Investigations on the Anionic Polymerisation of Butadiene in Capillaries by Kinetic Measurements and Reactor Simulation

For the first time the anionic polymerization of 1,3-butadiene (Bd) is successfully transferred from semi- batch into a continuous microfluidic setup with compara- ble product properties. The molecular weight distribution described by the polydispersity index (PDI) is commonly used as a key criterion for product quality. The steady state and the local resolution of a continuous setup provide the opportunity to investigate the progress of the PDI during ani- onic polymerization. In this work, the influence of kinetics (statistics) and fluid dynamics (FD) on the PDI of the product is investigated. Therefore a dedicated setup was designed and erected to keep Bd in the liquid phase and provide a pulsation free constant liquid flow. With optimized param- eter settings, a separation of initiation and propagation is obtained and the intrinsic kinetics of propagation are deter- mined. To explain the experimental results, an ideal plug flow and an ideal laminar flow model are applied and com- pared to computational fluid dynamics (CFD) simulations. Finally, it is concluded which FD and statistical contributions lead to the very low PDI of 1.04 found in the experiments.