a b s t r a c t We have investigated the dynamic mechanical behavior of films prepared from polystyrene solutions in chloroform containing oleic acid as an additive. The response of the films has been measured by means of a dynamic mechanical analyzer operated in tension mode over a temperature range of 30–150 °C, using sinusoidal motion with a maximum strain of 0.04% and a frequency of 2 Hz. The long term creep behavior has also been evaluated. Our results show that the oleic acid softens and disentangles the polystyrene chains backbone, resulting in a decrease in the dynamic mechanical properties of the polystyrene films. Ó 2010 Elsevier B.V. All rights reserved.