Influence of crystallizable units on the properties of aliphatic thermoplastic poly(ether urethane)s synthesized through a non-isocyanate route

Abstract

A simple non-isocyanate route synthesizing crystallizable aliphatic segmented thermoplastic poly(ether urethane)s (PEIUs) and elastomers with high melting temperature ( Tm) and good mechanical properties is described. Three poly(ethylene hexanediurethane) prepolymers (PrePEHDUs) were prepared through the self-transurethane polycondensation of bis(hydroxyethyl) hexanediurethane. Melt polycondensation of PrePEHDUs, poly(ethylene glycol)1500, and bis(hydroxyethyl) isophoronediurethane was conducted at 170°C under a reduced pressure of 399 Pa, and a series of segmented PEIUs containing irregular units were synthesized. The PEIUs were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, 1proton nuclear magnetic resonance, 13carbon nuclear magnetic resonance (C-NMR), 2D 13C–1H heteronuclear single quantum coherence (HSQC) NMR, distortionless enhancement by polarization transfer (DEPT)-135 13C-NMR, differential scanning calorimetry, thermogravimetric analysis, wide-angle X-ray diffraction, atomic force microscopy, and tensile tests. The PEIUs exhibited a number-average molecular weight up to 20700 g/mol, Tm up to 141.1°C, initial decomposition temperature at over 243.1°C, and tensile strength up to 49.44 MPa. By tuning the length and amount of crystallizable segments, crystallizable PEIU thermoplastic elastomers were prepared. They exhibited tensile strength up to 20.85 MPa, elongation at break above 125.43%, and resilience above 65.69%.