The name is absent

quires continuous line defouling. Therefore, in order to choose the optimal operating
conditions for the reactor, it is necessary to know the temperature, pressure, and
mixture compositions corresponding to the demixing points. Demixing or the cloud
points depends to a large extent on the polymer size, structure, MWD, and interac-
tions with the solvent.

Another important plastic material, high impact polystyrene (HIPS), is generally
produced by reactive processing. The styrene monomer is polymerized in the presence
of an elastomer like polybutadiene (PB). The starting phase is homogeneous system
of PB in styrene, in which increasing amount of PS is generated as the polymeriza-
tion progresses. At a characteristic concentration of PS, phase separation occurs and
the graft copolymer (PS backbone with PB branches) called HIPS is formed simul-
taneously in the system by a chain transfer reaction. HIPS is stronger than PS and
PB branches give it the elastic properties making it less brittle than PS. HIPS is
commonly used in fridge liners, food packaging, vending cups, and toys.

Hence, understanding the phase behavior of the polymer systems is of critical
importance for both polymer scientists and engineers. Many of the qualitative features
of (fluid-fluid) phase equilibria in polymer mixtures and blends can also be found
in mixtures of small molecules, and all the basic thermodynamic relations apply.
Yet, there are significant quantitative differences, mainly due to the large size of
the polymer molecules. Some of the common features that pose a challenge while
modeling the phase behavior of these systems are:

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