Post-Yield Fracture Behavior of Zeolite-Reinforced High Density Polyethylene Annealed Composite

Abstract

The fracture behavior of annealed composites of zeolite-filled high density polyethylene has been investigated using the essential work of fracture concept. The crack opening displacement (COD) was estimated starting from the essential work of fracture value. The morphology of the fracture surface was examined using the scanning electron microscopy and the fracture mechanisms were discussed. The results showed that the composite with a 5 wt.% zeolite concentration has a unique fracture behavior characterized by the highest resistance to crack initiation in accordance with COD but a low resistance to crack propagation. The non-essential work of fracture as the resistance to the stable crack propagation has shown a maximum of 2.5 wt.% of zeolite followed by a sharp drop at a higher content of zeolite indicating a zeolite induced ductile-to-brittle transition. The fractured surface morphology revealed that the zeolite particle clusters arrested the plastic crack growth, which was more effective at 5 wt.% zeolite concentration. At a higher zeolite content, the amount of particle clusters rose, leading to a decrease in the average distance between them. Consequently, a large-scale plastic deformation of the matrix effectively favored the small strain damage and the fracture eventually occurred in the ductile-to-brittle transition.