Synthesis and characterization of aliphatic polyesteramides mainly composed of alternating diester diamide units from N , N ′‐bis(2‐Hydroxyethyl)‐oxamide and diacids

This article provided a convenient method to synthesize aliphatic polyesteramides mainly composed of alternating diester diamide units by polycondensation and chain extension. Two kinds of polyesteramide prepolymers were prepared through melt polycondensation from N , N '‐bis(2‐hydroxyethyl)oxamide and adipic acid or sebacic acid. Chain extension of them was conducted with 2,2′‐(1,4‐phenylene)‐bis(2‐oxazoline) and adipoyl biscaprolactamate as combined chain extenders. The chain extended polyesteramides (ExtPEAs) were characterized by IR, 1 H NMR, differential scanning calorimetry, thermogravimetric analysis, wide‐angle X‐ray scattering, tensile test, and dynamic thermomechanical analysis. The results showed that the ExtPEA(0, m)s were mainly constituted with the diester oxamide alternating units. They had T m above 140.8°C and the initial decomposition temperature above 298.0°C. They crystallized in similar crystallites to Nylon‐66 and were thermoplastic materials with tensile strength up to 31.47 MPa. POLYM. ENG. SCI., 54:756–765, 2014. © 2013 Society of Plastics Engineers