Kinetic Modeling as a Tool to Understand and Improve the Nitroxide Mediated Polymerization of Styrene

Abstract

Kinetic modeling is used to obtain insight in the complex interplay between reaction rates and obtained polymer properties in the SG1 and the TEMPO mediated bulk polymerization of styrene at 396 K. The increase of the viscosity during NMP is accounted for. At higher targeted chain lengths, chain transfer to dimer and transfer from nitroxide to dimer are shown to cause the experimentally observed reduced control over the average polymer properties and to result in a clear fronting of the polymer chain length distribution. The potential of kinetic modeling to design tailor‐made synthesis strategies is illustrated. Simulations indicate that careful control of the polymerization conditions allows to obtain an important improvement of the polymer properties. The approach is also applicable for NMP mediated by other alkoxyamines/nitroxides and allows to expand the application range of NMP for styrene polymerization in particular to synthesize complex polymer architectures by assembly of functionalized polymers. magnified image

Exploring the Full Potential of Reversible Deactivation Radical Polymerization Using Pareto-Optimal Fronts

“…This dimer can undergo a retro Diels-Alder reaction forming two styrene molecules or it can undergo a molecule assisted homolysis to yield two additional initiator radicals R0,2 and R0,3. Chain transfer reactions to monomer and dimer are considered, based on literature data [62,68]. Again, chain length and conversion dependent apparent rate coefficients are taken into account [69,70].…”

“…A higher Pterm leads to an increase in Ð but also to a lowering of EGF. In the case of the NMP of styrene, the reaction probability for chain transfer to dimer (PtrD; Figure 7f) needs also to be considered, specifically at elevated temperature [62,74].…”

“…The initial fraction present has now a lower limit of 10 mol%. Note that this monomer addition approach can be seen as an extension of the work of Bentein et al [62] in which fixed small amounts of monomer were added for the NMP of styrene, using phenylethyl-SG1 as NMP initiator.…”

“…For RDRP, however, this methodology has not yet been explored. In this work, for the first time, the potential of MOO for RDRP will be illustrated, considering ARGET ATRP of butyl methacrylate (BMA) and NMP of styrene as model cases and using NSGA-II [61][62][63]. All kinetic and diffusion parameters are taken from literature [61,64,65] and a variety of optimization paths, such as temperature and fed-batch addition programs, are included, considering time, Ð and EGF as objectives.…”

Fed-Batch Control and Visualization of Monomer Sequences of Individual ICAR ATRP Gradient Copolymer Chains

“…fifty-five fed-batch additions results, corresponding to an almost negligible drop of the in situ monomer conversion upon each monomer addition, implying that the linear gradient microstructure is synthesized via very stable activation-growth-deactivation cycles. Note that the polymerization is conducted already under viscous conditions at low polymerization times, a similar strategy as followed by Bentein et al [41] in their work on the optimization of nitroxide mediated polymerization of styrene.…”