Each year vast amounts of plastic are produced worldwide. When released to the environment, plastics accumulate, and plastic debris in the world's oceans is of particular environmental concern. More than 60% of all floating debris in the oceans is plastic and amounts are increasing each year. Plastic polymers in the marine environment are exposed to sunlight, oxidants and physical stress, and over time they weather and degrade. The degradation processes and products must be understood to detect and evaluate potential environmental hazards. Some attention has been drawn to additives and persistent organic pollutants that sorb to the plastic surface, but so far the chemicals generated by degradation of the plastic polymers themselves have not been well studied from an environmental perspective. In this paper we review available information about the degradation pathways and chemicals that are formed by degradation of the six plastic types that are most widely used in Europe. We extrapolate that information to likely pathways and possible degradation products under environmental conditions found on the oceans' surface. The potential degradation pathways and products depend on the polymer type. UV-radiation and oxygen are the most important factors that initiate degradation of polymers with a carbon-carbon backbone, leading to chain scission. Smaller polymer fragments formed by chain scission are more susceptible to biodegradation and therefore abiotic degradation is expected to precede biodegradation. When heteroatoms are present in the main chain of a polymer, degradation proceeds by photo-oxidation, hydrolysis, and biodegradation. Degradation of plastic polymers can lead to low molecular weight polymer fragments, like monomers and oligomers, and formation of new end groups, especially carboxylic acids.

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Pathways for degradation of plastic polymers floating in the marine environment

Plastic waste is currently generated at a rate approaching 400 Mt year–1. The amount of plastics accumulating in the environment is growing rapidly, yet our understanding of its persistence is very...

Degradation Rates of Plastics in the Environment

In recent years the littering of plastics and the problems related to their persistence in the environment have become a major focus in both research and the news. Biodegradable polymers like poly(lactic acid) are seen as a suitable alternative to commodity plastics. However, poly(lactic acid) is basically non-degradable in seawater. Similarly, the degradation rate of other biodegradable polymers also crucially depends on the environments they end up in, such as soil or marine water, or when used in biomedical devices. In this Minireview, we show that biodegradation tests carried out in artificial environments lack transferability to real conditions and, therefore, highlight the necessity of environmentally authentic and relevant field-testing conditions. In addition, we focus on ecotoxicological implications of biodegradable polymers. We also consider the social aspects and ask how biodegradable polymers influence consumer behavior and municipal waste management. Taken together, this study is intended as a contribution towards evaluating the potential of biodegradable polymers as alternative materials to commodity plastics.

https://www.onlinelibrary.wiley.com/doi/epdf/10.1002/anie.201805766

Plastics of the Future? The Impact of Biodegradable Polymers on the Environment and on Society

http://petrops.com/files/article_pdf/article1.pdf

Recycling of PET

Designing and developing flexible electronics requires a thorough investigation of the substrates available for the fabrication of devices. Here, we present a practical study on a variety of significant substrates: polyethylene terephthalate (PET), its heat-stabilized (HS) derivative, HS-PET, and polyethylene naphthalate (PEN) plastic insulating films; indium tin oxide (ITO)-coated ITO/PEN and ITO/PET transparent conducting films; rigid ITO/glass and FTO/glass substrates; stainless steel and titanium foils. We put the substrates through a range of tests these actually undergo during device fabrication to determine their optical, mechanical flexibility (under different types of tensile and compressive stress bending with and without a PEDOT:PSS conducting polymer layer), solvent resistance, stability to temperature treatment (conductivity and deformation), and to UV irradiation. We highlight issues and propose solutions to improve substrate response. The results and thresholds extracted reveal limitations and windows of opportunity useful for the designer of flexible optoelectronics in determining manufacturing processes and the final applications under everyday operation.

Substrates for flexible electronics: A practical investigation on the electrical, film flexibility, optical, temperature, and solvent resistance properties

Physicochemical aspects of the environmental degradation of poly(ethylene terephthalate)

Aspects of poly(ethylene terephthalate) degradation for archival life and environmental degradation

Hydrolytic degradation of poly(ethylene terephthalate): Importance of chain scission versus crystallinity

UV and thermal hydrolytic degradation of poly(ethylene terephthalate) : importance of hydroperoxides and benzophenone end groups

Samples of poly(ethylene terephthalate) bottle material were degraded under dif ferent environmental conditions, including thermal degradation, hydrolysis, and photo oxidation. The extent of degrad...

Ken Jones

Papers

Physicochemical aspects of the environmental degradation of poly(ethylene terephthalate)

Aspects of poly(ethylene terephthalate) degradation for archival life and environmental degradation

Hydrolytic degradation of poly(ethylene terephthalate): Importance of chain scission versus crystallinity

UV and thermal hydrolytic degradation of poly(ethylene terephthalate) : importance of hydroperoxides and benzophenone end groups

Environmental Degradation of Poly ( ethylene Terephthalate )