The Effect of Grafted Polymeric Lubricant Molecular Weight on the Frictional Characteristics of Nylon 6,6 Fibers

摘要

Boundary friction between two crossed nylon 6,6 fibers has been reduced up to 6* by grafting polymeric lubricants to the sruface. A modified adhesion model of friction, accommodating multiple materials on the surface, explains the variation in the friction coefficient with the molecular wieght of the lubricant. The friction coefficient is proportional to the fraction of the surface covered by the grafted chain, represented by #pi#R_G /A, where A is the surface area per graft site, and R_G is the radius of gyration of the lubricant. It is also shown that for larger the grafted chains, the appropriate surface area fraction depends on #pi#R_G~2/3A. It is argued that if R_G of the grafted lubricant is larger than half the distance between graft sites, the next nearest graft site is uses due to steric blocking of the nearest graft site.