A novel polyurethane elastomer composite modified by polydimethylsiloxane and organic-montmorillonite was prepared by the following three steps:(1) grind the mixture of polyether triol N330 and organic-montmorillonite (OMMT) to obtain N330/OMMT compound

(2) mix the N330/OMMT compound with the polyurethane prepolymer modified by hydroxypropyl terminated polydimethylsiloxane (HTPDMS) and (3) cure the mixture of step two with dimethylthiotoluenediamine (DMTDA).The structures of the products were characterized by Fourier transform infrared (FTIR) spectrum.X-ray diffraction (XRD) and transmission electron microscopy (TEM) studies showed that galleries of the clay were expanded and the silicate layers were dispersed in the polyurethane matrix.Scanning electron microscopy (SEM) demonstrated that OMMT promoted the compatibility of PU phase and PDMS phase.Thermo-gravimetric analysis (TGA) data indicated that the HTPDMS/OMMT/polyurethane nanocomposites have better thermal stability in comparison with the HTPDMS modified polyurethane

when the OMMT content was 5 wt%

the thermal stability of the nanocomposite reached its maximum.Differential scanning calorimetry (DSC) data revealed that the glass transition temperature (Tg) of the composite modified polyurethane showed significant increase upon using 5 wt% of OMMT.The nanocomposites also showed good surface properties and mechanical properties

and the maximal values of tensile strength

elongation at break and hardness occurred at 3 wt% OMMT concentration.