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EPCEd is pleased to announce that Prof. Michael C. Cunningham recently receive the following awards: Fellow of the Canadian Academy of Engineering and Fellow of the Engineering Institute of Canada.
We have a new series in our popular “Did you know…..” issues! It’s a 3-part series about controlled radical polymerization. Part 1 has already been issued and the following parts will appear in three-month intervals. We hope that you enjoy this series and that you find the information contained to be both interesting and useful. The following is an excerpt from the first issue:
Did you know….that Reversible Deactivation Radical Polymerization (RDRP) can be a useful tool for those working with latexes and emulsion polymerization? RDRP is the IUPAC-recommended term for what used to be known as living/controlled radical polymerization, and includes different types of chemistries including Nitroxide-Mediated Polymerization (NMP), Atom Transfer Radical Polymerization (ATRP) and Reversible Addition Fragmentation Transfer (RAFT). Other less common types of RDRP include Iodine Transfer Polymerization (RITP) and Tellurium mediated Radical Polymerization (TERP). RDRP can be used to make a variety of valuable polymer structures that are not achievable using conventional radical polymerization, including for example di- and tri-block copolymers which may finds use as dispersants and stabilizers, and low molecular weight functional materials with star-like structures that can be used as rheology modifiers. These techniques, first developed in the 1990’s, used to be considered somewhat exotic but they should now be considered as routine tools to provide polymers with controlled microstructure at a much lower cost and ease of synthesis than anionic polymerization (formerly the only way to synthesize such materials). We are featuring a three part series on the most popular types of RDRP (NMP, ATRP, RAFT) that will describe for each system the most important features, advantages and potential concerns.
Chemical Engineering J. (2023), 144162. DOI 10.1016/j.cej2023.144162
Michael F. Cunningham et al
"One of the challenges in reversible deactivation radical polymerization (RDRP) in miniemulsion is identifying the optimal average particle size (dp), offering both high reaction rates and excellent control over chain length, branching level and functionality. In this work, a deterministic multi-dimensional Smith-Ewart model is com- bined with a method of moments model for nitroxide (N-(2-methyl-2-propyl)-N-(1-diethylphosphono-2,2- dimethylpropyl)-N-oxyl; SG1) mediated polymerization (NMP) of n-butyl acrylate in miniemulsion. This model accounts for reaction and phase transfer, to showcase for the first time seven instead of three kinetic regimes in a broad dp range from 5 to 300 nm. The reliability of the model prediction is high because of (i) successful model validation under miniemulsion conditions at 385 K; (ii) unique consideration of β-scission, allowing realistic prediction of the livingness; (iii) a validated temperature dependent SG1 partitioning coefficient; and (iv) many kinetic model parameters sourced from independent experimental validation under bulk/solution conditions. Pseudo-bulk kinetics (kinetic regime 1) and a dominance of the segregation effect (kinetic regime 2) are predicted at the highest dp. For decreasing dp, a novel regime 3 emerges in which exit of NMP initiator radicals is dominant. For even lower dp, dominance of free SG1 exit (kinetic regime 4), then dominance of the confined space effect first for NMP initiator radicals (kinetic regime 5), then the same but for free SG1 (kinetic regime 6), and rapid exit-entry dynamics with negligible termination (kinetic regime 7) are obtained. This work demon- strates that advanced population balance models for sustainable multiphase reactive processes can bridge
experiment and simulation for improved functional material design"
New publications by Mike:
