Detailed studies of effects of sample preparation method on the kinetics of
phase separation in a blend of polystyrene-co-maleic anhydride (SMA) with
a commercial sample of polymethyl methacrylate containing ethyl acrylate as
co-monomer (PMMAe) have been performed using light scattering techniques.
Two preparation methods, viz. solution casting and melt mixing in a mini tw
in screw extruder were employed in this work. The blend, which shows lower
critical solution temperature (LCST) behaviour, exhibits spinodal and binod
al curves at higher temperatures in the case of solution casting than those
from melt mixed samples. The relative values of the Cahn-Hilliard growth r
ate, R(q), obtained from the two preparation methods depend on blend concen
tration, R(q) being faster for solution cast samples at some concentrations
and slower at others. Comparison of the data with recent theoretical devel
opments for entangled polymer blends is reported. (C) 2001 Elsevier Science
Ltd. All rights reserved.