Characterization and Properties of Nucleated Polylactide, Poly(butylene adipate-co-terephthalate), and Thermoplastic Starch Ternary Blend Films: Effects of Compatibilizer and Starch

Abstract

Biodegradable ternary blend films of nucleated polylactide (PLA), poly (butylene adipate-co-terephthalate) (PBAT), and thermoplastic starch (TPS) with the presence of nucleating agent and compatibilizer were prepared via a twin screw extruder. The effects of compatibilizer types and starch contents on the thermal, morphological, and tensile properties of these blend films were evaluated. Two types of compatibilizer (methylene diphenyldiisocyanate (MDI) and polylactide-graft-maleic anhydride (PLA-g-MA)) were used for enhancing an interfacial adhesion of the blends, whereas TPS from tapioca starch was added as a filler at various concentrations (0 to 40 wt%). In addition, talc and PBAT acted as a nucleating agent and a flexible polymer were fixed at 1 phr and 10 wt%, respectively. The results indicated that the thermal stability of the blend films was affected from the presence of compatibilizer and TPS. In addition, the tensile properties and compatibility of PLA, PBAT, and TPS blends were improved with the addition of compatibilizer compared to uncompatibilized blend films as evidenced by SEM results. Furthermore, the blend films with MDI gave higher mechanical properties than those with PLA-g-MA at all compositions. The water absorption of the ternary blend films was evidently increased when the TPS amount was increased; in contrast, tensile strength and elongation at break (EB) of these blend films were significantly decreased.