Abstract :
Nowadays, along with requirements for developing heat-resistant electrical insulating materials, various kinds of high polymers with polar structures are used, which are characterized by high heat-stability, good electrical properties, hydrophilic nature, etc. While their heat-stability is beneficial to their uses, their hydrophilic nature is sometimes detrimental, since the existence of water in electrical insulation is apt to deteriorate their electrical properties and dimensional stability. How water interacts with the polymer molecules in electrical insulating materials is an important issue to be solved; how inadequately the water can be classified into its free and bound forms in the materials has always been an interesting question. Heat resistant electrical insulating materials to be studied were selected and specimens conditioned by exposing them to moisture or immersing in water. The materials chosen were the following high polymeric films: Aramid, polyamide, biaxially oriented polyethylene terephthalate (PET), and biaxially-oriented polyethylene naphthalate (PEN); and an aromatic polyamide (Aramid) paper.
Keywords :
dielectric measurement; humidity; infrared spectra; nuclear magnetic resonance; organic insulating materials; polymer films; thermal analysis; thermal stability; water; aramid; aromatic polyamide; biaxially oriented polyethylene terephthalate; biaxially-oriented polyethylene naphthalate; electrical properties; heat-resistant electrical insulating films; heat-stability; hydrophilic nature; polyamide; thermoanalytical behavior; water; Dielectric materials; Dielectrics and electrical insulation; Electrochemical impedance spectroscopy; Kinetic theory; Plastic insulation; Polyethylene; Polymer films; Resistance heating; Stability; Water heating;
