Living Polymerisation Reactors: Molecular Weight Distribution Control Using Inverse Neural Network Models

In principle, it is possible to exercise control over the molecular weight distribution (MWD) of the polymers produced from living polymerisation processes in flow reactors through the control of reactant feeds in a predetermined fashion. Some of the factors that influence the extent to which control can be achieved with feed perturbations to a single stage continuous flow stirred tank (CSTR) reactor have been reported previously. Here, attention is given to the problem of establishing inverse process models as a first step towards a fully automatic control strategy for the synthesis of polymers with pre-ordained MWD in a real process. Particular attention is given to the development of a neural network model for predicting the instantaneous reactor feed conditions for a specified product MWD and characterising the MWD for the purpose of dimension reduction using principal component analysis. Data collected from a simulated ideal reactor process are used in the study. The way in which this approach will underpin a real laboratory-scale polymerisation system is briefly outlined.