Chemistry Reference
In-Depth Information
Theory of Random Copolymer Fractionation
in Columns
Sabine Enders
Abstract Random copolymers show polydispersity both with respect to molecular
weight and with respect to chemical composition, where the physical and chemical
properties depend on both polydispersities. For special applications, the two-
dimensional distribution function must adjusted to the application purpose. The
adjustment can be achieved by polymer fractionation. From the thermodynamic
point of view, the distribution function can be adjusted by the successive establish-
ment of liquid liquid equilibria (LLE) for suitable solutions of the polymer to be
fractionated. The fractionation column is divided into theoretical stages. Assuming
an LLE on each theoretical stage, the polymer fractionation can be modeled using
phase equilibrium thermodynamics. As examples, simulations of stepwise fraction-
ation in one direction, cross-fractionation in two directions, and two different
column fractionations (Baker Williams fractionation and continuous polymer frac-
tionation) have been investigated. The simulation delivers the distribution accord-
ing the molecular weight and chemical composition in every obtained fraction,
depending on the operative properties, and is able to optimize the fractionation
effectively.
Keywords Continuous thermodynamics
Fractionation in column
Theory of
copolymer fractionation
