The preparation of polymers of improved stability requires an understanding of the relationship between structure and mechanism of decomposition. In this project, this relationship is explored for several classes of polymer. The main degradation techniques which have been used, described in Chapter 2, are thermogravimetry (TG), thermal volatilisation analysis (TVA) and differential thermal analysis (DTA). Degradation products have been separated and analysed using subambient TVA, and GC-MS, IR and MS spectroscopy. The preparation and spectroscopic analysis of poly(alkylene terephthalates), poly(ether-esters), polyarylates and alpha,o-bifunctional poly(methyl methacrylate) described in Chapter 3. In Chapters 4 and 5,studies of the thermal degradation of poly(alkylene terephthalates) and poly(ether-esters) made by melt polymerisation of terephthaloyl chloride with aliphatic diols and poly(ethylene glycols) (Mw 200, 1000) are reported. In order to achieve a detailed analysis of the degradation products, both temperature programmed and isothermal experiments were performed on these polymers. From the results obtained, the general mechanism of decomposition has been established. In Chapter 6, a similar investigation of nine different polyarylates, including fire retardant polyarylates, made by interfacial polycondensation from aromatic diols and terephthaloyl chloride is reported and the effects of fire retardant incorporated to the backbone of polymer are discussed. It is clear there are many close similarities in mechanism, especially in the sense that similar radicals are usually involved. In Chapter 7, the results of a comprehensive study of the thermal degradation of four different o,o-bifunctional poly(methyl methacrylates) made by the anionic route are analysed and the general mechanism of decomposition has been proposed. The effect of the functional end groups on the thermal stability and mechanistic behaviour are discussed
