Effect of repetitive recycling on the mechanical properties of polypropylene blends based on material value conservation paradigm

Contaminated plastic waste if undergo a mechanical recycling process will have a low value. This can be overcome by repetitive implementation of Material Value Conservation (MVC) through material purity protection from design stage to the end of the material life cycle. Repetition of recycling up to eight times caused degradation of mechanical properties of plastics by up to 20%. The repetition was done on a laboratory scale with pure polypropylene as raw material. This research was conducted to overcome the degradation of plastic properties by mixing recycled plastic pellets with virgin plastic in the most optimal proportion. Plastic blends with certain compositions were recycled up to 8 times, then its mechanical properties are tested with the American Society for Testing Materials (ASTM) methods. This research revealed the opportunities to utilize the 6^th recycled plastic pellets by mixing it with virgin plastic to improve its mechanical properties. Furthermore, this research shows that repetitive recycling of plastic blends with the implementation of material value conservation (MVC) could increase the value of recycled plastic pellets as raw materials and extend the life time of plastic materials.