Green synthesis process and properties of polyurethane completely using ethanol as solvent

It is a challenge to simultaneously retain high performance and green synthesis process of polyurethane (PU). Here, a PU was synthesized completely using ethanol as solvent based on the chain extender, hexanediamine (HMD), with higher reactivity towards isocyanate groups than ethanol. Chemical components in PU prepared by a green process (GPU) were characterized by Fourier Transform Infrared Spectroscopy (FTIR). Molecular weight and its distribution of GPU were characterized by Gel Permeation Chromatography (GPC). Mechanical properties and thermal-mechanical properties of GPU were characterized by Electronic Tensile Testing Machine and Dynamic Thermomechanical Analysis (DMA) separately. The glass transition temperature (Tg) and thermal stability of GPU were characterized by Differential Scanning Calorimeter (DSC) and Thermogravimetric Analysis (TGA). Results showed that this GPU presented superior mechanical properties of 61.4 MPa and low saturated water absorption of 6.6% compared with conventional solvent-based PU and waterborne PU whose synthesis process contained some toxic organic solvent.