Condensation polymerisations with unequal reactivity in segregated continuous-flow stirred tank reactors

Abstract

A parametric study of the molecular weight distribution and its moments has been made on the irreversible condensation polymerisation of ARB type monomers which do not obey the equal reactivity hypothesis. The reactions are simulated for a continuous-flow stirred-tank reactor with distributed residence times, the mean residence time being the operating variable. Two different kinetic schemes have been proposed which represent the limiting cases of the actual situations (models I and II) which are usually encountered and the effect of segration in a CSTR has been studied. The molecular weight distributions, number average chain lengths and the polydispersity indices have been computed. Results are found to lie intermediate between batch reactors and homogeneous, continuous-flow stirred tank reactors. Plots between the poly dispersity index and the monomer conversion with the reactivity ratio, R, and the number average chain length as parameters indicate that results are far more sensitive to variations in R for model II than for model I.