A Laboratory Study of the Friction of Rubber on Ice

Abstract

This paper describes the effect of velocity and temperature on the friction coefficient of both filled and unfilled rubber vulcanizates sliding on smooth ice. It has been shown that the mechanism of the friction of rubber on ice is the same as that on other smooth surfaces under similar low sliding speed conditions and that the maximum friction coefficients are similar. The Williams Landel and Ferry equation is used to superpose curves of the velocity dependence of the friction coefficient at different temperatures to produce a master curve and therefore to demonstrate the viscoelastic nature of the frictional mechanism. The frictional behaviour depends on the condition of the ice track and a tentative explanation for this observation is suggested. The frictional properties of vulcanizates containing various amounts of a reinforcing carbon black filler have been studied. The effect of the carbon black filler on the friction coefficient correlates with changes in the low temperature dynamic properties of the vulcanizate obtained using a torsion pendulum. The effect of contact pressure on the friction coefficient has been investigated using both filled and unfilled vulcanizates at low sliding velocities. The results are in accord with a theory which has been used successfully to describe the behaviour on other smooth surfaces. The combined effect of a high contact pressure of the order of 30 psi (2 kg cm^-2) with sliding speeds up to 40 mph has also received attention and the results are discussed in terms of frictional melting of the ice at the interface.