Kinetic Monte Carlo Generation of Complete Electron Spray Ionization Mass Spectra for Acrylate Macromonomer Synthesis

Abstract

Absolute electron spray ionization mass spectrometry (ESI-MS) data are reported, for the first time, over the complete chain length range for the synthesis of well-defined macromonomers (MMs) obtained via activation of bromine-capped poly(n-butyl acrylate) (0.1 mass %; solvent: anisole; 140 °C) with CuBr2/Me6TREN (Me6TREN: tris(2-(dimethylamino)ethyl)amine) and tin ethylhexanoate. These data are generated based on bivariate kinetic Monte Carlo simulations, tracking the chain lengths and the positions of radicals/characteristic groups along the chains (>100 reactions, 12 radical/dormant species types, and 7 characteristic end/mid-groups). Based on qualitative tuning to experimental data, migration is found to be 50 times slower than backbiting but 15 times faster than βC-scission, making it a dominant reaction. Benefiting from the absence of monomer, the chain transfer to polymer rate coefficient is assessed as 6 × 102 L mol–1 s–1 (140 °C). Model analysis shows that consecutive backbiting/migration/βC-scission leads to a favoring of MMs with even chain lengths and a hydrogen chain end over MMs with the nonreactive chain end originating from the initial dormant polymer. The obtained insights contribute to a better fundamental understanding of hydrogen abstractions in acrylate radical polymerization and open the path for a more detailed polymer product characterization in general.

Design of 2‐hydroxyethyl methacrylate‐functional macromonomer dispersants by semi‐batch cobalt chain transfer polymerization

“…Reactive dispersants covalently attach themselves to the nanoparticle, greatly enhancing utilization compared to nonreactive dispersants. The common way to allow for covalent bonding is to incorporate an unsaturated vinyl moiety into the oligomeric chains. Our group has compared vinyl‐terminated (i.e., macromonomer) poly(butyl methacrylate) dispersants to dispersants of poly(butyl methacrylate‐co‐methacrylic acid‐glycidyl methacrylate) with vinyl groups randomly grafted among and along the chains.…”

The Kinetics of n‐Butyl Acrylate Radical Polymerization Revealed in a Single Experiment by Real Time On‐line Mass Spectrometry Monitoring

“…In the present case, they were obtained from classical off‐line monitoring. It should be noted that modeling of the ESI‐MS data alone is highly rewarding and in principle sufficient . Off‐line molecular weight and conversion data can be used as pure crosscheck rather than a direct fitting parameter.…”

Method of Moments Applied to Most-Likely High-Temperature Free-Radical Polymerization Reactions

“…Mid-chain radicals formed by macromonomer propagation can also participate in this reaction. Although this reaction does not alter the tertiary nature of radicals, it may change branch sizes (if propagation occurs after migration) or the macromonomer length (if scission happens after migration) [48]. The migration reaction has been reported to be 50 times slower than backbiting but 15 times faster than β-Scission [48].…”

“…Although this reaction does not alter the tertiary nature of radicals, it may change branch sizes (if propagation occurs after migration) or the macromonomer length (if scission happens after migration) [48]. The migration reaction has been reported to be 50 times slower than backbiting but 15 times faster than β-Scission [48]. The occurrence of this reaction causes the generation of low mass macromonomers in polymerizing systems [49].…”