Thermomechanical investigation of hydroxyl-terminated polybutadiene-based linear polyurethane elastomers

The present work describes the trend of linear polyurethane elastomers for its thermal and mechanical behavior. The linear polyurethane elastomers have been synthesized in two different series by changing the composition of the polymers. Both series have common macrodiol of hydroxyl-terminated polybutadiene and butanediol while they vary in the presence of diisocyanate. One of the series, contain an aromatic diisocyanate, toluene diisocyanate (TDI), and the other consist of 1,6-hexamethylene diisocyanate (HDI) as an aliphatic diisocyanate. For linear structure, ratio of OH and NCO group has been maintained 1.0. The hydrogen bonding index is determined from Fourier transform infrared to calculate the extent of interchain hydrogen bonding which manifest the microphase separation. Young's modulus (5.79 MPa) and tensile strength (1.14 MPa) are recorded for HDI-derived elastomers, while Young's modulus varies from 1.14 to 1.63 MPa for TDI-based elastomers which also resulted in higher thermal stability. Thermogravimetric curves exhibit two-step degradation with the stability of 300 °C. HDI-based polyurethane elastomers show better tensile properties and HDI but poor thermal stability as compared to TDI-based elastomers.