Rayner, Georgina (2012) Verdazyl radicals as mediators in living radical polymerisation and dopamine end-functionalised polymers for application as friction modifiers. PhD thesis, University of Warwick.

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Abstract

Verdazyl Radicals as Mediators in Living Radical Polymerisation:
The aim of this work was to investigate verdazyl radicals as an alternative to
nitroxides as mediators in stable free radical polymerisation. Verdazyl radicals and
their unimolecular initiators were synthesised and utilised in the polymerisation of
styrene and n-butyl acrylate. Varying degrees of success was observed in the
polymerisations depending on the structure of the verdazyl radical. The
polymerisation of methyl methacrylate and the copolymerisation of styrene and
methyl methacrylate were also investigated. Correlations between observed
molecular weight and theoretical molecular weight were poor but may be improved
by optimisation of the reaction conditions. Electron paramagnetic resonance was
used to elucidate the radical structure as well as to confirm the living nature of the
polymerisation technique. Electron paramagnetic resonance was also utilised to
provide an insight into radical stability and reactivity in the various reactions
undertaken.
Dopamine End-Functionalised Polymers for Application as Friction
Modifiers:
The aim of this work was to synthesise oil soluble dopamine end-functionalised
polymers for mechanical testing to determine if the polymers can reduce friction by
film formation at a surface. A dopamine based initiator was synthesised and used in Cu(I) and Cu(0) mediated polymerisations with little success and the dopamine
catecholic end-group could not be identified as the polymer end-group. To enable a
successful living polymerisation, the catechol groups on dopamine required
protection. Complete deprotection of the catechol group can be achieved post
polymerisation. The polymerisation of lauryl methacrylate was achieved using a
polymerisation method designed for the long chain, non-polar molecule which
utilised Cu(I)Cl. The polymerisations were scaled up to obtain a baseline, protected
dopamine and deprotected dopamine polymers for mechanical testing. A reduction
in friction and wear observed for the deprotected dopamine polymer, however,
corrosion was also observed and may have affected the results.

Item Type:	Thesis or Dissertation (PhD)
Subjects:	Q Science > QD Chemistry
Library of Congress Subject Headings (LCSH):	Dihydrotetrazinyl, Polymerization, Styrene, Acrylates, Dopamine -- Synthesis
Official Date:	January 2012
Dates:	Date Event January 2012 Submitted
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Haddleton, David M.
Sponsors:	University of Warwick ; Lubrizol Ltd.
Extent:	xxxv, 287 leaves : ill., charts
Language:	eng

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