Polyurethane nanocomposites with varying concentration of different fillers are produced through hot melt extrusion by using nanotalc and Cloisite 30B as fillers. The TEM images show good dispersion of 30B while moderate agglomeration in nanotalc composite. The result is supported by the respective nanostructures (exfoliated in 30B vs. intercalated in nanotalc composites). A slight decrease in degradation temperature is observed but the nanocomposites are thermally stable upto 300°C. Permeability significantly decreases for nanocomposites. Young's modulus increases with increasing filler concentration while the toughness improvement exhibits a maximum at 4 and 6 wt% of 30B and nanotalc, respectively. Halpin–Tsai model is employed to predict the mechanical properties of the composites. The mechanical, thermal and gas barrier properties are better in 30B as compared to nanotalc nanocomposites, due to greater interaction in 30B nanocomposites evident from the large shift of peak position in UV–vis and FTIR measurements along with its good dispersion.