The synthesis and frictional properties of lubricant-impregnated cast nylons

In order to make a new dry-friction engineering material, lubricant-impregnated cast nylons were synthesized by anionic polymerization of ε-caprolactam (CL) in the presence of mineral oil and wax. The reaction rate of the products was not affected by the addition of lubricant less than 8%. Nylons from 0% to 8% lubricant content were synthesized and the frictional properties were tested. Under various sliding speeds and pressures, the lubricant-impregnated cast nylon with oil content of 6% showed the lowest coefficient of friction, while the cast nylon with wax content of 4% showed the smallest. At the wide range of sliding speeds, the PV limit of nylon with optimum lubricant content was 400% larger than that of the lubricant-free nylon. However, when the PV limit of oil-impregnated nylon was compared with that of wax-impregnated nylon, it was found that the higher PV limit of oil-impregnated nylon could be obtained only at lower sliding speed and lower content of lubricant than that of the wax-impregnated nylon.