Study of the Compatibilizer Effect in the Properties of Starch/Polyester Blends

The mechanical, viscoelastic and structural properties of starch/ poly (butylene adipate co-terephthalate) (PBAT) blown films produced by reactive extrusion were evaluated using citric acid (CA) and maleic anhydride (MA) as compatibilizers. Scanning electron microscopy images showed more homogeneous structure when CA and MA were included in the formulation. The tensile strength (MPa) was improved with the inclusion of the highest proportion of both compatibilizers (1.5 %wt). A larger elastic component with values between 0.42-0.45 for the degree of solidity (1-c(1)) was observed for the intermediate concentration of compatibilizers. A high level of glycerol (10 %wt) results in films with increased % elongation. Three partially miscible phases were observed in the blends. Biodegradable films of starch/PBAT with better properties could be produced by one-step reactive extrusion using CA and/or MA as compatibilizers.