Fracture performance of injected LLDPE/PP double gated injected blends

CAREN ROSALES; MARIA ALEJANDRA COSTANTINO; NOURREDINE AÏT HOCINE; CELINA BERNAL; VALERIA PETTARIN

Sevilla

Simposio; Fifth International Symposium Frontiers in Polymer Science; 2017

Polyethylene and propylene are two of the most abundant polymers in wastes. Their separation in common waste recovery operations is very difficult and a complete separation is sometimes not possible. For this reason, polymer waste recovery is providing an increasing motivation for improving their properties as a blend.In this work, fracture performance of blends of commercial polypropylene (PP) and linear low density polyethylene (LLDPE) is reported. A PP-PE copolymer was used as compatibilizer. Blends were prepared in a twin screw extruder, and then processed via injection molding into double-gated plaques that induced weld lines. Fracture tests were carried out on mode I double edge-notched tensile specimens (DENT) at quasi-static conditions. Different Fracture Mechanics approaches were applied depending on the materials´ fracture behavior. The Essential Work of Fracture methodology was adopted for blends that exhibited ductile fracture behavior, whereas the stress intensity factor (K1c) was chosen to characterize the resistance to unstable fracture. It was also observed that fracture behavior was dependent not only on the type of blend but also on the location of the specimen in the injected piece, and the loading direction, i.e. in-homogeneities and anisotropy in the pieces induced by processing were observed.