Thesis, 'Studies in the fluorination of some halogen containing polymers', by Brian Richard John Thomas D.Phil thesis submitted by B.J.R. Thomas as as candidate at the University of Birmingham, supervised by Professor W.N. Haworth FRS and Professor M. Stacey. List of contents; General Introduction Section I The production of fluorine The preparation of cobalt trifluoride The preparation of silver difluoride Description of apparatus Experimental Section II Stabilization of Polymeric Fluoro and Chlorofluoro lubricants Stabilisation of the benzotrifluoride polymer The effect of the silver difluoride method of stabilisation on some chlorofluoropolymers Production of a UF6 resistant lubricant from a polymer obtained by the polymerisation of perfluorovinyl chloride A review of the methods developed for the production of a lubricant resistant to uranium hexafluoride Considerations of the mechanism of polymerisation and stabilisation Experimental Section III Some reactions of silver difluoride Reaction of silver difluoride with non-chlorine containing substances Reaction of silver difluoride with chlorine containing compounds Experimental Concerns one of the fundamental problems of the atomic energy project, the efficient separation of the uranium isotope U235 from naturally occurring uranium which is principally a mixture of two isotopes U238 and U235, the ratio of the former to the latter being approximately 140:1 Of the two main methods available for their separation, namely electromagnetic separation and diffusion separation, the second appeared the most attractive since although it did not give as high a separation factor as the electromagnetic method, it was capable of operation on a much larger scale. Attention was accordingly fixed on the diffusion separation (although subsequently the electromagnetic method was developed elsewhere) for which a gaseous compound of uranium was required. October 1946