Living Polymerisation Reactors. Part II. Theoretical and Experimental Tests on an Algorithm Which Predicts Mwds From CSTRs with Perturbed Feeds

Abstract

ABSTRACT In Part 1 of this work (Gosden et al., 1996) a novel algorithm has been described for the fast calculation of complex molecular weight distributions (MWD) produced in living anionic polymerisation conducted in periodically perturbed continuous stirred tank reactor (CSTR). Here it is shown by rigorous derivation that the new formula of Gosden et al gives the correct solution of the sets of differential equations which describe living polymerisation reactions in CSTR reactors where mixing can be regarded as perfect. A numerical validation of the algorithm is also reported where computed solutions have been compared with the results obtained by traditional numerical integration methods and perfect agreement has been found. Experiments are also reported which have been carried out with a computer controlled laboratory-scale polymerisation reactor in an attempt to validate the simulation predictions. Results are presented which show that, for a simple square-pulse input perturbation in monomer and initiator feed concentrations, there is good agreement between theory and practice. In order to make realistic comparisons between theory and the gel permeation chromatography data obtained with samples taken from the reactor, the simulated data has been deliberately broadened with a Gaussian function in an attempt to mimic reactor and any other broadening effects which might stem from the method of analysis. Some wider issues relating to polymerisation reactor control using pulsed feeds and the wider application of the algorithm are briefly reviewed.