Ionic liquids based on tetraalkylphosphonium cations with long alkyl chains have been used as new compatibilizing agents of biopolymer blends composed of poly(butylene-adipate-co-terephtalate) (PBAT) and poly(lactic acid) (PLA). In this study, the influence of the chemical nature of the counter anion on the morphologies as well as the thermal and mechanical properties of the PBAT/PLA blends has been investigated. First, PBAT/PLA blends filled with a very low amount of ionic liquids (1% wt) have been prepared by melt mixing. Secondly, the effect of ILs on the dispersion of PLA phase within the PBAT matrix was characterized by transmission electronic microscopy (TEM). In a final section, the mechanical behavior of PBAT/PLA blends was studied. A very good compromise was obtained for PBAT/PLA/IL blends with a significant increase of the Young' modulus without loss of the fracture properties.

TEM micrographs of the epoxy–IL cured systems with 30 wt% of phosphonium ionic liquid.