Blow moulding of mechanically recycled post-consumer rigid polyethylene packaging waste

Journal article, 2024

Recycled post-consumer rigid polyethylene (PE) packaging waste was washed
and compounded on a pilot scale using different processing conditions and the
processability of recycled materials with blow molding was assessed. Compared
to virgin grade high-density PE, the recycled materials showed a lower crystallinity,
a lower thermo-oxidative stability, a higher ash content, a lower viscosity
and melt elasticity, and a lower melt strength and drawability. The thermooxidative
stability varied due to the different washing media. Rheological characterization
by frequency-sweep measurements indicated that the virgin grade
PE had as expected more linear-polymer-like characteristics whereas the
recycled materials showed chain branching or crosslinking related to the processing
condition during compounding. The recycled materials were successfully
blow molded into 4 L-containers where they showed less resistance to flow than
the virgin grade PE. The recycled materials differed in color when different
washing media were used. There were no significant differences in the mechanical
properties of the 4 L-containers made of virgin grade and recycled PE.