Thermal and mechanical properties of simultaneous and sequential full-interpenetrating polymer networks

An investigation of the thermal and mechanical characteristics of new full-interpenetrating polymer networks (full-IPNs), prepared by simultaneous and sequential synthesis paths, has been performed in the temperature regions above and below the glass transition. It has been observed that simultaneous full-IPNs exhibit higher values of density than sequential full-IPNs, as a consequence of an enhanced intermolecular packing. This peculiarity leads to an increase of the glass transition temperature and to a larger “gamma-suppression” effect for the gamma2-relaxation characterizing the polycyanurate phase of simultaneous full-IPNs, which has been ascribed to reduction of the free-volume available for the molecular group rearrangements.