Toughening of brittle epoxy using bitumen as a new modifier

This article describes the toughening of brittle epoxy using bitumen as a new modifier. The main objective of this study is to incorporate bitumen into epoxy matrix with the aim of obtaining an epoxy hybrid material with higher impact and fracture properties and lower cost without attenuating the other desired mechanical properties such as tensile strength. Mechanical properties of epoxy/bitumen hybrids with different bitumen contents were studied. With the addition of only 2% bitumen to epoxy, maximum improvements of 164% and 187% were obtained for impact strength and fracture resistance, respectively. The addition of bitumen to epoxy matrix had no significant effect on tensile properties. Morphological properties of the hybrid were studied by scanning electron microscopy and a dispersion of micron-sized bitumen particles in epoxy-rich matrix was obtained as main morphology. Thermogravimetric analysis of the hybrid in inert environment showed that the thermal stability decreases slightly with incorporation of bitumen into epoxy matrix. The chemical stability of the hybrid against different acids and alkalis was higher than neat epoxy but relatively lower stability was observed against organic solvents.