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New routes to [ n ]‐polyurethanes. [ 3 ]‐polyurethane: synthesis, characterization, and polymerization‐depolymerization equilibrium
Author(s) -
Kušan Jacqueline,
Keul Helmut,
Höcker Hartwig
Publication year - 2001
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/1521-3900(200103)165:1<63::aid-masy63>3.0.co;2-x
Subject(s) - depolymerization , polymer chemistry , polymerization , sulfonate , polyurethane , monomer , melting point , condensation polymer , crystallinity , materials science , polymer , chemistry , organic chemistry , composite material , sodium
The ring‐opening polymerization of dimethylene urethane ( 3 ) (systematic name: 2‐oxo‐1,3‐oxazolidine) with methyl trifluoromethane sulfonate as the initiator is inefficient. It was shown that equimolar amounts of dimethylene urethane and trifluoromethane sulfonate result in the expected active species ‐ 2‐methoxy‐4,5‐dihydro‐1,3‐oxazolium trifluoromethane sulfonate ( 5a ) ‐ : propagation, however, does not occur. Poly(dimethylene urethane) ( 4 ), was obtained by means of polycondensation of a linear monomer, i.e., 2‐(2‐phenoxycarbonylimino‐1‐ethoxycarbonylimino)‐ethanol ( 9 ). This [ 3 ]‐polyurethane is a semicrystalline material with a melting point of 200.7°C. Heating above its melting point leads to dimethylene urethane by ring‐closing depolymerization. The thermodynamical data support the experimental results with respect to the polymerization/depolymerization equilibrium.