rising from 268.7 °C in PLA-PEG to 333.8 °C in PLA-DCP systems. Additionally, the glass transition temperature (Tg) decreases to 38.3 °C, enhancing material ductility. The films retain certain transparency despite slight alterations in optical properties, and their increased water vapor permeability can be beneficial for applications in food packaging applications. These findings demonstrate that reactive extrusion (REX) with PEG-based plasticizers improves PLA's mechanical, thermal, and functional properties, broadening its industrial application while preserving its environmental advantages.