Synthesis and characterization of new poly(ester-amide)s containing oligo(oxyethylene) segments

Segmented poly(ester-amide)s were prepared by polycondensation of a series of monoaminooligo(oxyethylene) pentachlorophenyl succinates, containing 1-3 oxyethylene units. The monomers were prepared by a four-step procedure from oligo(oxyethylene) monoamines consisting of: (1) protection of the primary amine group by di(t-butyl) carbonate, (2) succinoylation of the free hydroxyl group, (3) esterification of the resulting acid group with pentachlorophenol, and (4) deprotection of the amine group in anhydrous acid conditions. Polycondensation experiments were performed in solution and in bulk at room temperature by using triethylamine as a base to restore the active amine group of the monomer. Only bulk polymerization gave rise to high molecular weight polymers. Solubility and thermal properties of the materials were found to be related to the length of the oligo(oxyethylene) segment and the presence of strongly interacting amide groups.