Small-angle X-ray scattering study of poly(ethylene-oxide) and styrene based ionomers blends

Small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) were used to determine the miscibility and the morphology of blends of poly(ethylene-oxide) (PEO) and styrene-acrylic acid (S-AA) copolymers neutralized with alkali metals (Na⁺, Li⁺). In this study, we investigated the effects of blend composition and the content of ionic groups in amorphous ionomers on the segregation of amorphous component. It was found that PEO is partially miscible with styrene based ionomers due to the ion-dipole interactions. These interactions reduce mobility of PEO chains and hence, they are responsible for the decrease of crystallinity and the thickness of PEO lamellar crystals. SAXS revealed that ionomers segregated interfibrillarly during the crystallization process of PEO.