Linking process conditions with rheological properties for the free-radical polymerization of acrylate-co-polymers in solution, emulsion and under pressure

• Applicant: Dr. Kristina Zentel
• Subject Area: Preparatory and Physical Chemistry of Polymers ; Technical Chemistry
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 537707035

In the field of polymer reaction engineering the saying "polymers are products by process" holds true: the polymerization process does not only affect selectivity and yield, but simultaneously determines polymer properties. To make use of this effectively, process-structureproperty- relationships have to be known and implemented in simulation models. This could be realized with a three-step multi-scale modeling strategy for the high-pressure polymerization of ethene to LDPE (Low Density Polyethylene) by the applicant. For this purpose, the detailed description of the formation of long-chain branches is necessary, as they are essential for the linear and non-linear rheology. Then, the mechanical properties of the polymer can be predicted and adjusted directly from process conditions. Building on this, three topics will be addressed in this project: (I) The three-step modeling strategy will be applied to the technically relevant acrylate monomers choosing n-butyl acrylate as model monomer. They exhibit a similar radical polymerization chemistry - with the formation of short- and long-chain branches. However, no model for the direct connection of polymerization conditions with flow properties has been established. (II) Emulsion polymerizations will be modeled by combining kinetic and thermodynamic modeling rigorously. This will test the universality of the model family in a very wide parameter space and extend the applicability to technically very widespread processes. A challenging system that has been studied little to date is the emulsioncopolymerization with a gaseous monomer and consequently four phases. Ethene will be used as comonomer, because it is used to produce LDPE, but also PE-acrylate-copolymers, under supercritical conditions on industrial scale. Thus, a copolymerization in emulsion offers a potential process alternative with mild reaction conditions and water as green solvent. (III) In addition, the proposed project aims at an enhanced process and property optimization with respect to sustainability. Effective approaches are improved mass and energy efficiencies as well as the reduction of waste and by-products. Those effects will be estimated via mass and energy balances based on the mini-plant set-up and will allow an estimation of the CO2-reduction. The special feature of the project is that the complex topic is investigated simultaneously from the experimental and the model-based side. This will enhance the understanding of the interlinked kinetic, thermodynamic and polymer dynamic processes. At the same time a model family will be developed, which can describe and predict polymer processes, the produced polymers and their viscosities, and can finally be applied for sustainable process and product development.

• DFG Programme: Research Grants