This paper discusses thermal and gas barrier properties of polypropylene (PP)-polyether treated clay nanocomposites.PP-polyether (poly(ethylene glycol) monolaurate, PEG) treated clay reinforced nanocomposites were obtained by melt intercalation.PP-PEGM reinforced nanocomposite exhibited enhanced thermal stability compared with neat PP and PP-PEGC nanocomposite.The increase in thermal stability was due to the intercalation or separation of the silicate layers as well as better dispersion (exfoliation) of the silicate layers.Incorporation of clay did increase the peak thermal stability by 65-70 ℃ compared with pure PP.Oxygen induction time of PP nanocomposites was evaluated and will be discussed.Clay reinforced PP nanocomposites have higher thermal stability than pure PP.