The production of polymers from fossil feedstocks and the greenhouse gases associated withthese processes are becoming unstainable. The development of drop-in bio-based plasticsto replace current petrochemical derived polymers is one solution to resetting ourrelationship with polymers. One potential solution is the replacement of petrochemicallyderived polyethylene terephthalate (PET) with bio-based polyethylene furanoate (PEF).Chapter 1 discusses the synthesis of polyesters and the challenges associated with theirproduction as well as the catalysts currently available for their synthesis.Chapter 2 details the initial optimisation of a large-scale glass reactor and small-scale thinfilmparallel reactor for PEF synthesis. A range of molecular and metal-organic frameworkcatalysts are tested for their activity towards PEF synthesis. The polymer molecular weightand colour are analysed via size exclusion chromatography (SEC) and UV/VIS spectrometryrespectively and promising catalysts identified.In chapter 3, ultra-pure titanium (IV) citrate is investigated as a replacement for the currentantimony-based polycondensation catalysts. The activity of ultra-pure titanium (IV) citratetowards PEF synthesis, in melt-phase reactions, is compared with antimony (III) oxide andtitanium (IV) isopropoxide at different catalyst loadings and reaction conditions. Thermalstability is investigated via melt degradation tests and the effect on polymer colour analysed.Phosphorous additives are added to improve the thermal stability of the polymer.Chapter 4 discusses the solid-state polymerisation (SSP) of PEF produced from melt-phasereactions. A process to increase molecular weight to application grade-levels is described.End group quantification is carried out before and after SSP, and the acetaldehyde contentof application-grade PEF determined before and after thermal degradation. Ultra-puretitanium (IV) citrate (20 ppm), in the presence a phosphorous additive, is found to give higherpolymerisation activity and similar colour performance to antimony (III) oxide (250 ppm), inthe presence of a phosphorous additive.Chapter 5 investigates the melt-phase activity of titanium and zirconium frameworks,demonstrating their use for the first time as polycondensation catalysts. PEF produced withMOF catalysts are trialled for SSP activity, and the polymer thermal degradation probed.
|Date of Award||1 May 2019|
|Supervisor||Darrell Patterson (Supervisor), Matthew Jones (Supervisor) & Matthew Davidson (Supervisor)|