Modeling and experimental studies of emulsion copolymerization systems. II. Styrenics

Abstract

Using a model previously published, predictions for evolution of conversion and average particle diameter in batch experiments are compared against experimental data for four emulsion copolymerizations of styrene with the following monomers: (1) methyl methacrylate, (2) butyl acrylate, (3) butadiene, and (4) acrylic acid. For each copolymerization system the experiments covered simultaneous variations in five variables: initiator and surfactant concentrations, water to monomer ratio, monomer composition, and temperature. It is shown that after data fitting for unknown or uncertain parameters, the model is capable of explaining quantitatively the experimental observations for conversion evolution and only qualitatively the particle size evolution data. This points out to the possible contribution of particle nucleation mechanisms other than the micellar one, which is the only mechanism included in the model. Some of the adjustable parameter values were found to depend on the copolymer composition. The only case in which the model does not perform well is in the prediction of the effect of initiator concentration on the copolymerization rate for butadiene‐rich formulations. It is also found that the model predictions are very sensitive to the value of the diffusion coefficients of monomeric radicals in the copolymer particle, which are not readily available in the literature. It is concluded that it is important to independently measure these parameters in order to enhance the predictive power of models. It is also concluded that the model can be useful for practical applications. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 79: 2380–2397, 2001

Emulsion terpolymerization of St/MMA/BuA: Modeling of composition, number of particles and the influence of n -DDM on the molecular weights

“…Besides, there is apparently another critical point at 78 wt% as seen in Figure 1, correlated to the k p -gel-glass effect, which was not considered in the k p gel models of this work. As corroboration, the critical points in Saldívar's work (Saldívar et al, 2001) in the copolymerization of St/BuA are also located near to 70 wt% and 80 wt% (See figure 7 of Saldívar's reference).…”

“…Also, a peak rose in the simulated diameter of particle D p,s at the beginning of semicontinuous process SC-1. Behavior similar to that reported for batch polymerization processes with hydrophilic monomers (Saldívar et al, 2001). We found that this peak results from a fast creation of smaller particles, which reduces the average initial diameter of the particles D p,s in the semicontinuous process SC-1 and can induce a bimodal distribution of D p,s .…”

“…It is important to emphasize that in our work the selection of a different model for each reaction process was similar to the Saldívar's procedure (Saldívar et al, 2001) in the sense of adjusting the better constants to each particular reaction process.…”

Is Modeling the PSD in Emulsion Polymerization a Finished Problem? An Overview

“…Hosseini et al [210] Sty 0-1 N Y Hosseini et al [23] Sty PB N Y Immanuel et al [211] VAc/BA PB N Y Immanuel et al [212] VAc/BA PB Y Y Jung and Gomes [26] Sty, BA 0-1/PB Y Y Kammona et al [213] Sty/2-EHA PB Y Y Kiparissides et al [214] VCM PB Y Y Marinangelo et al [215] Sty/BA PB N Y Meadows et al [216] Sty 0-1 N N Melis et al [217] VCM PB Y N Park et al [218] VAc/BA PB Y N Pohn et al [219] Sty 0-1 Y N Rajabi-Hamane and Engell [220] Sty PB N N Sajjadi [221] Sty 0-1-2-3 N Y Saldívar et al [4,[222][223][224] various binaries PB N Y Sood [225] Sty PB N N Sood [226] Sty PB N Y Sweetman et al [227] VAc/BA PB Y N Unzueta and Forcada [174] MMA/BA PB Y Y Vale and McKenna [38] VCM 0-1-2 Y Y Wulkow and Richards [228] -0-1-2 N Y Zeaiter et al [158,229] Sty…”

Emulsion Polymerization Kinetics

“…The parameters k tr,AA and k tr,BA are the rate coeffi cients for the chain transfer of free radicals terminated with a reactive unit of type A and free radicals terminated with a reactive unit of type B to [63] investigated the seeded emulsion copolymerization of styrene and n -butyl acrylate. Later, the validity of this kinetic model was justifi ed by the experimental data [67,68] . A mechanistic model was used to simulate the emulsion copolymerization kinetics.…”