Structure formation and hydrogen bonding in all-aliphatic segmented copolymers with uniform hard segments

Fully aliphatic segmented poly(ether ester amide) copolymers with uniform hard segments prepared by melt polycondensation of alpha,omega-hydroxyl end-functionalized polytetrahydrofuran and short glycine or beta-alanine bisester-bisoxalamide units hold promise for biomedical applications. For polymers with the hard block contents varying from 10% to 27%, differential scanning calorimetry and atomic force microscopy reveal a highly phase-separated morphology, with ribbon-like nanocrystals dispersed in the soft segment matrix. To relate the polymer properties to the structure of the hard segment, the monomers were prepared and studied by optical and X-ray diffraction measurements. It was shown that the glycine and B-alanine carbonyl ester groups are tilted away from the oxalamide plane, which can affect the degradation rate via hydrolysis of the ester bond. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.