Poly(ether urethane amide)s: A new family of biomedical elastomers

Poly(ether urethane amide)s (PEUAm), have been synthesized by chain extending macrodiisocyanates with dicarboxylic acids. A series of aliphatic, saturated and unsaturated diacids were incorporated into the polymeric backbone. Their length and molecular symmetry largely affected the hard block crystallizability and the morphology of the PEUAm matrices. When the polymer was chain extended with fumaric acid (PEUFA) or maleic acid (PEUMA), double bond-containing hard domains were generated. Due to the enhanced symmetry associated with its trans conformation, the fumaric acid created crystalline, better organized hard domains. These reactive double bonds performed as anchoring sites for further derivatization of these polymers. By grafting HEMA, a variety of polyurethane based matrices were obtained, covering a wide range of mechanical properties and water uptake levels. Amine-terminated PEG chains were successfully grafted onto the polyurethane backbone, derivatizing the polymer with a molecule of biological relevance.