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Title: Mechanistic Aspects of Polymerisation Catalysts
Author: Wilson, Polly Alexandra
ISNI:       0000 0004 2672 5093
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2008
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The primary aim of this PhD was to further develop the mechanistic understanding of well-defined ansa-metallocene catalyst systems. SBI and IPCF ligated pre-catalyst materials activated by the trisarylborane, B(C6FSh, and tetrarylborate, [Ph3C][B(C6Fs)4] and [HNMe2Ph][B(C6Fs)4], co-catalysts were studied [SBI = Me2Si(1-lndh and IPCF = Me2C(Cp)(Flu)]. Counteranion influence on the end group distribution of poly(hex-l-ene) was investigated. lH NMR analysis of the polymer samples revealed an end group dependence both on the counteranion and the temperature at which the polymerisation was conducted. The outer-sphere ion pair (OSIP) [(SBI)Zr(CH2SiMe3t..·B(C6Fs)4l gave only vinylene end groups. While the inner-sphere ion pair (ISIP) (SBI)Zr(CH2SiMe3)(Il-Me)B(C6Fsh gave both vinylidene and vinylene end groups; the relative amount of the former was found to increase with temperature. A feasibility kinetic study into hex-l-ene polymerisations monitored by an on-line gel permeation chromatography (GPC) system was performed. The use of this instrumentation permitted data acquisition approximately every three minutes, giving data relating to molecular weight, polydispersity and conversion. A novel combined UV-visiblej1H NMR approach was employed to unequivocally characterise the absorption bands of different starting materials and catalyst active species. This enabled an extensive library to be constructed for SBI and IPCF bearing systems, which should provide an invaluable basis for future work in this area. Several products from the reactions of (IPCF)ZrMe2 with other materials were isolated and characterised by single crystal X-ray diffraction.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available