Fiber Lubricant Properties and Dynamic Mechanical Properties of Polyoxyalkylene Fluids

Abstract

A correlation of the dynamic mechanical properties of various polyoxyalkylene lubricants with their yarn-to-metal lubricant behavior reveals that the glass-transition temperature (Tg) and the sliding speed for maximum frictional force ( Umax) are related to the reciprocal of the lubricant number average molecular weight ( Mn). In accord with accepted theory, the linear polyoxyalkylene fluids display a linearly decreasing Tg and a linearly increasing Umax versus the recip rocal of Mn. Branched polyoxyalkylene (triol) fluids, on the other hand, unexpectedly display a linearly increasing Tg as a function of the reciprocal of Mn, and Umax is independent of Mn. The distinct difference in the fundamental behavior of the linear and branched lubricants is attributed in part to their hydrogen-bonding characteristics. The frictional and dynamic mechanical properties are not affected by the alkylene oxide composition (ethylene oxide/propylene oxide ratio) nor the block or random arrangement of the monomer units within the polymer.