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Goodwin M.J.,Durham University | Musa O.M.,Ashland Speciality Ingredients | Steed J.W.,Durham University
Energy and Fuels | Year: 2015

Fossil fuels are still a necessary and important part of modern living, keeping cars running and houses heated for example. As demands have risen and reservoirs of oil and natural gas have depleted, it has become increasingly more important to tap into fields that were once classified as undesirable. Sour fields, fields high in acidic gases, such as hydrogen sulfide and carbon dioxide, are one such option. There are many difficulties and dangers associated with working sour fields, such as toxicity of the sour gases, hydrate formation, and corrosion of equipment, that have prevented these resources from being used in the past. Many varied methods of overcoming these problems have been developed, from removing the sour components to inhibiting their effects. This review highlights the major issues raised by sour fields as well as a wide range of solutions in use today. © 2015 American Chemical Society. Source

Perrin A.,Durham University | Musa O.M.,Ashland Speciality Ingredients | Steed J.W.,Durham University
Chemical Society Reviews | Year: 2013

This review aims to introduce the chemistry of low dosage inhibitors of clathrate hydrate formation within the context of their role in the oil and gas industry. The review covers both kinetic hydrate inhibitors and anti-agglomerants from the point of view of structure-function relationships, focussing on recent refinements in mechanistic understanding and chemical design, and the consequently evolving and increasingly fine-tuned properties of these fascinating compounds. This journal is © The Royal Society of Chemistry. Source

Joubert F.,Durham University | Sharples G.J.,Durham University | Musa O.M.,Ashland Speciality Ingredients | Hodgson D.R.W.,Durham University | Cameron N.R.,Durham University
Journal of Polymer Science, Part A: Polymer Chemistry | Year: 2014

Lactam groups were introduced onto the backbone of hydroxyethyl cellulose (HEC) to modify properties, such as solubility in organic solvents and solution viscosity and to introduce possible antibacterial activity. Functionalization was achieved using 1-(hydroxymethyl)-2-pyrrolidinone (HMP), and the functionalization reactions were investigated using NMR spectroscopy. The covalent attachment between HEC and HMP was confirmed using 1H-13C correlated NMR experiments. Degrees of functionalization were calculated using integrated 12C NMR spectra, with values of up to 0.9 being demonstrated on the primary alcohol functionality of HEC. The functionalized HECs showed markedly different properties to unfunctionalized HEC, including the ability to swell considerably in water. Functionalized HEC displayed increased thermal stability and reduced solution viscosity compared with unfunctionalized HEC. Moreover, functionalization altered the bacterial adhesion characteristics compared with unfunctionalized HEC. © 2014 The Authors. Journal of Polymer Science Part A: Polymer Chemistry Published by Wiley Periodicals, Inc. Source

Joubert F.,Durham University | Musa O.,Ashland Speciality Ingredients | Hodgson D.R.W.,Durham University | Cameron N.R.,Durham University
Polymer Chemistry | Year: 2015

We demonstrate how 15N labelling can be used to probe the success of 'grafting to' processes, through the preparation of well-defined graft copolymers of hydroxyethyl cellulose by combining RAFT polymerisation and copper-catalysed azide-alkyne cycloaddition (CuAAC). Using synthesised alkyne-functionalised chain transfer agents, short-chain (DP = 10) poly(N-vinylpyrrolidone) (PVP) and poly(N-isopropyl acrylamide) (PNIPAAM) were prepared in high conversion in a controlled manner (DM of ∼1.4 and 1.2 respectively). Separately, partially 15N-labelled N3-HEC was synthesised and characterised using solid state 13C, 15N CP-MAS NMR and FTIR spectroscopies. Alkyne-terminated PVP and PNIPAAM were grafted at different graft densities onto partially 15N-labelled N3-HEC using the click reaction. The hybrid HEC-g-polymer materials were fully characterised using solid state 13C and 15N CP-MAS NMR and FTIR spectroscopies. While 13C and FTIR spectroscopies gave indirect or weak evidence of CuAAC coupling, the cycloaddition of the alkyne-terminated polymers with N3-HEC was proven unambiguously by 15N solid state NMR spectroscopy. This indicates the utility of 15N labelling for probing the coupling efficiency of CuAAC reactions when employed in 'grafting to' processes with cellulosic substrates. This journal is © The Royal Society of Chemistry 2015. Source

Joubert F.,Durham University | Yeo R.P.,Durham University | Sharples G.J.,Durham University | Musa O.M.,Ashland Speciality Ingredients | And 4 more authors.
Biomacromolecules | Year: 2015

Poly(ionic liquid)s (P(IL)s) of different degrees of polymerization (10, 50, and 100) were prepared via RAFT polymerization using an alkyne-terminated xanthate as transfer agent, with a monomer conversion of up to ∼80% and a DM of 1.5 for P(IL)100. Subsequently, P(IL) chains were coupled to 15N-labeled azido-functionalized hydroxyethyl cellulose (HEC), forming graft copolymers of HEC with different chain length and graft densities, which were characterized using (13C and 15N) CP-MAS NMR and FT-IR spectroscopies. The antibacterial activities of HEC-g-P(IL)s were tested against Escherichia coli and Staphylococcus aureus and were comparable to ampicillin, a well-known antibiotic, demonstrating efficient activity of the graft copolymers against bacteria. Moreover, HEC-g-P(IL)s were slightly more effective against E. coli than S. aureus. A decrease in graft density of P(IL)10 on the HEC backbone decreased the activity of the graft copolymers against both bacteria. These findings suggest that HEC-g-P(IL) could find applications as an antiseptic compound, for example, in paint formulation. © 2015 American Chemical Society. Source

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