The microestructure of polyethylene foams produced by a nitrogen solution process

An experimental study on the cellular structure and polymer morphology of a collection of polyethylene foams produced by a nitrogen solution process is presented in this work. Scanning electron microscopy (SEM) was used to characterise the cellular structure. Raman spectroscopy, wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and SEM were utilised to analyse the polymer morphology. The experimental results showed that the polymer morphology of the solid phase, which comprises the cell walls of the foams is different to that observed in continuous polymers. Moreover, the final polymer morphology of a given foam depends on the cellular structure of the material.