Abstract: An expandable film includes a core layer and first and second non-expandable outer layers. The core layer includes expandable microspheres dispersed in a matrix having at least 40% of one or more matrix polymers selected from (i) ethylene/unsaturated ester copolymer having an unsaturated ester comonomer content of from 20% to 60%, (ii) ethylene/alpha-olefin copolymer having a density of less than 0.915 g/cc, and (iii) combinations thereof. The melting point of the one or more matrix polymers is at least 15° C. below the activation temperature of the expandable microspheres. The first and second non-expandable outer layers each independently include one or more thermoplastic polymers having a melting point at least 15° C. below the activation temperature of the expandable microspheres.

Abstract: A composite structure comprises a first substrate, a film, and a second substrate. The film comprises a first outer layer, a second outer layer, and an intermediate layer between the first and second outer layers. The first substrate comprises one or more polymers selected from polyurethane and polyester and is adhered to the first outer layer of the film. The second substrate is adhered to the second outer layer of the film. The first outer layer of the film comprises ionomer. The second outer layer of the film comprises one or more polymers selected from a) ionomer, b) polyamide having a melting point of at most about 200° C., c) amorphous polyamide, and d) polyester. The intermediate layer comprises one or more polyamides. The composite structure may be, for example, an automotive headliner assembly.