Relaxation in semi-interpenetrating polymers network of linear polyurethane and heterocyclic polymer networks

New semi-interpenetrating polymers (semi-IPN) of linear polyurethane (PU) and heterocyclic polymer networks prepared by trimerized dicyanate of Bisphenol-A (TDCE) have been analyzed by dynamic mechanical spectroscopy (DMS) in the 130-550 K temperature and 0.3-30 Hz frequency ranges. Single mechanical ?a-relaxations suggest a large-scale homogeneity ascribed to the affinity between TDCE and PU. Below the glass transition temperature, the interpenetration affects the local molecular motions as a consequence of modifications in the mutual local environments of pure components.