Synthesis and Characterization of Biodegradable Alternating Polyesteramides from Mixed Diamidediols and Sebacic Acid

A series of polyesteramide prepolymers[PrePEA(0/4,8)s] having mixed alternating bisesterdiamide units was synthesized via melt polycondensation from N,N'-bis(2-hydroxyethyl)oxamide(0) and N,N'-bis(2-hydroxyethyl)-adipamide(4) with sebacic acid(8) at different molar ratios. 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[ExtPEA(0/4,8)s] were characterized by proton nuclear magnetic resonance(¹H NMR), gel permeation chromatography(GPC), differential scanning calorimetry(DSC), thermogravimetry analysis(TGA), wide angle X-ray scattering, tensile test and enzymatic degradation. The results show that ExtPEA(0/4,8)s were crystalline polyesteramides. They had T_m up to 136.5 ℃ and initial decomposition temperature above 297.5 ℃. They crystallized in similar crystallites into Nylon-66 and degraded under the catalysis of protease or lipase. They are thermoplastic materials with tensile strength up to 21.5 MPa and elongation at break above 64.0%.