Structures and physical properties of rigid polyurethane foam prepared with rosin-based polyol

Rosin-based polyester polyols were synthesized from a rosin-maleic anhydride adduct, diethylene glycol, and ethylene glycol with and without adding adipic acid and phthelic anhydride, in the presence of catalyst. Rigid polyurethane (PU) foams were prepared with these rosin-based polyols and compared with foam made with an industrial polyester Daltolac(TM) P744. The experimental results show that the foaming behavior for the foams prepared from such rosin-based polyols is similar to that of industrial products, but their 10% compression strength, both parallel and vertical to foaming rise direction, is higher and the dimensional stability at 100 and -30degreesC is similar or somewhat better than that of a comparable system. Furthermore, the rosin-modified PU foams exhibit even lower thermal conductivity and much higher activation energies during the pyrolysis process. All these unique physical properties of the rosin-modified rigid PU foams were correlated to the structures of these PU foams. (C) 2002 John Wiley Sons, Inc.