The effect of nano-sized silicate layers from montmorillonite on glass transition, dynamic mechanical, and thermal degradation properties of segmented polyurethane

The glass transition temperature of the hard-segment phase and the storage modulus of segmented polyurethane increased substantially in the presence of a small amount of tethered nano-sized layered silicates from montmorillonite compared with their pristine state (by 44degreesC and by 2.8-fold, respectively). Furthermore, the heat resistance and degradation kinetics of these montmorillonite/polyurethane nanocomposites were enhanced, as shown by thermogravimetric analysis. In particular, a 40degreesC increase in the degradation temperature and a 14% increase in the degradation activation energy occurred in polyurethane containing 1 wt % trihydroxyl swelling agent-modified montmorillonite compared to that of the pristine polyurethane. (C) 2002 Wiley Periodicals, Inc.