Simultaneous Controllability of PSD and MWD in Emulsion Polymerisation

Abstract

A sensitivity study of particle size distribution (PSD) and molecular weight distribution (MWD) responses to perturbations in initiator, surfactant, monomer and chain transfer agent in a semi‐batch emulsion polymerisation is presented. The objective is to provide a systematic study on the ability to simultaneously control both PSD and MWD, towards inferential control of end‐use product properties. This would lead towards identification of the practical feasible regions of operability. All inputs appeared to have an intrinsic and simultaneous influence on end‐time PSD and MWD. Trends shown in experimental results have been explained in a mechanistic sense and also compared to simulation results from a combined PSD/MWD population balance model. The preliminary comparison between experiment and simulation highlights areas to be focussed on with respect to model improvement.

Emulsion polymerization of isoprene: Mathematical model for long‐chain branching

“…Emulsion polymerization models have been classified according to the adopted assumptions on the compartmentalization of radicals in the polymer particles 6. The simplest pseudo‐bulk models calculate the MWDs as in a bulk process4, 7–10; with the total concentration of radicals estimated from the product between the total number of latex particles and the average number of radicals per particle. Pseudo‐bulk models have proven adequate for emulsion systems where of the dead polymer is mostly generated in the polymer phase by chain transfer reactions (to the CTA and to the polymer) 6, 7.…”

“…The most sophisticated models assume a distribution of radical chain lengths among the polymer particles, that in turn can be either mono‐ or polydisperse in diameter 17–27. Several algorithms have been developed for the numerical resolution of the mentioned models: method of moments,4, 6, 7, 9, 10 orthogonal collocation on finite elements,12 numerical fractionation,13–16, 18, 19 Markov chains,22 and Monte‐Carlo simulations 24–27…”

Inferential closed‐loop control of particle size and molecular weight distribution in emulsion polymerization of styrene

“…They extended their research in another work to investigate simultaneous controllability of PSD and MWD through experimental studies. They concluded that the CTA is the most suitable candidate for MWD manipulation, with minimal alteration of PSD, but no input was suggested for the manipulation of PSD with the minimal alteration of MWD [12].…”