Mathematical Modeling of the Production of Elastomers by Emulsion Polymerization in Trains of Continuous Reactors

Abstract

A mechanistic model is proposed to describe the emulsion polymerization processes for the production of styrene–butadiene rubber (SBR) and acrylonitrile–butadiene rubber (NBR) elastomers in trains of continuous stirred tank reactors (CSTRs). A single model was used to describe both processes by choosing the proper physicochemical parameters of each system. Most of these parameters were taken from literature sources or estimated a priori; only one parameter (the entry rate coefficient) was used as an adjustable value to reproduce the kinetics (mainly conversion), and another parameter (the transfer to polymer rate coefficient) was used to fit the molecular weight distribution (MWD) experimental values from plant data. A 0-1-2 model for the number of particles and for the moments of the MWD was used to represent with more fidelity the compartmentalization effects. The model was based on approaches used in previous emulsion polymerization models published in the literature, with the premise of reaching a compromise between the level of detail, complexity, and practical value. The model outputs along the reactor train included conversion, remaining monomer composition, instantaneous and accumulated copolymer composition, the number of latex particles and particle diameter, polymerization rate, the average number of radicals per particle, average molecular weights, and the number of branches per chain.

Precise Modeling of the Particle Size Distribution in Emulsion Polymerization: Numerical and Experimental Studies for Model Validation under Ab Initio Conditions

“…The surfactant is solubilized in the aqueous phase (S f ) and adsorbed onto the surface of polymer particles (S a ) and monomer droplets (S d ). The mass balance for surfactant is given by Equations ( 14)-( 17) [17].…”

“…Another practical type of MWR is the method of moments (MMs), which is particularly useful for the computation of relevant average properties such as the number average particle diameter (D p ) and the average number of radicals per particle (n). Recently, a model based on the MMs for the 0-1-2 model has captured the effect of the number of reactors on the monomer conversion, molar mass, and copolymer composition of emulsion copolymerization of styrene-butadiene rubber and acrylonitrile-butadiene rubber in a train of CSTRs [17].…”

Digital Twin for the SBR Cold Emulsion Copolymerization Process

“…More recently, Guerra et al. [ 15 ] proposed a mechanistic model to describe the emulsion copolymerization of SBR and acrylonitrile/1,3‐butadiene rubber (NBR) in trains of continuous stirred tank reactors. The authors used one adaptive parameter (entry rate coefficient) for adjusting the conversion and another adaptive parameter (transfer to polymer rate coefficient) for fitting the molecular weight distribution according to the experimental data.…”

An Adaptive Soft Sensor for On‐Line Monitoring the Mass Conversion in the Emulsion Copolymerization of the Continuous SBR Process

“…More recently, Saldivar‐Guerra et al. [ 14 ] presented a mechanistic dynamic model for the production of elastomers in trains of CSTRs, where SBR was specifically considered.…”

“…The model was adjusted to reproduce experimental data collected from an industrial plant currently operated by Pampa Energy S.A. in Argentina. More recently, Saldivar-Guerra et al [14] presented a mechanistic dynamic model for the production of elastomers in trains of CSTRs, where SBR was specifically considered.…”