Influence of Chemical Structure of Petrochemical Polyol on Properties of Bio-polyurethane Foams

In this study, the influence of the chemical structures of petrochemical polyols on the foaming process of polyurethane compositions as well as on selected properties of the foams obtained has been investigated. Two types of petrochemical polyols were used—polyester and polyether polyols as well as their blends with a rapeseed oil-based polyol. Dielectric polarization, temperature and expansion velocity were determined during the foaming process of the polyurethane systems with different polyol components. The results show the highest reactivity of the polyester polyol and a decrease of the polyurethane system’s reactivity as a result of a partial replacement of the petrochemical polyol with the bio-based polyol. The content of the closed cells in the materials obtained strongly depends on the petrochemical polyol used. The results indicate that the chemical structure of the petrochemical polyol had a significant effect on the cellular structure as well as the physical–mechanical properties of the final products. A significant worsening of the foams’ mechanical properties was observed as an effect of a partial replacement of the polyester polyol with the rapeseed oil-based polyol. In contrast, a partial replacement of the polyether polyol caused an improvement of the cell structure keeping the mechanical properties of the modified foams at the same level.