Maleic Anhydride Based Ether-Ester Polyols for Rigid Polyurethane Foams

Abstract

A new class of polyols for rigid polyurethane foams and urethane isocyanuric foams based on Maleic Anhydride (MA) as raw material, having both ether and ester units , was developed. The synthesis of these polyols is based on the propyleneoxide addition to a mixture of a polyol (glycerine, trimethylolpropane, sorbitol, glucose) and maleic anhydride. The reaction is a cationic self-catalysis, the resulted acidic - COOH groups catalyse simultaneously three reactions: the esterification reaction (the addition of propyleneoxide [PO] to -COOH groups), the esterification reaction (the addition of PO to hydroxyl groups) and the addition of hydroxyl groups to the double bonds. The method is very flexible and has a high potential for th synthesis of new ether-ester polyols for rigid polyurethane foams. The resultant ether-ester polyols have low viscosities, high functionalities, and low cost. The synthesised polyols were successfully used in classical processes to obtain rigid polyurethane and urethane-isocyanuric foams with exceIIent physico-mechanical, thermal and flame resistant properties.