Fabrication and Testing of Soy-Based Polyurethane Foam

Polyurethane (PU) foam is a polymeric material widely used in industries such as infrastructure, transportation, refrigeration and consumer products. This study is focused on the fabrication and evaluation of soy-polyol based PU foam that can potentially replace conventional petroleum based PU foam. Commercially available soy-polyols are derived from soybean oil which is a renewable, abundant and relatively low cost resource. For use in the structural and insulating applications, the fabricated soy PU foams need to be relatively light weight but sufficiently rigid to resist the structural loadings. The foam products also need to avoid cracking during deflection and have high thermal resistance. Rigid soy PU foam samples were produced by co-polymerization of diisocynate with soy polyols in presence of silicone oil and dibutyltin dilaurate as a catalyst. Water was used as the blowing agent. Different formulations and varying amount of blowing agent were investigated to optimize the mechanical and insulating properties of soy-based PU foam when compared with petroleum based foam as a control sample. The prepared samples were tested for density, compressive strength, and thermal conductivity using the ASTM standards. It was observed that higher amount of blowing agent lead to lower foam density and lower compressive strength. Also the relation between density and thermal insulation was observed, with lower density leading to higher insulation. It was concluded that soy-based foams can result upto 85% reduction in thermal conductivity, as compared to petroleum-based foams