Felix H. Otey

Rigid Urethane Foam Extended with Starch

approach to reducing cost may be by using extenders. Among the more promising rigid foam extenders recently reported are wood resins (1-3). Significant cost reductions can be realized from systems based on wood resins, but such foams usually exhibit deficient physical properties without improving flame resistance. Dosmann and Steel (4) claimed the use of starch as an extender for flexible shock-absorbing urethane foam. This article describes a study in which corn starch was found to serve as both a low-cost extender and a flame retardant when incorporated in an N,N,N’,N’-tetrakis ( 2-hydroxypropyl ) ethylenediamine (Quadrol,OH No. 768) and polymeric isocyanate foam system. Conventional polyethers, having hydroxyl numbers of 400 to 500, do not yield starch-extended foam with acceptable properties.

Flame-Retardant Rigid Polyurethane Foam from Allyl Glucosides:

nology in FR foams is urgently needed to exploit fully the desired application of urethane foams as insulation in home and industrial buildings. By 1980, such applications could utilize a billion pounds of foam per year. The increased cost, about 10 cents per pound, and less desirable properties of foams containing FR additives tend to restrict their sale ( 1, 2). In our study we developed a practical procedure for chemically combining bromine with a polyether. Foams made from this polyether have good flame resistance, and their physical properties are comparable to flammable-type foams. Three steps are involved in the polyether synthesis. First, allyl alcohol is reacted with a-D-glucose to yield a mixture of allyl glucosides containing allyl aand ,,8-n-glucosides, dimers, and oligosaccharides. The composition of the glucoside mixture depends upon the ratios of reactants. When the molar ratio of «-n-glucose to allyl alcohol is 0.1:1, the product contains about 70 % aand ~-monomers and 30 % dimers and oligosaccharides; when the ratio is 0.05 :1, the product mixture contains 85% monomers and 15 % higher molecular weight products. At either concentration, the product has < 1 % free glucose (3). In the second step, the glucoside mixture is reacted with 4 to 5 moles of propylene oxide per mole of anhydroglucose units (AGU). In the final step, unsaturated allyl groups of the propoxylated glucosides are reacted with bromine. Although the final product is a complex mixture, the following structure is representative of the new polyether.

One-Shot Rigid Urethane Foam from Starch-Derived Polyethers:

ture of glycol glycosides that was sufficiently heatstable to withstand propoxylation. The polyethers obtained were successfully incorporated into &dquo;quasi-prepolymer&dquo; urethane formulations to make rigid foam with excellent properties. Additional evaluation has shown that glycol glycoside polyethers can be produced with uniform properties ( 4 ) by an economically feasible process (1). This paper describes the properties of handmixed &dquo;one-shot&dquo; foam made from laboratory preparations of glycol glycoside polyethers. In the one-