Effects of Mixing Sequence on the Morphological and Rheological Properties of Polymer-Clay Nanocomposites of Poly(Butylene Adipate-co-Terephthalate) and Poly(Lactic Acid) Blend

Abstract

The effect of sequential mixing of poly(butylene adipate-co-terephthalate) (PBAT) and poly(lactic acid) (PLA) with organically modified silicate layers on the dispersion of the organoclay particles and its effect on the morphology of the blended polymer clay nanocomposite (BPCN) was examined. The dispersion of the organoclay platelets, morphology of the blend composite, and rheological and thermomechanical properties of these composites with 50/50 ratio of PLA to PBAT were investigated using X-Ray diffraction analysis, scanning and transmission electron microscopy, dynamic mechanical shear test, and thermogravimetric analysis. The morphology of blends with 70/30 ratio of PLA to PBAT was also examined and compared. The sequential mixing of the organoclay with this BPCN enhanced the level of clay dispersion when compared to the simultaneously blended nanocomposites. Larger PLA domains and better clay dispersion in PLA phase were observed when clay was first mixed with PLA and then subsequently mixed with PBAT.