On the use of olive leaf powder to improve the performance of water-blown rigid polyurethane foam composites

Nowadays, polyurethane (PU) foams were preferred in a broad extent of applications particularly due to their lowest thermal conductivity values satisfying the demand for energy efficiency while their use as natural filler added foam composites can reduce the polymer content allowing a more environmentally friendly production. The purpose of this work was to research the impact of olive leaf powder of various particle sizes and weight ratios on the microstructure, thermal, and mechanical properties of rigid polyurethane foam composites. All results exhibited optimum mechanical, thermal, and microstructure properties for the finest particle sized and 3 wt% added foam composites. This foam composite demonstrated an enhancement by 54%, 41%, and 61% for the tensile strength, elongation at break, and compression strength values, respectively. The thermal degradation temperature of the foam composites was also improved in correlation with the reduction of the glass transition temperature of the soft segments while the glass transition of the hard segments increased. Concerning the thermal conductivity results, the highest reduction by 11% was observed for the finest particles filled at 5 wt%, compared to the pure rigid PU foam, in correlation with the cell size showing a maximum reduction by 18% for the same composite.