2015 Volume 60 Issue 5 Pages 342-348
Friction properties of the oils containing polyalkylmethacrylate with different alkyl group were studied in relation to adsorption and desorption ability of polymers. First, the coefficient of friction with a pendulum type tester were roughly correlated with a magnitude of frequency shift ΔF obtained using a quartz crystal microbalance with dissipation tester, in which ΔF was related to adsorption ability of polymers onto a metal surface. This suggests that the friction under the mild contact conditions is governed by surface coverage capacity of polymers. On the other hand, tribological properties under the severer conditions with a steel ball-on-steel disk type tester were evaluated under a temperature of 100°C, a mean Hertzian pressure of 0.73 GPa and a mean rolling speed of 0.05 m/s and a slide/roll ratio of 50%. Among the polymers, a mixed alkyl group containing methyl group was superior to the other polymers in terms of stability in friction with time, friction reducing effect and antiwear properties. It is inferred that the friction under the severe conditions was influenced by surface coverage capacity of polymers as well as adsorption preservation capability, which was evaluated as a separation degree during the tribotest.
