Aliphatic non-isocyanate thermoplastic polyurethane elastomers with polycaprolactone and poly(tetramethylene ether) double soft segments to improve thermal and mechanical properties

Abstract

A simple and efficient route is described for the synthesis of aliphatic non-isocyanate thermoplastic polyurethane elastomers (NI-TPUEs) with polycaprolactone (PCL) and poly (tetramethylene ether) (PTME) double soft segments (SSs). Melt transurethane co-polycondensation of bis(hydroxyethyl) hexanediurethane with a PCL glycol (PCLG) and two poly (tetramethylene glycol)s (PTMGs) was conducted at 170°C under a reduced pressure of 2 mmHg, and a series of NI-TPUEs were prepared. The NI-TPUEs were characterized by gel permeation chromatography, FT-IR, ¹H-NMR, wide angle X-ray scattering, DSC, TGA, dynamic mechanical analysis, atomic force microscopy, and tensile test. NI-TPUEs exhibited M_n above 20,800 g/mol, T_m of 99 °C–109°C, maximal tensile strength of 39 MPa, strain at break from 847% to 1285%, and resilience of up to 85%. PCL and PTME double SSs made the NI-TPUEs show excellent thermal and mechanical properties. PCLG/PTMG molar ratios and PTMG length affected the T_g, T_m, T_i, and resilience of NI-TPUEs.