Melt rheology and morphology of thermoplastic elastomers from polyethylene/nitrile-rubber blends: The effect of blend ratio, reactive compatibilization, and dynamic vulcanization
J. George et al., Melt rheology and morphology of thermoplastic elastomers from polyethylene/nitrile-rubber blends: The effect of blend ratio, reactive compatibilization, and dynamic vulcanization, J POL SC PP, 38(9), 2000, pp. 1104-1122
A study of the melt-theological behavior of thermoplastic elastomers from h
igh-density polyethylene and acrylonitrile butadiene rubber (NBR) blends wa
s carried out in a capillary rheometer. The effect of the blend ratio and s
hear rate on the melt viscosity reveals that the viscosity decreases with t
he shear rate but increases with NBR content. Compatibilization by maleic a
nhydride modified polyethylene has no significant effect on the blend visco
sity, but a finer dispersion of the rubber is obtained, as is evident from
scanning electron micrographs. The melt-elasticity parameters, such as the
die swell, principal normal stress difference, recoverable shear strain, an
d elastic shear modulus of the blends, were also evaluated. The effect of a
nnealing on the morphology of the extrudate reveals that annealing in the e
xtruder barrel results in the coalescence of rubber particles in the case o
f the incompatible blends, whereas the tendency toward agglomeration is som
ewhat suppressed in the compatibilized blends. (C) 2000 John Wiley & Sons,
Inc.