Preparation and characterization of thermoplastic polyurethane/organoclay nanocomposites by melt intercalation technique: effect of nanoclay on morphology, mechanical, thermal, and rheological properties

Abstract

Nanocomposites based on thermoplastic polyurethane (TPU) and organically modified montmoril-lonite (OMMT) were prepared by melt blending. Organically modified nanoclay was added to the TPU matrix in order to study the influence of the organoclay on nanophase morphology and materials properties. The interaction between TPU matrix and nanofiller was studied by infrared spectroscopy. Morphological characterization of the nano-composites was carried out using X-ray diffraction, transmission electron microscopy, and scanning electron microscopy techniques. The results showed that melt mixing is an effective process for dispersing OMMT throughout the TPU matrix. Nanocomposites exhibit higher mechanical and thermal properties than pristine TPU. All these properties showed an increasing trend with the increase in OMMT content. Thermogravimetric analysis revealed that incorporation of organoclay enhances the thermal stability of nano-composites significantly. Differential scanning calorimetry was used to measure the melting point and the glass transition temperature (Tg) of soft segments, which was found to shift toward higher temperature with the inclusion of orga-noclays. From dynamic mechanical thermal analysis, it is seen that addition of OMMT strongly influenced the storage and loss modulus of the TPU matrix. Dynamic viscoelastic properties of the nanocomposites were explored using rub-ber process analyzer. © 2010 Wiley Periodicals, Inc.