Application of ethoxylated inulin in water-blown polyurethane foams

Inulin, a polydisperse reserve polysaccharide from chicory, was chemically modified via alkoxylation using ethylene oxide, in a water free medium. The reaction resulted in a range of products with very distinct properties, such as a highly increased water solubility, moderate surface-active properties and high cloud points in electrolyte media. Because of the unique characteristics of inulin, such as its molecular weight range, and because of the high water solubility of the ethoxylates, the products were evaluated as additive in water-blown polyurethane foams. The addition of inulin ethoxylates resulted in an increased foam hardness and density, the latter in fact being unwanted. The foam properties were evaluated based on the indentation test, the foam density, the SAG factor, and the hysteresis curves of standard cubes. Based on these parameters inulin ethoxylates were shown to have a beneficial effect on the foam properties. The inulin ethoxylate with a theoretical degree of substitution of 0.5 proved to be the best derivative, since the increase in hardness was the highest, while the increase in density was negligible.