Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)To investigate aspects of the contribution of (thermal) self-initiation in nitroxide-mediated radical polymerization (NMRP) of styrene, selective styrene polymerizations with 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) in the absence of initiator were carried out at 120 and 130 degrees C. The results of these experiments (including conversion data, molecular weight averages, polydispersity and molecular weight distribution information) were compared with regular thermal polymerization of styrene and NMRP of styrene in the presence of a bimolecular initiator (benzoyl peroxide; BPO). It was observed that although the thermal polymerization of styrene can be controlled to some extent in the presence of TEMPO to provide polystyrene with low polydispersity, the polymerization was never as controlled as that obtained by a BPO-initiated NMRP. (C) 2008 Elsevier Ltd. All rights reserved.642304312Natural Sciences and Engineering Research Council (NSERC) of CanadaConsejo Nacional de Ciencia y Tecnologia (CONACYT) [CIAM U40259-Y]Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Inter American Materials CollaborationConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Consejo Nacional de Ciencia y Tecnologia (CONACYT) [CIAM U40259-Y]