Over the past decade, there has been an increased interest within the polyurethane industry to use natural oil based polyols, either as a stand alone product or in conjunction with petroleum-based polyols. The two main reasons for this growing interest are: heightened awareness of green issues that can minimize greenhouse gas emissions as well as reducing the dependency on non-renewable sources. In this paper we report on a preparation of urethanes-based polyols from soy meal that are suitable for polymerization into rigid foams. In this process, soy meal is hydrolyzed to a mixture of amino-acids, which are then condensed with ethylene diamine to produce amine terminated monomers. In a second step, these monomers are reacted with ethylene carbonate to yield hydroxyl terminated urethane oligomers. The carbohydrates that are also present in the meal are propoxylated and converted to active polyols. The final polyol mixture is characterized by a low viscosity and high hydroxyl functionality. These new hydroxyl terminated urethanes can be used to produce rigid foams by a conventional process. The preparation process and characterization of the soy meal-based polyols will be discussed (e.g. ~1H-NMR, FTIR, acid, amine and hydroxyl values) as well as key properties of the rigid foams (e.g. density, compressive strength, compressive strain at yield, friability, water absorption, burning rate, K factor and dimensional stability with ageing). It was observed that these polyols are much more reactive than conventional polyols, eliminating the need to add a polymerization catalyst in the foaming process. Furthermore, these soy meal-based polyols are compatible with many conventional polyols allowing the formulator to adjust the properties of the foams as needed. Thus, polyurethane foams prepared with 25% and 50% soy meal polyols exhibited comparable properties to foams prepared from a conventional polyol. These new biobased polyols with self-catalytic properties are best suited for rigid spray foam formulations that require fast cure and high crosslink density.
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