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Study of a new titanium dual initiator for the synthesis of poly(ε‐caprolactone)‐ b ‐polystyrene block copolymers by the combination of coordination and nitroxide mediated polymerizations
Author(s) -
Li Xinxin,
Jeanmaire Thomas,
Zerroukhi Amar
Publication year - 2007
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.27472
Subject(s) - nitroxide mediated radical polymerization , copolymer , prepolymer , polymer chemistry , caprolactone , polymerization , materials science , polystyrene , polymer , radical polymerization , living polymerization , end group , telechelic polymer , ring opening polymerization , polyurethane , composite material
Poly ε‐caprolactone‐polystyrene block‐copolymers (PCL‐ b ‐PSt) were synthesized using a modified titanium catalyst as the dual initiator. Alcoholysis of Ti(OPr) 4 by 4‐hydroxy 2,2,6,6 tetramethyl piperidinyl‐1‐oxyl (HO‐TEMPO) gave a bifunctional initiator Ti(OTEMPO) 4 . Poly ε‐caprolactone prepolymer end‐capped with the nitroxide group was first prepared by ring opening polymerization of ε‐caprolactone with this initiator at high conversion. The nitroxide‐end‐capped structure and molar mass ( M n ) of the polymers were demonstrated by typical UV absorption band. This analytical technique indicates a near‐quantitative nitroxide functionality and a M n in good agreement with size exclusion chromatography (SEC) ones. This polyester prepolymer was used to further initiate the radical polymerization with styrene and reach the block copolymers (PCL‐ b ‐PSt). All the prepolymers and block copolymers were characterized by SEC and NMR spectroscopy. Additionally, the preparation of star polymers bearing two kinds of arms (PCL and PSt) was envisaged and a preliminary result was given. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008