Cereal Chem 68:258-261   |  VIEW ARTICLE

Polyurethane Foams Extended with Corn Flour.

R. L. Cunningham, M. E. Carr, and E. B. Bagley. Copyright 1991 by the American Association of Cereal Chemists, Inc. 

Five levels of unmodified corn flour (5, 10, 20, 30, and 40%, based on weight of polyether polyol) were evaluated as fillers-extenders in rigid polyurethane foams. Densities of the flour-filled and control foams were similar (0.025-0.026 g/cm3) except for the foams containing 10% flour (0.029 g/cm3). The moisture in the flours at the various levels of addition appeared to have a significant effect on the structural formation of the foams. Force-deformation curves of foams with 5 and 10% flour were similar to those curves of the controls. Thermal conductivity of the foam filled with 10% flour was slightly lower (thus having greater insulating value) than were the values for the foam filled with 5% flour or the control foam (0.0232 versus 0.0242 W/m.K) (0.161 versus 0.168 BTU in./[ft2.hr. F]). Foams containing 5 and 10% flour did not increase more than 5% in volume when subject to thermal or humid conditions for 14 days. At the 40% level, foams expanded 14 and 16% under thermal and humid conditions, respectively, after 14 days.