Evaluating different alkyl ammonium modified organoclays in preparation of TPO nanocomposites with supercritical CO₂

This article examines the chemical structures of the surfactants associated with organically modified montmorillonites in order to understand how differences in the structure may influence the final properties of the nanocomposite materials. Five organically modified montmorillonites with different surfactants were examined in materials prepared using a novel technique for thermoplastic polyolefin nanocomposites, using supercritical CO₂ as a processing aid. The chain length and the number of alkyl chains attached to the quaternary ammonium surfactant were the main variables of study aimed at changing the interactions of an organoclay with compatibilizer and/or polymer matrix due to the CO₂ treatment. The goal of this work was to improve the exfoliation of the dispersed organoclay. The intermediate masterbatch containing organoclay and compatibilizer as well as the final TPO nanocomposites were characterized using X‐ray diffraction (XRD), transmission electron microscopy (TEM), and rheological analysis. The results showed that of the systems tested, significant changes in the state of exfoliation after processing with the supercritical fluid occurred only for surfactants possessing dialkyl tails and exhibiting a paraffin type arrangement within the montmorillonite. POLYM. COMPOS., 35:1592–1602, 2014. © 2013 Society of Plastics Engineers