Chapter 4 Oxidative Degradation of Polymers

Rabek, Jan F.

doi:10.1016/s0069-8040(08)70336-4

Cited by 48 publications

(26 citation statements)

References 468 publications

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“…additional influences also play a role), and particle shape can be accounted for by averaging overall possible particle shape [69]. The models used to describe these degradation process are often frequently complicated, but as a general rule focus on chain scission in the polymer backbone through (a) random chain scission (all bonds break with equal probability) characterised by oxidative reactions; (b) scission at the chain midpoint dominated by mechanical degradation; (c) chain-end scission, a monomer-yielding depolymerisation reaction found in thermal and photodecomposition processes; and (d) in terms of inhomogeneity (different bonds have different breaking probability and dispersed throughout the system) [71][72][73]. The estimation of degradation half-lives has also been considered for strongly hydrolysable polymers through the use of exponential decay eqs.…”

Section: Environmental Persistence and Degradationmentioning

confidence: 99%

Microplastics Are Contaminants of Emerging Concern in Freshwater Environments: An Overview

Lambert

Wagner

2017

The Handbook of Environmental Chemistry

212

137

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In recent years, interest in the environmental occurrence and effects of microplastics (MPs) has shifted towards our inland waters, and in this chapter we provide an overview of the issues that may be of concern for freshwater environments. The term 'contaminant of emerging concern' does not only apply to chemical pollutants but to MPs as well because it has been detected ubiquitously in freshwater systems. The environmental release of MPs will occur from a wide variety of sources, including emissions from wastewater treatment plants and from the degradation of larger plastic debris items. Due to the chemical makeup of plastic materials, receiving environments are potentially exposed to a mixture of microand nano-sized particles, leached additives, and subsequent degradation products, which will become bioavailable for a range of biota. The ingestion of MPs by aquatic organisms has been demonstrated, but the long-term effects of continuous exposures are less well understood. Technological developments and changes in demographics will influence the types of MPs and environmental concentrations in the future, and it will be important to develop approaches to mitigate the input of synthetic polymers to freshwater ecosystems.

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Section: Environmental Persistence and Degradationmentioning

confidence: 99%

Microplastics Are Contaminants of Emerging Concern in Freshwater Environments: An Overview

Lambert

Wagner

2017

The Handbook of Environmental Chemistry

212

137

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“…Figure 6b represents a comparative characteristic of the reduction in the weight of PLAP materials in argon and air atmosphere at 600 °C in the time period of 5-30 min. It can be clearly observed that the reduction in weight in case of air atmosphere is always a bit higher, and it can be explained as the polymers can be oxidized upon exposure to the oxygencontaining atmosphere [51].…”

Section: Thermal Disengagement Technology (Tdt) Of Plapmentioning

confidence: 99%

Microrecycling of the metal–polymer-laminated packaging materials via thermal disengagement technology

2019

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Polymer-laminated metals are widely used in the packaging industries due to their flexibility of applications, superior properties, and relatively lower cost. Despite the advantages accomplished by the polymer-metal multilayer packaging materials, the recycling is a very difficult task due to the complexities of multimaterial intrinsic behaviors during the processing of cast-off materials. This study represents an innovative and sustainable way of recycling polymerlaminated aluminum packaging (PLAP) materials (postconsumer food packaging) into high-quality aluminum and a potential source of high-energy hydrocarbon gases and particulate carbon coproducts. Both sides of the aluminum foil of the packaging were laminated by two different polymers (polyethylene terephthalate, and polypropylene). Volatiles from the PLAP materials were eliminated by the thermal disengagement technology at 400-650 °C (5-30 min) with and without an inert gas supply. The volatiles evaporated from the PLAP materials were about 32%, and the rest 68% were aluminum (~ 65%) and carbon (~ 3%) from the decomposition of the polymers. The oxidation behavior of the surface of the recycled aluminum was studied by XRD, XPS, and elementary mapping, and a nanoscale oxidized surface was found in both inert and air atmospheric TD. The purity of the aluminum was measured above 98% by two different methods (LIBS and ICP-MS). The gaseous products released in TD were detected as high energy-carrying hydrocarbon, CO 2 , CO, H 2 , H 2 O, and few other gases observed by real-time monitoring. The clean gases released in TD might be utilized upon reforming into CH 4 or H 2 by further processing or as it turns out might be utilized as a source of heat energy for other applications. Carbon found from the decomposition of the hydrocarbons can be another useful element of this study. This recycling process offers an economically and environmentally feasible recycling strategy for a complex multilayer polymer-metal packaging waste.

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“…In this case, there is an induction period during which the polymer may not reveal obvious modifications. However, small amounts of hydroperoxides may be formed and initiate subsequent rapid auto‐oxidation of the polymer …”

Section: Sterilization Of Hydrogel‐based Medical Devicesmentioning

confidence: 99%

“…However, small amounts of hydroperoxides may be formed and initiate subsequent rapid auto-oxidation of the polymer. 61 Sterilization of hydrogels can be more complex than in other types of polymers due to the presence of water in these materials that can potentiate the harmful effects of sterilizing processes.…”

Section: Sterilization Of Hydrogel-based Medical Devicesmentioning

confidence: 99%

Sterilization of hydrogels for biomedical applications: A review

et al. 2017

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Despite the beneficial properties and outstanding potential of hydrogels for biomedical applications, several unmet challenges must be overcome, especially regarding to their known sensitivity to conventional sterilization methods. It is crucial for any biomaterial to withstand an efficient sterilization to obtain approval from regulatory organizations and to safely proceed to clinical trials. Sterility assurance minimizes the incidence of medical device-related infections, which still constitute a major concern in health care. In this review, we provide a detailed and comprehensive description of the published work from the past decade regarding the effects of sterilization on different types of hydrogels for biomedical applications. Advances in hydrogel production methods with simultaneous sterilization are also reported. Terminal sterilization methods can induce negative or positive effects on several material properties (e.g., aspect, size, color, chemical structure, mechanical integrity, and biocompatibility). Due to the complexity of factors involved (e.g., material properties, drug stability, sterilization conditions, and parameters), it is important to note the virtual impossibility of predicting the outcome of sterilization methods to determine a set of universal rules. Each system requires case-by-case testing to select the most suitable, effective method that allows for the main properties to remain unaltered. The impact of sterilization methods on the intrinsic properties of these systems is understudied, and further research is needed. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 2472-2492, 2018.

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Chapter 4 Oxidative Degradation of Polymers

Cited by 48 publications

References 468 publications

Microplastics Are Contaminants of Emerging Concern in Freshwater Environments: An Overview

Microplastics Are Contaminants of Emerging Concern in Freshwater Environments: An Overview

Microrecycling of the metal–polymer-laminated packaging materials via thermal disengagement technology

Sterilization of hydrogels for biomedical applications: A review

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