Development and Characterization of Polyurethane Foams with Substitution of Polyether Polyol with Soy-Based Polyol

Bio-based polyols can replace petroleum-based polyols for the reaction with isocyanate groups to prepare a wide range of polyurethane (PU) products. They can be readily derived from various types of abundant and renewable bio-resources, however, their utilization is still limited due to the complex molecular structure and relatively low primary hydroxyl content. This study aims to substitute the petroleum-based polyether polyols with soy-based polyols for the fabrication of rigid PU foams that have comparable or better physical properties required for potential structural and insulation applications. Commercially available soy polyols with 230 mg KOH/g hydroxyl content were blended with the petroleum-based polyether polyols in 5% increments up to 50% substitution to fabricate the rigid PU foams. Isocyanate index of 1.14 was maintained for all formulations. Other constituents such as catalyst, surfactant, and blowing agent were also kept constant. The density, compressive strength, and thermal conductivity of prepared PU foam samples were determined by the ASTM standard methods. Densities of PU samples with 25% substitution were within the 20% range of the control sample. Thermal conductivity values of the PU foams prepared with 25% polyether polyol substitution were similar when compared to the control sample. Compressive strengths of the 25% substitution samples were approximately 30% higher. It was concluded that the polyols blended with 25% soy-based polyols yield the rigid PU foams that have the overall best quality in terms of compressive strength, tensile strength, and insulation