Morphology and properties of nylon 66 : effects of injection moulding on structure and performance

Nylon 66 injection-moulded insulators are used by British Rail outdoors for track insulation. It has been suspected that the conditions of initial moulding and treatment before use represent a significant factor affecting properties over a period of time in this application. A laboratory study has already been reported on the influence of spherulite size on mechanical properties, using a nucleated grade of Nylon 66 to compare with typical unnucleated polymer, but this work throws little light on the problem of unnucleated polymer as such or on the influence of injection conditions and the effects of moisture present after moulding. It was therefore decided to investigate these aspects using a standard unnucleated grade of Nylon 66....