Crystallizable and Tough Aliphatic Thermoplastic Polyureas Synthesized through a Nonisocyanate Route

Abstract

A simple nonisocyanate route for synthesizing crystallizable and tough aliphatic thermoplastic polyureas (TPUreas) is described. Melt transurethane polycondensation of diethylene glycol bis­(3-aminopropyl) ether with bis­(hydroxyethyl) hexanediurethane and bis­(hydroxyethyl) isophoronediurethane was conducted at 170 °C under a reduced pressure of 3 mmHg, and a series of TPUreas were prepared. The TPUreas were characterized by GPC, FT-IR, ¹H NMR, ¹³C NMR, 2D ¹³C–¹H HSQC NMR, DEPT-135 ¹³C NMR, DSC, TGA, wide-angle X-ray scattering, atomic force microscopy, and tensile tests. The TPUreas exhibited an <i>M</i>_n up to 12 000 g/mol, an <i>M</i>_w up to 17 600 g/mol, <i>T</i>_g between 2.8 and 18.1 °C, <i>T</i>_m from 140.5 to 149.8 °C, initial decomposition temperature of over 278.4 °C, and tensile strength up to 37.81 MPa with elongation at break of 691.25%. TPUreas with high <i>T</i>_m, good tensile strength, and good toughness were prepared through a nonisocyanate route