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Block copolymers derived from 2,2′‐azobis(2‐cyanopropanol). I. Synthesis of poly(urethane‐ block ‐methyl methacrylate) and poly(urethane‐ block ‐styrene)
Author(s) -
Cheikhalard Talal,
Massardier Valerie,
Tighzert Lan,
Pascault Jean Pierre
Publication year - 1998
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/(sici)1097-4628(19981017)70:3<613::aid-app24>3.0.co;2-#
Subject(s) - copolymer , block (permutation group theory) , styrene , polymer chemistry , materials science , methacrylate , methyl methacrylate , polymer , composite material , mathematics , combinatorics
Block copolymers with polyester‐urethane and polymethyl methacrylate (PMMA) or polystyrene (PS) sequences were obtained by the use of polyester‐ or polyether‐urethane macroazo initiators (PUMAI). PUMAI with a well‐defined number of azo groups per chain were prepared via a two‐stage reaction procedure using 2,2′‐azobis(2‐cyanopropanol) (ACP), 4,4′‐methylene diphenyl diisocyanate (MDI) and α, ω‐hydroxy polycaprolactone (PCL). The characteristics of the obtained block copolymers depend on the reaction conditions, and a yield of 98% was obtained for a P(U‐ b ‐MMA) synthesized with a ratio of macroazo initiator to monomer equal to 1/400. In similar conditions, copolymerization of styrene was more difficult, and the maximum block copolymer yield obtained in this work was only of 37% for a ratio of macroazo initiator to monomer equal to 1/150. Combination of different analyses Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance ( 1 H‐NMR), and size exclusion chromatography (SEC) carried out on both crude and fractionated copolymers showed this kind of synthesis yielding di‐ and triblock copolymers and only a little amount of PU homopolymer. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 613–627, 1998