Poly[(butylene succinate)-co-(butylene adipate)]-montmorillonite nanocomposites prepared by water-assisted extrusion: role of the dispersion level and of the structure-microstructure on the enhanced barrier properties

Composite films composed of a biodegradable poly[(butylene succinate)-co-(butylene adipate)] (PBSA) matrix with several contents (2.5; 5; 7.5; 10 wt %) of native (MMT) or organo-modified montmorillonite (OMMT) were successfully extruded using an innovative water-assisted extrusion process. As expected, better dispersion and exfoliation levels of nanofillers were obtained in PBSA+OMMT than in PBSA+MMT composite films, whatever the nanofiller content. Otherwise, the water-assisted extrusion process has also clearly enhanced the dispersion and exfoliation levels of native montmorillonite. This process was particularly efficient to delaminate and to disperse high amounts (≥5 wt %) of MMT in the PBSA matrix, which has highly increased tortuosity effects in the resulting composite films. The films prepared via the water-assisted extrusion have consequently exhibited better barrier properties to water and to gases than the films classically extruded and as the nanofiller content increases.