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Synthesis and characterization of ordered polyurethanes from nonsymmetric diisocyanate and ethylene glycol
Authors:Akinori Nishio  Amane Mochizuki  Jun‐Ichi Sugiyama  Kazuhiko Takeuchi  Michihiko Asai  Koichiro Yonetake  Mitsuru Ueda
Abstract:An ordered polyurethane with a head‐to‐head (H‐H) or tail‐to‐tail (T‐T) content over 95% was prepared by polyaddition reaction of a nonsymmetric monomer, p‐isocyanatobenzyl isocyanate (1) with a symmetric monomer, ethylene glycol (2). The model reactions were studied in detail to demonstrate the feasibility of polymer formation. The polymerization was conducted in THF in the presence of triethylamine (TEA) at 0 °C by slow addition of a half amount of 2 to 1, followed by removing THF and then adding the rest of 2 in DMF at once at 30 °C in the presence of dibutyltin dilaurate (DBTL). The microstructure of the polymer obtained was investigated by 13C NMR spectroscopy, and it was found that the polymer had the expected structural regularity. The constitutional regularity of polymers influenced their thermal properties. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 2106–2114, 2000
Keywords:polyurethane  constitutional isomerism  structure–  property relationships  nonsymmetric monomer  p‐isocyanatobenzyl isocyanate
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