Dispersion Polymerisations in Supercritical Carbon Dioxide for the Production of Core-Shell Particles

Kortsen, Kristoffer (2023) Dispersion Polymerisations in Supercritical Carbon Dioxide for the Production of Core-Shell Particles. PhD thesis, University of Nottingham.

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Polymer additives are an essential part of the plastics industry. Impact modifiers are a class of additives widely used to improve impact resistance of typically brittle plastics. However, they are currently produced in water but sold as a dry powder, necessitating a very energy intensive spray-drying process. This thesis reports on the exploration of using CO2 as the rection medium to produce impact modifiers, as this will allow the drying step to be bypassed, reducing overall energy costs by over 90%.

While polymerisations had been conducted in scCO2 previously, three large questions appeared towards assessing the suitability of this solvent in producing impact modifiers. Firstly, reactions in scCO2 have been difficult to monitor, so could we develop a more accessible monitoring method? secondly, what are the limits of the system and what are the effects of changing reaction conditions in scCO2? Finally, impact modifiers are polymer particles with intricate core-shell morphology, so could we develop a synthesis method to achieve this morphology in scCO2?

These questions were addressed one-by-one in this thesis. Firstly, using a novel sampling cylinder, a method was developed that allowed for the reliable on-line monitoring of a wide range of polymerisations. The sampling cylinder also helped to assess the effect of varying reactor conditions real time. It was discovered that, beyond conventional reactor loading effects, the pressure of the reactor affects particle size. Finally, the gained insights of kinetics and control were exploited to synthesise the first ever core-shell particles in scCO2. While a very narrow operating window was determined, the fundamental understanding gained in this work showed it was possible to make core-shell particles with controlled domain ratios and sizes.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Howdle, Steve
Keywords: supercritical carbon dioxide, polymers, synthesis, additives, impact modifiers, dispersion
Subjects: Q Science > QD Chemistry > QD241 Organic chemistry
T Technology > TP Chemical technology
Faculties/Schools: UK Campuses > Faculty of Science > School of Chemistry
Item ID: 72413
Depositing User: Kortsen, Kristoffer
Date Deposited: 26 Jul 2023 04:40
Last Modified: 26 Jul 2023 04:40
URI: https://eprints.nottingham.ac.uk/id/eprint/72413

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