Closed-Loop Recycling: Mechanical Recycling of Polypropylene Cups

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F70883521%3A28110%2F24%3A63579899" target="_blank" >RIV/70883521:28110/24:63579899 - isvavai.cz</a>

Result on the web

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DOI - Digital Object Identifier

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Result language

angličtina

Original language name

Closed-Loop Recycling: Mechanical Recycling of Polypropylene Cups

Original language description

The recycling of plastic products is an integral part of the life cycle of polymers. This work focuses on the mechanical recycling of polypropylene (PP) thermoformed cups used in the food industry. The prepared shredded flakes from the PP dairy products (e.g. yogurt) cups were used to produceregranulate in twin screw extruder. To maintain comparative quality, the virgin polypropylene, from which these cups are normally made, was also regranulated, as well as the same PP with 2 wt. % of titanium white (again based on the composition of the original cups). In addition, a 30% blend ofrecycled and pure PP was also prepared. Materials were then analyzed by capillary rheometry, wide angle X-ray scattering, differential scanning calorimetry, thermogravimetric analysis, spectrophotometry and mechanically tested by tensile and impact testing. It can be concluded that recycled PP shows slight decrease in viscosity, crystallinity and melting point, and a significant increase in crystallization temperature. Mechanical testing shows that the addition of recycled PP into virgin material significantly increases the impact toughness, while the recycled material alone does not show such a rapid improvement, and the tensile modulus and maximum tensile strength slightly decrease. The relative elongation decreases as well. The addition of 2 wt.% titanium white to the virgin material slightly increases the crystallization temperature and significantly promotes formation of b-phase, as well as increase in impact toughness.Thus, it plays a role of specific b-nucleating agent. All in all, the processing and performance properties of the recycled PP were found to be comparable to the virgin material while it is thus suitable for application to same products, i.e. thermoformed cups. The reuse of food cup recycled PP in new products is a simple and effective way to increase the circular economy of PP and reduce the cost of producing disposable packaging materials. However, the potential contamination of the material still needs to be eliminated. Logistics issues also remain open.

Czech name

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Czech description

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Type

O - Miscellaneous

CEP classification

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OECD FORD branch

10404 - Polymer science

Project

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Continuities

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů