Reactive Compatibilization of Poly(lactic acid) and Polycarbonate Blends Through Catalytic Transesterification Reactions

Abstract

The combination of poly(lactic acid) (PLA) with polycarbonate (PC) which presents high inherent thermal stability and mechanical properties is an attractive strategy to overcome PLA brittleness and poor thermal resistance. To improve affinity between the two materials and their dispersion into the blend, an organophilic montmorillonite (MMT) has been added and reactive compatibilization through catalyzed transesterification has been investigated. The properties were studied using differential scanning calorimetry (DSC), thermogravimetry (TG), dynamic mechanical analysis (DMA) and scanning electron microscopy (SEM). The study of the thermal properties revealed the immiscibility of the uncatalyzed blend but noticeable changes were detected on the PLA crystallization and melting behaviors after the addition of the catalyst. The SEM observations showed that MMT and the catalyst contribute in the improvement of the dispersion. The TG results revealed that MMT increases the thermal stability of the blend and showed new stages of decomposition due to the different structures resulting from the interchange reactions.