• interpenetrating polymer networks;
  • castor oil-based polyurethanes;
  • dynamic mechanical properties;
  • tensile strength;
  • impact strength


A series of graft interpenetrating polymer networks (IPNs) were prepared from epoxy (EP) and castor oil-based polyurethane (PU). The dynamic mechanical properties, as well as the tensile and impact strength, of the IPNs were studied systematically. Results revealed that PU/EP IPNs showed improved damping properties compared with that of EP matrix. In addition, the PU content and testing frequencies had much influence on the damping properties of the IPNs. The IPN composites showed better damping properties with higher PU content or under higher testing frequencies. Mechanical analysis showed that the tensile strength of IPN composites was higher than that of pure EP. However, higher PU content (beyond 5 wt %) impaired the impact strength of the IPNs. It is expected that PU/EP IPNs may be potentially used as structural damping materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010