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Title: Oxidation and degradation of polymers in near and supercritical water
Author: Cameron, R. M.
Awarding Body: University of Cambridge
Current Institution: University of Cambridge
Date of Award: 2000
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Polymer disposal and recycling is an important issue in society today, particularly in Europe and the USA where pressures to recycle waste materials are intense. Existing recycling technologies are often expensive and result in low-grade applications, which are less likely to be recycled again. Most waste polymers end up at landfill sites and some, at worst, get incinerated and create 'green house gases'. The ideal solution to polymer waste treatment is to consider it as a resource, where the objective is to recover useful chemicals, which have a commercial value. The unique properties of near and supercritical water (374 oC, 218 atm) mimic polar organic solvents thus acting as a medium for organic synthesis. It also has the ability to be miscible with gases, at the critical temperature, which makes it ideal for oxidation reactions. The ion dissociation constant (Kw) changes by an order of magnitude from the ambient temperature to the cortical, thus facilitating acid and base catalysed reactions, making it ideal for hydrolysis chemistry. A full discussion of the latest developments in near and supercritical water are discussed in Chapter One. Chapter Two demonstrates the successful use of near and supercritical water to oxidise polyethylene and polypropylene at a variety of temperatures and pressures. The mechanism of oxidation is also discussed. The oxidations of polystyrene and block co-polymer elastomer are covered in Chapter Three. Chapter Four details an extensive investigation into potential oxidation catalyst for polymers in superheated water, which have demonstrated selectivity and yields of oxidation products. The hydrolysis of polymers is discussed in Chapter Five, with particular attention to polyvinyl acetate (PVAC). PVAC was converted to polyvinyl alcohol (PVA) at varying degrees of hydrolysis.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available