Utilizing model calculations may lead to a better understanding of the complex kinetics of the controlled radical polymerization. We developed a universal simulation tool (mcPolymer), which is based on the widely used Monte Carlo simulation technique. This article focuses on the software architecture of the program, including its data management and optimization approaches. We were able to simulate polymer chains as individual objects, allowing us to gain more detailed microstructural information of the polymeric products. For all given examples of controlled radical polymerization (nitroxide mediated radical polymerization (NMRP) homo- and copolymerization, atom transfer radical polymerization (ATRP), reversible addition fragmentation chain transfer polymerization (RAFT)), we present detailed performance analyses demonstrating the influence of the system size, concentrations of reactants, and the peculiarities of data. Different possibilities were exemplarily illustrated for finding an adequate balance between precision, memory consumption, and computation time of the simulation. Due to its flexible software architecture, the application of mcPolymer is not limited to the controlled radical polymerization, but can be adjusted in a straightforward manner to further polymerization models.

The IUPAC working group on “Experimental Methods and Data Evaluation Procedures for the Determination of Radical Copolymerization Reactivity Ratios” recommends a robust method to determine reactivity ratios from copolymer composition data using the terminal model for copolymerization. The method is based on measuring conversion (X) and copolymer composition (F) of three or more copolymerization reactions at different initial monomer compositions (f₀). Both low and high conversion experiments can be combined, or alternatively only low conversion experiments can be used. The method provides parameter estimates, but can also reveal deviations from the terminal model and the presence of systematic errors in the measurements. Special attention is given to error estimation in F and construction of the joint confidence interval for reactivity ratios. Previous experiments measuring f₀ − F or f − X can also be analyzed with the IUPAC recommended method. The influence of systematic errors in the measurements on the reactivity ratio determinations is investigated, including ways to identify and mitigate such errors.

Semi-batch emulsion polymerizations of vinylidene fluoride (VDF) are reported. The molar mass control is achieved via iodine transfer polymerization (ITP) using IC₄F₈I as chain transfer agent. Polymerizations carried out at 75 °C and pressures ranging from 10 to 30 bar result in low dispersity polymers with respect to the molar mass distribution (MMD). At higher pressures a significant deviation from the ideal behavior expected for a reversible deactivation transfer polymerization occurs. As identified by kinetic Monte Carlo (kMC) simulations of the activation–deactivation equilibrium, during the initialization period of the chain transfer agent already significant propagation occurs due to the higher pressure, and thus, the higher monomer concentration available. Based on the kMC modeling results, semi-batch emulsion polymerizations were carried out as a two pressure process, which resulted in very good control of the MMD associated with a comparably high polymerization rate.

High‐temperature butyl acrylate polymerizations in bulk and in solution are investigated experimentally and by kinetic Monte Carlo (kMC) simulations. The experimental data comprise conversion‐time data, molar mass distributions, and branching levels per polymer chain derived from size‐exclusion chromatography with a multiangle laser light scattering detector. A kMC model is established, which allows for the description of the impact of solvent and temperature on molar mass distribution as well as type and content of macromonomers. Within the study kinetic coefficients for transfer to solvent and the thermal self‐initiation of the monomer are determined according to the Metropolis Hastings algorithm. The kMC simulations provide information, which are otherwise not accessible, for example, the number of branch points per molecule as a function of molar mass or the molar mass distribution of various macromonomer species. Moreover, molar ratios of mid‐chain and chain‐end radicals are at hand for temperatures up to 160°C, which are important for the interpretation of the experimentally and via simulation‐derived polymer topology as a function of molar masses.

Acrylate polymerizations are associated with intra- and intermolecular H transfer to polymer and the formation of tertiary midchain radicals. At high temperatures β scission reactions of the midchain radicals may occur. To obtain more insights into the reaction mechanism in free radical butyl acrylate polymerizations at high temperature batch and semi-batch reactions were carried out in two solvents. The polymerizations were thermally initiated either by the monomer itself or a peroxide initiator. Molar mass distributions determined by size-exclusion chromatography (SEC) indicate the presence of low molar mass species in all products. To facilitate further analyses each sample was fractionated via preparative SEC. The separated low molar mass species were characterized via electro spray ionization – mass spectrometry and various nuclear magnetic resonance spectroscopy methods. Macromonomer species of chain lengths two to twelve were identified. The data are indicative of significant radical migration along the backbone prior to β scission.

A kinetic Monte Carlo model for emulsion polymerizations based on elemental reactions and radical transfer into particles is introduced.