(560jc) Modeling of Polymerization of Methyl Methacrylate in Homogeneous Systems As a Framework for Processes Improvements
AIChE Annual Meeting
2019
2019 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Poster Session: Catalysis and Reaction Engineering (CRE) Division
Wednesday, November 13, 2019 - 3:30pm to 5:00pm
The kinetics of acrylic polymerization is very complex in nature. Diffusion-limited problems such as gel and glass effects impact directly the polymerization kinetics and molar masses. Attempts to model these phenomena based on physical properties of the system have been presented, but models based on adjustable parameters (semi-empirical models) have shown a more pragmatical approach for prediction of molecular weight and conversion of such polymerizations.
In the present study, the polymerization of methyl methacrylate is selected and tested with recent kinetics models of the literature, either partially based on free-volume parameters, or based solely on empirical parameters. These models were extended to include additional reactions, such as depropagation, termination by combination and transfer to monomer, in a first attempt to generalize them to batch and semi-batch polymerizations in temperature range from 50°C to 140°C, under isothermal and non-isothermal conditions. The particular case of chain transfer agents was also tested. The molecular weight distribution was calculated with the method of moments.
A simulation program (Reactormodel) was developed for this study. New parameters were adjusted to fit experimental data taken from the literature using a simplex search method, applied to the normalized sum of squared errors between experimental and calculated values, generating two new models. These models were then compared with an extensive range of experiments, and showed improved prediction of polymerization parameters, when compared with the original models. The models were then submited to a sensitivity analysis, which qualitatively demonstrate their behavior and limitations in extrapolated conditions.
In the present study, the polymerization of methyl methacrylate is selected and tested with recent kinetics models of the literature, either partially based on free-volume parameters, or based solely on empirical parameters. These models were extended to include additional reactions, such as depropagation, termination by combination and transfer to monomer, in a first attempt to generalize them to batch and semi-batch polymerizations in temperature range from 50°C to 140°C, under isothermal and non-isothermal conditions. The particular case of chain transfer agents was also tested. The molecular weight distribution was calculated with the method of moments.
A simulation program (Reactormodel) was developed for this study. New parameters were adjusted to fit experimental data taken from the literature using a simplex search method, applied to the normalized sum of squared errors between experimental and calculated values, generating two new models. These models were then compared with an extensive range of experiments, and showed improved prediction of polymerization parameters, when compared with the original models. The models were then submited to a sensitivity analysis, which qualitatively demonstrate their behavior and limitations in extrapolated conditions.