The performance of a novel microwave-induced pyrolysis process was evaluated by studying the degradation of high-density polyethylene and aluminum/polymer laminates in a semibatch bench-scale apparatus. The results showed that the new process has the same general features as other, more traditional, pyrolytic processes but with the advantage that it is able to deal with problematic wastes such as laminates. Degradation experiments were performed between 500 and 700 °C and the relationship between temperature, residence time of the pyrolytic products in the reactor, and the chemical composition of the hydrocarbon fraction produced was investigated. Toothpaste tubing was used as an example of a laminated material to be treated with the novel process. Clean aluminum was recovered together with hydrocarbons and the trial proved that the process has excellent potential for the treatment of plastic wastes on a commercial scale.

Plastics play an enormous role in modern manufacturing, but the extraction and refining of raw materials, followed by the synthesis of plastics themselves, represents an enormous energy investment into a product that is all too often simply "thrown away" into a landfill after a single use. Microwave-assisted pyrolysis is a recycling technique that allows the recovery of chemical value from plastic waste by breaking down polymers into useful smaller hydrocarbons using microwave heat in the absence of oxygen. This dissertation examines the use of a catalytic activated carbon bed in this procedure, using high density polyethylene (HDPE) as a model plastic. Initial tests with the batch input of HDPE produced a condensed pyrolysis oil comprising 35.5-45.3% aromatics, with the remainder primarily short-chain aliphatics. This oil was approximately three times lighter than that produced in the absence of catalyst, with a narrower range of molecular masses that matched those of the liquid transport fuels petrol and diesel (C 5-C 21). The non-condensable gases that resulted were short-chain aliphatics that could be used as feedstock for the creation of new chemicals (such as virgin HDPE), or fuels such as natural gas and LPG. The development of apparatus capable of adding sample in a continuous fashion enabled the processing of larger quantities of HDPE, and resulted in condensed products with a significantly higher aromatic content (>80% at 450°C), and which I owe a debt of thanks to many people for the support and kindness they have shown me throughout my time in Cambridge. I would like to thank my supervisor, Professor Howard Chase, for his generous provision of tutelage, expertise, and support throughout the production of this work. A further thank you to my colleagues and the department support staff for their extremely skilled time and advice. I would also like to acknowledge the generous financial support that I have received from the Cambridge Commonwealth Trust, The Higher Education Funding Council for

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