Influence of the Temperature upon the Durability of Rubber in Corrosion Cracking

Abstract

1. The rate of reaction of an undeformed rubber stock with a reactive medium is determined by the diffusion, while the rate of destruction of a deformed stock is determined by its chemical interaction with the medium. 2. The magnitude of the apparent activation energy (u) of the rupture of a stock in the presence of a reactive medium does not undergo perceptible alteration in the range of deformations 30 to 80%, while on transition to deformations of 500 to 700% the values of the apparent activation energy increase. 3. The temperature coefficient of rupture depends upon the nature of the bonds being destroyed and upon the capacity of the reactive medium for adsorption on the stock. On rupture in the gaseous phase the apparent activation energy has a lower value than on rupture in a solution of the same agent. 4. In a wide range of deformations the time to rupture of stocks obeys a complex system of laws, passing through a minimum value in the region of the critical deformation, εcrit. The position of εcrit depends upon the temperature, type of ‘aggressor’ (i.e. reactive agent) and physical state of the medium (gas, solution). 5. As a result of the shift of εcrit with alteration in temperature there is possible the phenomenon of anomalous dependences for certain deformations, i.e., the time to rupture at low temperatures are less than for higher temperatures with identical deformations and concentrations of the medium.