The antihydrolytic effect and properties of crosslinked polyurethane containing natural dimer fatty acids building blocks

Four series of cross-linked polyurethanes with polyester polyols as soft segments were prepared by selfcuring of isocyanate-terminated polyurethanes. Polyester polyols herein were derived from different dimer fatty acids weight content, such as dicarboxylic acid leading to various hydrophobicity and steric hindrance. The structure of cross-linked polyurethane was characterized by Fourier transform infrared spectroscopy (FTIR). The surface properties and mechanical and thermal properties of cross-linked polyurethane were investigated using contact meter, tensile tester, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The results indicated that with increasing dimer fatty acid weight content from 0% to 100%, the cross-linked polyurethanes exhibited increased hydrophobicity (water contact angle increased from 91o to 96o), improved water resistance (water uptake decreased from 1.41% to 0.34%), toluene resistance (weight loss decreased from 33.2% to 22.7%), and hydrolytic resistance (weight loss decreased from 0.60% to 0.27%), enhanced mechanical properties (tensile strength increased from 1.3 to 4.8 MPa), and thermal stability (decomposition temperature of 50% weight loss increased from 425 to 462 °C).