Multifunctional step growth polymerizations in cascades of isothermal, continuous flow, stirred tank reactors

Abstract

The step growth polymerization of RAf type multifunctional monomers (with A reacting with A) in cascades of isothermal, homogeneous, continuous flow stirred tank reactors (HCSTR's) is simulated. It is found that our equations reduce to those of Cozewith, et al. If either f or the molecular weights are large. However, under certain conditions, the low molecular weight correction is significant and the more exact equations of the present work must be used. Several possible start-up strategies are discussed, of which one is amenable to analytical solution. This is the one in which all HCSTR's are filled initially with the steady state feed from the previous reactor and the outputs from any reactor, during its start-up period, are discarded to an 'off spec' tank. It is found that for this case, in order to ensure nongelling operation, the mean residence time of any HCSTR must lie below a certain critical value, depending on the value of f and the feed conditions.