Kinetic Modeling of Hyperbranched Polymer Synthesis through Atom-Transfer and Nitroxide-Mediated Radical Polymerization of Vinyl/Divinyl Monomers

Kinetic models describing the controlled radical polymerization (CRP) of vinyl and divinyl monomers are presented. The main focuses of this work are the atom-transfer radical polymerization (ATRP) of n-butyl acrylate/diacrylate monomers (nBA/diacrylate) and of methyl methacrylate with ethylene glycol dimethacrylate (MMA/EGDMA). Nitroxide-mediated radical polymerization (NMRP) of styrene with divinylbenzene (S/DVB) is also considered as a case study. For the three chemical systems, this analysis is restricted to the formation of soluble (hyperbranched) polymers. Particular kinetic mechanisms associated with the synthesis of hyperbranched polymers based on these chemical systems are considered, such as crosslinking involving radicals and double bonds with different reactivities, branching due to polymerization of terminal double bonds and/or chain transfer to polymers, the presence of two isomers in the commercial DVB and thermal polymerization of styrene. For the three polymerization systems, predicted values of dynamics of monomer conversion, molecular weights and z-average radius of gyration are compared with the measured values of these properties obtained through the characterization by SEC/RI/MALLS of the synthesized materials.