Effect of addition of montmorillonite and carbon nanotubes on a thermoplastic polyurethane: High temperature thermomechanical properties

Thermoplastic polyurethane (TPU) and thermoplastic polyurethane/polyamide 11 (TPU/PA) nanocomposites were prepared via melt compounding, incorporating Cloisite((R))30B (Cl) and multi-walled carbon nanotubes (MWNT). Morphological characterization of all samples was conducted using X-ray diffraction, transmission electron microscopy, differential scanning calorimetry, and Fourier transform infrared spectroscopy. Thermophysical properties were characterized using dynamic mechanical analysis and thermogravimetric analysis at 500 degrees C/min. A correlation was drawn between addition of nanoparticles and degree of phase separation (DPS), and further between DPS and the thermomechanical property termed the "reinforcement gap." This gap has been associated with TPU dripping behavior at high temperatures. It is postulated that only polar-type reinforcing nanoparticles will reduce DPS. Rate of chemical degradation of TPU was reduced by both Cl and MWNT. (c) 2014 Elsevier Ltd. All rights reserved.