The formation of poly(ester–urea) networks in the absence of isocyanate monomers

The polymerization of N,N' carbonylbis (caprolactam) (CBC) and polyol in the presence of alcoholate as catalyst produced cross-linked poly(ester–urea)s via ring opening addition reaction. In contrast to conventional synthetic routes, the use of non-toxic CBC eliminates the need for toxic isocyanate-based monomers. The structure of the molecules resulting from model reactions was confirmed using FT-IR and 1H- and 13C-NMR spectroscopy. Poly(ester–urea) networks exhibit rubber-like mechanical properties and high-temperature stability. Cell adhesion and cell growth on the polymers evidenced the high biocompatibility of the material. Degradation of the poly(ester–urea)s was investigated at 70°C in neutral and basic aqueous solution. The degradation depends on the swelling behavior of the samples. Mechanical properties, good biocompatibility, and degradation behavior of the CBC/polyol-based polymers make them interesting materials for biomedical applications.