the present invention is directed to flexible polyurethane foams useful as seat cushioning material for vehicles , aircraft , furniture and the like . the polyurethane foams are characterized by improved wet compression set properties , improved firmness , resilience and elongation . the foams are made by a process which comprises reacting a polyol having a hydroxyl equivalent of from 800 - 10 , 000 , a glycerin derivative having oxyethylene groups thereon but characterized by having a significant number of unreacted secondary hydroxyl groups of glycerin , water and an organic polyisocyanate .