“…[1,5] Recently, the focus of NMP research has shifted to the development of other nitroxides, such as N-(2-methyl-2-propyl)-N-(1-diethylphosphono-2,2-dimethylpropyl)-N-oxyl [DEPN, also known as SG1; Figure 2(b)], [9,[26][27][28][29] that lead to higher polymerization rates and that also enable the controlled NMP of other monomers, such as acrylates. [1] Several side reactions can interfere with the NMP activation/deactivation, such as alkoxyamine decomposition yielding terminally unsaturated polymer and hydroxylamine, [30][31][32] chain transfer to the thus formed hydroxylamine, [33] transfer reactions involving the nitroxide, [34] and nitroxide decomposition. [9,35] For styrene, the NMP is typically performed at temperatures above 373 K, and a further complication arises due to the occurrence of thermal initiation through the Mayo mechanism ( Figure 3) by which initiator radicals are continuously generated.…”