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Polymerization of 2,2‐dimethyltrimethylene urethane; a disfavoured process
Author(s) -
Neffgen Stephan,
Keul Helmut,
Höcker Hartwig
Publication year - 1998
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/(sici)1521-3935(19980201)199:2<197::aid-macp197>3.0.co;2-u
Subject(s) - polymerization , depolymerization , condensation polymer , polymer chemistry , activation energy , catalysis , chemistry , yield (engineering) , ring opening polymerization , gibbs free energy , polymer , materials science , organic chemistry , physics , quantum mechanics , metallurgy
The ring‐opening polymerization of 2,2‐dimethyltrimethylene urethane (DTU, 1 ) is a thermodynamically disfavoured process. According to calorimetric measurements by Lebedev et al., the Gibbs energy of polymerization in bulk varies between 29 kJ · mol −1 and 23 kJ · mol −1 . Poly(DTU) ( 2 ) was synthesized by polycondensation of an activated dimeric hydroxyurethane (DDPP, 3 ) in an end group selective reaction. The selectivity of the polycondensation is influenced by temperature and the catalyst chosen, and best results were obtained at 120°C employing Bu 2 Sn(OOC(CH 2 ) 10 CH 3 ) 2 as a catalyst, which favours end group reaction rather than intramolecular transurethanization. Poly(DTU) ( 2 ) was degraded at 120°C in a closed system to yield a mixture containing 94 wt.‐% of DTU and 6 wt.‐% of oligomers. The depolymerization proceeds via formation of cyclic oligomers as intermediates.