A foam comprising a nanocomposite comprising a bulk linear semi-crystalline polyolefin containing no cross-links or branched polymers; an organoclay; and a polymeric compatibilizer for enhancing physical interactions between the bulk linear semi-crystalline polyolefin and the organoclay, wherein the linear semi-crystalline polyolefin combines with the organoclay to form the nanocomposite is provided. Novel nanocomposites and methods of producing the nanocomposites and foams, such as flexible foams, are also provided. The resulting products are useful in a variety of applications, including thermoplastic flexible foam seals, thermoplastic foamed panels in vehicles, and thin-walled blow molded bottles.