Experimental method for creep characterization of polymeric foam materials in media immersion

Polymeric flexible foam materials are widely used as damping materials in structural applications primarily to reduce unwanted system vibrations and related noise generation. Due to the viscoelastic nature of polymers and high compressibility of soft polymeric foams, their damping quality is strongly dependent on the overall loading situation, which occasionally means complex mechanical loading scenarios combined with specific ambient service conditions. In the case of superimposed constant compressive loading the deformation of the damping components is basically dependent on the fundamental creep tendency of certain material type and is also strongly influenced by service temperature and the surrounding contact media. Thus the chosen test methodology for proper creep characterization has to reflect these major influencing parameters. In this regard, a specific creep testing device was built up for the performance of small load compression creep experiments on soft foam specimens immersed in liquid media, which was mineral oil in the present study. Moreover, the thermo-mechanical behavior of the foam materials was investigated by dynamic-mechanical analysis (DMA). The resulting temperature-dependent modulus and damping characteristics showed a good correlation with the corresponding creep behavior, enabling a rough estimation of the creep tendency within corresponding temperature ranges.