It can be seen
that for all blends the stabilization torque increases
with increasing NBR content. As the NBR content in
the blend increases, the blend viscosity is increased.
The increase in viscosity as a result of incorporation
of rubber has been reported by various researchers
[9–12]. However, at a similar blend composition,
PVCw=NBR þ MAH blends exhibit higher stabilization
torque than PVCw/NBR and PVCv/NBR blends.
Since stabilization torque is indicative of stable melt
viscosity, it is clear from the above results that
incorporation of MAH in the PVCw/NBR blends has
resulted in higher energy requirement. In our previous
work [13] we have reported that the work done to process
the blends, dE=dt, is energy consumed during
rotation and can be expressed as WM, where W is the
angular velocity and M is the torque. Thus, an
expression for the energy can be derived as
dE ¼WM dt. By integration, the mechanical energy
for processing the blends at a