Environmental stress cracking resistance in recycled high density polyethylene

Plastic bottles for laundry detergent and cleaning products are made from a tough type of plastic called HDPE. This material needs to withstand harsh chemicals and long-term use without cracking.
When HDPE is recycled, it becomes more prone to cracking, making it less suitable for new detergent bottles. Many assumed this was due to contamination from bottle caps, but research by Amir Khaki shows that’s not the case.
The issue mainly arises because detergent bottles are recycled together with other HDPE bottles, like milk bottles. Milk bottles don’t need to be as strong as detergent bottles. Mixing them weakens the recycled plastic, making it less fit for demanding conditions.
Amir’s research identified an additive that significantly improves the strength of recycled HDPE. His work also explains why this works. These findings pave the way for better recycling and even more effective additives in the future. These results help increase the use of recycled plastic in new packaging and supports a more sustainable, circular economy.