Abstract
The inherent value and use of hydrocarbons from waste plastics and solvents can be extended through open-loop chemical recycling, as this process converts plastic to a range of non-plastic materials. This process is enhanced by first creating plastic–solvent combinations from multiple sources, which then are streamlined through a single process stream. We report on the relevant mechanics for streamlining industrially relevant polymers such as polystyrene (PS), polypropylene (PP), high-density polyethylene (HDPE), and acrylonitrile butadiene styrene (ABS) into chemical slurries mixed with various organic solvents such as toluene, xylene, and cyclohexane. The miscibility of the polymer feedstock within the solvent was evaluated using the Relative Energy Difference method, and the dissolution process was evaluated using the “Molecular theories in a continuum framework” model. These models were used to design a batch process yielding 1 tonne/h slurry by setting appropriate assumptions including constant viscosity of solvents, disentanglement-controlled dissolution mechanism, and linear increase in the dissolved polymer’s mass fraction over time. Solvent selection was found to be the most critical parameter for the dissolution process. The characteristics of the ideal solvent are high affinity to the desired polymer and low viscosity. This work serves as a universal technical guideline for the open-loop chemical recycling of plastics, avoiding the growth of waste plastic by utilising them as a carbon feedstock towards a circular economy framework.
Highlights
IntroductionPlastics are undoubtedly one of the most useful materials to mankind
Publisher’s Note: MDPI stays neutralPlastics are undoubtedly one of the most useful materials to mankind
Open-loop recycling provides a more sustainable solution to the plastics pollution problem than other recycling techniques because the lifetime of the hydrocarbon is extended beyond the first use as a plastic
Summary
Plastics are undoubtedly one of the most useful materials to mankind. Their versatility can meet almost any requirement, which is something that can be proven by taking a glance at their daily use [1]. Despite their benefits, the majority are thrown away after only a single use. Hydrocarbons are highly versatile and can be used as feedstock for creating various materials other than plastics; ideally, they would be used to make materials with high asset value and intrinsic beneficial material properties, and this can be done using open-loop recycling. Open-loop recycling is required to make any with regard to jurisdictional claims in published maps and institutional affiliations
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