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Title Circular Economy of Mechanical Recycled Post-Consumer PP:
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Publication Date
Degree Level masters
University/Publisher Delft University of Technology
Abstract Background: The growth of the global population in combination with technological development results in the need to improve the living conditions. This led to a significant and unsustainable increase in production of products. The unstable increase is especially the case for plastics, which have an annual worldwide production of over 288 million tons, that grows exponentially. Sustainable solutions and a circular economy are required to limit the unsustainable increased demand on natural resources. Solutions to this unsustainable situation include: the use of bio-based polymers, increased use of flexible packaging or improved recycling; either chemical or mechanical. Objective: This study focuses on the possibility to create a circular economy of plastics by applying mechanical recycling. Mechanical recycling is a promising solution, especially with the new separation technology that is currently in development. The current separation technology of mechanical recycling separates plastic by type, but does not take any further separation criteria into account. This results in a mixed waste stream of many different grades, which cannot be used in a circular economy. However, the separation technology currently being developed can separate plastic on flake level. In addition to accurate density separation on flake level, the technology is able to separate flakes based on wall thickness and color. Separation based on wall thickness enables the possibility to separate based on manufacturing type. This study investigates whether this new separation technology can realize a circular economy for mechanical recycled post-consumer plastic. Methods: The study is performed on post-consumer polypropylene (PP) from the packaging industry, as this industry counts for majority of plastics production. PP is one of the key plastic types used in packaging and its popularity is expected to increase, as transparent PP already replaces poly(ethylene terephthalate) (PET) in many applications. PP is a thermoplastic semi-crystalline polymer which properties are strongly correlated to its molecular parameters. Tacticity, crystallinity, molecular weight and copolymerization impact the properties of PP. The optical, mechanical and rheological properties of further categorized pure post-consumer PP (based on manufacturing type and color) are studied, as these properties give insight in their possibility to address the market needs. Results: A first separation based on blow mold, thermoformed and injection mold leads to recycled material streams with well defined rheological and mechanical properties. The melt flow indices (MFI) of the categorized mechanical recycled waste streams address the needs of plastic manufacturers. Additionally, the thermoformed and blow mold waste streams show a ductile fracture behavior. However, the injection mold grade shows a brittle fracture mechanism. Categorization based on manufacturing type is correlated with a slight color separation. Further categorization of injection mold into a white and transparent…
Subjects/Keywords Plastics recycling
Contributors Rem, P.C.; Dingemans, T.J.; Janssen, M.; Wever, R.
Language en
Rights (c) 2015 Van Bruggen, E.P.A.
Country of Publication nl
Record ID oai:tudelft.nl:uuid:eb01f234-3098-4b2a-bb24-700a22e70652
Other Identifiers uuid:eb01f234-3098-4b2a-bb24-700a22e70652
Repository delft
Date Indexed 2017-06-19

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…create a circular economy for plastic materials. Figure 1: Human development index over ecological footprint[2] 1.1. Plastic Production The use of plastics is enormous, 288 million tons worldwide in 2012, and still grows exponentially every…

…plastic waste. The demand for plastic materials is increasing enormously as is illustrated in Figure 2. The latter shows the ever increasing need for a solution of the treatment [4]. Figure 2: World/European plastics production 1950-2012 [5…

…x5D; 1.2. Trends in Europe As the production of plastic products correlates with its footprint, not only treatment of post-consumer plastic waste, but also the production of plastic products is a key area of focus. For the majority of plastics, raw…

…quantities for the production of plastics in recent decades, but the shortage of resources is growing rapidly. This issue, in combination with the challenge around the treatment of plastic waste, emphasizes the need to find alternatives that meet current…

…sources such as algae can be used for manufacturing. [8] Compared to their petroleum counterparts, biopolymers are relatively new to the market, but a more promising approach to 2 sustainable plastics in the future. Fossil fuel consumption and…

…CO2 emissions will decrease by an increased use of bio-based polymers. Other important factors that influence replacement of current plastics by more sustainable plastics include price, fit for use in all applications and laws and regulations. An…

…the needs of the market. Current technologies and new developments will be discussed in more detail. Current Recycling Process The current recycling process starts with the collection of plastic. The main method of recycling of plastics is mechanical…

…scission and therewith modify the flow behavior of the material. However, this treatment only results in the formation of injection mold grade PP. This means that the plastics cannot be used for the same purposes as their origin. Additionally, NIR system is…

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