Conformational changes in a polyethylene model under tension and compression

Using a realistic model for polyethylene (PE), the molecular dynamics technique is used to simulate atomic motion in a crystal. The calculations reveal conformational disorder above a critical temperature. The rate of isomerization computed from molecular dynamics is compared to transition‐state theory and leads to an activation energy under stress of ∼ 30 kJ/mol, 15 kJ/mol above the single‐bond rotation value. In the unstressed case, the activation energy for the process is less.