Development of PLA-PBAT and PLA-PBSA bio-blends: Effects of processing type and PLA crystallinity on morphology and mechanical properties

In this study, immiscible blends of 75 wt% polylactide (PLA) with 25 wt% of poly[(butylene adipate)-co-ter-ephthalate] (PBAT) were prepared through an injection-molding (IM) process as well as a twin-screw extruder (TSE) followed by IM. An amorphous and a semi-crystalline PLA were also used as the matrix to investigate the matrix crystallization effect on morphology and properties development of the blends. Blend of PLA with 25 wt% of poly[(butylene succinate)-co-adipate] (PBSA) was also prepared through IM to compare its mechanical properties with those of PLA-PBAT blends. Eventually, the tensile and flexural properties of the prepared blends were explored and their dependency on the evolution of the blend morphology was investigated. The tensile results showed that when IM is used as the sole processing technique, the ductility and toughness were significantly improved only when the semi-crystalline PLA was used as the matrix. Preprocessing through TSE also resulted in enhancement of the PLA blends' strain at break. According to the flexural experimental results, the morphology variation effect on the PLA blends' flexural properties was not as determinative as it appeared in PLA blends' tensile properties.