The phenomenon of depropagation or reverse polymerization for multicomponent polymerizations has been studied in detail. The monomer Alpha-Methyl Styrene (AMS) has been copolymerized with Methyl Methacrylate (MMA) and Butyl Acrylate (BA) at temperatures ranging from 60oC to 140oC and the kinetics have been studied in the form of propagation/cross propagation and depropagation parameters. There have been multiple attempts with varying amounts of success in the past to determine the kinetic parameters for depropagating systems including work by Lowry and Wittmer as well as other modelling methodologies that are not as mechanistic. The most recent development of the mechanistic terminal model is that of the Kruger model. The model is robust and can take into account all special cases as well as all reactions being reversible. The kinetic parameters have been estimated for each of the three binary systems using the Kruger model (MMA/AMS, MMA/BA, BA/AMS). The Alfrey-Goldfinger model is inadequate to describe depropagating terpolymer systems and in order to study them, a new model was developed based upon the binary Kruger model. This new model takes into account a fully depropagating terpolymer system leading to a total of 15 parameters to be estimated. These 15 parameters have the same definitions as those estimated from the binary Kruger model, thus making accurate analysis of the binary systems crucial since these will be used as first estimates for the terpolymer system. Extensive experimental data (composition, conversion and molecular weights) was collected and analysed for the MMA/AMS and BA/AMS systems. For the BA/AMS system both the bulk and solution copolymerizations were studied in detail with the results from the Kruger model not showing a significant difference in the reactivity ratios between the two types of polymerization. For the MMA/AMS system, a bulk study only was done which revealed an interesting phenomenon that points toward a break down of the long chain approximations used for all of the models being studied. For both of these systems, extensive ¹H NMR analysis was done to determine the copolymer composition. Data collected in previous research for the MMA/BA system was reanalysed using the Kruger model and it was found that the parameter estimates did not differ significantly from the published values. Extensive benchmarking was done with the newly developed terpolymer model on non-depropagating systems using data from the literature to ensure it worked for the simplest cases. It was found that the model matched the parameter estimates from the literature and in some cases improving upon them to fit the data better. Along with the benchmarking a sensitivity analysis was done which revealed some interesting information. For the MMA/BA/AMS terpolymer system a set of experiments (based upon practical considerations) were performed and the composition of the polymer was determined using ¹³C NMR instead of the usual ¹H NMR due to the difficulty of peak separation for the complex terpolymer. Using the depropagating terpolymer composition data in conjunction with the parameter estimates from the three binary systems allowed for estimation of the 15 kinetic parameters, which showed only minor variation from the binary estimates.

The phenomenon of depropagation or reverse polymerization for multicomponent polymerizations has been studied in detail. The monomer Alpha-Methyl Styrene (AMS) has been copolymerized with Methyl Methacrylate (MMA) and Butyl Acrylate (BA) at temperatures ranging from 60oC to 140oC and the kinetics have been studied in the form of propagation/cross propagation and depropagation parameters. There have been multiple attempts with varying amounts of success in the past to determine the kinetic parameters for depropagating systems including work by Lowry and Wittmer as well as other modelling methodologies that are not as mechanistic. The most recent development of the mechanistic terminal model is that of the Kruger model. The model is robust and can take into account all special cases as well as all reactions being reversible. The kinetic parameters have been estimated for each of the three binary systems using the Kruger model (MMA/AMS, MMA/BA, BA/AMS). The Alfrey-Goldfinger model is inadequate to describe depropagating terpolymer systems and in order to study them, a new model was developed based upon the binary Kruger model. This new model takes into account a fully depropagating terpolymer system leading to a total of 15 parameters to be estimated. These 15 parameters have the same definitions as those estimated from the binary Kruger model, thus making accurate analysis of the binary systems crucial since these will be used as first estimates for the terpolymer system. Extensive experimental data (composition, conversion and molecular weights) was collected and analysed for the MMA/AMS and BA/AMS systems. For the BA/AMS system both the bulk and solution copolymerizations were studied in detail with the results from the Kruger model not showing a significant difference in the reactivity ratios between the two types of polymerization. For the MMA/AMS system, a bulk study only was done which revealed an interesting phenomenon that points toward a break down of the long chain approximations used for all of the models being studied. For both of these systems, extensive ¹H NMR analysis was done to determine the copolymer composition. Data collected in previous research for the MMA/BA system was reanalysed using the Kruger model and it was found that the parameter estimates did not differ significantly from the published values. Extensive benchmarking was done with the newly developed terpolymer model on non-depropagating systems using data from the literature to ensure it worked for the simplest cases. It was found that the model matched the parameter estimates from the literature and in some cases improving upon them to fit the data better. Along with the benchmarking a sensitivity analysis was done which revealed some interesting information. For the MMA/BA/AMS terpolymer system a set of experiments (based upon practical considerations) were performed and the composition of the polymer was determined using ¹³C NMR instead of the usual ¹H NMR due to the difficulty of peak separation for the complex terpolymer. Using the depropagating terpolymer composition data in conjunction with the parameter estimates from the three binary systems allowed for estimation of the 15 kinetic parameters, which showed only minor variation from the binary estimates.

This thesis is directed towards expanding and refining a free radical multi-component polymerization model. The model considers up to six monomers (unique in the literature), both in bulk and solution polymerization, for either batch or semi-batch reactor modes. As the simulator database contains 13 monomers, 5 initiators, 4 solvents, 3 chain transfer agents and 2 inhibitors, all tested over a wide range of polymerization conditions, from data in both academic and industrial laboratories, several hundred combinations of ingredients can be modeled. The many outputs generated by the model include conversion, molecular weight, polymer composition, branching indicators, sequence length, as well as many others polymerization characteristics related to both production rate and polymer quality. Although the only literature data found to-date contains a maximum of four monomers, model predictions for homo-, co-, ter- and tetra-polymerizations show reasonable agreement against the data at both regular and elevated temperatures. Recently, with the basic polymerization kinetics modeled sufficiently, several expansions to the simulation software have been added. Specifically, depropagation, multiple initiators, back-biting, and composition control have been incorporated and/or improved, each adding to the advancement of the polymerization simulation tool. Depropagation is a vital mechanism that should be accounted for at elevated temperatures. Currently the software has the functionality to implement depropagation but requires further literature resources for improving the kinetic predictions for conversion and polymer composition. Consequently, depropagation research is ongoing. Back-biting and beta-scission of butyl acrylate (BA) is a recent development in free radical polymerization. The completed extension can model BA under the same diverse conditions as the base model, in homo-, co- and ter-polymerizations with depropagation, if applicable. The ability to generate a polymer with a constant (or controlled) composition throughout the reaction has several practical uses. Originally, three composition control scenarios were considered. At present, several methods as well as combinations of methods have been integrated into the model. With these new expansions and the ability to simulate several initiators at the same time, this model is directed towards becoming a complete free radical polymerization tool for training and educational uses both in industry and academia.

This thesis is directed towards expanding and refining a free radical multi-component polymerization model. The model considers up to six monomers (unique in the literature), both in bulk and solution polymerization, for either batch or semi-batch reactor modes. As the simulator database contains 13 monomers, 5 initiators, 4 solvents, 3 chain transfer agents and 2 inhibitors, all tested over a wide range of polymerization conditions, from data in both academic and industrial laboratories, several hundred combinations of ingredients can be modeled. The many outputs generated by the model include conversion, molecular weight, polymer composition, branching indicators, sequence length, as well as many others polymerization characteristics related to both production rate and polymer quality. Although the only literature data found to-date contains a maximum of four monomers, model predictions for homo-, co-, ter- and tetra-polymerizations show reasonable agreement against the data at both regular and elevated temperatures. Recently, with the basic polymerization kinetics modeled sufficiently, several expansions to the simulation software have been added. Specifically, depropagation, multiple initiators, back-biting, and composition control have been incorporated and/or improved, each adding to the advancement of the polymerization simulation tool. Depropagation is a vital mechanism that should be accounted for at elevated temperatures. Currently the software has the functionality to implement depropagation but requires further literature resources for improving the kinetic predictions for conversion and polymer composition. Consequently, depropagation research is ongoing. Back-biting and beta-scission of butyl acrylate (BA) is a recent development in free radical polymerization. The completed extension can model BA under the same diverse conditions as the base model, in homo-, co- and ter-polymerizations with depropagation, if applicable. The ability to generate a polymer with a constant (or controlled) composition throughout the reaction has several practical uses. Originally, three composition control scenarios were considered. At present, several methods as well as combinations of methods have been integrated into the model. With these new expansions and the ability to simulate several initiators at the same time, this model is directed towards becoming a complete free radical polymerization tool for training and educational uses both in industry and academia.