Selective dispersion of carbon nanotubes and nanoclay in biodegradable poly(ε-caprolactone)/poly(lactic acid) blends with improved toughness, strength and thermal stability

Abstract

Poly(ε-caprolactone)/poly(lactic acid) (PCL/PLA) blends are promising biomaterials with biodegradable characteristics. However, poor compatibility of the two components may lead to undesirable mechanical properties. In this work, the effect of combining carboxyl multi-walled carbon nanotubes (CNTs) and organically modified montmorillonite (MMT) on the morphology and properties of PCL/PLA blend was investigated. The morphological observations and rheological analysis showed that exfoliated MMT platelets enhanced interfacial adhesion of the two phases, whereas CNTs formed a percolating network in PCL matrix. The addition of CNTs/MMT (0.5 wt%: 0.5 wt%) led to an increase by 137.4% in elongation at break, 79.6% in tensile strength, and 14 °C in decomposition temperature without sacrificing its rigidity apparently for the PCL/PLA matrix. Obvious synergistic effect was demonstrated in comparison to the blends containing single nanofiller. This study demonstrated that combining CNTs and MMT is a facile way to preparing immiscible PCL/PLA blends based nanocomposites with interesting structure and properties.

Keywords: Bionanocomposites; Carbon nanotubes; Nanoclay; Poly(lactic acid); Poly(ε-caprolactone).