No abstract

The formation of polyurethanes based on vegetable oils is very complex and thus for industrial production of this materials it is important to determine the optimal temperature for polymerisation and finally to obtain materials with the proper mechanical properties. The goal of this work was to assess the kinetic of catalysed and noncatalysed reactions for polyurethanes based on castor oil as the polyol component and different types of diisocyanates. Due to the presences of hydroxyl groups on ricinoleic acid, castor oil is suitable for polyurethane preparation. The differential scanning calorimetry has been employed to study the polyurethane formation reaction using Ozawa isoconversion method. It was estimated that the catalyst addition decreases the activation energy. The highest reduction of activation energy was observed for the reactive systems with hexamethylene diisocyanate. Validity of obtained kinetic model was examined by FTIR spectroscopy following the apsorption of reactive groups. Obtained results of mechanical characteristics of the polyuretahane networks (with different NCO/OH ratio) confirmed that applied method could be used for prediction of optimal reaction condition in polyurethane networks synthesis

This study reports the fabrication of environmentally friendly polyurethane materials using either 2,4-toluene diisocyanate or isophorone diisocyanate, castor oil as a polyol component, and TiO2 nanoparticles. Samples were prepared with stoichiometric balance of reactive groups. Dynamic viscoelastic properties of prepared samples were studied. The ratio of the loss component to the storage component (tanδ) was used as a measure of the material damping properties. The glass transition temperature was determined as a position of the tanδ curve maximum. The temperature range with tanδ > 0.3 was used to evaluate damping capacity of elastomers. Thermal stability of prepared samples was estimated by TGA method. It was assessed that PU based on aliphatic diisocyanate have higher thermal stability. Obtained values of the glass transition temperature and the starting degradation temperature are important for the application window of novel materials.