Fruit seed oils as a starting resource in the synthesis of new viscoelastic biofoams

Various fruit (plum, apricot, peach, chokeberry and raspberry) seed oils were used as renewable raw materials in the synthesis of hydroxyl derivatives to obtain biobased polyurethanes. The oils underwent modification through transesterification reactions using triethanolamine. It was found that regardless of the initial oil used the obtained biopolyols had similar properties. In particular, the hydroxyl value of the biopolyols was approximately 350 mg KOH/g, and the content of derivatives containing two hydroxyl groups was above 45%, as determined by gel chromatography. In the modified formulations, 20% of petrochemical polyols were replaced with different biopolyols. The cellular structures and physical–mechanical properties of the foams were evaluated. The addition of biopolyol resulted in a slight increase in apparent density and a decrease in hardness. Moreover, a favorable increase in hysteresis and support factor was observed. The biopolyol-modified foams were characterized by an apparent density of 89–91 kg/m3, hysteresis values in the range of 0.80–0.84, comfort factor of 2.73–2.88, hardness of 1.75–2.00 kPa and resilience of 5.1–6.2%.