A new alkoxyamine based on a highly thermally stable nitroxide is used for the controlled polymerization of styrene at temperatures up to 200 �C. High monomer conversions are reached in a few minutes with a linear increase in polymer chain-length with conversion, a final polydispersity index (PDI) of ~1.2 (Figure 1), and successful chain-extension of the resulting material. The alkoxyamine concentration was altered to target various chain lengths, with autopolymerization dictating the polymerization rate regardless of alkoxyamine concentration. Controlled polymerization of acrylate and methacrylate monomers under similar reaction conditions was successful, with the addition of 5-10 mol% styrene leading to improved control. The new material opens the possibility to increase the range of specialty products made for applications in coatings, inks, overprint varnishes and adhesives. Figure 1.   Molar mass distributions measured for the alkoxyamine-mediated batch polymerization of bulk styrene at 200 �C; the initial molar ratio of alkoxyamine to styrene is 1:50 (DPn = 50). Reaction time, conversion and polydispersity index (PDI) are presented in the legend.

High temperature nitroxide mediated polymerization

248th National Meeting (2014)

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