Effects of Physical and Chemical Modification of Sunflower Cake on Polyurethane Composite Foam Properties

Sunflower cake (SC), which is waste during the production of sunflower oil, was selected as a modifier of properties in polyurethane (PUR) foams. The SC was chemically modified with triphenylsilanol (SC_S) and physically modified with rapeseed oil (SC_O). The influence of SC on the rheological properties of the polyol and the kinetics of foam growth were investigated. PUR foams were characterized by morphological, mechanical, and thermal analysis. The results show that the physical and chemical modification of SC contributes to the changes in the properties of the foams in different ways. Too high hydrophobicity of SC_O affects the structure deterioration, and thus the mechanical properties, and in turn, reduces the affinity for water. In turn, chemical modification with silane allows for obtaining foams with the best mechanical properties.