Recycling of Polyolefins for Multiple Lifecycles

The recycling of polyolefins for multiple life cycles is becoming a legislative requirement in the South African plastics industry. This study shows that this cannot be a blanket requirement for all polyolefins. While HDPE displays good resistance to weathering, the decrease in molecular weight limits the maximum number of life cycles before which the resultant product has lost all integrity. Impact polypropylenes fare much worse during weathering and more than 50% of impact properties are lost within the first 12 months of exposure. The blending of virgin material into degraded material can recover some properties of HDPE but not in the case of impact polypropylenes. The same legislation can therefore not be applied to all plastics and specific targets should depend on polymer composition.