GLYCOLS IN POLYURETHANE FOAM FORMULATIONS WITH A STARCH-OIL COMPOSITE

A dry starch-oil composite was blended with each of three glycols; eth ylene, polyethylene, and propylene, and then reacted with isocyanate t o produce polyurethane foams. The liquid glycols permitted the dry com posite to blend well with the other ingredients in the foam formulatio ns. Infrared spectra confirmed the presence of urethane structures in the composite-glycol foams. Polyethylene glycol provided a slightly le ss dense foam than the other glycols in the composite-glycol products. Microscopy showed a greater number of larger cells in the composite-p olyurethane glycol foams. Infrared spectra indicated essentially no qu alitative differences in the composite-glycol foams with the three gly cols. By prestaining starch with toluidene blue and oil with sudan red , the location of the starch and oil components of the milled composit e were observed in the composite-propylene glycol foam. Intact flakes of the composite were observed in the foam. An apparent loss of mobili ty of oil in the composite-polyurethane foam as evidence by NMR analys is, is probably due to crosslinking by isocyanate diffusing into the f lakes. Both the cell structure and uniformity of blending were improve d by using these glycols rather than the polyester polyol describe pre viously. (C) 1998 John Wiley & Sons, Inc.double dagger J Appl Polym Sc i 69: 957-964, 1998.