Quantifying the environmental benefits of a solvent-based separation process for multilayer plastic films

Abstract

Food packaging often appears in the form of multilayer (ML) plastic films, which leverage the functional properties of different polymers to achieve specific food protection goals (e.g., oxygen, water, and...

Large-scale computational polymer solubility predictions and applications to dissolution-based plastic recycling

“…Temperature-controlled precipitation has been shown to be preferred in STRAP processes based on prior technoeconomic analysis. 17,22 We selected solvents from those that satisfy the following rules: the predicted solubility of the polymer to be dissolved must be greater than 5 wt% while the solubility of other polymers must be lower than 3 wt%, the difference in the predicted solubilities must be greater than 5 wt% to achieve selectivity, and the predicted solubility of the dissolved polymer at room temperature must be 80% lower than its solubility at high temperature to assure the feasibility of temperature-controlled precipitation. Fig.…”

“…11,13 Dissolution-based plastic recycling has several advantages over chemical or mechanical recycling methods: it can process multicomponent plastic mixtures, it maintains the chemical structures and properties of recovered polymers, and it does not require a high-purity input stream because impurities and additives can be removed by selective dissolution. 14–18 Dissolution-based recycling is also a green process that has over 40% lower greenhouse gas emissions than producing virgin resins, saving 3–6 tons CO 2 for each ton of plastic waste. 19 In addition, dissolution-based technologies can reduce emissions to an extent comparable to closed-loop mechanical recycling, and have 65–75% less environmental impact than incineration.…”

“…For example, a STRAP process that recycles PE, EVOH and PET from a multilayer plastic film generates 54% fewer emissions than producing the virgin films. 17,22 Some dissolution-based plastic recycling technologies are also being developed industrially, although limited information about their process conditions and solvent selections is openly available. 5,13,16 These processes highlight the feasibility and broad applicability of recycling polymers from complex input streams via dissolution-based approaches.…”

“…These considerations affect the efficiency, economics, and environmental impact of the process. 17,22 The key information needed to guide these choices is the temperature-dependent solubilities of polymers in different solvent systems. Several past studies have reported known solvents and non-solvents for some common polymers at various temperatures; 24,25 examples are included in Table S1 of the ESI †.…”

Mid-infrared spectroscopy and machine learning for postconsumer plastics recycling

“…13 Consequently, there has been an unprecedented surge of multi-disciplinary research aimed at reducing plastic waste, limiting the production of virgin polymers, and improving pathways for PCPW to re-enter the value chain. [14][15][16][17][18][19][20][21][22][23][24][25][26][27] The development of automated optical sorting technologies for implementation at MRFs is one of these active research thrusts in the plastics recycling community. 28,29 This is because MRFs currently rely on air jets, magnetic separators, mechanical pistons, and human intervention to sort PCPW, all of which are methods that have been deemed insufficient to meet growing recycling demands.…”