MALEIC-ANHYDRIDE BASED ETHER-ESTER POLYOLS FOR RIGID POLYURETHANE FOAMS

A new class of polyols for rigid polyurethane foams and urethane isocy anuric foams, based on Maleic Anhydride (MA) as raw material, having b oth ether and ester units, was developed. The synthesis of these polyo ls is based on the propyleneoxide addition to a mixture of a polyol (g lycerine, trimethylolpropane, sorbitol, glucose) and maleic anhydride. The reaction is a cationic self-catalysis, the resulted acidic -COOH groups catalyse simultaneously three reactions: the esterification rea ction (the addition of propyleneoxide [PO] to -COOH groups), the ester ification reaction (the addition of PO to hydroxyl groups) and the add ition of hydroxyl groups to the double bonds. The method is very flexi ble and has a high potential for the synthesis of new ether-ester poly ols for rigid polyurethane foams. The resultant ether-ester polyols ha ve low viscosities, high functionalities, and low cost. The synthesise d polyols were successfully used in classical processes to obtain rigi d polyurethane and urethane-isocyanuric foams with excellent physico-m echanical, thermal and flame resistant properties.