Upcycling Polystyrene

Abstract

Several environmental and techno-economic assessments highlighted the advantage of placing polystyrene-based materials in a circular loop, from production to waste generation to product refabrication, either following the mechanical or thermochemical routes. This review provides an assortment of promising approaches to solving the dilemma of polystyrene waste. With a focus on upcycling technologies available in the last five years, the review first gives an overview of polystyrene, its chemistry, types, forms, and varied applications. This work presents all the stages that involve polystyrene’s cycle of life and the properties that make this product, in mixtures with other polymers, command a demand on the market. The features and mechanical performance of the studied materials with their associated images give an idea of the influence of recycling on the structure. Notably, technological assessments of elucidated approaches are also provided. No single approach can be mentioned as effective per se; hybrid technologies appear to possess the highest potential. Finally, this review correlates the amenability of these polystyrene upcycling methodologies to frontier technologies relating to 3D printing, human space habitation, flow chemistry, vertical farming, and green hydrogen, which may be less intuitive to many.

Initiator‐Activation Strategy‐Enabled Organocatalyzed Reversible‐Deactivation Radical Polymerization Driven by Light

“…Polymers with repeating units of styrene, 4-styrenesulfonic acid and its salt have found various applications, [24] where the units could directly convert into aryl sulfonyl chloride through electrophilic substitution of aromatic CÀ H bond, or chlorination of sulfonic acid and sulfonate groups.…”

“Functional upcycling” of polymer waste towards the design of new materials

“…PS accounts for approximately 10 wt% of the total plastic waste produced annually in the last ten years due to its high abundance as an industrial, packaging, and household polymer. 71,346 By 2024, it is forecasted to grow to an expected production capacity of 15.68 Mt. 347 The most common forms of PS include solid blocks, films, and expanded foams.…”

Ionic Liquid‐Assisted Depolymerization of Condensation Polymers: A Review

“…These polymers are easily depolymerized into monomers via a nucleophilic attack on the C=O bond, which facilitates cleavage of the C−N or C−O bond. On the other hand, depolymerization is much slower in polystyrene, polyvinyl chloride, polypropylene, and polyethylene due to the high energy input [72–78] . Alcoholysis (glycolysis and methanolysis), hydrolysis, aminolysis, and ammonolysis are polymers′ most common chemical recycling mechanisms (Figure 5).…”