Decomposition of polyurethane foams by alkanolamines

Methylene diphenyl isocyanate (MDI)-based polyurethane flexible foams were decomposed by alkanolamines without a catalyst at 150°C. The decomposition products were completely separated into two layers. The upper liquid layer was a polyether polyol, and the lower liquid layer was methylene diphenyl amine (MDA) and alkanolamine derivatives. These layers were analyzed using gel permeation chromatography (GPC) and ¹³C-NMR. The upper layer was obtained as a relatively pure polyether. The lower layer was observed to be MDA and 2-hydroxyethyl carbamic acid ester prepared from alcoholysis products during the decomposition reaction. It was thought that the decomposition process of polyurethane foam by alkanolamines was not aminolysis but alcoholysis. © 1994 John Wiley & Sons, Inc.