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Graft copolymers and high‐molecular‐weight star‐like polymers by atom transfer radical polymerization
Author(s) -
Masař Bohumil,
Janata Miroslav,
Látalová Petra,
Netopilík Miloš,
Vlček Petr,
Toman Luděk
Publication year - 2006
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.23196
Subject(s) - dispersity , polymer chemistry , copolymer , monomer , atom transfer radical polymerization , molar mass distribution , methyl methacrylate , polystyrene , styrene , methyl acrylate , polymer , chain transfer , butyl acrylate , polymerization , molar mass , side chain , grafting , materials science , chemistry , radical polymerization , organic chemistry
Grafting of tert ‐butyl acrylate ( t BuA), methyl methacrylate (MMA), and styrene (St) monomers (M) by Cu(I)‐mediated ATRP from polystyrene (PSt) macroinitiator ( M n = 5620, polydispersity index, PDI = 1.12), containing initiating 2‐bromopropionyloxy groups (I) (bound to 34% of aromatic cores; 11 groups per backbone), was performed using conditions suitable for the respective homopolymerizations. The preparation of PSt‐ g ‐P t BuA in bulk using an initial molar ratio [M] 0 /[I] 0 = 140 had a controlled character up to M n = (132–148) × 10 3 (PDI = 1.08–1.16). With MMA and St and using the same [M] 0 /[I] 0 , preliminary experiments were made; the higher the monomer conversion, the broader was the distribution of molecular weight of the products. Graft copolymerizations of all these monomers at [M] 0 /[I] 0 = 840 or 1680 were successfully conducted up to high conversions. Low‐polydispersity copolymers, with very long side chains, in fact star‐like copolymers, were obtained mainly by tuning the deactivator amount in the reaction mixture. (PSt‐ g ‐P t BuA, DP n,sc (DP of side chain) = 665, PDI = 1.24; PSt‐ g ‐PMMA, DP n,sc = 670, PDI = 1.43; PSt‐ g ‐PSt, DP n,sc = 324, PDI = 1.11). Total suppression of intermolecular coupling was achieved here. However, the low concentrations of initiator required long reaction times, leading sometimes to formation of a small amount (∼5%) of low‐molecular‐weight polymer fraction. This concomitant process is discussed, and some measures for its prevention are proposed. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 3662–3672, 2006