Flexible Poly(Lactic acid) suitable for deep freeze packaging synthesized using lactic acid-based ester precursors

Abstract

Polylactide (PLA) is an alternative to traditional petroleum-based polymers; however, its brittleness and tendency to produce rustling in the film form limit its applications in deep freeze packaging and at quiet public facilities. Herein, a PLA-based biodegradable packaging material was prepared by blending transparent flexible PLA (TF-PLA) with various lactic acid-based ester precursors (LAEPs), which were synthesized using l-lactic acid, poly (tetrahydrofuran), sebacic acid, and 1,4-butanediol, thereby producing TF-PLAs with good transparency and biodegradability, low-level migration, low rustling, and improved mechanical properties. The glass transition temperature (Tg) values and chemical structures of the synthesized LAEPs were studied using differential scanning calorimetry (DSC) with the Gordon–Taylor equation and proton nuclear magnetic resonance (1H NMR) spectroscopy. The obtained TF-PLA showed better elongation at room temperature as well as flexibility, with a bending angle comparable to that of neat PLA at extremely low temperatures. The evaluated barrier property and migration level of the TF-PLA film indicated the untapped market potential of TF-PLA. The biodegradability test of sorted TF-PLAs over eight weeks indicated good biodegradability, similar to that of neat PLA. Therefore, TF-PLAs have a high potential for deep freeze packaging applications.