The accumulation of mismanaged plastic waste (MPW) in the environment is a global growing concern. Knowing with precision where litter is generated is important to target priority areas for the implementation of mitigation policies. In this study, using country-level data on waste management combined with high-resolution distributions and long-term projections of population and the gross domestic product (GDP), we present projections of global MPW generation at ~1 km resolution from now to 2060. We estimated between 60 and 99 million metric tonnes (Mt) of MPW were produced globally in 2015. In a business-as-usual scenario, this figure could triple to 155–265 Mt y−1 by 2060. The future MPW load will continue to be disproportionately high in African and Asian continents even in the future years. However, we show that this growth in plastic waste can be reduced if developing economies significantly invest in waste management infrastructures as their GDP grows in the future and if efforts are made internationally to reduce the fraction of plastic in municipal solid waste. Using our projections, we also demonstrate that the majority of MPW (91%) are transported via watersheds larger than 100 km2 suggesting that rivers are major pathways for plastic litter to the ocean.

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Future scenarios of global plastic waste generation and disposal

Spectrometric Identification of Organic Compounds

The current global plastics economy is highly linear, with the exceptional performance and low carbon footprint of polymeric materials at odds with dramatic increases in plastic waste. Transitioning to a circular economy that retains plastic in its highest value condition is essential to reduce environmental impacts, promoting reduction, reuse, and recycling. Mechanical recycling is an essential tool in an environmentally and economically sustainable economy of plastics, but current mechanical recycling processes are limited by cost, degradation of mechanical properties, and inconsistent quality products. This review covers the current methods and challenges for the mechanical recycling of the five main packaging plastics: poly(ethylene terephthalate), polyethylene, polypropylene, polystyrene, and poly(vinyl chloride) through the lens of a circular economy. Their reprocessing induced degradation mechanisms are introduced and strategies to improve their recycling are discussed. Additionally, this review briefly examines approaches to improve polymer blending in mixed plastic waste streams and applications of lower quality recyclate.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/marc.202000415

Mechanical Recycling of Packaging Plastics: A Review.

Understanding plastic degradation and microplastic formation in the environment: A review

Photo- and thermal-oxidation of polyethylene: Comparison of mechanisms and influence of unsaturation content

Photodegradation characterization and heterogeneity evaluation of the exposed and unexposed faces of stabilized and unstabilized LDPE films

https://www.omicsonline.org/2469-9764/2469-9764.C1.003-006.pdf

Identification of carbonyl species of weathered LDPE films by curve fitting and derivative analysis of IR spectra

Anisotropy evolution of low density polyethylene greenhouse covering films during their service life

This work analyzes the influence of thermal degradation on the microstructure and the mechanical properties of low-density polyethylene subjected to aging at 70°C in the dark for times up to 21 months. It is found that the polymer shows a gradual increase of its elastic modulus and a dramatic reduction of its ductility, due to secondary crystallization. Infrared spectroscopy (FTIR) reveals the autoaccelerated oxidation of the polymer after 5 months aging. It is observed that the unsaturated vinylidene groups initially present in the material are gradually overridden by vinyl groups and, eventually, by t-vinylene groups. Nuclear magnetic resonance (13C NMR) shows that the initial butyl chain branches are progressively completed by shorter ramifications, namely ethyl branches. These results are discussed in term of macromolecular mechanisms: (i) oxidation, (ii) chain scission, and (iii) crosslinking. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Oxidation and crosslinking processes during thermal aging of low-density polyethylene films

Blown extruded films of low-density polyethylene (LDPE) have been subjected to climatic ageing in a sub-Saharan facility at Laghouat (Algeria) with direct exposure to sun. Samples were characterized by complementary techniques after prescribed amounts of time up to 8 months. It was shown by tensile testing that the mechanical properties are quite sensitive to ageing: (i) the elastic modulus increases and saturates, (ii) the tensile stress increases slightly, and (iii) the rupture energy decreases dramatically after 4 months weathering. Fourier-transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (13C NMR) were performed to identify the evolution of the polymer microstructure. The FTIR spectra reveal the initial presence of vinylidene groups that exhaust rapidly after 4 months ageing. Also, it detects the progressive multiplication of vinyl groups and oxidation products of many kinds. The NMR technique revealed specifically the carbon–carbon configurations in the polymer chains. By contrast to the original film that contained almost exclusively butyl chain branches, the aged specimens presented shorter ramifications, namely ethyl branches. Also, the presence of quaternary atoms was detected after long ageing times. The discussion of these complementary results in the light of current literature makes possible to identify the leading mechanisms that control the decay of LDPE film properties. Although these mechanisms are numerous and complex, they can be schematically summarized within three main classes: oxidation, scission, and crosslinking. Each class is discussed in details. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008

S. F. Chabira

Papers

Photodegradation characterization and heterogeneity evaluation of the exposed and unexposed faces of stabilized and unstabilized LDPE films

Identification of carbonyl species of weathered LDPE films by curve fitting and derivative analysis of IR spectra

Anisotropy evolution of low density polyethylene greenhouse covering films during their service life

Oxidation and crosslinking processes during thermal aging of low-density polyethylene films

Influence of climatic ageing on the mechanical properties and the microstructure of low‐density polyethylene films