Influence of Glycine Betaine Based-Ionic Liquids on Rheological, Mechanical and Barrier Properties of Poly(butylene-adipate-co-terephthalate)/Poly(lactic acid) (PBAT/PLA) Blends.

Abstract

Various industrial sectors require the development of biodegradable polymer blends with good interfacial adhesion, melt processability, mechanical performance, water, and gas barrier properties. To achieve these objectives, research efforts are focused on the discovery of promising alternatives to conventional compatibilizers. Recently, ionic liquids (ILs) have emerged as innovative compatibilizing agents due to their infinite possible combinations. Here, biopolymer blends based on poly(butylene-adipate-co-terephthalate)/poly(lactic acid) (PBAT/PLA) blends were processed by melt extrusion process using glycine betaine-based ILs as more environmentally friendly interfacial agents. In fact, only 1 wt% of ILs was incorporated into PBAT/PLA blends, leading to a co-continuous morphology characterized by the formation of PLA fibrils with various thicknesses and lengths, having a significant influence on the rheological, mechanical, water, and gas barrier properties. Then, we have demonstrated that the use of these ILs induced good mechanical performance (Young's modulus ~540 MPa, % strain: 270%-400%), combined with a reduction of almost 10 times in water vapor permeability (WVP). In addition, for a better understanding, the prediction of the permeability to gas of the formulations was performed by using the Nielsen model and compared to the experimental values (40%-75%), highlighting a good correlation between both methods.