Emulsion copolymerization of styrene and butyl acrylate in the presence of a chain transfer agent.

Abstract

This paper deals with the development of a mathematical model for emulsion copolymerization of styrene and butyl acrylate carried out in the presence of n-dodecyl mercaptan as chain transfer agent (CTA). The model consisted of a system of differential algebraic equations in which the population balances is based on a new approach that reduces significantly the number of equations involved and the corresponding computational time. Most of the unknown kinetic and thermodynamic parameters of the model were estimated from experimental measurements using a stochastic optimization method based on a genetic algorithm. The results showed a fairly good agreement between model predictions and experiments. The model was then successfully validated through additional experiments carried out in batch and fedbatch reactors and clearly showed that the model was able to predict the time-evolution of overall conversion, amounts of each residual monomer, number and weight average molecular weights of the resulting copolymers and average diameters of the corresponding latex particles for different operating conditions, mainly CTA concentration and reaction temperature. The model was finally used to investigate and confirm the effects of CTA concentration, previously observed by several authors, on the kinetics of this polymerization process and on the main properties of the resulting macromolecules and latex particles.

Analysis of optimal operation of a fed-batch emulsion copolymerization reactor used for production of particles with core–shell morphology

“…An initiator is fed to the reactor by means of a separate inlet stream. The mathematical model of the considered emulsion copolymerization reaction was derived, identified and validated in one of our previous studies [7]. This section presents the model in compact form where we show its crucial features, i.e.…”

“…It is set equal to 1000 in order to balance the difference in magnitude between the first two terms in the objective function and the last one. The last set of inequalities expresses operational conditions of the real plant which was used for validation of the process model and for experimental control of the process in our previous studies [7,8]. Here Q f,max denotes the maximal flowrate achievable with the present plant instrumentation.…”

“…considered reaction mechanism and resulting model equations. The detailed model can be found in the original modeling paper [7]. Emulsion polymerization is driven by radical mechanisms where the monomers are mainly located in droplets dispersed in an aqueous phase.…”

“…The most representative ones are reviewed by Gao and Penlidis [5] and Chern [6]. In this study, we use the mathematical model developed in our recent research activities [7]. The model is of hybrid type with several differential and algebraic equations and with state-dependent switching being present.…”

Emulsion copolymerization of styrene and butyl acrylate in the presence of a chain transfer agent. Part 2: Parameters estimability and confidence regions

“…This model consisted of a system of differential algebraic equations (DAEs), derived from mass, population and moment equations (Benyahia et al (2010)). In this paper, we implement the sequential orthogonalization method developed by Yao et al (2003).…”