a material that retains its properties for a long time under the conditions of a tropical climate, for example, high temperatures and humidity, a high level of solar radiation, a high abundance of atmospheric ozone, and sea fog. Such conditions promote extensive destruction, that is, the corrosion and aging of materials. Deterioration of the properties of materials may also be caused by various microorganisms, particularly molds, and by termites. Tropic stability depends on the actual conditions under which the materials are used and on the properties of the materials. Most tropic-stable building materials are corrosion-resistant metals. Tropic-stable electrical insulation materials include plastics with inorganic fillers, fiberglass, mica, asbestos, synthetic fibers, and ceramics. Polyvinyl chloride, polyfluoroethylene resins, polyethylene, paronite, and certain rubbers are tropic-stable materials. In order to increase their tropic stability, many materials are treated with antiseptics, or fungicides and antioxidants are added to the materials. Ordinary materials with protective coatings, some of which contain stabilizers, may be used as tropic-stable materials.
L. G. ANGERT