Abstract

M. ROJAS, G; RINK, M  and  J. MULLER, A. Rev. LatinAm. Met. Mat. [online]. 2002, vol.22, n.2, pp.66-72. ISSN 0255-6952.

The fracture of different Polyethylenes (PEs) was studied using the Essential Work of Fracture (EWF) technique on DENT (Double Edge Notched Tension) specimens under mode I of fracture. This method is used to characterize the fracture of ductile polymers under plane stress state. Three different PEs were used: a High Density Polyethylene (HDPE), a Low Linear Density Polyethylene (LLDPE) and a Very Low Density Polyethylene (VLDPE). The essential work of fracture, we, of both HDPE and LLDPE were determined using the EWF method, but in the case of the VLDPE this could not be done due to the elastomeric behavior of the material and to the lack of similarity between its load-displacement curves. The crystallinity of the material was found to have an important influence in the value of we, as the HDPE had a lower value than the LLDPE due to a possible sharpening of the crack in the HDPE promoted by the higher crystal content in this polymer.

Keywords : Essential Work of Fracture; Polyethylene; Crystallinity degree; Fracture; Crack Sharpening.