Weathering of Soft Vulcanized Rubber

When rubber goods are exposed to the agencies which constitute “weather”, they undergo profound changes. The rubber may lose elasticity, it may split or crack, or the surface may take on a crinkled appearance in a wide variety of designs. Figure 1 shows a small selection of such weathered rubbers. The course of deterioration, or the ultimate condition of any particular rubber specimen, moreover, is not always the same, but depends to a considerable extent on the kind of weather encountered which, in turn, depends on geography, topography, and season. The components of weather are air, heat, water, and sunlight, each varying in quantity and quality so that infinite combinations are possible. Among the major (nitrogen and oxygen), minor (carbon dioxide, argon, helium, neon, krypton, xenon), and trace (ozone, nitrogen oxides, ammonia, sulfur dioxide, sulfuric acid, hydrogen sulfide, carbon monoxide, hydrocarbons, hydrogen, mineral salts, hydrogen peroxide, organic peroxides) components of the atmosphere, only oxygen, ozone, and nitrogen oxides are capable of reacting with rubber. Trial shows steadily that, of these, only oxygen and ozone produce any perceptible effect at the concentrations in which they are present.