Uniaxial compression and stretching deformation of an i-PP/EPDM/organoclay nanocomposite

In this study, the morphology and rheological properties of nanocomposites prepared by melt mixing of isotactic polypropylene (i-PP), ethylene-propylene-diene terpolymer rubber (EPDM), and Cloisite 15A organoclay, were investigated at rest and under of uniaxial compression and stretching deformations at room temperature. Transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) experiments revealed that intercalation took place between the clay and the blend. The lamellar long period (L) of the polymeric structure determined by small-angle X-ray scattering (SAXS) was found to increase upon the addition of nanoclay, which also resulted in variations in the angle of rotation (ϕ) between the polymer and clay lamellae. The intercalated nanoclay improved the storage and loss modulus of the resulting materials in the melt state significantly, as determined from oscillatory rheology analyses. Finally, we verified that the uniaxial plane deformation caused by compression of the nanocomposites contributed to the reduction of crystalline domains in the blend, while the crystallinity remained almost constant in the case of uniaxial stretching deformation.