Polymer based nano-composites reinforced with a small amount of nanosize clay particles (<5 vol.%) significantly improve the mechanical, thermal and barrier properties of the pure polymer matrix. These improvements are achieved through conventional processing techniques and without affecting substantially the density of the matrix. These composites are now being considered for a wide range of applications including packaging ,coating, electronic, automotive and aerospace industries. It is generally believed that the improvement of properties of clay nano-composites is directly related to the complete exfoliation of silicate layers in the polymer matrix. A model of visco-elastic deformation is presented which predicts linear to non-linear visco-elastic deformation dependent on the density and spacing of the silicate layers.