Epilogue: Sorting, Depolymerizing, and Recycling Polymers: The Long Road to a Circular Plastics Economy

Abstract

After Hermann Staudinger laid the foundations of polymer science 100 years ago, an extraordinary scientific, technological, and industrial saga has been written by a long list of academic and industrial scientists. As a result, polymers are present in practically all sectors of human activity, transforming human societies in terms of quality of life, safety, hygiene, etc. Yet the expansion in the production and use of polymeric materials comes at a price for the environment because the polymer economy has been organized since its inception under the “ take, make, dispose ” pattern. Such a linear organization of the polymer economy causes considerable damages to the environment, wastes resources, and harms wildlife. This article discusses the steps that need to be taken worldwide to turn a still linear polymer economy into a circular one. Questions such as the sorting of polymer waste, their mechanical recycling, their recycling through nonchemical processes, the depolymerization of some polymers into monomers, the pyrolysis of nondegradable polymers, the potential of biodegradation processes are critically reviewed. Recommendations are made in this article to dramatically reduce the carbon footprint of the whole production chain from monomer synthesis to the manufacture of polymers and build a truly circular polymer economy with reuse, repair, and recycle as its foundations.

Understanding Alkali Cation-Assisted Ring-Opening Polymerization of Macrocyclic Carbonate: Kinetics and Thermodynamics

“…The semilogarithmic plots of ROP of 4EGMC catalyzed by different cations with TBD showed the first-order polymerization, where the observed rate constant (k obs ) of the Li +mediated reaction is the highest among these cations, and Na + is the lowest (Li + k obs 0.36 min −1 > K + k obs 0.23 min −1 > Na + k obs 0.16 min −1 , Figure 3c). Moreover, the polymerization of 4EGMC assisted by alkali cations revealed comparable molecular weights and dispersity characterized by 1 H NMR and SEC (M n NMR = 4.0−4.3 kg mol −1 , M n SEC = 5.8−6.3 kg mol −1 , and D̵ = 1.13−1.20, Table S3). In comparison with TBD-catalyzed polymerization (k obs = 0.0013 min −1 ), the addition of alkali cations shows extremely rapid kinetics with ca.…”

“…40−42 We therefore postulated that 4EGMC with high electron density could accommodate Na + to yield a complex. 1 H NMR spectroscopy analysis of the mixture of 4EGMC/Na + with different ratios depicted a maximum downfield shift of α proton of the carbonate group by +0.079 ppm, demonstrating the interaction between 4EGMC and Na + (Figure S4). Moreover, Job's plot depicted a maximum at χ = 0.5, revealing a complex with a 1:1 ratio of 4EGMC and Na + in the solution (Figure 1, top).…”

“…Engineering polymers with on-demand physical properties through controllable polymerization accelerates the innovation in polymer production. – Ring-opening polymerization (ROP), – one of the most important methods of polymerization, has been applied to the generation of versatile polymers. – For cyclic monomers including lactides, lactones, etc., polymerization occurs through an ester bond assisted by both the release of the ring strain and the change of conformational and translational entropy, yielding a well-defined polymer structure. While the field in the design of benign catalytic systems to active ester bonds, thereby kinetically regulating the polymerization, is significantly developed, – studies focusing on modulating the thermodynamics to influence the outcome of polymerization remain a challenge, resulting from the ring strain and the change of enthalpy, Δ H p , of a given cyclic structure are difficult to be affected by external conditions.…”

Membangun Kultur Zero Waste Di Sekolah

“…Alhasil, permasalahan bukan hanya pada pemakaian plastik tetapi juga perilaku dan kebiasaan dari masyarakat itu sendiri. (Gnanou, 2022). Kebiasaan kurangnya pengelolaan sampah menyebabkan seperti lingkungan yang kumuh, bau tidak sedap serta sebagai sumber penyakit (Ristya & Khasanah, 2020).…”