Blends of ethylene-octene copolymers prepared by Dow's INSITE(TM) cons
trained geometry catalyst and process technology were characterized. (
INSITE(TM) is a trademark of The Dow Chemical Company.) A previously d
escribed classification scheme based on density, or comonomer content,
was the basis for the choice of blend components. The blends combined
a low density Type I copolymer (0.865 g cm(-2)) with a higher density
copolymer. The second component was either another Type I copolymer (
0.887 g cm(-3)), a Type II copolymer (0.901 g cm(-3)), or a Type III c
opolymer (0.913 g cm(-3)). The melting and crystallization behaviour s
uggested that the components crystallized separately in all the blends
. However, dynamic mechanical analysis indicated that the noncrystalli
ne portions of the Type I blends formed a single phase, whereas the no
ncrystalline regions of blends with the Type II or Type III copolymer
appeared to be phase separated in the solid state. The stress-strain b
ehaviour at ambient temperature correlated with density, or total crys
tallinity, regardless of whether the material was a copolymer or a ble
nd. (C) 1997 Elsevier Science Ltd.