Modeling and experimental studies of emulsion copolymerization systems. III. Acrylics

Abstract

ABSTRACT:Using a previously published model and continuing the series of papers started with styrenic copolymers, predictions for evolution of conversion and average particle diameter in batch experiments are compared against experimental data for four emulsion copolymerizations involving at least one acrylic monomer: (1) methyl methacrylate/butyl acrylate, (2) methyl methacrylate/butadiene, (3) methyl methacrylate-vinyl acetate, and (4) butyl acrylate/vinyl acetate. For each system a fraction of factorial experiments were run covering simultaneous variations in five variables: initiator [I] and surfactant [E] concentrations, water to monomer ratio (W/M), monomer composition, and temperature. Data fitting is performed to represent the experimental data as several parameters are not available from independent experimental sources. The model is able to explain the effects of simultaneous changes in emulsifier concentration, initiator concentration, and water to monomer ratio on conversion and average particle size histories, although in some cases only qualitatively. An assessment of the degree in which a general emulsion copolymerization model is useful for practical applications is made. Physical insight is also gained by observing the trends of adjusted parameters with temperature and copolymer composition.

Modeling Vinyl Acetate and n‐Butyl Acrylate Emulsion Copolymerization Process

“…Difficulties to quantitatively describe the changes of the particle diameter in VA/BA emulsion copolymerization reactions were also reported by Saldívar et al [5], despite having used eight adjustable parameters to fit the experiments. Problems in measuring this property [22] and failures in improving the theoretical description of particle nucleation phenomena [5,6] contribute to this. Future improvements in the model need to address these issues.…”

“…In addition, a sensitivity analysis has shown that these parameters play an important role in the model predictions. A similar procedure has been adopted in the literature [4,5,22,23]. Tab.…”

“…The simulation of the particle monomer swelling has made it possible to determine the overall propagation rate constant, its changes as a function of conversion, and the changes in the average number of radicals per particle. Saldívar et al [4][5] also proposed a model to represent the VA/BA copolymerization reactions in batch reactors. Using four adjustable parameters for each set of temperature and monomer feed ratio, they represented the evolution of conversion and average particle diameter, and compared against experimental data determined by Araujo et al [6].…”

High‐Throughput Method for RAFT Kinetic Investigations and Estimation of Reactivity Ratios in Copolymerization Systems

“…The instantaneous copolymer composition at various conversions was determined from the individual monomer to polymer conversions estimated by 1 H‐NMR, which, in general, showed that MA was consumed much more rapidly than VAc. The co‐monomer composition results were then fitted to the integrated version of the copolymerization composition (Mayo‐Lewis) equation 1, 40–42. Point estimates for reactivity ratio of MA ( r MA ) and reactivity ratio of VAc ( r VAc ) were determined to be 8.2 and 0.17, respectively.…”

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…”