High performance poly(lactic acid)/poly(ether-block-amide) blend-based bionanocomposites containing carbon nanotubes and/or organoclay

Abstract

High-performance poly(lactic acid) (PLA) blend-based composites were fabricated with a poly(ether-block-amide) (PEBA) elastomer acting as the blend counterpart. It was confirmed that a compatibilizer (ADR) enhanced the interaction between PLA and PEBA. Carbon nanotubes (CNTs) and organoclay (30B) were added individually and simultaneously into the blend to produce bionanocomposites. Morphological results showed that CNTs were mainly dispersed in PEBA domains, whereas 30B was mainly localized at the interfacial region of PLA and PEBA phases. The selective localization of added CNTs and 30B led to significant modification of the properties of the compatibilized PLA/PEBA blend. The brittleness and flammability of PLA were evidently improved after forming the bionanocomposites. Differential scanning calorimetry results revealed that CNTs and 30B assisted the crystallization of both PLA and PEBA in the composites, with CNTs providing superior nucleation efficiency to 30B. Thermogravimetric analysis revealed the thermal stability enhancement of the blend after adding CNTs and/or 30B, with up to 16 °C increase at 20 wt% loss with inclusion of 2 phr 30B. Addition of CNTs and/or 30B improved the blend's anti-dripping performance during burning tests, and CNT exhibited better anti-dripping efficiency. Ductility of PLA was drastically improved after forming the compatibilized blend, and further improved with incorporation of CNTs and/or 30B (increased from 9 % for neat PLA to 252 % for the hybrid composite containing CNT/30B). The impact strength of 1 phr CNTs-added composite was about 3 times that of PLA. Rheological properties indicated the (pseudo)network formation of added filler(s), leading to a significant reduction in electrical resistivity, up to six orders of magnitude with addition of 3 phr CNTs.