Abstract
In this contribution, the separation of polyethylene terephthalate (PET)–polyethylene (PE) and
polyethylene terephthalate (PET)–polypropylene (PP) mixtures was studied in order to improve the
grade of the raw input used in PET bottle recycling. First, PET bottles and their caps (made of PE or
PP) were shredded and the floatability of each polymer was tested. Even with the addition of the
wetting reagents dodecylamine acetate (DAA) or polyvinyl alcohol (PVA), the results did not suggest
that the required 99.995% purity of PET plastic could not be achieved by floatation. Second, the
mixtures were separated with a sink–float process using a drum separator. Finally, as the required
purity of PET could not be obtained by either technique alone, a system utilising a combination of the
two processes was developed. This system easily achieved the desired PET grade. At last, some sink–
float experiments were performed with a medium of