Thin dense films composed of a thermoplastic elastomer [polystyrene-block-poly(ethylene butylene)-block-polystyrene triblock copolymer (SEBS)] and two polyolefins, poly(ethylene-co-ethylacrylate) and poly(ethylene-co-propylene), were obtained by blow molding, uniaxial hot stretching, and cooling to room temperature. In the resulting films, the dispersed polyolefin phase formed a 3D-network structure which constrained the elastic recovery of the SEBS matrix phase. The presence of this network structure was a key factor in forming the thin dense films. (c) 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013