Efficient polyester resin synthesis using microwave heating with scale-up from 50 mL to 5 L

Hargreaves, George William

Efficient polyester resin synthesis using microwave heating with scale-up from 50 mL to 5 L

Publication Date

December 13, 2017

Creator

Hargreaves, George William

Abstract

Polyesters are a vital part of modern day life, with a plethora of different uses such as clothing, coatings, biomedical engineers, drug encapsulation and much more. This means that the synthesis of these products from the raw materials is vital and investigating a way to increase the synthesis efficiency is an important topic of research. The work discussed within this thesis aims to assess in depth the impact which microwave energy has on a melt polycondensation system, suggesting that implementing a microwave heating into the polycondensation, there is potential to reduce production times and potentially increase product molecular weights. This is explained through a discussion about catalytic mechanisms and selective microwave heating. This led to the design and commissioning of a 5 L scale-up vessel with hybrid conventional and microwave heating capabilities to show that these technologies can be scaled to an industrially meaningful scale. Chapter 1 introduces the background to polymers and polymer chemistry, with a detailed assessment of polyester synthesis routes and properties. Powder coatings are presented with the different types and application methods discussed. Microwave theory is then presented with the challenges and potential benefits toward scale-up outlined. Finally, a literature review is completed on polyester synthesis using microwave heating as well as recent developments in large scale microwave reactions. Chapter 2 discusses the specific microwave equipment used throughout this thesis. The materials used and synthesis methods are then discussed. There is also a brief discussion about the characterisation techniques implemented. Chapter 3 focusses on the polymerisation of adipic acid and 1,6-hexanediol using both conventional and microwave heating. A detailed investigation into catalyst effects on the polymerisation are discussed. This focusses on mechanistic differences between the catalysts and heating methods. Chapter 4 furthers the catalyst investigation from chapter 3 but with an industrially used monomer system. This focusses on the importance of catalyst selection for the polymerisation and outlines how microwaves can be used to efficiently produce product within reduced reaction times. There is also a brief examination into whether microwaves increase product qualities. Chapter 5 discusses the impact of using a high powered pulse on a polyesterification compared to a lower powered, continuous pulse. This is discussed for both previously investigated polymerisations and outlines if continued high power application is better than a more intermitted use. Finally, the scale-up process is discussed and initial reactions using the vessel are detailed. Again, differences in product quality are investigated. Lastly, Chapter 6 provides the overall conclusions from the body of work with potential future work detailed for each section.

Item Type

ethesis

Thesis Type

PhD

Supervisors