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WEE-Solve GmbH – removing troublemakers

The purification and fractionation of polymers using innovative methods is of huge importance in many areas, including pharmacy and cosmetics. This is due to the fact that some polymers can only exert their full effect after fractionation. WEE-Solve GmbH offers innovative methods and scientific experience in polymer fractionation and rheology.

WEE-Solve GmbH based in Mainz is a good example of how 35 years of research can be brought together in a company. The company in question was established by Prof. Bernhard A. Wolf at the University of Mainz in 2007 along with two of his colleagues, Dr. John Eckelt and Dr. Andreas Eich and it brought together their know-how in the fractionation and purification of polymers as well as in rheology. The company name is based on the first letter of the surnames of the three company founders.

Polymers such as plastics and polysaccharides consist of a mix of different-length chains; currently available synthesis methods do not allow the synthesis of polymers with a defined chain length. “This broad chain length distribution makes many applications difficult or even impossible,” said Dr. John Eckelt, WEE’s Managing Director. The patented fractionation method, developed by John Eckelt during his doctoral studies, enables the modification of the mixture’s molecular weight distribution and allows certain plastics to be used for certain applications.

Fractionation for medical applications

Two-phase solution during CSF. © WEE-Solve GmbH

A method known as "continuous spin fractionation" (CSF) involves the separation of polymers on the basis of liquid-liquid phase separation. The polymer is contained in the liquid phase to which a precipitation agent is added. "The precipitation agent gradually reduces the solubility of the polymer until the system is no longer able to homogeneously solubilise the polymer. This leads to the formation of two liquid phases that contain all three components: solvent, polymer and precipitation agent," said the chemist. The two phases differ in the composition of polymers, i.e. one phase contains short-chain polymers and the other long-chain polymers. High throughput can be achieved using spinning nozzles such as those used in the textile industry. The process can be adapted to any new problem that arises. "Our know-how is the speed with which we can adapt the process and the continuous operation of the process," said Eckelt.

The feed solution (FD) is pressed through the spinning nozzle into the extraction agent. The threads of the viscous polymer solution break up into tiny droplets. The better soluble macromolecules can be easily extracted because of the short distance that they need to be transported. The droplets, freed from the low molecular weight material, contain the gel fraction (GL) while the continuous phase comprises the sol fraction (SL). The insets show the respective molecular weight distributions. © WEE-Solve GmbH
Feed solution (FD) and extraction agent (EA) are pumped into the mixing vessel. FD is spun through a spinning nozzle into a vessel. The two-phase mixture is then transferred to a separation column where one phase sediments and leaves the column at the lower end, whereas the other phase exits at the upper end. The molecular weight distributions of the initial polymer and the two obtained fractions are shown in the insets. © WEE-Solve GmbH

Hydroxyethyl starch (HES) is an excellent example of the use of CSF. The polymer is produced from cornstarch and used in medicine to maintain the colloid-osmotic pressure. “It is worth noting that short-chain polymers are excreted through the kidneys, while the long-chain polymers are incorporated into the skin,” said Eckelt. CSF is able to remove both long and short chains, thereby enabling HES to exert an optimal effect.

CSF can also be applied to hyaluronic acid, a biotechnologically produced biopolymer that is injected into the eye during surgery in order to maintain the eye pressure. Short hyaluronic acid chains have been found to lead to post-operative eye inflammations. In cooperation with the University Hospital of Mainz, WEE-Solve GmbH was able to use CSF to remove the short chains.

Everything that flows

Rheological measurement © WEE-Solve GmbH

WEE-Solve GmbH's second area of expertise is rheology, the study of the flow of matter, which is of major interest to the plastics and food industries as well as in the paints and varnishes sector. "We investigate everything that flows," said the managing director. The company carries out standard measurements as well as rheological investigations in research and development. "We develop methods for quality control applications and we characterise materials," said Eckelt. As a specialist in the field of physical chemistry and thermodynamics, WEE-Solve GmbH also offers viscosity pressure measurements of up to 2000 bar.

Pressure rheology is applied for example in the automotive industry, where the direct injection of fuels into the combustion chamber generates an extremely high pressure. "It is important to find out how biodiesel, for example, behaves under such high pressure," said Eckelt. Together with many other services, such as the preparation of phase diagrams and the determination of material densities, WEE-Solve GmbH offers a comprehensive portfolio of tailor-made problem solutions for clients in the polymer chemistry, pharmaceutical as well as food and cosmetics industries.

Website address: https://www.biooekonomie-bw.de/en/articles/news/wee-solve-gmbh-removing-troublemakers