Abstract

A comparison has been made of the aging of rubber compounds under tropical conditions. Two localities were chosen, one of which has a dry climate, the other heavy rainfall and high humidity. The results are compared with those obtained by ordinary Geer oven aging and by aging at the same temperature, but with 100 per cent relative humidity. This artificial moist heat aging is found to be much more severe than the tropical moist aging, but it is not different in kind to aging in a Geer oven and a simple conversion factor can be used to transpose results. Samples aged under dry conditions in the tropics are more influenced by bright sunlight, even though shielded from its direct rays, than by the heat aging. Recommendations are made concerning both the use of materials in the tropics and methods of accelerating aging to assess their behavior in the tropics.