Improving the barrier character of poly(caprolactone): transport properties and free volume of immiscible blends

Abstract

Miscible and thermally stable blends of biodegradable poly(butylene adipate-co-terephthalate) (PBAT) with poly(hydroxy ether of bisphenol A) (PH) are investigated to obtain membranes for packaging applications. Previously the miscibility and adequate degradability of these blends was proven, therefore this system is a good candidate for packaging applications. The crystallinity degree and the free volume, both of crucial importance in transport properties, are analysed as a function of blend composition. The transport properties to different gases and vapours are greatly reduced with the addition of PH. The blends show high elongational viscosity values, which allows expecting good film processability. Overall, this work sheds light on the factors involved in the reduction of permeability which would allow to broaden this strategy to other promising biodegradable materials.