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Verdazyl‐Mediated Polymerization of Styrene
Author(s) -
Teertstra Steven J.,
Chen Eric,
ChanSeng Delphine,
Otieno Peter O.,
Hicks Robin G.,
Georges Michael K.
Publication year - 2007
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200750212
Subject(s) - styrene , polymer chemistry , adduct , benzoyl peroxide , polymerization , radical , dispersity , nitroxide mediated radical polymerization , chemistry , molar ratio , radical polymerization , copolymer , organic chemistry , catalysis , polymer
Attempted controlled polymerizations of styrene, conducted in the presence of either 1,3,5‐triphenyl‐6‐oxoverdazyl or 1,5‐dimethyl‐3‐phenyl‐6‐oxoverdazyl radicals initiated with benzoyl peroxide or 1,1′‐azobis(cyclohexanecarbonitrile) were universally unsuccessful regardless of the reaction temperature and the initiator/verdazyl molar ratio. No improvement was observed using a verdazyl‐terminated styrene initiator adduct prepared by an exchange reaction between a styrene‐TEMPO alkoxyamine and a 1,3,5‐triphenyl‐6‐oxoverdazyl radical. However, controlled polymerizations of styrene were achieved at 125 °C using a styrene‐verdazyl adduct containing the 1,5‐dimethyl‐3‐phenyl‐6‐oxoverdazyl radical. Polydispersity indexes remained low throughout the polymerizations and plots of number average molecular weight ( $\overline M _{\rm n}$ ) versus time were linear. However, the actual $\overline M _{\rm n}$ values were considerably lower than theoretical, an unexpected result that is under investigation.