Application of time‐temperature superposition principle to long term engineering properties of plastic materials

Abstract

Abstract Time‐temperature equivalence was used to predict the long term engineering behavior of highly crystalline ethylene‐butene copolymers. The long term behavior (greater than 1000 hrs.) was accurately predicted from tests of short duration (30 hrs.). This time‐temperature principle was applied to stress‐relaxation and creep at stresses, strains and temperatures normally encountered in engineering practices. It was also used to solve a design problem involving the creep deformation of metal plastic laminates. Long term tests were performed to confirm the predicted results. This technique was not applicable to rubber modified polystyrene because of an unexpected transition at 88°F.