Camelina sativa (L.) Crantz straw and pomace as a green filler for integral skin polyurethane foam

The development of efficient methods for obtaining cellular materials with improved functional properties is a constant challenge for the plastics industry, including the polyurethane industry. In recent years, efforts have been made to obtain cheap and easily available raw materials that can be used as foam fillers. In addition to commercially used synthetic fillers, more and more attention is paid to materials of natural origin, in particular to agricultural and industrial waste. This solution not only meets the assumptions of the "Green Chemistry" concept but also creates the opportunity to improve the properties of plastics while reducing their production costs. This study focuses on the use of naturally derived materials as fillers in flexible integral polyurethane foams (Integral Skin Foams, ISFs) to produce economically advantageous and ecologically sustainable composite materials. Waste materials such as Camelina sativa (L.) Crantz straw and pomace were used as biofillers. The obtained samples were used to determine the processing parameters and functional properties of the foams: hardness, tensile strength, elongation at break and permanent deformation after compression. In the case of both straw and pomace, an increase in growth time and an increase in the free density of the foams were observed with an increase in the amount of added plant material. The analysis of morphology and chemical structure of the obtained composites led to the conclusion that the cellular structure, skin thickness, and functional groups present in biofillers had a direct impact on the functional properties of ISF. For most composites, a significant improvement in mechanical parameters was observed compared to the reference foam. The obtained results confirmed the utility potential of Camelina sativa (L.) Crantz straw and pomace. The main research assumption has been fully implemented that focused on obtaining innovative polyurethane composites with improved functional properties.