The effects of the saturation temperature and high-pressure dissolved CO2 on the crystallization behavior of polyether-block-amide (Pebax®) containing various amounts of polyamide-12 hard segment were studied. Non-isothermal and isothermal analyses were conducted using differential scanning calorimetry (DSC) to evaluate the crystallization kinetics of Pebax® samples. Wide angle X-ray diffraction (WAXD) was used to characterize the crystalline morphology of Pebax® under various conditions. A higher cell density was observed from the foams of the broader distribution of the hard segment length and the hard segment crystalline phase obtained by twin-screw compounding. It appears that the hard-segment crystals are the heterogeneous nucleating sites that govern the nucleation phenomena of Pebax®. Therefore, the broader distribution of crystalline phase offers better foaming characteristics because of the larger number of nano-/micro-scale heterogeneous nucleation sites.
