Abstract
It has already been shown that liquids consisting essentially of aliphatic hydrocarbons, e.g., petroleum ether, paraffin, and transformer oil, had practically no swelling action at 34° C on two samples of hard rubber composed of rubber and sulfur only. Hard rubber shows a pronounced change in properties at temperatures above a critical value (“yield temperature”) in the neighborhood of 50° –80° C, the most noticeable effect being that it becomes much softer and more susceptible to plastic flow. It seemed likely, therefore, that the swelling action of liquids such as those mentioned above might be much greater at temperatures above this critical value. This view was strengthened by the statement of Dunton and Muir that hard rubber is “badly attacked” by immersion for 7 days in “hot” transormer oil. As no data appear to have been published on the effect of temperature on the swelling of hard rubber, experiments were made to examine this effect. Details of the hard rubber samples used are as follows.