Modeling of strain rates and temperature effects on the yield behavior of amorphous polymers

Three molecular theories are used to prediet the yield behavior of amorphous polymers for a wide range of temperatures and strain rates. These include the state transition theory of Ree-Eyring, the conformational change theory of Robertson and the disclinations theory of Argon. For each of these models, the yield stress behavior of polymethylmethacrylate (PMMA) is described over a wide range of strain rates and temperatures. According to experimental values for polycarbonate (PC), the Ree-Eyring model seems to be the suitable theory at high strain rates for the prediction of the yield stress of amorphous polymers. 1.