Preparation and Characteristics of Poly(butylene adipate-co-terephthalate)/Polylactide Blend Films via Synergistic Efficiency of Plasticization and Compatibilization

Polylactide (PLA) films blended with poly(butylene adipate-co-terephthalate) (PBAT) were hot melted using a twin screw extruder with the addition of triethyl citrate (TEC) as a plasticizer and toluene diisocyanate (TDI) as a compatibilizer. The synergistic effects of the two additives on the mechanical, thermal, and morphological properties of the PLA/PBAT blend films were investigated. The influence of TEC content on the plasticized PLA films and the effect of TDI’s presence on the PLA/PBAT blend films were also studied by comparing them with neat PLA. The results showed a pronounced increase in elongation at break of the plasticized PLA films with increasing TEC levels, but a slight reduction in thermal stability. Also, the addition of TEC and TDI to the blend system not only synergistically enhanced the tensile properties and tensile-impact strength of the PLA/PBAT blends, but also affected their crystallinity and cold crystallization rate, a result of the improvement of interfacial interaction between PLA and PBAT, including the enhancement of their chain mobility. The synergy of the plasticization and compatibilization processes led to the improvement of tensile properties, tensile-impact strength, and compatibility of the blends, accelerating cold crystallization without affecting crystallization.