Rheological and thermal properties of binary blends of polypropylene and poly(ethylene-co-1-octene)

Dynamic viscoelastic properties of binary blends consisting of an isotactic polypropylene (i-PP) and ethylene-1-octene copolymer (PEE) were investigat ed to reveal the relation between miscibility in the molten state and the m orphology in the solid state. In this study, PEE with 24 wt % of 1-octene w as employed. The PEE/PP blend with high PEE contents showed two separate gl ass-relaxation processes associated with those of the pure components. Thes e findings indicate that the blend presents a two-phase morphology in the s olid state as well as in the molten state. The PEE/PP blend with low PEE co ntent showed a single glass-relaxation process, indicating that PEE molecul es were probably incorporated in the amorphous region of i-PP in the solid state. The DMTA analysis showed that the blends with low PEE contents prese nted only one dispersion peak, indicating a certain degree of miscibility b etween the components of these blends. These results are in accordance with the results of the rheological analysis. (C) 2000 John Wiley & Sons, Inc.