Nitroxide-mediated radical copolymerizations of styrene and divinylbenzene using 2,2,6,6-tetramethyl-1-piperidinoxyl (TEMPO) as controller were performed to produce crosslinked polymers. Tert-butylperoxy 2-ethylhexyl carbonate (TBEC) was used instead of conventional initiators such as benzoyl peroxide (BPO) in order to enhance the polymerization rate while trying to keep the controlled characteristics of the system. The effect of temperature, initial concentration of initiator, and ratio of TEMPO to initiator on conversion, molecular weight averages, and polydispersity was investigated. It was observed that, when using TBEC, it was possible to produce controlled copolymer in a faster rate when compared to conventional initiators, like BPO.