Adhesion strength and fracture behavior between carbon black-filled rubber sheets

Adhesion behavior at the interface between a partially-crosslinked and a fully-crosslinked sheet of carbon black-filled rubber compound was investigated over a temperature range from 30 to 120°C. The values of adhesion fracture energy Ga were compared with those of cohesive tear energy Gc. A considerable chemical, as well as physical, interfacial bonding is formed when the uncrosslinked or partially-crosslinked sheet is crosslinked in contact with even a fully-crosslinked sheet. However, there is only a small possibility of chemical bonding when the two fully-crosslinked rubber layers are again crosslinked in contact with each other. An interesting failure mode, termed 'interfacial knotty tearing' was found for a strain-induced crystallizable natural rubber.