Method and apparatus for monitoring nylon 11 made from polyamide plastic made from aminoundecanoic acid

摘要

The molecular weight of NYLON 11 TM (a polyamide made from aminoundecanoic acid) has been found to be a reliable indicator of the mechanical properties and remaining useful life of parts made therefrom. By periodically monitoring the molecular weight, and comparing the measured molecular weight to a standard curve or table, the expected useful life remaining, rate of deterioration, time of part replacement, and mechanical properties of a part can be determined. The molecular weight may advantageously be determined using witness coupons placed in close proximity to the part such that they are exposed to the same processing and environmental conditions as the part. These witness coupons can advantageously be retrieved at the required time period using a spooled piece of pipe or the like. Alternatively, the molecular weight may advantageously be determined from core samples taken from the part being monitored, during use in the field, on a periodic basis. In addition, the molecular weight might also be inferred from a sample held in a laboratory which is exposed to substantially the same environmental conditions as the part. The molecular weight measurements can be made using standard techniques and equipment such as a viscometer, gel permeation equipment, or light scattering equipments.