A catheter balloon formed of a polymeric material such as expanded polytetrafluoroethylene (ePTFE) bonded to a second layer formed of a low tensile set polymer and/or impregnated with a low tensile set polymer. In a presently preferred embodiment, the low tensile set polymer is a silicone-polyurethane copolymer elastomer or a diene polymer elastomer. The low tensile set polymer has high strength, low modulus, high elongation, and low tensile set. The diene or silicone-polyurethane has a low tensile set, which facilitates deflation of the balloon to a low profile deflated configuration. One aspect of the invention provides improved attachment of the diene to the ePTFE. In one embodiment, the second layer is formed of a diene mixed with a bonding promoter such as a vulcanizing agent which is covalently bonded to the diene.