Thermomechanical behavior of polyurethane nanocomposite foams containing organoclay particles modified with bio-based fatty acid

In this study, rigid polyurethane (PU) foams containing 1.0-2.0 wt% organoclay (OC), PU-OC, modified from nanoclay (NC) using octadecanoic acid, a bio-based chemically stable low-cost fatty acid, were synthesized and investigated for their structural, thermal and thermo-mechanical properties in comparison with pure PU and PU-NC foams. PU-OC foams provided good structural integrity and host-guest morphology. Thermogravimetric analyses revealed that the one with 2.0 wt% OC showed improved thermal stability with a significant delay in the decomposition temperatures, with maximum loss rates at 345 degrees C and 408 degrees C, respectively, which were at least 26 K and 8 K higher than their counterparts. PU-OC foams developed more elastic responses in dynamic mechanical tests from -80 degrees C to +155 degrees C and from -60 degrees C to +60 degrees C under cyclic compression of 0.1 N, as well as under linear deformation of 1.0-9.5N at 25 degrees C, indicating that PU-organoclay foams are promising for use in severe environmental conditions.