SURFACE PLASTICIZATION OF NYLON-6,6 BY WATER

Tribological studies have been carried out on Nylon 6,6 with particula r emphasis placed on the examination of the effect of water on this po lymer. An examination of the sliding frictional behaviour of Nylon 6,6 against a steel substrate shows that the friction decreases with incr easing load, probably due to the formation of thermally softened inter faces in the contact. After exposure of this polymer to water, dramati c changes to the frictional behaviour of the Nylon are observed; the f riction increases with increasing load. From the application of the ad hesion model of friction it is postulated that the observed changes ar e caused by extensive plasticisation of the Nylon and, as a consequenc e, an increase in the contact area. This proposition is confirmed by t he reported scratch hardness data. After treatment with water the scra tch friction mechanism changes significantly and a notable reduction i n the hardness of Nylon is observed.