Experimental and modelling studies with mixers for potential use with fastpolymerisations in tubular reactors

Mixing can have a significant effect on the quality of the product in any f ast polymerisation process, notably molecular weight distribution (MWD) in homopolymerisations. Here attention is given to the measurement of the mixi ng quality required to avoid reactor conditions influencing the MWD for a v ery fast living anionic polymerisation carried out in a flow reactor system which embodies a mixing device for the reactants as they are introduced to the reactor. The mixing measurements have been carried out using a well-es tablished two-stage reaction, which has been shown to be suitable for the p urpose of assessing mixing quality. The key variables known to influence th e Reynolds number have been explored, i.e. geometry of the mixing device, r eactant flow rates and reactant viscosity. Deterministic modelling methods have been used to describe the processes studied and computational fluid dy namics (CFD) methods have been used to investigate the spatial flow behavio ur of the reactor system. The approach adopted is generic and might be empl oyed for many other fast polymerisation processes.