The kinetics of cluster fragmentation and depolymerisation

Ziff, Robert M.; McGrady, E. D.

doi:10.1088/0305-4470/18/15/026

Cited by 359 publications

(298 citation statements)

References 19 publications

Supporting

Mentioning

285

Contrasting

Order By: Relevance

“…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

213

137

View full text Add to dashboard Cite

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.

show abstract

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

213

137

View full text Add to dashboard Cite

show abstract

“…Such equations play an important role in reversible polymerization processes and in related aggregation and fragmentation processes. [30][31][32][33][34][35] In our model, the variable window sizes for the chain fusion/fragmentation processes and for the irreversible mechanical breakage of chains imposes somewhat intricate constraints on the corresponding fusion/fragmentation and breakage kernels which must be accounted for correctly as many detailed features, revealed by the subsequent numerical simulations, depend non-linearly on these window sizes themselves. The details of how these window size constraints are handled are explained in the Appendix.…”

Section: Modelmentioning

confidence: 99%

Mechanically Induced Homochirality in Nucleated Enantioselective Polymerization

2017

View full text Add to dashboard Cite

“…If the breakage is also binary, it can be represented by an following overall function β ′ b (υ/υ ′ ) = 2/υ ′ . Other possibilities are a parabolic "U-shape" function for the daughter paricle size distribution (rigid particles are more likely to break into unequal pieces); considerable work in this area has been contributed by Coulaloglou and Tavlarides [34], Prince and Blanche [191] and Luo and Zvendsen [142] For analytical solutions to fragmentation problems, the reader may also consult Ziff and McGrady [268] or Ziff [267] and references within.…”

Section: Transport Equation With Collisions and Sourcesmentioning

confidence: 99%

Population balance modelling of polydispersed particles in reactive flows

Rigopoulos

2010

Progress in Energy and Combustion Science

135

View full text Add to dashboard Cite

Polydispersed particles in reactive flows is a wide subject area encompassing a range of dispersed flows with particles, droplets or bubbles that are created, transported and possibly interact within a reactive flow environment -typical examples include soot formation, aerosols, precipitation and spray combustion. One way to treat such problems is to employ as a starting point the Newtonian equations of motion written in a Lagrangian framework for each individual particle and either solve them directly or derive probabilistic equations for the particle positions (in the case of turbulent flow). Another way is inherently statistical and begins by postulating a distribution of particles over the distributed properties, as well as space and time, the transport equation for this distribution being the core of this approach. This transport equation, usually referred to as population balance equation (PBE) or general dynamic equation (GDE), was initially developed and investigated mainly in the context of spatially homogeneous systems. In the recent years, a growth of research activity has seen this approach being applied to a variety of flow problems such as sooting flames and turbulent precipitation, but significant issues regarding its appropriate coupling with CFD pertain, especially in the case of turbulent flow. The objective of this review is to examine this body of research from a unified perspective, the potential and limits of the PBE approach to flow problems, its links with Lagrangian and multifluid approaches and the numerical methods employed for its solution. Particular emphasis is given to turbulent flows, where the extension of the PBE approach is met with challenging issues. Finally, applications including reactive precipitation, soot formation, nanoparticle synthesis, sprays, bubbles and coal burning are being reviewed from the PBE perspective. It is shown that popualtion balance methods have been applied to these fields in varying degrees of detail, and future prospects are discussed.

show abstract

The kinetics of cluster fragmentation and depolymerisation

Cited by 359 publications

References 19 publications

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

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

Mechanically Induced Homochirality in Nucleated Enantioselective Polymerization

Population balance modelling of polydispersed particles in reactive flows

Contact Info

Product

Resources

About