X-ray Characterizations of Polyethylene Polyhedral Oligomeric Silsesquioxane Copolymers

Abstract

A novel nanocomposite containing polyethylene and polyhedral oligomeric silsesquioxane (POSS) nanoparticles has been characterized using wide-angle X-ray scattering (WAXS). In copolymers formed between ethylene and POSS containing macromonomers, the POSS units, attached as pendant groups off the polyethylene backbones, are found to aggregate and crystallize as nanocrystals. The POSS nanoparticles in such PE-co-POSS copolymers form a lattice separate from the PE lattice with characteristic diffraction signals. From both line broadening of the diffraction maxima and also the oriented diffraction in a drawn material, we conclude that POSS crystallizes as anisotropically shaped crystallites. The presence of POSS disrupts the crystallization of polyethylene and results in less and smaller/disordered polyethylene crystallites. POSS nanocrystals are covalently connected to the PE crystallites via an intermediate disordered interfacial region. The PE crystallites are reinforced by the POSS crystallites, maintaini...