Eckelt, J., Wolf, B.A.
"Continuous Spin Fractionation: A large scale method to improve the performance of polymers"
POLYMERIC MATERIALS IN POWER ENGINEERING 2007, submitted.
Abstract: 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 Fractionation (CSF). The better soluble macromolecular species are preferentially
transferred from a feed phase (concentrated polymer solution) into a pickup
phase (solvent of tailored thermodynamic quality). The main problem of the procedure
lies in the high viscosities of reasonably concentrated polymer solutions, impeding
the attainment of thermodynamic 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 examples.
preprint number: 285