  Most technical polymers and many biopolymers contain very different molecular
species (unlike chain length, molecular architecture and/or chemical
composition) in contrast to pure low molecular weight compounds. This
inconsistent constitution of macromolecules proves very adverse in many cases.
An adequate fractionation of polydisperse polymers is therefore mandatory.
  Very efficient means are available for analytical purposes. However, these
methods break down as soon as the required amount of product exceeds some ten
grams. In order to gain access to large enough quantities of sufficiently
uniform polymer samples, we have developed a special kind of extraction process
called Continuous Spin Fractiona-tion (CSF). The better soluble macromolecular
species are preferentially transferred from a feed phase (concentrated polymer
solution) into a pickup phase (solvent of tai-lored thermodynamic quality). The
main problem of the procedure lies in the high vis-cosities of reasonably
concentrated polymer solutions, impeding the attainment of ther-modynamic
equilibria. This hurdle could be cleared by means of spinning nozzles through
which the feed is pressed into the pickup phase. CSF can be implemented to any
soluble polymer and is likewise apt for the production of small and of large
amounts of polymer samples with the required uniformity. This contribution
explains how to customize CSF to the polymer of interest and presents a number
of typical ex-amples.
