Crosslinking nitroxide-mediated radical copolymerization of styrene with divinylbenzene

• Critical comparison between free radical and controlled crosslinked polymerizations.
• Crosslinked STY/DVB was synthesized with TIPNO and characterized in detail.
• Controlled polymerization behavior was observed in the presence of TIPNO.
• Effects of [DVB] and [TIPNO] on MWD and gelation characteristics were studied.
• Predictions from mathematical modeling agreed with experimental results.

Results from the crosslinking kinetics of nitroxide-mediated radical polymerization (NMRP) of styrene (STY) in the presence of a small amount of divinylbenzene (DVB) are presented. The performance of styrene polymerization with N-tert-butyl-N-(2-methyl-1-phenylpropyl)-O-(1-phenylethyl) hydroxylamine (referred to as TIPNO-based alkoxyamine or I-TIPNO) is first examined to see if the system exhibits controlled behavior. Then, typical profiles for crosslinking NMRP of STY/DVB in the presence of this alkoxyamine (as controller) are presented and contrasted with crosslinking under regular free radical polymerization, and NMRP of styrene (in the absence of crosslinker). Subsequently, the performance of crosslinking NMRP is evaluated based on rate of polymerization, molecular weights, polydispersity values and gel content under different operating conditions (different crosslinker and nitroxide concentrations). Finally, prediction profiles from a mathematical model are contrasted with experimental data to check the validity of the developed model with respect to both NMRP and crosslinking NMRP of STY/DVB with this TIPNO-based alkoxyamine.

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