Influence of Repeated Recycling and Aging Effects on Mechanical Performance of WEEEBR

Abstract

WEEE is a complicated waste stream from a recycling point of view. About 20-35 wt% of WEEE is usually plastics, which previously have been found possible to mechanically recycle. One way to recycle the WEEEBR plastic is to improve the mixing state by extrusion compounding, such as previously done at Chalmers. The influence of combined accelerated aging and repeated extrusion on mechanical and thermal performance is studied in this work. Although the onset temperature of the thermo-oxidative degradation was almost the same for different accelerated aging times, the difference in mechanical properties was significant. The aging performed was found to cause a substantial decrease in elongation at break, an increase in stiffness and an unchanged ultimate tensile strength, also after relatively low aging times corresponding to 2-4 years use time at room temperature. For longer aging times, corresponding to 10-16 years use time at room temperature, there was a small decrease in both tensile strength and elongation at break, while the stiffness remained at about 1,2GPa. After the combined extrusion and accelerated aging corresponding to 2 years cycles, the elongation at break decreased after aging, while stiffness and tensile strength decrease after the extrusion of the third cycle. The thermal evaluation indicated the state of physical aging of the amorphous styrenic polymers part of the material.