SYNTHESIS OF SOLVENT-MODIFIED EPOXIES VIA CHEMICALLY-INDUCED PHASE-SEPARATION - A NEW APPROACH TOWARDS VOID TOUGHENING OF EPOXIES

The fracture toughness has been investigated with single edge notched bending specimens in solvent-modified epoxies, which were prepared via the Chemically Induced Phase Separation technique. The generation of a controlled morphology with liquid droplets in the micrometer range l eads to a substantial increase in the fracture energy of nearly 400% c ompared to the non-modified epoxy network. The critical stress intensi ty factor of these highly crosslinked thermosets does not vary signifi cantly. These results demonstrate the general potential of the Chemica lly Induced Phase Separation technique to prepare porous thermosets, t hus combining increased toughness with lowered density.