The rheological and morphological behaviors of commercially available three
binary blends of ethylene 1-octene copolymer (EOC) regarding the melt inde
x (MI), density and comonomer contents, one component made by the Ziegler-N
atta and the other by the metallocene catalysts, were investigated to eluci
date miscibility and phase behavior. Miscibility of the EOCs blend in a mel
t state was related to the value of the MI, density, and comonomer content.
If the comonomer contents are similar, then the melt viscosity is weight a
verage value, otherwise it is positively or negatively deviated. The microt
omed surface prepared by two different cooling processes-one is fast coolin
g and the other is slow cooling-indicated that all the blends were not homo
genous regardless the density, MI, and comonomer content. The Ziegler-Natta
catalyzed EOCs exhibited bigger spherulitic diameter and larger ring space
than those of the metallocene EOCs prepared by a cooling process. The blen
ds consisting of similar MI showed banded spherulites with different diamet
er, whereas the blend consisting of different MI and density takes place of
explicit phase separation and phase inversion at 1 : 1 blend composition.
The melt rheology appeared to influence the mechanical and film properties
in the solid state. (C) 2000 John Wiley & Sons, Inc.