Unlocking the Potential of Polylactic Acid: Exploring Its Thermal and Mechanical Properties for Vitrimerization via Double Reactive Extrusion and Transesterification

Abstract

Polylactic acid (PLA) is a biosourced thermoplastic polymer widely used in various fields such as biomedical, packaging, and prototyping. Enhancing PLA thermal and mechanical properties has been a research focus, by transforming it into a vitrimer, a new polymer class. This study demonstrated the effectiveness of a dual reactive extrusion process followed by vacuum compression molding to improve a thermoplastic's properties with vitrimer tendency, using PLA as the main component, diglycidyl ether bisphenol A (DGEBA) as an additive, and zinc acetate as a catalyst. Several characterizations were carried out to assess the thermal, morphological, and mechanical properties of the developed PLA mixtures. Moreover, a kinetic study using three iterative isoconversional integral models (iterative Kissinger–Akahira–Sunose (it-KAS), iterative Flynn–Wall–Ozawa (it-FWO), and Trache–Abdelaziz–Siwani) was employed to analyze the effects of the catalyst and DGEBA on the cross-linking reaction kinetics after the process employed in this work. Results demonstrated the presence of a cross-linked structure in addition to a promising polymer behavior characterized by enhancements in toughness, ductility, and cross-linking density by 290%, 127.5%, and 80.5%, respectively. Finally, the optimal composition exhibited almost 96% self-healing of its surface, demonstrating significant potential for advanced material applications.