User:Signalvsnoise/plastic fracture

Polymer fatigue is characterized by very different behavior than other materials. Polymers are not generally at thermodynamic equilibrium, but instead are frozen in higher energy states at local minima, essentially frozen by high viscosities and long relaxation times of entangled long polymer chains. Motion of individual kings and sidegroups can cause significant relaxation peaks at temperatures well below the glass transition temperature of the material.