PBAT/thermoplastic starch blends: Effect of compatibilizers on the rheological, mechanical and morphological properties

The effect of maleic anhydride (MA), citric acid (CA) and maleated poly(butylene adipate-Co-terephthalate) PBAT (PBATg-MA), as compatibilizer, on properties of blends of plasticized starch/PBAT in a weight ratio of 60/40 were investigated using rheological measurements, tensile tests, SEM observations and mechanical dynamic analyses. A strong evolution in the mechanical, morphological and rheological properties of the blend was observed according to the type of additives used. The type of compatibilizer was shown to control the morphology and continuity development of the TPS/PBAT 60/40 wt% blend. In the absence of the compatibilizer and in presence of PBAT(g)-MA, the PBAT was the continuous phase, while the TPS became the continuous one in presence of MA and CA. These evolutions were explained by the change in the melt rheological properties of TPS in the presence of the compatibilizer and its aptitude to promote interfacial adhesion between TPS and PBAT phases. A huge evolution in the tensile strength and strain at break were also observed according to the structure of the compatibilizer.