Blends of PBAT with plasticized starch for packaging applications: Mechanical properties, rheological behaviour and biodegradability

Poly(butylene adipate-Co-terephthalate) (PBAT) is a completely biodegradable aliphatic-aromatic copolyester with competitive mechanical properties in comparison to commodity plastic, although it is about three times more expensive than low-density polyethylene (LDPE). The blending of PBAT with plasticized starch is an effective way to develop more accessible PBAT-based bioplastics for wide application in packaging, but the addition of an appropriate compatibilizer is recommended. Here, we investigate the effect of maleated PBAT (PBATg-MA) and maleic anhydride (MA) coupling agents, on the mechanical properties, morphology, melt rheology and biodegradability of PBAT/TPS blends. It was found that PBATg-MA is an effective reactive compatibilizer promoting the interfacial adhesion between TPS and PBAT phases with a beneficial effect on the tensile strength as well as the elongation at break. The morphology and continuity index change considerably according to the compatibilizer. The biodegradation kinetics was also affected by the presence of compatibilizers, with a decrease in the degradation rate noted when PBATg-MA was used as compatibilizer.