The Effect of Crosslink Density on the Physical and Mechanical Properties of Bio-Based Polyurethane Foams

Rigid low-density closed-cell polyurethane foams with different crosslink densities have been produced using biobased polyols derived from tall oil. Mechanical and dilatometric tests reveal that the transverse stiffness and tensile strength of the foams increased with growing crosslink density both at the room and cryogenic temperatures, while the coefficient of linear thermal expansion exhibited an opposite trend. Cryogenic safety factors, estimated based on the foam properties obtained, reveal no consistent trend with changing crosslink density of the polyurethane polymer.