The Synthesis Pathway as Method for Regulation of Polyurethane Morphology and Properties: A Comparative Study of Direct Mixing and Prepolymer Methods

The influence of the synthetic pathway (direct mixing of polyol and isocyanate component versus prepolymer method) of polyurethane (PU) preparation on thermal properties (glass transition temperature) and mechanical performance was studied. As a polyol component for the synthesis, castor oil from different suppliers was used. The obtained PU was studied using DSC calorimetry, mechanical testing, FTIR spectroscopy, and SEM microscopy. It was shown that the thermal and mechanical properties of PU samples are determined by the synthetic pathway of their preparation. The main factor determining their properties is the morphology of PU samples. The formation of an ordered lamella‐like structure of the amorphous phase of PU by using a direct mixing synthetic pathway leads to an increase in mechanical performance and glass transition temperature values. The formation of a disordered, unstructured soft phase of PU at the prepolymer method synthesis leads to a decline in these properties.