Polymer Solutions under High Pressures

Phase behavior and the phase separation dynamics of
polymers in fluid and fluid mixtures are of
importance for many processes encountered in polymer
synthesis, purification, processing, and
modifications. High pressure fluids/fluid mixtures,
i.e. near-critical or supercritical fluids, have
been considered as a replacement for many
conventional organic solvents because they are
environmentally benign and tunable for processing.
As one of the approaches to achieve this goal,
binary mixtures of an organic solvent and CO2 under
high pressures can be used to replace the organic
solvents. This book discusses the phase behaviors
and phase separation dynamics of two model polymers
in such systems. The polymer systems chosen are
polysulfone in tetrahydrofuran and CO2 mixtures and
polyethylene in n-pentane and CO2 mixtures. The
former system is selected in that polysulfone is a
very important commercial polymer for membrane
formation, for which phase separation is the key to
desired structure. The latter is chosen as a model
system for semicrystalline polymers to study the
fluid-fluid and solid-fluid phase separations and
their interplay.