Fracture Mechanical Behaviors of Various Polymers from Brittle Glasses to Elastomers*

We expand our research on mechanical performance of glassy and semicrystalline polymers to include evaluation of their toughness in the language of fracture mechanics, i.e., in terms of critical energy release rate at which crack growth become inevitable. By showing how various thermoplastics can be made to avoid brittle fracture in plane-strain deformation, we dive into the molecular origins of structural failures as observed in the form of crack propagation and search for alternative explanation of fracture mechanical properties of thermoplastics and elastomers.