The carbon nanotubes effects on the morphology and properties of poly(lactic) acid/poly(butylene adipate-co-terephthalate) blends

Poly(lactic acid) (PLA), as a biodegradable semicrystalline thermoplastic, is usually blended with degradable poly(butylene-adipate-co-terephthalate) (PBAT) to improve toughness for the sake of environmental concerns. To obtain controllable properties of PLA/PBAT composites, the use of nanoparticles is increasing from a technical point of view, thus making the blends more widely used in the final products. In this study, immiscible blends of PLA and PBAT (70/30 wt%) and PLA/PBAT with different carbon nanotube (CNT) contents (0.5, 1, and 2 wt%) were prepared using a twin-screw extruder followed by injection molding. The preferential distribution of CNTs in the PBAT phase was characterized by SEM and thermodynamic analysis, and reason for selective localization is discussed. The morphology of the PLA/PBAT composite showed PBAT particles dispersed within the PLA matrix with an average diameter of 0.38 mu m. For the nanocomposites, the CNTs in the minor PBAT phase produced larger elongated PBAT domains with a maximum average diameter of 1.3 mu m. The elongation at break of binary PLA/PBAT blends was 160.9%, while the maximum elongation at break of the nanocomposite was 294.3%. Additionally, the influence of CNTs on the crystallization behavior and rheological and mechanical properties of PLA/PBAT/CNT blends was systematically investigated.