Qualification testing of engineering thermoplastics for electrical distribution applications

Engineering thermoplastic materials are continually being incorporated as a cost competitive alternative for improving the performance characteristics of electrical distribution equipment and their accessories. Proper utilization of any material requires a thorough understanding of not only the inherent properties of the material, but also how it will react under various environments over a prolonged period of time. The material selection process requires that special consideration be given to how the electrical, physical and chemical properties of the material are affected during product operation. Material durability is measured as a function of exposure to elevated temperatures, humidity, outdoor weatherability and chemical resistance as dictated by the application. Numerous polymer types and grades of potential material candidates exist and can include, but are not limited to, the following classes of compounds: polyamides, polyesters, polysulfones, syndiotactic polystyrenes, polyphenylene sulfides and polyimides. Qualification testing should be designed to accelerate the aging characteristics of the material without changing the degradation mechanisms. Various forms of analytical testing are required to assess the degree of degradation, which has occurred to the material, and to allow for a quantitative evaluation of the long-term performance of the material.