On the Physics Required for Prediction of Long Term Performance of Polymers and Their Composites

National Institute of Standards and Technology, Gaithersburg, MD 20899-0001 The long term performance of polymers and their composites is an important aspect of their increasing use in engineering applications. Temporal, thermal, and mechanical stresses can all contribute to the deterioration of performance. Here we examine the concepts of the physics of glassy polymers and how they are important in developing constitutive equations that describe their volume/temperature/stress time re sponse. The understanding of such response forms the basis of the prediction of long term performance.