Burnett, Connah Andrew (2018) Radical block copolymers of linear low density polyethylene macromonomers. PhD thesis, University of Warwick.

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Abstract

Chapter 1 introduces the concept of wax crystal modification in middle distillate fuels and reviews the more common chemical additives used commercially, and by examination of the advantages and drawbacks of these additives discusses the possible benefits of polyolefin block copolymers. From this end functionalisation of polyethylene (PE) as a route to block copolymers is reviewed from different literature methods for their synthesis.

Chapter 2 introduces the catalytic hydride insertion polymerisation mechanism as a route to end functional polyolefins and goes on to focus on the production of end functional ethylene/hexene copolymers. Using a range of comonomer concentrations and a number of catalysts, end-functional copolymers with a range of comonomer incorporation are produced. The thermal properties of these polymers are investigated and matrix assisted laser desorption/ionisation (MALDI) mass spectra were acquired. Finally, the chapter discusses the synthesis of short chain analogues of end functional PE.

Chapter 3 describes the production of polyolefin-polar block copolymers via the free radical polymerisation of the functional polyolefins with a range of polar monomers. A reversible termination mechanism similar to nitroxide mediated polymerisation is proposed. The products are analysed by gel permeation chromatography (GPC) and by an in detail 2D NMR study to confirm block copolymer structure.

Chapter 4 examines the physical properties of the synthesised block copolymers. The tendency of the copolymers to aggregate in solution into particles of varying size is investigated by VT NMR and dynamic light scattering (DLS), these findings were supported by transmission electron microscopy (TEM). The thermal properties of these copolymers were studied by differential scanning calorimetry (DSC). Following this the efficacy of these polymers as wax crystal modifiers (WCM) for fuels was investigated by cold flow plugging point (CFPP), optical microscopy and DSC of the treated fuels. Finally, the behaviour of the polymers in solid polyethylene wax was investigated by drop shape analysis (DSA) and x-ray photoelectron spectroscopy (XPS).

Chapter 5 details the various experimental procedures used to carry out the work in this thesis.

Appendix A gives an overview of polymerisations between ethylene and α- methylstyrene comonomers catalysed by hafnocene catalysts and goes on to detail the investigation of the materials acquired. Analysis was conducted using 2-D NMR, MALDI and diffusion-ordered spectroscopy (DOSY). Appendix B contains the DLS correlograms for samples analysed in chapter 4. Appendix C contains the schematic diagram for the gas burettes system used for metallocene polymerisations

Item Type:	Thesis or Dissertation (PhD)
Subjects:	T Technology > TP Chemical technology
Library of Congress Subject Headings (LCSH):	Petroleum as fuel -- Additives, Polyolefins -- Synthesis, Block copolymers, Addition polymerization
Official Date:	2018
Dates:	Date Event 2018 UNSPECIFIED
Institution:	University of Warwick
Theses Department:	Department of Chemistry
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	Scott, Peter, (Professor of chemistry)
Sponsors:	Engineering and Physical Sciences Research Council, Infineum UK Ltd
Extent:	xxiv, 152 leaves : illustrations, charts
Language:	eng

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