Compatibilisation of starch/poly(butylene adipate co‐terephthalate) blends in blown films

Summary Reactive extrusion was utilised for starch/poly(butylene adipate co‐terephthalate) (PBAT) blown film production, using maleic anhydride (MA) and citric acid (CA), alone or combined, as compatibilisers. These compounds (2% w/w) were added to the starch/PBAT (55:45) mixture after dispersion on glycerol. More rigid films, with greater tensile strength (9.82 ± 0.45 MPa), were produced when 2.0% CA was used. The opposite, little homogeneity and poor tensile strength (0.77 ± 0.12 MPa) and elongation (2.67 ± 0.67%) were found in films produced using 2.0% MA. Barrier properties to water vapour were improved by compatibilisers. FTIR analysis showed that CA and MA were able to promote esterification/transesterification reactions. Blends containing CA also showed better phase compatibilisation in the scanning electron microscopic images. It was found that in mixtures containing MA, the process and the concentration of this reagent need to be adapted to produce films with improved properties.