Acrylic-modified polyolefin ionomers as compatibilizers for poly(ethylene-co-vinyl alcohol)/aromatic copolyester blends

Polymeric alloys of poly(ethylene-co-vinyl alcohol) (EVOH) with an amorphous copolyester (PETG) were prepared using the sodium or the zinc ionomer of acrylic-modified polyolefin ionomers. Composition parameters examined were the main components ratio and at a fixed ratio the compatibilizer content. The techniques applied to assess compatibilization were: tensile testing, dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC) and morphology examination of cryofractured surfaces using scanning electron microscopy (SEM). Both ultimate tensile properties and morphological features indicated that the ionomer, Na+ is a more efficient compatibilizer, the amount required (ca 5 wt%) being 1/3 to that of the ionomer, Zn2+. A plausible explanation for this finding is proposed. Analysis of DMA moduli data supports the view that films obtained are laminar in structure — a significant result for film barrier applications.