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Gelation and Hollow Particle Formation in Nitroxide‐Mediated Radical Copolymerization of Styrene and Divinylbenzene in Miniemulsion
Author(s) -
Zetterlund Per B.,
Saka Yuichi,
Okubo Masayoshi
Publication year - 2009
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200800451
Subject(s) - miniemulsion , copolymer , nitroxide mediated radical polymerization , divinylbenzene , polymer chemistry , styrene , monomer , polymerization , chemistry , polymer , radical polymerization , particle (ecology) , materials science , organic chemistry , oceanography , geology
Network formation in the nitroxide‐mediated cross‐linking copolymerization of styrene and divinylbenzene (3 or 8.2 mol‐% relative to total monomer) using the nitroxide 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy (TEMPO) at 125 °C can proceed markedly differently in aqueous miniemulsion compared to the corresponding solution polymerization depending on the organic‐phase composition. When the organic phase comprises 54 vol‐% of the hydrophobe tetradecane, gelation occurs at much lower conversion in miniemulsion than in solution, and at significantly lower conversion than predicted by Flory–Stockmayer gelation theory. This is proposed to be a result of an effect of the oil–water interface, whereby the concentration of polymer with pendant unsaturations is higher near the interface than in the particle interior.