Bonding properties of rubber to steel, aluminium and nylon 6,6

Bonding properties of rubber to steel, aluminium and nylon 6,6 substrates were studied by means of peel tests. Preliminary test results have shown that lightweight aluminium alloys and nylon 6,6 can replace steel in rubber-to-metal bonding applications without compromising integrity and strength of the bond. Peeling energies up to 24 kJ/m2 for nylon 6,6, and 13 kJ/m2 for steel and aluminium were recorded, when rubber was peeled at an angle of 90° either at a constant rate of grip separation or under constant load. Under constant load, bond failure occurred in a time-dependent manner, and was cohesive within the rubber somewhere between 20 and 700 mu m from the covercoat. The bond failed either slowly, where the peel propagated at or near the interface at rates down to ~10-6 mm/s, or rapidly, where the peel front advanced along the bond at rates reaching about 240 mm/s. Interestingly, these two modes of failure occurred randomly and unexpectedly in a single peel test.