Deformation behavior of polyethylene/silicate nanocomposites as studied by real-time wide-angle X-ray scattering

Maleated polyethylene/silicate nanocomposite (PEMA/20A) and maleated polyethylene/SiO2 composite (PEMA/SiO2) were prepared by the melt compounding. Transmission electron microscopy and X-ray scattering results confirmed the exfoliation of the silicate layers (20A) throughout the maleated polyethylene (PEMA) matrix, but the SiO2 particles were not well dispersed in the matrix. The long axes of exfoliated silicates were aligned along the tensile axis during deformation and showed no sign of cavity formation in the matrix. In PEMA/SiO2, however, extensive amount of cavities were created along the tensile direction. During the tensile deformation the crystallographic changes of pure PEMA and composites containing 20A and SiO2 were investigated using the real-time X-ray scattering. The 20A and SiO2 particles in composites made little effects on the initiation of martensitic transformation, but they effectively inhibited the orientation of polyethylene lamellae in the tensile direction. The lamellar fragmentation was higher in PEMA/20A than in PEMA/SiO2, while the former was less effective in inhibiting lamellar orientation.