The production of polymer fibres with high performance and FT-raman spectroscopy at 1.3um

The work described in this thesis involved the role of molten metal baths in the quench cooling of polyethylene in the production of polymer Abres with high performance. A melt-spinning rig was designed and constructed. Chapter 2 describes how polymer fibres were produced from the melt by spinning fibres through a reservoir of molten melt which was held at temperatures near the melting point of the polymer. Polyethylene fibres with a tensile modulus of the order of 25 GPa and tensile strength approaching 1 GPa were produced by a process of melt spinning followed by cold drawing to a draw ratio of 15. Raman spectroscopy is an invaluable analytical tool used in a multitude of applications. The ease and versatility of the technique provides a simple method for identification and studying ciystallinity of specimens. The fbremost choice of laser source for FT-Raman has been the continuous wave Nd^^: YAG solid state laser operating at 1.064 |im. Chapter 4 investigates the possibility of using the 1.319 p,m lasing emission from the Nd''^; YAG laser as an alternate source. The sensitivity of the source is determined, applications are illustrated and the limitations commented upon.