Controlled "Grafting-from" of poly[styrene-co-maleic anhydride] onto polydienes using nitroxide chemistry

High-throughput experimentation was used for the functionalization of polybutadiene and polyisoprene with several kinds of nitroxide moieties at 135 degrees C, as well as for kinetic investigations of the controlled free radical grafting of styrene and maleic anhydride onto the functionalized polyclienes at 125 degrees C. The functionalized polymers were analyzed by GPC, H-1 NMR and FT-IR and the control of the grafting process was assessed by kinetic measurements and GPC analysis. The best control in the molecular weight of the grafts was observed for the polyclienes functionalized with 4-oxo-TEMPO. TEMPO functionalization did not render sufficient nitroxide moieties to achieve controlled grafting, while polyclienes functionalized with other 4-hydroxy TEMPO derivatives exhibited some level of grafting control at early reaction times, which was lost in later stages. of the polymerization reaction. SG1 apparently decomposed at the tested reaction temperatures, as polyclienes functionalized with SG1 did not show any level of control during the grafting process. (C) 2009 Elsevier Ltd. All rights reserved.