Influence of Microstructure and UV-Conditioning on the Mechanical Response of Polymeric Foam Under Compressive Loading

The aim of this study is to evaluate the influence of microstructure, specifically, variations in foam cell size and density, on the compressive stress-strain behavior of polymeric foam material. Foams with varying densities are examined under incremental loadings to different prescribed strain levels. A comparison is made of the maximum stress level attained during deformation and residual strain on complete unloading and following recovery. Additionally, the durability of the foam material on exposure to service environment, namely, exposure to ultra-violet (UV) light and humidity, is considered. Cylindrical compression samples are exposed to Xenon Arc (63°C, 18 minutes water and light/102 minutes light only) and spectral intensity of 0.3 to 0.4 watts/m² for 288 cycles. Parameters investigated include changes in modulus, maximum stress, residual strain and linear shape recovery due to conditioning and mechanical cycling.