Macroscopic deformation and failure of ductile polyethylene: The dominant role of entangled amorphous network

Abstract

Ductile polyethylenes with various molecular weights have been adopted to stress the dominant role of entangled amorphous network in the macroscopic deformation and failure behaviors. The true draw ratio at break and permanent strain of broken samples after total shrinkage at 140°C for 10 min demonstrate that entangled amorphous network undergoes more significant relaxation in the sample with lower molecular weight. With aid of Essential Work of Fracture (EWF) method, most of importance, the fracture toughness of ductile polyethylene is effectively evaluated and can be directly related to the network modulus. Furthermore, fracture toughness is strain rate dependent and can be enhanced to some extent by suppressing relaxation of entangled network. © 2007 The Society of Polymer Science.