Paper Number
RS1
Session
Real-World Rheology & Sustainability
Title
Rheology-driven melt phase separation of PE/PET blends, a new approach to recycling. Part 1: PET chain-extension
Presentation Date and Time
October 14, 2024 (Monday) 9:50
Track / Room
Track 7 / Room 502
Authors
- Lu, Max (Case Western Reserve University, Macro)
- Vecchi, Steven (Case Western Reserve University, Macro)
- Hampton, Lauren (Case Western Reserve University, Macro)
- Kone, Ezra (Case Western Reserve University, Macromolecular Science & Engineering)
- Ghassemi, Hossein (Case Western Reserve University, Macro)
- Schiraldi, David (Case Western Reserve University, Macro)
- Maia, Joao (Case Western Reserve University, Macromolecular Science and Engineering)
Author and Affiliation Lines
Max Lu, Steven Vecchi, Lauren Hampton, Ezra Kone, Hossein Ghassemi, David Schiraldi and Joao Maia
Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, OH 44106
Speaker / Presenter
Lu, Max
Keywords
experimental methods; active systems; data-driven rheology; particles; polymer blends; polymer melts; polymers; real-world rheology; sustainability
Text of Abstract
Multilayer, multicomponent films are widely used for their excellent barrier properties, which makes them the construction of choice in flexible packaging. More than 40 million tons of the more than 400 million tons of plastic being produced annually are composed of multilayer polymer systems, which creates an enormous challenge as recycling of these multilayer systems is not technically feasible at large scales. In fact, the component plastics often have differing recycling pathways which prevents these films from being recycled. This work is the first part of a more general project aimed at developing a novel hybrid chemical-mechanical approach that leads to achieving continuous in-process melt separation of polyethylene/polyethylene terephthalate (PE/PET) blends in twin-screw extrusion for posterior individual recycling of the separated polymers. Herein, we use various levels up to 1.00% w/w of pyromellitic dianhydride (PMDA) as a PET chain extender and demonstrate that significant chain-extension occurs up to 0.5% w/w of PMDA, while chain-branching becomes dominant above this PMDA level. The corresponding increase in PET viscosity and consequently blend viscosity ratio, induces coalescence of PET droplets, which can then be mechanically filtered out of the main PE melt stream, with over 80% of all PET being extracted. This work further studies the optimal amount of PMDA content for coalescence before long-chain branching begins to hinder coalescence during the typical processing window in twin-screw extrusion, and mechanical methods to separate the PE/PET blends post coalescence.