Photo: Hereon/Prokopios Georgopanos
In the laboratories and technical rooms of the department of "Polymer Technology", tailor-made polymers are developed and synthesized as well as processed and characterized. The focus is on the synthesis of new materials for membrane applications for filtration and gas separation.
The department aims at the production of polymers on a scale close to industry, paying special attention to the development of more environmentally friendly methods for polymer synthesis. Various controlled polymerization methods (e.g., RAFT, anionic polymerization) are used in combination with new reactor systems (e.g., Microfluidics).
Photo: Hereon/Prokopios Georgopanos
In the department of Polymer Technology, tailor-made polymers (homo- and copolymers) for all departments of the institute are synthesized according to the requirements, with the focus on upscaling using new, large-volume batch reactors (up to 20 L) and microfluidic reactors. Classical controlled polymerization methods (e.g., anionic polymerization) are in use here as well as more environmentally friendly methods (e.g., RAFT Emulsion polymerization) where a greater amount of the organic solvents is replaced by water. In addition, specific non-commercial monomers are synthesized and further polymerized in order to deliver materials for new membrane development. The synthesis is controlled in situ by inline spectroscopy methods (1H, 13C, 19F NMR, IR, UV-VIS).
To realize a sustainable process, an important element in the upscaling of the polymer synthesis is the approach of largely recovering the contaminated solvents arisen during the polymer production by using membrane technologies developed at Hereon.
The Research focuses of our department:
From micro to big
The microfluidic reactors are types of reactors in which a given reaction (e.g., polymerization reaction) takes place on a micro scale. A high surface to volume ratio allows for rapid heat and mass transfer, permitting the chemical reaction to proceed in an efficient and safe way.
By controlling the flow, temperature, and pressure in-line, as well as the ability to intervene in the on-going reaction process, the synthesis can be optimized to automate operation and to scale up product synthesis through continuous operation.
Radical polymerization in water - less organic solvents
Emulsion polymerization is a type of radical polymerization in which a polymer is synthesized in an emulsion of water, monomer, and surfactant. In the department of Polymer Technology, emulsion polymerization is even carried out without surfactant in order to synthesize polymers via controlled polymerization.
Polymers conventionally synthesized by other solvent-based polymerization techniques can thus also be prepared in the emulsion, thereby avoiding large amounts of organic solvents.
Sufficient quantities for the technology transfer
In order to produce polymers in sufficient quantities for the technology transfer, in addition to the microfluidic reactors also classic large batch reactors (up to 20L) are used. Polymer synthesis will be performed via controlled radical polymerization, via anionic polymerization as well as via polycondensation with the help of modern batch reactors. It is planned to start with the preparation of the monomers and solvents in specific reactors, followed by the polymerization in another reactor and finally the precipitation in specific precipitation reactors to collect the product in solid form for further applications. In the near future, it is planned to recycle the contaminated solvents resulting from the polymer production using Hereon membrane technology so that they can be reused.
Optimization of the polymerization by simulation and modeling
For the successful synthesis of the polymer in pilot scale, it is important to optimize the polymerization processes. For this purpose, the digitalization of the synthesis process in batch reactors as well as in continuous flow microfluidic reactors will be an important issue in the department of polymer technology. Models will be developed capable of describing and of performing the synthesis of the polymers in “digital form” with the help of a computer instead of consuming chemicals in the lab. A variety of scientific software is available for such an application such as COMSOL Multiphysics, MATLAB, Aspen Custom Modeler, etc.
For the validation of the models, it is essential to conduct the necessary experiments and to characterize the synthesized products thoroughly. This classical characterization is carried out in close collaboration with the other departments of the Institute of Polymer Research. Additionally the synthesis process is monitored in-situ: via the implementation of NMR, FTIR and UV-VIS spectroscopy that are inline connected with the reactors, analysis of the samples is provided in real time. In this way, not only the necessary data for the model validation are provided, but it is also possible to intervene in the ongoing process to optimize synthesis and thus to avoid unwanted by-products.