High-Density Polyethylene Layered Silicate Nanocomposites: Effect of Mechanical Stretching on the Crystal-to-Crystal Transformations, orphology, and Extent of Exfoliation

High-density polyethylene/clay nanocomposites were elongated until breakage to investigate the effect of the mechanical stretching on the crystal-to-crystal transformations and their morphology. Crystalline transformations of the polymer matrix were studied via Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction measurements. It was concluded that the stress-induced crystal-to-crystal transformations from orthorhombic structures to monoclinic and pseudohexagonal structures as well as the back-transformation during relaxation were hindered by the presence of the clay. X-ray diffraction studies on stretched samples showed that the mechanical stretching led from an intercalated structure to an almost exfoliated structure. These findings agreed with scanning electron micrographs, in which the eneficial effect of stretching on the exfoliation of the clay was evident