Morphology and rheological behavior of poly(butylene terephthalate)/polypropylene blends filled by two types of organoclays

Abstract

The present research investigates the morphology and rheological behavior of poly(butylene terephthalate)/polypropylene (PBT/PP) blends containing hydrophilic and hydrophobic organoclays. The distribution of nanoclays and morphology of nanocomposites were analyzed using X-ray diffraction (XRD) and transmission and scanning electron microscopies. The XRD patterns show that the level of intercalation structure in nanocomposites reinforced by hydrophilic nanoclay is significantly higher than nanocomposites filled by hydrophobic one. According to morphological analysis, both types of nanocomposites indicate the reduction of droplet size, whereas hydrophilic nanoparticles illustrate more compatibilization efficiency than hydrophobic. According to transmission electron microscopy, hydrophilic nanoclays are mainly localized in the PBT matrix and at the interface, whereas hydrophobic nanoparticles are confined in the PP-dispersed phase and at the interface. From the rheological point of view, the results show that nanocomposites with hydrophilic nanoclay show stronger pseudoplasticity, higher viscosity, and more elasticity than nanocomposites with the hydrophobic one. The localization of hydrophilic organoclay in the PBT matrix aids to finer morphology of the PBT/PP blend, whereas hydrophobic one resists the breakup of droplets by confinement in dispersed phase.