Supercritical CO₂–Ionic Liquids: A Successful Wedding To Prepare Biopolymer Foams

Abstract

In this work, tetraalkylphosphonium and dialkyl imidazolium ionic liquids have been studied as surfactant agents of layered silicates (montmorillonite, MMT). The influence of the chemical nature of the cations as well as the counteranions on the thermal behavior (TGA), on the structural analysis (XRD) and on the surface energies of organically modified montmorillonites has been investigated. Then, poly­(butylene adipate-<i>co</i>-terephthalate) (PBAT)–clay nanocomposites were processed by melt mixing using a twin screw extruder in order to achieve the better dispersion of MMT and were used to prepare cellular foams with supercritical carbon dioxide (ScCO₂). Thus, a small amount (2 wt %) of imidazolium-treated montmorillonite is the relevant candidate to decrease the cell size (600 to 125 μm)