Effects of Modified Used Cooking Oil on Structure and Properties of Closed-Cell Polyurethane foams

The aim of this work is to evaluate the influence of bio-polyol synthesized from used cooking oil on selected properties of rigid polyurethane foams. Application of bio-polyol allows utilization of used cooking oil in the preparation of polyurethane foams according to circular economy. In our work, bio-polyurethane foams were obtained by replacing 20, 60 and 100% of petrochemical polyol with bio-polyol from waste oil. It was observed that the introduction of the bio-polyol caused an increase in the reactivity of the polyurethane system during the foaming process, which was also confirmed by dielectric polarization changes. A complete replacement of petrochemical polyol with the bio-polyol caused cell opening in the foams. A replacement of 20 wt% of petrochemical polyol with the bio-polyol allowed preparation of polyurethane foams with improved thermal insulating properties. The introduction of 20% of the bio-polyol resulted in an increase of the compressive strength in a parallel direction compared to the reference material. The dimensional stability of bio-foams was very high since none of the dimensions differed by more than 0.5% upon treatment with an elevated temperature (70 °C).