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Selectivity of PEO‐ block ‐PPO Diblock Copolymers in the Microwave‐Accelerated, Anionic Ring‐Opening Polymerization of Propylene Oxide with PEG as Initiator
Author(s) -
Malik Muhammad Imran,
Trathnigg Bernd,
Kappe C. Oliver
Publication year - 2007
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.200700320
Subject(s) - propylene oxide , copolymer , polymer chemistry , monomer , ethylene oxide , polymerization , polymer , materials science , oxide , chemical engineering , chemistry , organic chemistry , composite material , engineering
Diblock copolymers of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) were synthesized by the anionic ring‐opening polymerization of propylene oxide (PO), with controlled microwave heating in sealed vessels. A detailed study was carried out to investigate the effects of different parameters on the formation of unwanted byproducts. Parameters that were considered include temperature; the concentration of NaH, monomer and hydroxy groups in the feed; and the polarity of the reaction medium. A continuous decrease of internal pressure during the sealed‐vessel experiment reflected the consumption of PO monomer and the completion of the reaction was confirmed by a drop of the internal pressure to zero when reactions were performed in bulk. The products were characterized by using different chromatographic techniques. A comparison of the reaction times and composition of the polymers prepared by microwave and conductive heating is given.