Synthesis and properties of polyurethanes bearing urethane moieties in the side chain

Polyurethanes bearing urethane groups in the side chains were prepared by the addition of isocyanates to the hydroxyl groups in poly(hydroxyurethane) prepared by the polyaddition of a bifunctional cyclic carbonate with 1,12-diaminododecane. The urethanization proceeded quantitatively in the presence of a catalytic amount of di-n-butyltin dilaurate. The resulting polyurethane had a higher glass transition temperature than the original poly(hydroxyurethane), although its esterified product had a lower glass transition temperature. The urethanization with 3-(triethoxysilyl)propyl isocyanate also proceeded effectively to afford both soluble and insoluble polymers, depending on the reaction conditions. (C) 2007 Wiley Periodicals, Inc.